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[EVDL] Can you charge Lead Acid Batteries too frequently?

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#1 ·
I've recently purchased an S-10 pickup conversion, with a new set of
twenty Sam's Club Energizer EC8 6v 105 reserve minute golf cart
batteries (120v).

I have been driving the truck 5,10,15,20 miles and then re-charging to
"break in" the battery pack.

I am in the enviable position of having a short (4.5 mile round trip)
daily commute, which is well under the maximum range of the battery pack.


My question is about how frequently I should charge the pack. I want to
maximize battery lifetime, and I don't plan on ever needing to drive the
truck past a 50% state of discharge.

My question:
Is it better to drive it a few trips (down to 25-45%) before recharging,
to lower the total number of charges?

Or is it better to charge it every night, even if only down 10-15%
because at the lower depth of discharge the more cycles I'll get?

Or some hybrid combination of charging every night usually and once a
month drive the pack to 80% depth of discharge to "exercise" it?

Any comments?
-Jay



P.S. Some details about my two chargers:

1. A Quick Charge 110V charger (possibly the SCO -120-10), it draws
about 10 amps max. It is currently set to mode F3 (Gas & then float),
but I could re-set it to mode F2 (Gas and then turn-off). This is the
easiest charger to use, as I don't have an outdoor 240v outlet (yet).
The length of charging time doesn't matter, as it will easily recharge
from 10-25% overnight. [Also, I like being able to use my Kill-o-Watt
meter on it, as I do not yet have a way to track how much power the 240v
Zivan charger uses.]

2. A 240v Zivan NG3 "high frequency charger". To use this I have to
leave my back door cracked open with a high capacity extension cord
going from my dryer vent out to the truck. This charger appears to work
fine (I have tried it once), and after it is done charging it turns it's
fans off. However, the LED indicator light is broken, and does not light
up, so I have no indicator of how far along in the charge it is at any
point in time. It has no "mode settings" that I could find, looks to be
a plug it in and forget it type of charger.


I'm wondering about the "gas" setting on the QuickCharge, as I don't
think I actually need to do a gas/equalization charge every time if I'm
charging from a low percentage discharge, and doing one too frequently
may lower the lifespan of the pack. (Or should I gas the batteries on
every charge? I have no idea what the Zivan charger is doing.)


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#2 ·
Hello Jay,

I use to charge a 180 volt Trojan 245 AH battery pack every four days
driving only 1.1 mile a day and every time I went 5 miles or more. I charge
with a PFC-50B charger at 40 amps at 7.5 volts per battery at a 70 F in
about 4 minutes for the 1.1 mile run. Did not temperature compensate for
lower battery temperature, because the batteries never went below 60 F in a
insulated battery box.

These type of batteries are rated for minimum of 1000 ampere capacity and in
3200 cycles at that charging rate I had 6 batteries that had a reading of
about 500 ampere capacity. The remaining 24 batteries are now in another EV
and is still going today.

3200 cycle life is about equal to a 20% DOD according to the U.S. Battery
Manufacturing Co. Expected Cycle Life vs. DOD. Just type U.S. Cycle Life
vs. DOD in your search engine and it should bring this graph up.

I am now running U.S. 6 volt 251 AH and now charging them at 25 amps at 7.75
volts per battery at a battery temperature of 60 F. every time I go my daily
run for 1.1 mile for about 6 minutes.

Now according to the U.S. Battery cycle Life chart, I am charging these
batteries at about 2% DOD which should give 90,000 cycles. At 1.1 mile that
would be 130 years and 5 miles it about 5% DOD at 15,000 cycles in 40 years.

At 50% DOD, its at 1150 cycles or about 3 years.

Therefore I am going to tried these shallow DOD discharges at 2 to 5% DOD
and see what happens.

Roland






----- Original Message -----
From: "Jay Summet" <xxx@xxx.xxx>
To: "Electric Vehicle Discussion List" <xxx@xxx.xxx.edu>
Sent: Friday, March 04, 2011 3:01 AM
Subject: [EVDL] Can you charge Lead Acid Batteries too frequently?


> I've recently purchased an S-10 pickup conversion, with a new set of
> twenty Sam's Club Energizer EC8 6v 105 reserve minute golf cart
> batteries (120v).
>
> I have been driving the truck 5,10,15,20 miles and then re-charging to
> "break in" the battery pack.
>
> I am in the enviable position of having a short (4.5 mile round trip)
> daily commute, which is well under the maximum range of the battery pack.
>
>
> My question is about how frequently I should charge the pack. I want to
> maximize battery lifetime, and I don't plan on ever needing to drive the
> truck past a 50% state of discharge.
>
> My question:
> Is it better to drive it a few trips (down to 25-45%) before recharging,
> to lower the total number of charges?
>
> Or is it better to charge it every night, even if only down 10-15%
> because at the lower depth of discharge the more cycles I'll get?
>
> Or some hybrid combination of charging every night usually and once a
> month drive the pack to 80% depth of discharge to "exercise" it?
>
> Any comments?
> -Jay
>
>
>
> P.S. Some details about my two chargers:
>
> 1. A Quick Charge 110V charger (possibly the SCO -120-10), it draws
> about 10 amps max. It is currently set to mode F3 (Gas & then float),
> but I could re-set it to mode F2 (Gas and then turn-off). This is the
> easiest charger to use, as I don't have an outdoor 240v outlet (yet).
> The length of charging time doesn't matter, as it will easily recharge
> from 10-25% overnight. [Also, I like being able to use my Kill-o-Watt
> meter on it, as I do not yet have a way to track how much power the 240v
> Zivan charger uses.]
>
> 2. A 240v Zivan NG3 "high frequency charger". To use this I have to
> leave my back door cracked open with a high capacity extension cord
> going from my dryer vent out to the truck. This charger appears to work
> fine (I have tried it once), and after it is done charging it turns it's
> fans off. However, the LED indicator light is broken, and does not light
> up, so I have no indicator of how far along in the charge it is at any
> point in time. It has no "mode settings" that I could find, looks to be
> a plug it in and forget it type of charger.
>
>
> I'm wondering about the "gas" setting on the QuickCharge, as I don't
> think I actually need to do a gas/equalization charge every time if I'm
> charging from a low percentage discharge, and doing one too frequently
> may lower the lifespan of the pack. (Or should I gas the batteries on
> every charge? I have no idea what the Zivan charger is doing.)
>
>
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#3 ·
Jay Summet wrote:

> My question:
> Is it better to drive it a few trips (down to 25-45%) before
> recharging, to lower the total number of charges?
>
> Or is it better to charge it every night, even if only down
> 10-15% because at the lower depth of discharge the more
> cycles I'll get?

Which one ends us being optimal will depend on how your charger(s) treat the batteries, but it is usually advised to operate the batteries between 50-80%DOD for lowest cost of ownership.

