Have a mid 2000's that set 3 months unplugged. ( normally I disconnect the batteries but didn't this time)
Wouldn't charge and a couple connections in the first two batteries were replaced. First two were dead reminder had about 3 volts on the 6 volt battery. Got the first two charged enough that the normal charger would work. Initially it would not due first two being too low.
All six now read over six volts and the series is above 36.
But cart initially would only barely move. Then yesterday it operated normally during a 100 yard test drive. Next test drive it dies and now is completely dead.

When testing the individual batteries I thought one showed 9 volts once and same battery had a temperature of 104 vs the 84 degrees of the remaining 5.

I suspect one of two things.
1. Bad cell in said battery.
2. Solenoid is bad.

If I were to replace the one battery would that potentially fix it?
Batteries are 3-4 years old and usually last 6 years or so. Full set of batteries will run me $600 that I really don't want to spend and from what I can tell they are accepting a charge and can work.

Leaning towards trying to replace the one if that may work.

Thanks in advance for any insight.

Sounds like you're going to have to bite the bullet and buy six batteries to me but I'm not an expert. You can try one and if it doesn't work out get the other 5 in short order.

Sounds like a battery failure to me, too.

Often, lead acid batteries damaged by over-discharge can still charge to an apparently good voltage, but under load the voltage crashes and they can barely supply any current.

If you take the batteries to an auto parts store, they generally will have a battery load tester that can check this for you (and usually do it for free).

With batteries in series, even one damaged battery can stop the whole thing from working. If it is a battery problem, you might not need to replace all of them, and a load test is the best way to figure out which one(s) need it.

quote:

Originally posted by Krazeehorse:
Sounds like you're going to have to bite the bullet and buy six batteries to me but I'm not an expert. You can try one and if it doesn't work out get the other 5 in short order.

Best Idea! Be Thankful they are Not 12 volt batteries, like mine (Now that's Expensive!)..

Best deal on Golf Cart batteries is East Penn, I have a 48V cart, and it's just over $600.

https://www.eastpennmanufactur...ontact/where-to-buy/

Click there, enter your zip and see where the closest distributor is located, take the old in for core and swap.

If the solenoid or some component was bad it probably would never have moved and you'd have 36 V across the set.

I've never had a set last 6 years here in FL, 3-4 is the limit. Check water level, be sure to put in distilled water, publix sells it for a buck a gallon.

One of the batteries is bad and has a high impedance. You need to put a load test on each battery to find the bad battery. Also, there could be more than one battery bad.

After the cart wouldn't run, what did the total voltage in the batteries read? Remember, you need a total of 36V.
Also after charging let them sit an hour or so and re-check the voltage.
Get a hydrometer (looks like an antifreeze tester) at an auto parts store so you can check the individual cells in each battery after charging. That will tell you exactly where the problem is.

Only way to know is to load test each battery individually. They are all showing 6 volts, but as soon as you load them one (or more) is probably cratering. When the load disappears, the voltage probably pops back up to 6 volts so it looks fine.

41 and Perception are on it.

Open circuit voltage will not tell you if the cell is bad, you need to measure it loaded and see that the cell can push a constant current under a stable voltage. That indicates the cell has capacity. If the voltage drops under load, even after a period of trickle charging, it can't hold a charge and is due for a trip behind the barn. A bad cell in the series pack will tax the other cells. Get em out of there.

Lead acid battery testers are little more than a voltmeter connected across a dummy load resistor.

I think the OP has identified the bad battery. And load testing the rest will tell him that maybe the others are on their last leg as well. The question is would it be ok to replace just one. Put me in the "NO" column. It's been my experience that rarely works out well.

I replaced the one that heated up. 90% sure it's fixed. Keeping fingers crossed.

quote:

Originally posted by maladat:
Sounds like a battery failure to me, too.

Often, lead acid batteries damaged by over-discharge can still charge to an apparently good voltage, but under load the voltage crashes and they can barely supply any current.

If you take the batteries to an auto parts store, they generally will have a battery load tester that can check this for you (and usually do it for free).

With batteries in series, even one damaged battery can stop the whole thing from working. If it is a battery problem, you might not need to replace all of them, and a load test is the best way to figure out which one(s) need it.

This and you need to replace all of the batteries. Changing one will put a big load on that one batteries as the old ones will drag it down...... Batteries work as a set, just like tennis shoes........Trojan seems to make the longest lasting golf cart batteries (for the price).

We replace the batteries pretty much every year or two.

Basic electrical: if the batteries total 36 volts, that means they are connected in series (positive of one to negative of the next). In a series circuit, if one fails, so does the rest of the circuit, like one burned-out bulb in a Christmas tree light string taking out the string.