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  #1  
Old 04-23-2010
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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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Old 04-23-2010
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Quote:
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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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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Old 04-23-2010
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My guess is somewhere around 280aH.
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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.

Bill
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Old 04-23-2010
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Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice
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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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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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 :-)

Bill
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Old 04-27-2010
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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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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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Last edited by mitiempo; 04-27-2010 at 02:16 AM. Reason: cor
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