The cycle life curve is logarithmic (i.e. # of cycles possible at shallow DOD is much higher than at high DOD), however, this only tells part of the story. The lifetime energy throughput (lifetume Ah) of the battery is almost constant regardless of the DOD, and the battery has a calendar life as well as a cycle life.

Using the US Battery cycle life vs DOD chart that Roland refers to (<http://www.usbattery.com/usb_images/cycle_life.xls.pdf>), notice that at 100%DOD 500 cycles are predicted, and at 10%DOD, 7000 cycles are predicted; so the lifetime Ah at 10%DOD is only 40% greater than at 100%DOD, even though the cycle curve makes it look like the battery will last over 10x longer.

You might think that if you use only 10%/day and recharge each night, then 7000 cycles means your battery will last you >19yrs, however, the rated calendar life for a lead acid battery used in standby service (i.e. discharged about 1x per month or less) is typically 10yrs at 20-25 degrees C. For every 7-10C that the battery temperature is warmer than this, the calendar life is reduced by a factor of 2; that is, batteries at 30-35C (86-95F) would have an expected calendar life of 5yrs.

A recent recommendation I came across in one battery manufacturer's literature is that if the battery is discharged less than 40% in a day, then charge every other day; if it is discharged more than 40% in a day, then charge daily.

Your mission, should you choose to accept it, is to use and care for your batteries such that they wear out just before dying of old age. ;^>

Cheers,

Roger.

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#4 ·
Jay Summet wrote:
> I've recently purchased an S-10 pickup conversion, with a new set of
> twenty Sam's Club Energizer EC8 6v 105 reserve minute golf cart
> batteries (120v).

> I am in the enviable position of having a short (4.5 mile round trip)
> daily commute... My question is about how frequently I should charge the pack. I want to
> maximize battery lifetime, and I don't plan on ever needing to drive the
> truck past a 50% state of discharge.

I had almost exactly the same situation with my ComutaVan EV. This is a
"postal jeep" size mail truck EV. My pack was twelve 6v Sam's Club golf
cart batteries, and my daily commute was 4 miles each way.

I didn't recharge daily; instead, I drove 2-3 days until the pack was at
about 50% state of charge. Then I recharged. But I didn't do a full
equalizing charge; I stopped when the batteries reached "full" but did
not go beyond this to equalize them. I charged at 40 amps initially
until the voltage reached 7.2v per 6v battery, then held the voltage
constant until the current fell to about 4 amps, then hold the current
at 4 amps for about an hour, then shut off. The shutoff voltage would be
around 7.4v per 6v battery. This is the normal charge cycle for the
"Lester Computime II" charger I was using.

Then once or twice a month, I did a full equalizing charge. This means
continuing to charge at 4 amps until the voltage stops rising. It will
take the batteries over 7.5v, and takes an extra 1-2 hours.

My pack lasted 7 years and 12k miles with this regimen (though I had one
early battery failure at 5 years that got replaced). At the end, the
pack was down to about half of its original range, and I had to turn the
current up from 4a to 8a, and the ending voltages were lower (7.3v
normal and 7.4v when equalizing).
--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

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#5 ·
To add another fly in the ointment is if you charge at a higher or lower ra=
te =

that will affect battery life and performance. Seems leadacid likes t=
o be hit =

hard butI'll leave that to the experts to expalin as I frequently charge=
below =

10 amps. Lawrence Rhodes..........

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#6 ·
The long and the short of it ...

First the short:
Do nothing different, plug in every chance you get.
Assuming your chargers are setup correctly, this is best way to always
have a full charged pack and reduce sulfation for a longer pack life.
Full charges after a shallow discharge is a good thing.

The long of it:
Remember, you are driving around with an equivalent to a 2 gallon fuel
tank [ http://www.fueleconomy.gov/feg/findacar.htm ]. Having the
pack always fully charged, & ready to go adds to your EV grin (a good
thing).

What little electrolyte you bubble off, you will replace during your
monthly maintenance by adding only "Distilled Water" (Do Not Use
anything else. Water sold that states "distilled" has to be
distilled, thus a known-quantity and quality. Besides, distilled water
is cheap, I get it for $.85 a gallon at Walmart/Kmart/Foodsco/Smart-
n-Final, etc. On pack like yours, you should never need to use more
than a half a gallon per month. You can afford less than a 1/2 a buck
a month to have a healthy pack.).

I learned a trick to make my monthly pack maintenance quick and easy.
After an overnight full charge, I unplug the AC and pull the pack
DC kill switch (opens the circuit).

I use a Windex-like window/glass cleaner (the blue-stuff) on the tops
of the batteries (caps still on). This not only cleans them making
them look nice for showing off, but removes road grime/grit/grease,
and the cleaner is slightly base which will neutralize what little
acid spray occurs during the gassing/equalizing stage.

I take the caps/tops off the batteries setting them on a clean paper
towel. I have a $15 dedicated garden sprayer
http://common1.csnimages.com/lf/3/hash/3677/3492594/1/1.jpg
with the plastic spray tip unscrewed/taken off so it now squirts. I
fill with a gallon of distilled water, a few pumps ... adding
distilled water to the cells is now a breeze. Usually I spent more
time yakking EVs to the public that sees me watering and just has to
ask EV questions, than the actual maintenance itself.

Fill to the internal ring 1/4" from the top, Do Not fill to the
tippy-top, that is too much. Recap/top the batteries, and clean again
as before getting what you missed.

Connections should checked/tightened during this monthly maintenance
(things get shaken loose over time). If you see any acid corrosion
build-up, neutralize with baking soda+water solution, clean, and apply
a anti-acid protective coating (I do not like the quickie sprays as
they do not last. I use the thicker, dark colored anti-acid grease to
coat connectors). If done right, I only have to apply that once when
the new pack was put in.


Some web research tells me:
http://www.summet.com/blog/2011/02/27/s-10-electric-pickup/
http://www.cc.gatech.edu/~summetj/

Some light reading for you:
http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
http://www.chargingchargers.com/tutorials/charging.html

Your Sam's Club batteries are likely re-badged Exide GC8-110 types
http://www.ebatteriestogo.com/Exide_Golf_Cart_Batteries.htm

You can find details on your Quick Charge model
http://www.quickcharge.com/Select a Charge portable new.htm

I recommend you keep the chargers at the gas, then float setting.
If you really-really want to only gas occasionally, the Quick
Charge manual states there is a charge to stop (no float) setting,
but I do not recommend using it. Don't mess with the Zivan's
settings.

The gas/equalization phase, is a low current over charge for a couple
hours that brings all cells up to the same SOC, and the slight
bubbling churns the electrolyte reducing acid stratification. During
this phase an occasional small bubble will come to the top. It
should not be a boiling roar of bubbles during gassing (if so
something is not set correctly! I have seen this with the Zivan
chargers I have had, but not with the pfc chargers I have owned).

