[EVDL List]

I'm trying to stay neutral in all this as I know there are some negative feelings toward Thundersky batteries. Here are the facts.

Today the people who own the Elite Power Solutions business did a presentation at the Phoenix EAA's meeting this morning. They brought in some cells and the BMS and a charger to show us so the products do exist. They had a sample 4 cell "12 volt" pack of their 40, 60 and 90ah cells. When lifting the 4 cell 90ah block it's amazing to think that that much energy can fit in something of that size. They also had the BMS system they will be offering. It's scalable depending on the pack size and is more of a monitoring system, it doesn't do equalizing, but it does interface with the charger so it will stop charging if one cell gets too high in voltage or will also do the opposite if a cell gets to the lower voltage limit. It also came with a touch screen so I'm interested to see how it works once it's up and running.

They also had a charger for a 21 cell motorcycle pack which did not include a BMS, but worked by just slightly under charging the cells.

I brought along a load tester and Yuan agreed to let me put a load on one of the cells to see how it would behave. I guess they lost the cell inter connectors in shipping so I couldn't test a whole 12 volt module, and my instrumentation consisted just of the ammeter and volt meter on the 500A load tester so this is hardly scientific, but it's an idea. At about 50A (most I could get the littler carbon pile to pull from the 3.2V battery) the voltage went from about 3.2 volts to 3.0 volts. This was one of the 40ah cells too so for a motorcycle it seems like it would work. When he gets the inter connectors I can get a batter idea of how a 12 volt block behaves under load.

He really wants to convert a car and I guess he's already got a deposit down on a Zilla so we'll find out if they really work. They said that each pack of cells also shipped with a printout showing all specs for each battery with capacity and internal resistance and such.

We'll see.

Later,
Rick
92 Saturn SC Conversion
AZ Alt Fuel Plates "ZEROGAS"




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[EVDL List]

Hi Rick,

Ive had a similar experience with the lfp 40s on my scooter.

A while ago I put my carbon pile tester across 4 of them, at 250A they were
still 2vpc (for another reference point).

If their "BMS" doesn't do charge balancing, you can achieve this yourself by
putting a 3.6v zenner and resistor across each cell. A cheap and easy
solution (though time consuming I suppose).

Matt



-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On Behalf
Of Ricky Suiter
Sent: Sunday, 27 July 2008 7:30 AM
To: EV List
Subject: [EVDL] Thundersky and Elite Power Solutions,I got to see them
today.

I'm trying to stay neutral in all this as I know there are some negative
feelings toward Thundersky batteries. Here are the facts.

Today the people who own the Elite Power Solutions business did a
presentation at the Phoenix EAA's meeting this morning. They brought in some
cells and the BMS and a charger to show us so the products do exist. They
had a sample 4 cell "12 volt" pack of their 40, 60 and 90ah cells. When
lifting the 4 cell 90ah block it's amazing to think that that much energy
can fit in something of that size. They also had the BMS system they will be
offering. It's scalable depending on the pack size and is more of a
monitoring system, it doesn't do equalizing, but it does interface with the
charger so it will stop charging if one cell gets too high in voltage or
will also do the opposite if a cell gets to the lower voltage limit. It also
came with a touch screen so I'm interested to see how it works once it's up
and running.

They also had a charger for a 21 cell motorcycle pack which did not include
a BMS, but worked by just slightly under charging the cells.

I brought along a load tester and Yuan agreed to let me put a load on one of
the cells to see how it would behave. I guess they lost the cell inter
connectors in shipping so I couldn't test a whole 12 volt module, and my
instrumentation consisted just of the ammeter and volt meter on the 500A
load tester so this is hardly scientific, but it's an idea. At about 50A
(most I could get the littler carbon pile to pull from the 3.2V battery) the
voltage went from about 3.2 volts to 3.0 volts. This was one of the 40ah
cells too so for a motorcycle it seems like it would work. When he gets the
inter connectors I can get a batter idea of how a 12 volt block behaves
under load.

He really wants to convert a car and I guess he's already got a deposit down
on a Zilla so we'll find out if they really work. They said that each pack
of cells also shipped with a printout showing all specs for each battery
with capacity and internal resistance and such.

We'll see.

Later,
Rick
92 Saturn SC Conversion
AZ Alt Fuel Plates "ZEROGAS"




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[EVDL List]

[quote]Ricky Suiter wrote:
> Today the people who own the Elite Power Solutions business did a
> presentation at the Phoenix EAA's meeting this morning. They brought
> in some cells and the BMS and a charger to show us so the products do
> exist. They had a sample 4 cell "12 volt" pack of their 40, 60 and
> 90ah cells. When lifting the 4 cell 90ah block it's amazing to think
> that that much energy can fit in something of that size.

Yes, it is impressive. One way I demonstrate the characteristics of the
various battery technologies to people is to line up a 68ah Hawker
lead-acid, 79ah GM/Ovonic nimh, and 90ah Thundersky 12v packs. The
lead-acid weighs 50 lbs; the nimh 40 lbs, and the lithiums 22 lbs.

