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post #1 of 12 Old 04-23-2010 Thread Starter
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Battery AMP Question

We have to 2 pair of 6 volt deep cell batteries that are connected in seriers, creating 12 volts. Their model is Deka Promaster GC15/115 min. Any idea how to figure the total amp hours available ?
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post #2 of 12 Old 04-23-2010
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Originally Posted by dougshipl View Post
We have to 2 pair of 6 volt deep cell batteries that are connected in seriers, creating 12 volts. Their model is Deka Promaster GC15/115 min. Any idea how to figure the total amp hours available ?
Is this it?

http://www.europrospect.com/pdf/ProM...d%20acidEP.pdf

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post #3 of 12 Old 04-23-2010
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Find aH at 6v for an individual battery. Multiply by 2. That gives your aH at 12v.

Approximately.
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post #4 of 12 Old 04-23-2010
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My guess is somewhere around 280aH.
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post #5 of 12 Old 04-23-2010
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NO....you don't multiply AH x 2 when batteries are in series.

You multiply VOLTAGE x 2, as the OP already did. The AH remains the same.

Golf-cart batteries typically are rated between 210 and 225AH. So, two 6-volt golf carts in series will be somewhere between 210 and 225AH @ 12 volts.

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post #6 of 12 Old 04-23-2010
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The 20 hour rating on the GC15 is 215 Ah ea. or when in series 215 for 2 or when in fours 430 Ah @ 12v..

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Last edited by Maine Sail; 04-23-2010 at 06:53 AM.
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post #7 of 12 Old 04-23-2010
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But if he has "2 pair" (4 batteries) he's got a total 430Ah. The OP asked how many Ah are available. Which would be 215 from a full charge, since you shouldn't go below 50%. Actually he should only count on 143 Ah from the typical operating range between 80% and 50% charge. You only get to 100% by being on a very long charge i.e. 24 hours.
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post #8 of 12 Old 04-23-2010
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Yes, Steve is right!

Note to self: "2 pair" equals 4 batteries.

Four 215AH golf-cart batteries in series/parallel equals 430AH total capacity.

Thanks, Steve. Too early to figure right :-)

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post #9 of 12 Old 04-27-2010 Thread Starter
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To JARCHER - yes that's the battery.

Ok - so if Im following you guys-

1) it's 430 amp hrs available capacity for the 4 batteries (215 x 2 pair) but not good to run batteries below 60% of the 430.
2) safe to assume at 12.6 volts (on meter/approx) the 4 batteries are charged almost 100%?
3) at 12.2 volts (on meter/approx) I assume I have 60% remaining and have used up my safe max of 172 ah (430x40% usage)...and at that point would need to recharge or risk damage to batteries.
4) to add more nausa - if I bought 2 more 6 volt similiar batteries Id go from 430 ah to 645 ah.... times 40% safe max usage for a total of 258 ah to burn before recharging.

Sound correct?

Doug
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post #10 of 12 Old 04-27-2010
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Correct except voltage is not an accurate way to measure battery capacity unless they have been resting unused and not charging for 12 to 24 hours. Buy a basic battery monitor like the Victron BMV-600 ($175 at Jamestown Dist) and find out what is really happening to your batteries. You won't really know until you do and your batteries will probably last longer.

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