You can find details on your Zivan NG3
http://www.zivanusa.com/NG3BatteryCharger.htm
http://www.zivanusa.com/ChargeCurve.htm

If you have access to a 220VAC 20A or better circuit (i.e. a dryer
outlet) but it is too far from the driveway, consider getting/making
an 10-3 extension cord so you can use the NG3 charger at home. If
25' or less you could get away with a 12-3 extension cord, but I
have found you will have more uses for the more expensive, heavier
gauge 10-3 cord.


I would verify both chargers are set correctly. That is, their
charging stages transition at the correct pack voltages. Assuming you
have a fairly accurate DVM (meter), after a pack has finished a full
charge, let it stand/sit for at least an hour. Take SOC measurements.
Then spend an hour taking pack voltage and charging current
measurements.

If your two chargers are set correctly you are good to go. If not,
I suggest you don't mess with them, but get them adjusted by the
manufacturer (especially the Zivan). I 'do' have experience with
Zivan chargers, both K and NG series. I do not have experience
with Quick Charge models.


If you decide to expand your EV grin and use public charging you
will need the appropriate adapters (i.e. J1772 to 14-50, AVCON to
14-50, etc.). Note: the NG3 220VAC charger will not work with an
EVII ICS-200 AVCON because the Auto Manufacturers required EVII
have a circuit to sense the EV charger's power factor correction (pfc)
rating. Any charger (like the Zivan NG series) with a pfc lower than
95% the EVII AVCON EVSE will shut off after 1.5 minutes into the
charge. I do not know if the newer J1772 EVSE have this same
restriction.

Looking at what public EV charging is near you in Atlanta, GA:

http://www.afdc.energy.gov/afdc/locator/stations/
Cole Electric Technology
Electric
3980 Martin Luther King Jr Dr
Atlanta GA 30336
Type: Level 2
Phone: 404-691-9119
Distance: 7.7 Miles
Intersection Directions: Located in fenced area at company warehouse
Access: Public - call ahead

http://www.mychargepoint.net/find-stations.php
Name: SIEMENS / E-FTC
Address: 200-398 Technology Dr, Alpharetta, Georgia, 30005, United States
Status as of : 2011-03-04 12:26:54 (EST)
Port 1: 120V, 16A, NEMA 5-20R:Available
Port 2: 240V, 30A, J1772:Available

http://electric.carstations.com/
Georgia Power Headquarters, Atlanta
241 Ralph McGill Boulevard NE
Atlanta, Georgia 30308
Type: Level 2 J1772



I hope this helps.
{brucedp.150m.com}



-
From: Jay Summet
I've recently purchased an S-10 pickup conversion, with a new set of
twenty Sam's Club Energizer EC8 6v 105 reserve minute golf cart
batteries (120v).

I have been driving the truck 5,10,15,20 miles and then re-charging to
"break in" the battery pack.

I am in the enviable position of having a short (4.5 mile round trip)
daily commute, which is well under the maximum range of the battery
pack.

My question is about how frequently I should charge the pack. I want
to maximize battery lifetime, and I don't plan on ever needing to
drive the truck past a 50% state of discharge.

My question:
Is it better to drive it a few trips (down to 25-45%) before
recharging, to lower the total number of charges?

Or is it better to charge it every night, even if only down 10-15%
because at the lower depth of discharge the more cycles I'll get?

Or some hybrid combination of charging every night usually and once
a month drive the pack to 80% depth of discharge to "exercise" it?

Any comments?
-Jay



Some details about my two chargers:

1. A Quick Charge 110V charger (possibly the SCO -120-10), it draws
about 10 amps max. It is currently set to mode F3 (Gas & then float),
but I could re-set it to mode F2 (Gas and then turn-off). This is the
easiest charger to use, as I don't have an outdoor 240v outlet (yet).
The length of charging time doesn't matter, as it will easily recharge
from 10-25% overnight. [Also, I like being able to use my Kill-o-Watt
meter on it, as I do not yet have a way to track how much power the
240v Zivan charger uses.]

2. A 240v Zivan NG3 "high frequency charger". To use this I have to
leave my back door cracked open with a high capacity extension cord
going from my dryer vent out to the truck. This charger appears to
work fine (I have tried it once), and after it is done charging it
turns it's fans off. However, the LED indicator light is broken, and
does not light up, so I have no indicator of how far along in the
charge it is at any point in time. It has no "mode settings" that I
could find, looks to be a plug it in and forget it type of charger.

I'm wondering about the "gas" setting on the QuickCharge, as I don't
think I actually need to do a gas/equalization charge every time if
I'm charging from a low percentage discharge, and doing one too
frequently may lower the lifespan of the pack. (Or should I gas the
batteries on every charge? I have no idea what the Zivan charger is
doing.)
-


--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Can-you-charge-Lead-Acid-Batteries-too-frequently-tp3335046p3336201.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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| Multiple-address or CCed messages may be rejected.
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#7 ·
The long and the short of it ...

First the short: do nothing different, plug in every chance you get.
Assuming your chargers are setup correctly, this is best way to always
have a full charged pack and reduce sulfation for a longer pack life.

The long of it:

Remember, you are driving around with an equivalent to a 2 gallon fuel
tank [ http://www.fueleconomy.gov/feg/findacar.htm ]. Having the
pack always fully charged, ready to go is a good thing.

What little electrolyte you bubble off, you will replace during your
monthly maintenance by adding only "Distilled Water". Do Not Use
anything else. Water sold that states it is "distilled" has to be
distilled thus a known-quantity and quality. Besides, distilled water
is cheap, I get it for $.85 a gallon at Walmart/Kmart/Foodco/Smart-
and Final, etc. On pack like yours, you should never need to use more
than a half a gallon per month.

I learned a trick to make my monthly pack maintenance quick and easy.
After an overnight full charge, I unplug the AC and pull the pack
DC kill switch (opens the circuit).

I use a Windex-like window/glass cleaner (the blue-stuff) on the tops
of the batteries (caps still on). This not only cleans them making
them look nice for showing off, but removes road grime/grit/grease,
and the cleaner is slightly base which will neutralize what little
acid spray occurs during the gassing/equalizing stage.

I take the caps/tops off the batteries setting them on a clean paper
towel. I have a $15 dedicated garden sprayer
http://common1.csnimages.com/lf/3/hash/3677/3492594/1/1.jpg
with the plastic spray tip taken off so it now squirts. I fill with a
gallon of distilled water, a few pumps ... adding distilled water to
the cells is a breeze.

Fill to the internal ring 1/4" from the top, Do Not fill to the
tippy-top, that is too much. Recap/top the batteries, and clean again
as before getting what you find you see you missed when the caps were
off.

Connections should checked/tighten at this monthly maintenance for
the first three months, and every six months there after (things get
shaken loose over time). If you see any acid corrosion buildup,
neutralize, clean, and apply a anti-acid protective coating. I do not
like the quickie sprays as they do not last, I use the thicker, dark
colored anti-acid grease to coat connectors. If done right, I only
have to apply it once when the new pack was put in.

