Nominal voltage of golf cart batts

[Sidney777]

Trojan battery site says 6.37 is 100%.
Look for trojan battery days sheet

[captainwd40]

I used 6 Duracell GC2 batteries bought from Sam's Club in my 36 volt golfcart and got 7 good years out of them.

Flooded cell batteries brand new should rest at 2.25 volts per cell right after a full charge (3 cells x 2.25 volts = 6.75) so your voltage should be good. Most times it's the age of battery or tale-tell signs (low voltage or won't hold a charge) that indicates battery end of life.

Cheers!

JCW

[Dieseldude]

Do your batteries have removable caps? If so, a hydrometer test is your simplest indication, and very reliable. Will vary slightly with temperature. If any cells have low electrolyte level, be sure to test before adding water. It can take a long time for the water to mix in, and you could draw up mostly water and get a falsely low reading. If electrolyte level is so low that plates have been exposed to air, I would not bother trying to use them.



I find that the plastic oval shaped hydrometers sold at most auto supply shops are not reliable. The pointer jams sometimes, and you have to give it a sharp tap to jar it. I prefer the cylindrical shaped ones available at battery specialty shops. Forget the glass ones though. Get yourself a plastic hydrometer to save yourself the grief of breaking it.


If your used batteries test at least 75% or at least 1.2 after charging a few hours, they still have some useful life. Much less, they are probably not worth the effort.

The following shows the approximate state of charge at various specific gravities at 77ºF / 25ºC.

100% 1.255-1.275
75% 1.215-1.235
50% 1.180-1.200
25% 1.155-1.165
0% 1.110-1.130

[rob d]

6-1/2 volts on a fully charged 6 volt battery is pretty well spot on.

Before I did anything else I'd carry them to who ever I usually buy my batteries from and have them run load tests on both batteries. If you are in the pacific northwest Le Schwab stores usually have the latest in battery test equipment that quickly shows if they are good or not or good enough to go to the effort of lugging them down to the boat to use in the boat.

It isn't the exact voltage they hit as long as it is right in the ballpark, it is how well they hold up to the drain when you are using them on the boat. That may go back to the reason why your mom decided that she wanted to change them. Not having it make the number of holes she wants to play before it gets plugged in and charged could be an issue. Changed because they are X years old may not be an issue at all on the boat.



They may work fine for a few hours hooked to the trolling motor even if they aren't quite up to snuff to stick in down in the boat though.

[Ted and Relinda]

You can get a battery amp tester for about 20 bucks at Harbor Freight or a little more at most any auto parts store. It takes about 15 seconds to load test the battery and it will show if it is any good.
Ted

[ShoreFun]

I can chime in on this one.

My brother and a friend started a golf car company. My brother went back to car repair, this was decades ago. So I have access to golf car batteries, cheap or free.

You only know the state of a battery by looking that the hygrometer levels. I guess a smart thing would be to take it to a mechanic because they all have battery capacitor testers that automatically check a battery. Of course setting a full charge with a low current charger is always a good thing.

When I was doing car flea markets I would borrow 2 batteries from the used discard pile. I would charge them on my trailer connected to the trailer system for a few days. Then we would go 4 days not worrying about power. Running heat and TV and such. When tested at home you could not tell they were discharged.

My brother's boss had a sailboat. He put in 2 golf car batteries. While the others on the dock needing new batteries every year or two he got over 5 years on the pair of used batteries.

While they may not be the proper choice if you are using batteries hard, they are likely good for weekend sailor types. Even used old ones.

[boatpoker]

Originally Posted by ShoreFun

You only know the state of a battery by looking that the hygrometer levels.

Hygrometer ?

[hirondeller]

Lots of good suggestions here, I agree that a static voltage test does not mean much on a potentially marginal battery.


Many suggestions for testing under load. How about a 'battery load tester' (google this)? 'These are simple and inexpensive, push the button and read the dial'. I have an older harbor freight model (now, $20), you enter the amp-hour and voltage ratings on the battery and hit a button. It puts a large load on the battery with a giant resistor, the needle swings into 'good', 'bad' and 'fair' ratings. I doubt that a 'bad' battery, with low capacity, would pass this test. It is a severe test. For me, the load tester has consistently revealed bad batteries when a voltmeter check seemed fine.

[Dieseldude]

Originally Posted by hirondeller

Lots of good suggestions here, I agree that a static voltage test does not mean much on a potentially marginal battery.


Many suggestions for testing under load. How about a 'battery load tester' (google this)? 'These are simple and inexpensive, push the button and read the dial'. I have an older harbor freight model (now, $20), you enter the amp-hour and voltage ratings on the battery and hit a button. It puts a large load on the battery with a giant resistor, the needle swings into 'good', 'bad' and 'fair' ratings. I doubt that a 'bad' battery, with low capacity, would pass this test. It is a severe test. For me, the load tester has consistently revealed bad batteries when a voltmeter check seemed fine.

Not sure how reliable those load testers are. They are quite a quick test. But what counts is the battery's endurance over a longer time. You can get a simple, easily stored hydrometer for perhaps less than 10 bucks. Just flush them with fresh water after using, and they last a long time. The specific gravity of the cell electrolyte is the most reliable indication of a battery's state. But for sealed batteries, the load test is the next best indication. I do not use a load tester, I just keep it simple with a hydrometer. Any trend toward deterioration can be tracked by keeping record of the specific gravity of each cell. It is rare for a battery to suddenly fail, unless by neglect.

[OldManMirage]

Hey, for what it's worth, if you read the whole post you'll see my replies and what I ended up doing. It came out ok for what I want right now. The batteries have plenty of life left in them for now.

You really have to read through the whole thread before you reply. So often you end up missing the drift of the conversation if you don't.

Just saying...

[PaulCrawhorn]

OP you can request a mod to lock your thread

[Wotname]

Or unsubscribe from the thread using the Thread Tools pull down menu.

[OldManMirage]

No I'm good. It's really kinda funny, you see this all the time when people read the first post of a 10 page thread and reply only to that original post - that might even be 10 years old ! Lol

I just thought my mildly sarcastic post might help a few people.

And there's always the chance that something relevant could get posted.

[sailorboy1]

Originally Posted by OldManMirage

I just thought my mildly sarcastic post might help a few people.

It did, people got new meat to post about

[OldManMirage]

Originally Posted by sailorboy1

It did, people got new meat to post about

Well, I was kinda thinking of the people who might not fully understand how a forum works.

But yeah, if some get some amusement out of it or more ammo for their cannon then that's even better !