8volt battery problem

[beach cart]

I have 6, 8v t875's. Two years old, well maintained no visible sulfation.

Normally I get 20 plus miles with a 3 to 4 volt drop riding, I can see this on the run with an xray volt meter. I have done voltage checks under load and checked with a hydrometer. Tonight went 10 miles at the end of run after, 5 batteries read, 8.2, one 7.4 which is 30%. I think I have one bad battery. Voltage drops since this started 4 weeks ago is 5 to 7 volts after 5 or so miles.

I plan to have them load tested by a pro next week. Any all opinions out there are appreciated. Hope Johnnie B. sees this. Thank's.

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[JohnnieB]

7.4V is less than 10%, but you said 30%, which is about 7.9, so is suspect a typo.

Just like you need to let the batteries rest about 12 hours after the charger shuts off to read the voltage for a SoC estimate, you need to let the batteries rest after using them to get an accurate SoC estimate.

Here is a chart I made for the T-105 batteries that were in my cart when I got it, they were about 2 years old and had lived a hard life on a golf course in Arizona.

AS you see, most of the recovery is in the first half hour. (about 12.7% SoC gain). When I do range testing I let the batteries sit for 30 minutes and add 1% Soc to the SoC the voltage translates to, but I have waited a full hour also.

That aside, all six batteries ought to be within 0.1V to 0.3V of each other before the cart is driven, while the cart is being driven and after it has been driven.

The low battery is troubling. Maybe it might perk up with some individual attention from a 8V charge. Or you can use a 12V, but you'll have to babysit the battery with a DVM so you don't overcharge it.

When using a 12V charger on a 8V battery, don't let the on-charge voltage climb above 10.8V.

[cgtech]

If the numbers are correct, you answered your own question. Crap battery. If you were fishing to "beat their warranty process". Dont bother arguing. We hate the battery warranty process just as much as you. And they hate sending new batteries. If you think getting a new battery out of them is easy, well pack a lunch. Awe jeeezs, out of warranty.

[beach cart]

First thank you both for the great responses. I have no intention to try the warranty route. Tried that once didn't work. I'll recheck as stated. And report back. I'll do more testing this am.

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[beach cart]

I have done another full set of under load tests for 10 miles. 5 batteries all 8.2 to 8.3, one battery 7.2 basically dead.

My question with this one bad battery, will this lower mileage in half and voltage drops from 2 to 4 volts to 6 to 9 volts for the whole pack. Can I put a new battery in to fix this problem.

I'm going to have pack load tested mon. To be sure.

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[JohnnieB]

Try to find a used battery the same make, model and age as the other batteries.

If you can't find one, go with a new one that is the same make/model as the others, but be aware it will soon become the same age as the other batteries and will have to be replaced at the same time the other are replaced.

[beach cart]

Old batteries are hard to find around here, I'll probably just buy a new. Haven't had the best luck with batteries, these just 2 years old, but the do go bad sometimes.

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[JohnnieB]

Originally Posted by beach cart

Old batteries are hard to find around here, I'll probably just buy a new. Haven't had the best luck with batteries, these just 2 years old, but the do go bad sometimes.

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Probably location more than luck.

Batteries don't last very long in hot climates no matter how well they are maintained. Check out the attached map.

Looks like 2.5 years is the average for your neck of the woods.

[beach cart]

Originally Posted by JohnnieB

Probably location more than luck.



Batteries don't last very long in hot climates no matter how well they are maintained. Check out the attached map.



Looks like 2.5 years is the average for your neck of the woods.

Yeah weather is tuff on batteries here. I called around this morning no one had a used trojan. I had the questionable battery load tested and it was dead would not take a charge. I replaced it with a duracell gc8 from sams. I checked the amp rating its 5 less then a trojan 875. I placed on charge, it read 8.7 before charger. Currently the pack is around 57 at the final 5 amp finish, the new battery read 8.8 all others 9.5, one 10.1. I'll check the real voltage after 12 hours. I know to check for real voltage after turn off and 12 hours. It will probably take sometime to level all out. Also keep an eye on other 5 for more gassing, may need water.

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