Some web research tells me:
http://www.summet.com/blog/2011/02/27/s-10-electric-pickup/
http://www.cc.gatech.edu/~summetj/

Some light reading for you:
http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
http://www.chargingchargers.com/tutorials/charging.html

Your Sams Club batteries are likely re-badged Exide GC8-110 types
http://www.ebatteriestogo.com/Exide_Golf_Cart_Batteries.htm

You can find details on your Quick Charge model
http://www.quickcharge.com/Select a Charge portable new.htm

I recommend you keep the chargers set to gas, then float setting.
If you really-really want to only gas occasionally, the Quick
Charge manual states there is a charge to stop (no float) setting,
but I do not recommend using it.

A gas/equalization phase, is a low current over charge for a couple
hours that brings all cells up to the same SOC, and the slight
bubbling churns the electrolyte reducing acid stratification.

You can find details on your Zivan NG3
http://www.zivanusa.com/NG3BatteryCharger.htm
http://www.zivanusa.com/ChargeCurve.htm

If you have access to a 220VAC 20A or better circuit (i.e. a dryer
outlet) but it is too far from the driveway, consider getting/making
an 10-3 extension cord so you can use the NG3 charger at home.

I would verify both chargers are set correctly, that is their stages
stop at the correct pack voltages. Assuming you have a fairly
accurate DVM, after a pack has finished a full charge, let it stand/
sit for at least an hour. Take SOC measurements. Then spend an hour
taking pack voltage and charging current measurements.

If your two chargers are set correctly you are good to go. If not
I suggest you don't mess with them, but get them adjusted by the
manufacturer (especially the Zivan). I do have experience with
Zivan chargers, both K and NG series. I do not have experience
with Quick Charge models.

If you decide to expand your EV grin and use public charging you
will need the appropriate adapters (i.e. J1772 to 14-50, AVCON to
14-50, etc.). Note the NG3 220VAC charger will not work with an
EVII AVCON because the Auto Manufacturers required EVII install
a circuit to sense the EV charger's power factor correction (pfc)
rating. Any charger like the NG series with a pfc lower than 95%
the EVII AVCON EVSE will shut off. I do not know if the newer J1772
EVSE have this same restriction.

Looking at what public EV charging is near you:

http://www.afdc.energy.gov/afdc/locator/stations/
Cole Electric Technology
Electric
3980 Martin Luther King Jr Dr
Atlanta GA 30336
Type: Level 2
Phone: 404-691-9119
Distance: 7.7 Miles
Intersection Directions: Located in fenced area at company warehouse
Access: Public - call ahead

http://www.mychargepoint.net/find-stations.php
Name: SIEMENS / E-FTC
Address: 200-398 Technology Dr, Alpharetta, Georgia, 30005, United States
Status as of : 2011-03-04 12:26:54 (EST)
Port 1: 120V, 16A, NEMA 5-20R:Available
Port 2: 240V, 30A, J1772:Available

http://electric.carstations.com/
Georgia Power Headquarters, Atlanta
241 Ralph McGill Boulevard NE
Atlanta, Georgia 30308
Type: Level 2 J1772

I hope this helps.
{brucedp.150m.com}



-
From: Jay Summet <xxx@xxx.xxx>
I've recently purchased an S-10 pickup conversion, with a new set of
twenty Sam's Club Energizer EC8 6v 105 reserve minute golf cart
batteries (120v).

I have been driving the truck 5,10,15,20 miles and then re-charging to
"break in" the battery pack.

I am in the enviable position of having a short (4.5 mile round trip)
daily commute, which is well under the maximum range of the battery
pack.

My question is about how frequently I should charge the pack. I want
to maximize battery lifetime, and I don't plan on ever needing to
drive the truck past a 50% state of discharge.

My question:
Is it better to drive it a few trips (down to 25-45%) before
recharging, to lower the total number of charges?

Or is it better to charge it every night, even if only down 10-15%
because at the lower depth of discharge the more cycles I'll get?

Or some hybrid combination of charging every night usually and once
a month drive the pack to 80% depth of discharge to "exercise" it?

Any comments?
-Jay



Some details about my two chargers:

1. A Quick Charge 110V charger (possibly the SCO -120-10), it draws
about 10 amps max. It is currently set to mode F3 (Gas & then float),
but I could re-set it to mode F2 (Gas and then turn-off). This is the
easiest charger to use, as I don't have an outdoor 240v outlet (yet).
The length of charging time doesn't matter, as it will easily recharge
from 10-25% overnight. [Also, I like being able to use my Kill-o-Watt
meter on it, as I do not yet have a way to track how much power the
240v Zivan charger uses.]

2. A 240v Zivan NG3 "high frequency charger". To use this I have to
leave my back door cracked open with a high capacity extension cord
going from my dryer vent out to the truck. This charger appears to
work fine (I have tried it once), and after it is done charging it
turns it's fans off. However, the LED indicator light is broken, and
does not light up, so I have no indicator of how far along in the
charge it is at any point in time. It has no "mode settings" that I
could find, looks to be a plug it in and forget it type of charger.

I'm wondering about the "gas" setting on the QuickCharge, as I don't
think I actually need to do a gas/equalization charge every time if
I'm charging from a low percentage discharge, and doing one too
frequently may lower the lifespan of the pack. (Or should I gas the
batteries on every charge? I have no idea what the Zivan charger is
doing.)
-



--
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#8 ·
Brucedp5 wrote:

> Do nothing different, plug in every chance you get.
> Assuming your chargers are setup correctly, this is best way
> to always have a full charged pack and reduce sulfation for a
> longer pack life.
> Full charges after a shallow discharge is a good thing.

As you see, there are dissenting opinions on this. Sulphation is not an issue for batteries that are discharged less than 10%/day and are charged every few days. There are other things going on inside the batteries when regularly fully charging after every shallow discharge, such as accelerated grid corrosion, that cannot be reversed.

> Fill to the internal ring 1/4" from the top, Do Not fill to
> the tippy-top, that is too much. Recap/top the batteries, and
> clean again as before getting what you missed.

A word of caution about this: some makes of batteries have a fill well (short tube that sticks down inside the cell from the battery cover); some of these will have a "fill to" level marked on them, if so, fill to the mark; if not, fill to 1/4" below the bottom of the well. Other makes do not have a fill well, they just have a bit of a 'flange' around the cell cap opening: do not fill these to 1/4" below the flange or they will be overfilled!

Cheers,

Roger.

