DIY Electric Car Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
I have a 73 VW bus I converted for business use in Portland, OR www.electricbus.blogspot.com

I am using generic golf cart batteries, 24 6v for 144 V. All they say on them is "105 min"

They charge to 155V when fully charged, and I have a few questions about my set up to help me take care of them.

1. I have heard that other batteries, like US batts chargeup to 180V with the same number of batts. Does that mean with those batteries I'd be getting more power and more range? Is my charger perhaps not charging them enough or does this sound fine.

2. I know you aren't supposed to de-charge them too often. I have gone 40 + miles and done a bunch of hills lately and my pack will read 144V by the end. Is this maxing them out? The car certainly can't climb big hills fast by the 144V mark, and hitting the gas hard makes the motor momentarily stall for lack of Volts. Can I de-charge further than that, or is than max. I suppose my batts just don't have the output of others, but my range seems pretty good.

3. I seem to max out at 48 mph or so, this seems a function of lack of V rather than engine power (kit #4 from www.e-volks.com)

4. And a charging question. There is a slight gurgle to the batteries when charging completely, This I suppose is bubbling battery water, it really is faint and not too vigorous, although a friend of mine has 8V us batteries and his gurgle like mad. Is either of these situations more normal?

Thanks

I am trying to learn more about batteries and this is a really cool source of info.

Soren
 

·
Registered
Joined
·
183 Posts
Where did you get the batteries from? Can the dealer help you figure out what a proper charging cycle should be?

What info do you have on the charger that came from the E-volks kit. Does it tell you what type of charging cycle it does?

http://www.electricvehiclesusa.com/product_p/mo-es-31b.htm
http://www.cloudelectric.com/inc/sdetail/169

According to those 2 places, that is not a 90 HP motor.... I think having that motor get a VW bus filled with 24 batteries and a couple of people over 40 is pretty good. I think if you want a higher speed you will need to upgrade that motor. 144 volts it plenty to get a motor up to its top speed.

The gurgling sound is the water inside the batteries boiling. The more it boils, the more often you should be checking the water levels and specific gravity of the batteries.

http://www.evdl.org/archive/index.html#nabble-to13117033|a13117033
http://www.evdl.org/archive/index.html#nabble-to14238985|a14238985

Here are a couple of threads from the EVDL archive that discuss 6 volt battery charging


Do you have kind of battery monitoring? A shunt and meter? an Emeter or a PakTraker? At a minimum you should get a shunt and analog meter to watch your battery current in real time
 

·
Registered
Joined
·
408 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #4 ·
I have teh Zivan NG-3 charger, which I believe is not reprogramable by me. The batteies are 220 Amp hours, I'll have to ask if they have any info on charging them. Not sure what type of charging cycle it does, or even what the possibilities are.

Yes I do have a shunt and ampmeter. I draw 300 amps at big acceleration and cruise at 25-50 on the flats. What other info would be usefull?
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
As far as the aquagen system, I don't believe I have any more room above my batteries for anything to stick up. Do you have all that room? It looks like they stick up 6 inches higher than the battery?

Soren
 

·
Registered
Joined
·
408 Posts
As far as the aquagen system, I don't believe I have any more room above my batteries for anything to stick up. Do you have all that room? It looks like they stick up 6 inches higher than the battery?

Soren
I'm using lithium ion batteries - bone dry. The AquaGen was just a suggestion :) You could try tubing the batteries together, as some do for easier topping up, and hook the tube to 1 or 2 AquaGens - provided it's an otherwise sealed system. The goal is to recapture the water that attempts to evaporate.
 

·
Registered
Joined
·
183 Posts
I did some rough estimates and it seems like 40ish miles is a good range/charge.
According to trojan (this is for their batteries, but a generic 6 v flooded should be similar i think) 6.05 volts per battery = 50%DOD.
6.05 x 24 = 145.2 volts, and your reading 144 volts.
A fully charged battery should be 6.37 volts, or 152.88 for 24 of them.
http://www.green-trust.org/battfaq.htm

Look into getting a hydrometer to check the specific gravity of the cells as that is the most accurate way to determine the State of Charge
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
Thanks Mrcrabs, The Trojan site is the first info I've seen that makes me think I'm doing the right thing. Unfortuanately my charger really doesn't offer any controls, but maybe its smarter than I think. Equalization charges may be difficult, unless it does those too occasionally (I doubt it)

Seems like I got a limited though expensive charger.

So, why do most people I've read about, including those links to battery talk you gave me, charge their systems so much higher than 6.37 V each? Are they using that much of a different battery? "2.48 v x 3 = 7.44 v per 6 volt battery" was a quote from Roland at http://www.evdl.org/archive/index.html#nabble-to13117033|a13117033

I've had other people online tellign me I am undercharging my pack.

Thanks
 

·
Registered
Joined
·
183 Posts
Your right about the numbers I linked to being lower than other's recommendations..... I guess its too late for me to be researching :confused:

Are you monitoring the voltage during the charge? It could be possible that your charger is going to a higher voltage, and by the time you check them with the dash gauge, the surface charge has dissipated.
Can you monitor the voltage while charging or right after the charge is done?
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #11 ·
Yes, I think I have been confused, I didn't realize that the charger is probably charging that high, but then my resting V after is 154V because the charger has a 2 step (at least) chargign cycle... I'll try to look tonight.

Thanks for all your help.

Soren
 
1 - 11 of 11 Posts
Top