> They had the BMS system they will be offering. It's scalable
> depending on the pack size and is more of a monitoring system, it
> doesn't do equalizing, but it does interface with the charger so it
> will stop charging if one cell gets too high in voltage or will also
> do the opposite if a cell gets to the lower voltage limit. It also
> came with a touch screen so I'm interested to see how it works once
> it's up and running.

Sounds like a Battery *Monitoring* System, not a Battery *Management*
System. It will tell you if there's a problem, but won't do anything
about it. The charger can prevent overcharging, but it can't do anything
to re-balance the cells.

> I brought along a load tester and Yuan agreed to let me put a load on
> one of the cells. At about 50A the voltage went from about 3.2 volts to
> 3.0 volts. This was one of the 40ah cells...

That's 0.004 ohms, which isn't great for a 40ah cell. However, your test
method was pretty basic, so the error could be large.

For comparison, a 40ah lead-acid AGM is around 0.003 ohms for a 12v
battery (6 cells in series, so 0.0005 ohms per cell).

> He really wants to convert a car and I guess he's already got a
> deposit down on a Zilla so we'll find out if they really work. They
> said that each pack of cells also shipped with a printout showing all
> specs for each battery with capacity and internal resistance and
> such.
>
> We'll see.

Yes; we will see! Thundersky needs some design "wins" to convince people
that they really can deliver good batteries.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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[EVDL List]

[quote]Lee Hart wrote:
> Ricky Suiter wrote:

>> I brought along a load tester and Yuan agreed to let me put a load on
>> one of the cells. At about 50A the voltage went from about 3.2 volts to
>> 3.0 volts. This was one of the 40ah cells...
>
> That's 0.004 ohms, which isn't great for a 40ah cell. However, your test
> method was pretty basic, so the error could be large.

That's wrong way to determine R_int.

R_int = deltaV/deltaI, bun in delta I one of the currents
cannot be zero amps. In other words, you must measure
delta I at two different currents, preferably both close to
typical driving current, none equal to zero. You cannot use
unloaded battery condition as one of the data points, you will
get erroneous result.

Victor

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[EVDL List]

A Zenner and a resistor would only work at low current levels. Would
not work for a car size battery.

>
>
>
> If their "BMS" doesn't do charge balancing, you can achieve this
> yourself by
> putting a 3.6v zenner and resistor across each cell. A cheap and easy
> solution (though time consuming I suppose).
>
> Matt
>
>

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[EVDL List]

The zenner and resistor is only meant to keep the batteries in balance, not
to balance an unbalanced pack.
The lithiums (particularly the LiFePO4 and LiTi chemistries) don't have any
secondary reactions in their normal voltage operating range, so unlike say
lead acid, they don't go out of balance as easily. The only thing that
causes the lithiums to become unbalanced is the internal current leakage. So
shunting 0.5A for an hour a day for a 200AH cell when it gets ahead of the
rest of the pack is all that's needed.

The other half of such a bms is disconnecting the charger completely when
the charge voltage gets too high, which would be when the pack gets too far
out of balance for the zenner and resistor setup to deal with. In this case
you have the oppurtunity to manually balance the pack by putting a 0.5A
charge current through the pack, or to find the specific cell(s) that are
causing the bms to trip and put a load on them for a while.

Matt

-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On Behalf
Of Roger Heuckeroth
Sent: Monday, 28 July 2008 10:36 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Thundersky and Elite Power Solutions,I got to see them
today.

A Zenner and a resistor would only work at low current levels. Would not
work for a car size battery.

>
>
>
> If their "BMS" doesn't do charge balancing, you can achieve this
> yourself by
> putting a 3.6v zenner and resistor across each cell. A cheap and easy
> solution (though time consuming I suppose).
>
> Matt
>
>

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[EVDL List]

Ooops, LiTi was meant to be LiTiO3

Matt

-----Original Message-----
From: matt [mailto:mc.xxx@xxx.xxx.au]
Sent: Tuesday, 29 July 2008 11:16 AM
To: 'Electric Vehicle Discussion List'
Subject: RE: [EVDL] Thundersky and Elite Power Solutions,I got to see them
today.


The zenner and resistor is only meant to keep the batteries in balance, not
to balance an unbalanced pack.
The lithiums (particularly the LiFePO4 and LiTi chemistries) don't have any
secondary reactions in their normal voltage operating range, so unlike say
lead acid, they don't go out of balance as easily. The only thing that
causes the lithiums to become unbalanced is the internal current leakage. So
shunting 0.5A for an hour a day for a 200AH cell when it gets ahead of the
rest of the pack is all that's needed.

The other half of such a bms is disconnecting the charger completely when
the charge voltage gets too high, which would be when the pack gets too far
out of balance for the zenner and resistor setup to deal with. In this case
you have the oppurtunity to manually balance the pack by putting a 0.5A
charge current through the pack, or to find the specific cell(s) that are
causing the bms to trip and put a load on them for a while.

Matt

-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On Behalf
Of Roger Heuckeroth
Sent: Monday, 28 July 2008 10:36 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Thundersky and Elite Power Solutions,I got to see them
today.

A Zenner and a resistor would only work at low current levels. Would not
work for a car size battery.