_______________________________________________
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| Multiple-address or CCed messages may be rejected.
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#9 ·
When I had my Lawn business I got to see batteries and what they
liked and didn't like but in many ways what they like and don't like
is still a mystery . Now days I do so little driving that I haven't
bought a new battery in 3 years and just use all the old stuff I take
out of cars when I up grade them. For the 15 years that I ran my
lawn business with the electric truck, using golf cart batteries, I
got about 2 years on each pack. This was driving 20 to 30 miles a
day, towing a lawn trailer with a lawn mower. Over the years I
charged them higher Amps and had been said by a few people, 40 Amps
for a Golf Cart Battery is pretty good. Charging at 10 Amps or lower
will cut 20% off their life, ( my guess). The last 3 years of the
Lawn Business, I had the Electric Lawn Mower with a AGM Batteries and
would charge 5 to 10 times a day at 100 to 150 Amps. I never really
got to wear out a set of Batteries. I killed the first pack, after a
year, while cutting my OWN grass and leaving them plugged in.. (
dahhhh) ...Thought someones septic tank had broken...what a smell !
From the lawn mower experience and the Golf Cart batteries in my
truck, I would say that, fast charging is under rated when it comes to
taking care of Batteries. Yes letting them go flat is definitely a
nail in their coffin, but I have seen a lot of people who charged
their batteries at a low current and I don't think they are getting
the life that they could, if they charged them at a higher current.
The last 3 years of the lawn business, when I had the electric lawn
mower, I had 38 Golf Cart Batteries on the truck so that I would
have enough power on board to charge all day long. I also did a lot
of opportunity charging. I had the PFC 50 charger and any place that
had 3 yards to cut ( about an hour) I would plug in to a dryer
outlet and pump away. When I went from 20 to 38 batteries ( this
was 2 strings, with the Voltage being 114V, which dump charged my 96V
lawn mower just right, giving me a 10 min. charge time). Even though
I was still using 80% of the power in the batteries, by having 2
strings and not stressing the Golf Cart Batteries out as much as with
one string, at the end of 3 years ..one year longer than what I
normally got on the Golf Cart Batteries,...they were still doing good
when I sold the business. So, keeping the discharge rate below
75Amps for the Golf Cart Batteries seemed to give me 1/3 more life. I
was not the best "care taker" of my Hawker Odyssey's on the lawn
Mower, I was always going to work on a management system, didn't have
the famous Lee Hart Regulators and many times came home from work, so
tired that I didn't even charge them. I would get them in the
morning. I would charge them a bit, but didn't bring them up to a
full charge with equalization with all that stuff, even after a hard
day of work, and them being charged 10 times. I still have the lawn
mower now ( I had to re po my equipment as the guy I sold the lawn
business to ruined everything) and I am still using some of those
batteries today, that were on the Mower 4 years ago. In my shop, I
have 4 PFC Chargers so I can BLAST batteries with 100 Amps and look
forward to cutting the grass here at the shop whenever I can.

Steve Clunn





<
xxx@xxx.xxxa-q.local>
Content-Type: text/plain; charset=3D"us-ascii"

Brucedp5 wrote:

> Do nothing different, plug in every chance you get.
> Assuming your chargers are setup correctly, this is best way
> to always have a full charged pack and reduce sulfation for a
> longer pack life.
> Full charges after a shallow discharge is a good thing.

As you see, there are dissenting opinions on this. Sulphation is not
an issue for batteries that are discharged less than 10%/day and are
charged every few days. There are other things going on inside the
batteries when regularly fully charging after every shallow discharge,
such as accelerated grid corrosion, that cannot be reversed.

> Fill to the internal ring 1/4" from the top, Do Not fill to
> the tippy-top, that is too much. Recap/top the batteries, and
> clean again as before getting what you missed.

A word of caution about this: some makes of batteries have a fill well
(short tube that sticks down inside the cell from the battery cover);
some of these will have a "fill to" level marked on them, if so, fill
to the mark; if not, fill to 1/4" below the bottom of the well. Other
makes do not have a fill well, they just have a bit of a 'flange'
around the cell cap opening: do not fill these to 1/4" below the
flange or they will be overfilled!

Cheers,

Roger.



------------------------------

_______________________________________________
xxx@xxx.xxx.edu
For general EVDL support, see http://evdl.org/help/

--
Tomorrows Ride TODAY !
Visit our shop web page at: www.Greenshedconversions.com

_______________________________________________
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
 
#10 ·
Those are great real life data points, thanks for posting.

Did you do any balancing on your batteries? Or did they just naturally stay in
balance? Or did you have to top up a low battery manually once in a while?




________________________________
From: Steve Clunn <xxx@xxx.xxx>
To: xxx@xxx.xxx.edu
Sent: Mon, March 7, 2011 9:18:02 AM
Subject: [EVDL] Can you charge Lead Acid Batteries too frequently?

When I had my Lawn business I got to see batteries and what they
liked and didn't like but in many ways what they like and don't like
is still a mystery . Now days I do so little driving that I haven't
bought a new battery in 3 years and just use all the old stuff I take
out of cars when I up grade them. For the 15 years that I ran my
lawn business with the electric truck, using golf cart batteries, I
got about 2 years on each pack. This was driving 20 to 30 miles a
day, towing a lawn trailer with a lawn mower. Over the years I
charged them higher Amps and had been said by a few people, 40 Amps
for a Golf Cart Battery is pretty good. Charging at 10 Amps or lower
will cut 20% off their life, ( my guess). The last 3 years of the
Lawn Business, I had the Electric Lawn Mower with a AGM Batteries and
would charge 5 to 10 times a day at 100 to 150 Amps. I never really
got to wear out a set of Batteries. I killed the first pack, after a
year, while cutting my OWN grass and leaving them plugged in.. (
dahhhh) ...Thought someones septic tank had broken...what a smell !
>From the lawn mower experience and the Golf Cart batteries in my
truck, I would say that, fast charging is under rated when it comes to
taking care of Batteries. Yes letting them go flat is definitely a
nail in their coffin, but I have seen a lot of people who charged
their batteries at a low current and I don't think they are getting
the life that they could, if they charged them at a higher current.
The last 3 years of the lawn business, when I had the electric lawn
mower, I had 38 Golf Cart Batteries on the truck so that I would
have enough power on board to charge all day long. I also did a lot
of opportunity charging. I had the PFC 50 charger and any place that
had 3 yards to cut ( about an hour) I would plug in to a dryer
outlet and pump away. When I went from 20 to 38 batteries ( this
was 2 strings, with the Voltage being 114V, which dump charged my 96V
lawn mower just right, giving me a 10 min. charge time). Even though
I was still using 80% of the power in the batteries, by having 2
strings and not stressing the Golf Cart Batteries out as much as with
one string, at the end of 3 years ..one year longer than what I
normally got on the Golf Cart Batteries,...they were still doing good
when I sold the business. So, keeping the discharge rate below
75Amps for the Golf Cart Batteries seemed to give me 1/3 more life. I
was not the best "care taker" of my Hawker Odyssey's on the lawn
Mower, I was always going to work on a management system, didn't have
the famous Lee Hart Regulators and many times came home from work, so
tired that I didn't even charge them. I would get them in the
morning. I would charge them a bit, but didn't bring them up to a
full charge with equalization with all that stuff, even after a hard
day of work, and them being charged 10 times. I still have the lawn
mower now ( I had to re po my equipment as the guy I sold the lawn
business to ruined everything) and I am still using some of those
batteries today, that were on the Mower 4 years ago. In my shop, I
have 4 PFC Chargers so I can BLAST batteries with 100 Amps and look
forward to cutting the grass here at the shop whenever I can.

