Load test - Okay, tell me what I think I already know :(

NCPW

Been having excessive charge times where it takes close to 24hrs for the charger to go into float mode over the past few weeks. Excessive acid spray/pooling around battery caps and topping off batteries more than usual. My run time has definitely decreased and overall speed/torque has declined also.

My batteries are dated April, 2016 and have always been on a DPI Gen 3 charger and very well maintained.

Resting pack voltage (24hrs after charging) is 53.1V - Under load the pack voltage drops down as low as 30.8V.

Battery resting voltage/ under load voltage:
1: 8.89V - 5.79V
2. 8.82V - 5.15V
3. 8.82V - 5.34V
4. 8.83V - 5.38V
5. 8.82V - 5.35V
6. 8.82V - 5.25V

Equal wait times between each test run and this was done on pavement going up a slight incline.

Are my batteries shot already???

BGW

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radelon

Holy cow!

You should only see around a .5v drop per battery or 5 to 6v total. Now I would probably check every connection creating more amp pull, make sure you don't have a brake sticking or anything like that. Since the voltage drop is pretty equivalent across all batteries it seems to me something else is wrong that's causing the huge drop.

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dundeebarnbuggy

I'd get an ammeter on the cables and see what your cart is actually drawing under various conditions. Will help with diagnosis.

NCPW

What about the excessive charge time? Shouldn't that show 1 or more bad batteries causing the charger to run longer than it should??? I get up 60.X during the absorption phase and float at 59.X when complete but it takes forever to get there.

radelon

I had that problem about 1 month ago. But I just let them boil and balance and kept maintaining them (keeping levels correct) and they came out of it. Usually now mine will be floating within 6-8 hours.

But also, a bad connection in the battery circuit causes they same thing and causes the batteries to overcharge.

NoleFan4Ever

NCPW, the issues you describe are exactly what happens when the plates have deteriorated to the point they do not charge/discharge as they should and can no longer support sustained current transfer.

One they I like to do to verify it is the pack itself is run the cart until you are <70% 49.5v) and close to or above =/>50% (~48v). Then recheck each battery and see if the they are all about the same. If so, and based on your previous 24 hours after charge readings, the pack is gone.... (And yes, very unusual at that short duration)

Do you frequently drain them low (below 50%?)

I have definitely seen that in cheap batteries, actually a whole lot, but not in a quality set like you most likely have like the US's in your signature.

NCPW

I'll do like you suggested Nole and run them down then take measurements again. I'm noticing a lot of battery case bloating it seems too.

I've never discharged this pack anywhere near 70%. The lowest resting voltage I can remember was in the 50.8 50.9 neighborhood. I use my cart once to twice a week for short trips. It gets it's most use on the weekends. Always on the charger when not in use.

NoleFan4Ever

I swear that makes NO sense on 2 year old batteries. And if it is bad, I would call US and ask to speak to their Tech/Engineering support as you do not have enough cycles on those batteries to be even close to where you are now.... They need to check the build date and see if they had other issues reported. Can't hurt anyways....

WalterM6

That excessive acid spray/pooling around battery caps has decreased the battery specific gravity. It may be just one battery and you may get away with just replacing just one since your batteries are fairly new. Get you one of the items shown in the link below. It is far more accurate and cleaner than a hydrometer. Expect a 1.30 SG reading from each cell.

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1