>
>
>
> If their "BMS" doesn't do charge balancing, you can achieve this
> yourself by putting a 3.6v zenner and resistor across each cell. A
> cheap and easy solution (though time consuming I suppose).
>
> Matt
>
>

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[EVDL List]

Matt,

The only time you would have to worry about your voltage getting to
high is during the top-off, equalization phase of your charge. I
wouldn't worry about internal leakage especially if you use it as a
daily driver.

The idea behind most shunting circuits is to stop and hold the voltage
in a cell right at the target voltage while the other cells in series
get the opportunity to get fully charged. A zenner can supply the
reference voltage to compare the cell voltage to, but you are going to
need a semiconductor that can handle a lot more current than a zenner
to do the shunting. It has to handle the full charging current. At
0.5 A a 200 Ah pack would take forever to charge.

Roger

[quote] matt wrote:

> Ooops, LiTi was meant to be LiTiO3
>
> Matt
>
> -----Original Message-----
> From: matt [mailto:mc.xxx@xxx.xxx.au]
> Sent: Tuesday, 29 July 2008 11:16 AM
> To: 'Electric Vehicle Discussion List'
> Subject: RE: [EVDL] Thundersky and Elite Power Solutions,I got to
> see them
> today.
>
>
> The zenner and resistor is only meant to keep the batteries in
> balance, not
> to balance an unbalanced pack.
> The lithiums (particularly the LiFePO4 and LiTi chemistries) don't
> have any
> secondary reactions in their normal voltage operating range, so
> unlike say
> lead acid, they don't go out of balance as easily. The only thing that
> causes the lithiums to become unbalanced is the internal current
> leakage. So
> shunting 0.5A for an hour a day for a 200AH cell when it gets ahead
> of the
> rest of the pack is all that's needed.
>
> The other half of such a bms is disconnecting the charger
> completely when
> the charge voltage gets too high, which would be when the pack gets
> too far
> out of balance for the zenner and resistor setup to deal with. In
> this case
> you have the oppurtunity to manually balance the pack by putting a
> 0.5A
> charge current through the pack, or to find the specific cell(s)
> that are
> causing the bms to trip and put a load on them for a while.
>
> Matt
>
> -----Original Message-----
> From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu]
> On Behalf
> Of Roger Heuckeroth
> Sent: Monday, 28 July 2008 10:36 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Thundersky and Elite Power Solutions,I got to
> see them
> today.
>
> A Zenner and a resistor would only work at low current levels.
> Would not
> work for a car size battery.
>
>>
>>
>>
>> If their "BMS" doesn't do charge balancing, you can achieve this
>> yourself by putting a 3.6v zenner and resistor across each cell. A
>> cheap and easy solution (though time consuming I suppose).
>>
>> Matt
>>
>>
>
> _______________________________________________
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> http://evdl.org/help/index.html#conv
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>
>
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> Checked by AVG.
> Version: 7.5.524 / Virus Database: 270.5.6/1577 - Release Date:
> 28/07/2008
> 6:55 AM
>
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[EVDL List]

do you know what boltsize the battery takes?

Does it come with the bolts?

[quote] Ricky Suiter <xxx@xxx.xxx> wrote:

> I'm trying to stay neutral in all this as I know there are some negative
> feelings toward Thundersky batteries. Here are the facts.
>
> Today the people who own the Elite Power Solutions business did a
> presentation at the Phoenix EAA's meeting this morning. They brought in some
> cells and the BMS and a charger to show us so the products do exist. They
> had a sample 4 cell "12 volt" pack of their 40, 60 and 90ah cells. When
> lifting the 4 cell 90ah block it's amazing to think that that much energy
> can fit in something of that size. They also had the BMS system they will be
> offering. It's scalable depending on the pack size and is more of a
> monitoring system, it doesn't do equalizing, but it does interface with the
> charger so it will stop charging if one cell gets too high in voltage or
> will also do the opposite if a cell gets to the lower voltage limit. It also
> came with a touch screen so I'm interested to see how it works once it's up
> and running.
>
> They also had a charger for a 21 cell motorcycle pack which did not include
> a BMS, but worked by just slightly under charging the cells.
>
> I brought along a load tester and Yuan agreed to let me put a load on one
> of the cells to see how it would behave. I guess they lost the cell inter
> connectors in shipping so I couldn't test a whole 12 volt module, and my
> instrumentation consisted just of the ammeter and volt meter on the 500A
> load tester so this is hardly scientific, but it's an idea. At about 50A
> (most I could get the littler carbon pile to pull from the 3.2V battery) the
> voltage went from about 3.2 volts to 3.0 volts. This was one of the 40ah
> cells too so for a motorcycle it seems like it would work. When he gets the
> inter connectors I can get a batter idea of how a 12 volt block behaves
> under load.
>
> He really wants to convert a car and I guess he's already got a deposit
> down on a Zilla so we'll find out if they really work. They said that each
> pack of cells also shipped with a printout showing all specs for each
> battery with capacity and internal resistance and such.
>
> We'll see.
>
> Later,
> Rick
> 92 Saturn SC Conversion
> AZ Alt Fuel Plates "ZEROGAS"
>
>
>
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
>
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