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macbob · 05-09-2014, 06:13 PM

With the 4 battery ystem how do you check the voltage on each battery?? I have a volt meter but not surevhow to check the batteries when all four are hooked together

Skip426 · 05-09-2014, 06:19 PM

You can go to each battery's posts and check , maybe not as accurate as disconnecting all the cables but would show a real low , that would require further testing, with the cables off.
Look for 6.5, if anything under 6 shows up , disconnect and retest.

dennis45 · 05-09-2014, 06:27 PM

You don't really say what prompts your question. How old are they? Are you having trouble?
If you want to look at each battery, I suggest using a Hydromter to test each cell. That will tell you if there are cells not taking a charge.
The total battery voltage should not be any higher than 13.6 - 13.7 VDC when you are plugged in to Shore Power. Anything higher will result in excessive gassing, frequent water adding, corroded terminals and shortened battery life.

distaff · 05-11-2014, 08:52 AM

You can't check them individually unless you disconnect them. If you have doubts about a battery a meter will help, but they probably all show the same voltage - this is called a surface charge.

You need either a load test or check the specific gravity of the electrolyte when they are showing fully charged. If in doubt, take them all to a battery dealer - there are no shortage of them in most good sized towns.

distaff · 05-11-2014, 09:49 AM

Should have also mentioned that you can check specific gravity without disconnecting them. The testers are cheap and available at any auto parts store.

Remember to check every cell.

gemini5362 · 05-12-2014, 09:38 PM

All great answers on how to do a very specific check. Or you can just put the red lead of your voltmeter on the plus post of each battery and the black lead on the minus and look for about 6 volts.

ohhwell · 05-13-2014, 08:17 AM

Quote:

Originally Posted by gemini5362

All great answers on how to do a very specific check. Or you can just put the red lead of your voltmeter on the plus post of each battery and the black lead on the minus and look for about 6 volts.

If you had say, one almost dead 6V in a 2 battery bank and it was at maybe 2 volts and the other battery was somehow at a full 6.4 volts or so, would the bad battery read the correct 2 volts, or like 4.2 volts being influenced by the good battery when testing with all the leads hooked up?

GaryKD · 05-13-2014, 09:04 AM

Hi macbob,
Batteries connected in series (assuming 6 VDC batteries for the house) can not be checked while connected to each other. Wires to each terminal need to be disconnected.

We need to hear from macbob to understand why the question is being asked. Once we understand the situation, further and more accurate suggestions can be provided to help macbob solve the problem.

gemini5362 · 05-13-2014, 09:59 PM

Quote:

Originally Posted by GaryKD

Hi macbob,
Batteries connected in series (assuming 6 VDC batteries for the house) can not be checked while connected to each other. Wires to each terminal need to be disconnected.

We need to hear from macbob to understand why the question is being asked. Once we understand the situation, further and more accurate suggestions can be provided to help macbob solve the problem.

Actually batteries in series can be checked very easily. You can check each individual battery by just checking across each pair of terminals. Batteries in Parralel cannot be checked individually. Because the batteries are hooked in series parallel that might be an issue. I have never tried it but I think what happens is that the parallel string would prevent you from checking two of the batteries as a 12 volt entity but I still believe you can check each one of the 6 volt batteries independently.

This ONLY works if you check each battery across its individual positive and negative post not if you check across the battery positive post to ground.

glemo81540 · 05-14-2014, 07:13 PM

I believe a 6 volt battery in series can be checked w/o disconnecting by checking across the pos/ neg poles. I remember checking both connected and unconnected and had the same reading. Has anyone tested to see what they get?

Skip426 · 05-14-2014, 07:41 PM

Quote:

Originally Posted by glemo81540

I believe a 6 volt battery in series can be checked w/o disconnecting by checking across the pos/ neg poles. I remember checking both connected and unconnected and had the same reading. Has anyone tested to see what they get?

I remember doing this on a golf cart a few years back and tracked down the low one. Coach is in the yard, I'll disconnect from shore power tonight and test in AM and post my results, cables on, cables off. time for a full system check and water add if necessary, anyhow.

vsheetz · 05-14-2014, 07:59 PM

If wet cells with removable caps you can even check each cell by dipping a meter lead into the electrolyte. One lead on a post, with the other lead check each cell across the battery.

Skip426 · 05-15-2014, 12:38 PM

OK, I'm back and the test results are in.
16 hours after turning of a 13.28v maintenance charge.
Note: someone , who shall remain unidentified , forgot the battery disconnect, but this over-site probably didn't effect the results.
Battery bank total, with all cables connected, includes draw from forgotten disconnect. 12.49v
With main ground removed. 12.54v
4 golf cart batteries tested, in order from the first at the main ground cable. With ground cable hooked up.
6.30, 6.18,6.25, & 6.24
with main ground cable removed and interconnect cables in place.
6.33, 6.20, 6.28 & 6.26
Each battery with interconnect cables removed.
6.34, 6.21, 6.30 & 6.28.
Cable clean up, hydrometer tests and adding electrolyte , are up next.
Test shows; IMHO; that a volt test with cables hooked up show little difference than with, cables removed.
And in answer to the question about a battery with 2v hooked to one with 6.4 , yes the voltage of the two batteries will equalize , very quickly

the rapid discharge, straining the battery with the good charge, the reason you always replace battery banks as a set. After a few cycles of discharge that rapid even the good battery is compromised .

distaff · 05-16-2014, 07:38 AM

Skip, one point. I have replaced one bad battery in a bank of 6. The other 5 were still good (not excellent) and I wasn't prepared to toss them all. What it means is that the new battery will only last as long as the other 5, but on a 5 to 1 trade off, that was a fair proposition.