Battery question for the Guru(s)

[jonnys_walkers]

I have two battery banks.
Each bank consists of two 6 volt golf cart batteries in series to give me 12 volts.
They are Exide GC-145's.
The RC min @ 25 amp is 525
The RC min @ 75 amp is 145
The 20 hour rate (AH) is 245

I have borrowed a fancy Load Tester for 12 volt batteries.
The Load Tester will test:
Cold Cranking Amps max 1000
Amp Hour max 160
Amps max 500

I know it is a long way around to my question. Which one of the Load Tester scales do I use?

[LadyWindrider]

Gonna take a stab at this. Forget cold cranking amps, that is for starting a car. I'm gong to assume also that Amps max 500 is for starting purposes. That leaves Amp Hour max 160 for you to test with. Are you having problems, or just testing the batteries? Might want to separate and test each one individually.

[Herk7769]

Won't be able to test individually as it is a 12 volt tester. The "bank" would need to be tested (12 volts).

I agree; you need to test using the AH setting.

Remember the AH of the batteries with be the same as ONE 6 volt battery.

Connecting in series, the AH does not double, the voltage does.
When connecting in parallel, the AH doubles and the voltage does not.

To convert RC at 25 amps to AH:

To convert RC to Ampere-Hours at the 25 amp rate, multiply RC by .4167. More ampere-hours (or RC) are better in every case when looking for a deep cycle battery. Within the same battery footprint or industry group size, the battery with higher ampere hours (or RC) will tend to deliver longer cycle lives. This conversion method will allow you to convert and compare competitive data.

Using this calculation for your RC @25 number the AH for your bank is 220AH.

I would be curious to learn what the bank actually tests out as.

[jonnys_walkers]

Thanks for the prompt replies.
I was going to use the 245 AH for testing purposes, but the problem is that the tester is rated for Amp Hour max of 160.
Back to the drawing board.

John

[Triguy]

I don't own a load tester so I have a question as to its use with deep cycle batteries. Is there something that a load tester does that a hydrometer doesn't do?

[Bennington Camper]

Many true deep cycle battery manufacturers say not to use a standard carbon pile load tester to perform tests. Check the fine print from the manufacturer...

-Glenn

[BlakeB]

You sure that load tester wont test 6v too? Most of them are 6v and 12v capable. The one I have is...and it's old

[Bennington Camper]

Exide maintenance manual:

http://www.exide.com/Media/files/Dow...aintenance.pdf

Don't know how many batteries are in series in a golf cart, but that is the reference voltage they refer to for their load testing - more than 31.5V... Maybe 6 in series for 36VDC nominal? If you can find this, you can do a proportional modification to the procedure listed for both voltage and time.