Steve Clunn





<
xxx@xxx.xxxa-q.local>
Content-Type: text/plain; charset="us-ascii"

Brucedp5 wrote:

> Do nothing different, plug in every chance you get.
> Assuming your chargers are setup correctly, this is best way
> to always have a full charged pack and reduce sulfation for a
> longer pack life.
> Full charges after a shallow discharge is a good thing.

As you see, there are dissenting opinions on this. Sulphation is not
an issue for batteries that are discharged less than 10%/day and are
charged every few days. There are other things going on inside the
batteries when regularly fully charging after every shallow discharge,
such as accelerated grid corrosion, that cannot be reversed.

> Fill to the internal ring 1/4" from the top, Do Not fill to
> the tippy-top, that is too much. Recap/top the batteries, and
> clean again as before getting what you missed.

A word of caution about this: some makes of batteries have a fill well
(short tube that sticks down inside the cell from the battery cover);
some of these will have a "fill to" level marked on them, if so, fill
to the mark; if not, fill to 1/4" below the bottom of the well. Other
makes do not have a fill well, they just have a bit of a 'flange'
around the cell cap opening: do not fill these to 1/4" below the
flange or they will be overfilled!

Cheers,

Roger.



------------------------------

_______________________________________________
xxx@xxx.xxx.edu
For general EVDL support, see http://evdl.org/help/

--
Tomorrows Ride TODAY !
Visit our shop web page at: www.Greenshedconversions.com

_______________________________________________
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
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#11 ·
The equalization stage is the balancing of the pack cells.
Current is forced through both fully charged and less-charged
cells, bringing them all up to their maximum.

According to the Trojan report
http://brucedp.150m.com/evbatt.txt

"3. Equalization to 2.55-2.58 volts/cell will increase performance
and life. If the batteries are constantly undercharged, their
performance and life will decrease. Equalization must be done
once every 5-10 cycles. If equalization is done every cycle,
the cost per charge increases.


I interpret the 'cost per charge', as meaning electrical power cost.
I can afford a couple of pennies to always be at my best/maximum
pack capacity.

With each charger I have tried (and I have tried many), each has
their own idea of what a PbSO4 wet-cell equalization stage is. Ask
an EAA old-timer, and you might get about 4 Amps DC recharging
current into the pack for 2 hours (depending who you ask).

In the late 1990's when agms were being used, for best performance
balancing circuits/smoothers were put on the batteries to balance
the agm pack.

I asked a smoother manufacturer if putting smoothers on my wet-cell
pack would be a benefit. He said yes, for him (he would sell more
product), but also said why? ... when a simple equalization/gassing
charge would do the same thing. He would lose money, but he thought
it wiser to just have me check that my chargers are doing a proper
equalization stage.

Without a full and complete charge, no, PbSO4 wet-cell pack cells do
not 'naturally stay in balance'. Since all cells are in series
the weaker cell determine the performance of the pack. Best to have
all of them at their peak, always. Which is why, I charge at every
opportunity.

Example:
I drove my S10 Blazer conversion EV to and from, Silicon Valley to
Sacramento and back six different time using the public EV charging
available (pre-j1772). Each time I would charge, while my e-meter
(now called a xantrex linklite
http://search.yahoo.com/search?p=xantrex+linklite
) would say I got all my amp-hours back, but because I did not stick
around to do a complete/equalizing charge, the pack was less-stiff
and acceleration felt mushy. After each charging toward Sacramento,
it got progressively worse. But after I stayed and charged overnight,
I got my ol' stiff-pack mojo back. Because an equalizing charge had
been performed during the night.

One of the work-around's is instead of one charger to charge all
batteries in series, is to use multiple chargers to charge batteries
individually.

At the time years ago, I was poo-poo'd for idea because it added
extra variables that could fail. But today there are several EVs
using multiple 12V chargers to give each battery in the pack what
it wants.

I suggest you read Cor's post on thread
http://evdl.org/archive/#nabble-tt3309742|a3311328
if you are considering such a charger design. He mentions the charger
he likes toward the end.


Lastly, IMHO the aforementioned e-meter (above) is a must for every
EV. If not that brand/model then something to let you know how many
amps are going/gone in or out. It is useful in many ways and well
worth the purchase price. A analog surface voltage meter is
inaccurate, thus a waste of your time, and dash cluster space.



{brucedp.150m.com}




> ----- Original Message -----
> From: David Dymaxion <xxx@xxx.xxx>
> To: Electric Vehicle Discussion List <xxx@xxx.xxx.edu>
> Subject: Re: [EVDL] Can you charge Lead Acid Batteries too frequently?
> Date: Mon, 7 Mar 2011 08:31:09 -0800 (PST)
...
> Did you do any balancing on your batteries? Or did they just
> naturally stay in
> balance? Or did you have to top up a low battery manually once in a while?
...


--
_______________________________________________
Surf the Web in a faster, safer and easier way:
Download Opera 9 at http://www.opera.com


_______________________________________________
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
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#12 ·
Bruce,

Increased cost per charge is not only spending current
(and thus money) generating gas and heat in the battery
instead of in active usable charge, but also the cost
can increase because too often equalizing can lead to a
sooner demise of the batteries due to grid corrosion
and the lower cycle life means higher cost per charge.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: xxx@xxx.xxx Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: xxx@xxx.xxx
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On
Behalf Of bruce parmenter
Sent: Monday, March 07, 2011 1:34 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Can you charge Lead Acid Batteries too frequently?

The equalization stage is the balancing of the pack cells.
Current is forced through both fully charged and less-charged cells,
bringing them all up to their maximum.

According to the Trojan report
http://brucedp.150m.com/evbatt.txt

"3. Equalization to 2.55-2.58 volts/cell will increase performance
and life. If the batteries are constantly undercharged, their
performance and life will decrease. Equalization must be done
once every 5-10 cycles. If equalization is done every cycle,
the cost per charge increases.


I interpret the 'cost per charge', as meaning electrical power cost.
I can afford a couple of pennies to always be at my best/maximum pack
capacity.

With each charger I have tried (and I have tried many), each has their
own idea of what a PbSO4 wet-cell equalization stage is. Ask an EAA
old-timer, and you might get about 4 Amps DC recharging current into the
pack for 2 hours (depending who you ask).

In the late 1990's when agms were being used, for best performance
balancing circuits/smoothers were put on the batteries to balance the
agm pack.

I asked a smoother manufacturer if putting smoothers on my wet-cell pack
would be a benefit. He said yes, for him (he would sell more product),
but also said why? ... when a simple equalization/gassing charge would
do the same thing. He would lose money, but he thought it wiser to just
have me check that my chargers are doing a proper equalization stage.

Without a full and complete charge, no, PbSO4 wet-cell pack cells do not
'naturally stay in balance'. Since all cells are in series the weaker
cell determine the performance of the pack. Best to have all of them at
their peak, always. Which is why, I charge at every opportunity.

Example:
I drove my S10 Blazer conversion EV to and from, Silicon Valley to
Sacramento and back six different time using the public EV charging
available (pre-j1772). Each time I would charge, while my e-meter (now
called a xantrex linklite
http://search.yahoo.com/search?p=xantrex+linklite
) would say I got all my amp-hours back, but because I did not stick
around to do a complete/equalizing charge, the pack was less-stiff and
acceleration felt mushy. After each charging toward Sacramento, it got
progressively worse. But after I stayed and charged overnight, I got my
ol' stiff-pack mojo back. Because an equalizing charge had been
performed during the night.

One of the work-around's is instead of one charger to charge all
batteries in series, is to use multiple chargers to charge batteries
individually.

At the time years ago, I was poo-poo'd for idea because it added extra
variables that could fail. But today there are several EVs using
multiple 12V chargers to give each battery in the pack what it wants.

I suggest you read Cor's post on thread
http://evdl.org/archive/#nabble-tt3309742|a3311328
if you are considering such a charger design. He mentions the charger he
likes toward the end.


Lastly, IMHO the aforementioned e-meter (above) is a must for every EV.
If not that brand/model then something to let you know how many amps are
going/gone in or out. It is useful in many ways and well worth the
purchase price. A analog surface voltage meter is inaccurate, thus a
waste of your time, and dash cluster space.



{brucedp.150m.com}




> ----- Original Message -----
> From: David Dymaxion <xxx@xxx.xxx>
> To: Electric Vehicle Discussion List <xxx@xxx.xxx.edu>
> Subject: Re: [EVDL] Can you charge Lead Acid Batteries too frequently?
> Date: Mon, 7 Mar 2011 08:31:09 -0800 (PST)
...
> Did you do any balancing on your batteries? Or did they just naturally

> stay in balance? Or did you have to top up a low battery manually once

> in a while?
...


--
_______________________________________________
Surf the Web in a faster, safer and easier way:
Download Opera 9 at http://www.opera.com


_______________________________________________
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
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_______________________________________________
| REPLYING: address your message to xxx@xxx.xxx.edu only.
| Multiple-address or CCed messages may be rejected.
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#13 ·
> Did you do any balancing on your batteries? Or did they just
> naturally stay in
> balance? Or did you have to top up a low battery manually once in a while?
.
I have a 10 position switch and can look at the voltage of each battery and
I also could toggle a light bulb or a small dc to dc converter to either
pump up a low battery or pull down one that was going high..When I was
working and dump charging most times I would stop charging at about 14.volts
and most yards used between 10 to 15 amp hours ,, I first had the hawker
1200 and then the 1500. Another thing I noticed was that as the pack got
older , If I didn't use the mower for a week or so they would drift apart in
voltage, i would cut 1/2 a yard and then charge just to get them warmed up ,
then they would start all looking the same again and after a 5 or 10 dump
charges they'd all come around .ahh the good old days :)
http://www.youtube.com/watch?v=OqiAGU5cLjY
http://www.youtube.com/watch?v=OqiAGU5cLjY

<<<Lastly, IMHO the aforementioned e-meter (above) is a must for every
EV. If not that brand/model then something to let you know how many
amps are going/gone in or out. It is useful in many ways and well
worth the purchase price. A analog surface voltage meter is
inaccurate, thus a waste of your time, and dash cluster space.>>>>>
{brucedp.150m.com}

Very true ,,, without knowing the ah of your batteries you can't tell there
real health .

Steve Clunn

Tomorrows Ride TODAY !
Visit our shop web page at: www.Greenshedconversions.com
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#14 ·
So did you find that the dump charges would equalize the batteries, or did you
actively balance them when doing the 5 to 10 dump charges?




________________________________
From: Steve Clunn <xxx@xxx.xxx>
To: xxx@xxx.xxx.edu
Sent: Tue, March 8, 2011 7:09:43 PM
Subject: [EVDL] Can you charge Lead Acid Batteries too frequently?

> Did you do any balancing on your batteries? Or did they just
> naturally stay in
> balance? Or did you have to top up a low battery manually once in a while?
.
I have a 10 position switch and can look at the voltage of each battery and
I also could toggle a light bulb or a small dc to dc converter to either
pump up a low battery or pull down one that was going high..When I was
working and dump charging most times I would stop charging at about 14.volts
and most yards used between 10 to 15 amp hours ,, I first had the hawker
1200 and then the 1500. Another thing I noticed was that as the pack got
older , If I didn't use the mower for a week or so they would drift apart in
voltage, i would cut 1/2 a yard and then charge just to get them warmed up ,
then they would start all looking the same again and after a 5 or 10 dump
charges they'd all come around .ahh the good old days :)
http://www.youtube.com/watch?v=OqiAGU5cLjY
http://www.youtube.com/watch?v=OqiAGU5cLjY



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#15 ·
Chuck Hursch wrote:
> Why does charging batteries at low current reduce their life?

I think high charging current tends to decrease the size of the crystals
that form (improving their surface area), and increases the mixing and
diffusion rates of the sulfuric acid back into the electrolyte.

But I think Nawaz monitors this list. Maybe he (or other battery
experts) can provide more definitive data.
--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

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#16 ·
You can get a hold of Nainaz Qur eshi at xxx@xxx.xxx

He will recommend the charging and voltage rate for your batteries.

Roland


----- Original Message -----
From: "Lee Hart" <xxx@xxx.xxx>
To: "Electric Vehicle Discussion List" <xxx@xxx.xxx.edu>
Sent: Friday, March 11, 2011 6:46 PM
Subject: Re: [EVDL] Can you charge Lead Acid Batteries too frequently?


> Chuck Hursch wrote:
> > Why does charging batteries at low current reduce their life?
>
> I think high charging current tends to decrease the size of the crystals
> that form (improving their surface area), and increases the mixing and
> diffusion rates of the sulfuric acid back into the electrolyte.
>
> But I think Nawaz monitors this list. Maybe he (or other battery
> experts) can provide more definitive data.
> --
> Lee A. Hart | Ring the bells that still can ring
> 814 8th Ave N | Forget the perfect offering
> Sartell MN 56377 | There is a crack in everything
> leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
>
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>

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#17 ·
On 12 Mar 2011 at 13:48, Chuck Hursch wrote:

> US Battery recommends C/10 ... about 23A. I'd love to charge that fast
> ... gang up my two 120V chargers ...

I may have missed something here, but I think that maybe you can come close.

A bit of history here as a side note. Twenty-five or 30 years ago, EV
hobbyists didn't have so many choices in chargers. But even then, at least
one popular charger did exactly what you're asking for, though not on 120v.

I think it was a volume request by Jet Industries that prompted Lester to
build a special version of their Lestronic II golf car charger for 96 volt
batteries. For some years after, that charger was something of a hobbyist
EV standard. It charged at 25 amps from a 20 amp 240v receptacle, and it
had a surprisingly sophisticated logic board that used dv/dt (slope of the
rising on-charge voltage) to provide automatic shutoff. I'd guess that a
few hundred were sold, maybe several hundred.

Lester chargers, with their big ferroresonant transformers, were absolute
boat anchors. It took two people (or one fairly strong one) to lift one.
They were about the size of a large breadbox. Thus, they were better suited
as offboard than onboard chargers.

> at home here at the apt., all I have is a 20A 120V NEMA 5-20 outlet ...

Well, this poses a few challenges, but I don't think they're insurmountable.

As far as capacity goes, you have enough there as long as you don't try to
drive too much. If my quickie math is right, you should be able to charge
almost 12kWh per day (assuming 12h to charge, 6h to 80% and 6h for the
remaining 20%, 80% charger efficiency).

16 * 120 = 1920W * .8 (eff) = 1536 * 6h = 9216WH * 1.25 (last 20%) =
11.52kWh

With an EV that uses 250WH/mi, that should let you commute up to 46 miles
per day if you match your battery capacity to what you can get from your
receptacle. This adds up to 40 golf car batteries if you discharge to 50%
DOD, and 29 batteries if you discharge to 70%. So if you have fewer than
that (16, no?) AND you have 12h to charge, you should have enough capacity
even in your feeble little carport receptacle.

As for peak charging rate, although the NEC says you can't exceed 16a on
your 20a circuit for sustained loads, a short term load of 20a should be
possible. You only need it for a little while - from what I've read in
Hawker's literature, batteries mostly just need that C/10 rate for the first
few minutes of charging. With an 80% efficient charger and 20a at 120v, you
can put 20a into a 96 volt battery. That's pretty close to C/10. If you
can do that for 5-10 minutes, you might be OK. Now you just need the
charger(s) that can do it.

David Roden - Akron, Ohio, USA
EVDL Administrator

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#18 ·
From: David Dymaxion

>So did you find that the dump charges would equalize the batteries, or did=
you
actively balance them when doing the 5 to 10 dump charges?<

I didn't always get the chance to take care of my batteries the way I
would have liked to . Most of the time when I was dump charging , I'd
but weeding wacking or collecting the money. I had AGM's in other
cars and had done a lot more balancing with them and not gotten near
the cycles as on the lawn mower . I had over 50 yards and most got
between 20 to 30 cuts a year , some where very big and would use 2 to
3 charges to cut . If I had more time I would have set things up
better but don't know how much more life I might have gotten if I had.
I think the time between charges has a lot to do with un balancing
batteries . There difference in there self discharge gets amplified
with time , and this could also be happening with the cells inside
each battery . I did a lawn mower for a young man in South Carolina
who was very enthusiast but had very little knowledge of battery . He
has a walk behind with 4 agm's and 20 old golf cart batteries in his
trailer . He charges the GC batteries with a bad boy charger and
splits the pack in half then parallel the two to get 60v for charging
, Much to my surprise he's still running after a year . I'm putting
together a weed wacker and blower for him now. The lawn mower for me
worked out much better electric than gas for a few reasons , Lawn
mower engines use a lot more gas vs work done then cars , they also
don't last near as lone and are get replaced every few years , and
they also have to work in very dirty environment which require daily
cleaning of air filters and weekly oil changing, starter motors only
last 1/2 the life of the engine. With all that being said why are
there so few EV mowers and so many EV cars :-(..
Steve Clunn



--
Tomorrows Ride TODAY !
Visit our shop web page at: www.Greenshedconversions.com

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#19 ·
Chuck (and All),
As I've posted about in the past, I was able to get a used 144VDC 30A
charger that was built by a defunct California subsidiary of Lester,
which I call the FrankenLester, and I would agree that the floodies
seemed to really enjoy it! When I needed a quick bulk charge,
especially away from home when 240VAC 50A was available, I would use
both the FrankenLester and the on-board 120VAC Zivan in the S10 pickup
at the same time.
Anyway, regarding your situation, it occurred to me while reading your
post that regenerative braking could keep the batteries happy when
only 120VAC 15 or 20A is available, especially in your area, which I
remember as being hilly? Again, as I've posted about before, I have
the poor-man's version of regen with a system that came with the RX-7,
which I later installed on the truck:
http://www.evalbum.com/tech/regen.jpg
This is a system that could be added to an existing DC series motor
like yours, although now that I think about it, you probably don't
have very much existing room in your Rabbit? Just something for people
to think about when considering a grid upgrade.
-- =

Suck Amps,
Dave (Battery Boy) Hawkins
Check out our website!
http://bbevs.com/

> Date: Sat, 12 Mar 2011 13:48:18 -0800
> From: Chuck Hursch
>
> Hi Roland,
>
> Yes, I've already had my direct discussion with Nawaz. Several months
> ago, maybe a year or more ago by now. US Battery recommends C/10, which
> for my 96V pack of US2200XCs, which are rated at about 234A-hr at the
> C/20 rate, is going to be a recommended charging rate of about 23A. I'd
> love to charge that fast, and have in the distant past, when I'd be out
> in the "field" (ie. at one of the EAA meetings a good 25 miles or better
> from home). Would gang up my two 120V chargers (K&W and Zivan) and get
> about 27A to the pack. The batteries would lap that current up, and go
> yippee!, we're ready to rock! It really wakes them up. 65mph down t=
he
> freeway without breaking a sweat for about the first 10 miles, and then
> you'd start to feel the fatigue build up. I can only imagine how
> charging with a real 240V charger (or multiple 240V chargers) cranking
> in 60, 70, or even 100A into the pack off of a juicy 14-50 outlet would
> wake them up. I feel like Bob Rice talking here. I know Bruce
> Parmenter could chime in with some memories from his S-10's charger
> bank. And I remember Stan Skokan charging with four of his isolated
> 240V chargers for 100A into his 96V 6V-FLA pack in his postal van at EAA
> E. Bay rallies back in the mid to late '90s.
>
> Fact is, though, at home here at the apt., all I have is a 20A 120V NEMA
> 5-20 outlet (in the ceiling of the carport underneath the building, no
> less). NEC derating for that is 16A, which is what my installing
> contractor back in 1994 wrote on the spec sheet (cost me $500 to get
> that outlet).
<snippage>
> Chuck

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#20 ·
David "Battery Boy" Hawkins wrote:
> Chuck (and All), What a great "Ampabout" post, just like the good old
> days on the list...

Yes, it was fun reading.

On the Bycan (or other chargers that have no easy way to adjust the
current): You can always add something between the charger and batteries
to "fool" it into drawing less current. It could be a simple resistor,
or one or more diodes, an inductor to knock down the peaks, etc. Which
technique is best will depend on the charger.

The Bycan and Lester chargers generally use constant-voltage
transformers. For this type, adding resistance will work the best, as
the charger will deliver as much current as it can in an effort to get
the voltage up to its design voltage.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

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