Author Topic: Watts per cell to Amp Hours  (Read 10014 times)

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kittysmitty

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Watts per cell to Amp Hours
« on: January 11, 2015, 07:51:07 AM »
I have been using these batteries for a few years and would like to know what is the amp hour rating.
 Thanks

Sprinter S12V500(F)

Nominal Voltage: 12 Volts
Nominal Capacity: 500 Watts Per Cell, 15 minute rate to 1.67 volts per cell @ 25°C (77°F)
Alloy: Positive: Lead, Tin, Calcium, and Silver
Negative: Lead, Calcium
Terminal: Threaded (M6) copper alloy
Container: Standard: Reinforced Polypropylene
Optional: Reinforced Flame Retardant Polypropylene UL94 V-0/28%
L.O.I.
Safety Vent: One-way, self-resealing vent. Recessed design accommodates
applications requiring central degassing
Float Voltage: 2.25 VPC to 2.30 Volt Per Cell Range. Recommended 2.27 VPC @
25°C (77°F)
Dimensions: 13.55” (344 mm) Length x 6.76” (172 mm) Width x 10.90” (277 mm)
Height
Weight: 106lbs. (48.1 kg.)

dnix71

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Re: Watts per cell to Amp Hours
« Reply #1 on: January 11, 2015, 11:49:15 AM »
12 volts x 40 amps is 480 watts
15 minutes is 1/4 hour
1/4 hour x 40 amps is 10 amp-hours (at rated 40-amp | 500-watt discharge rate) The amp-hour rating would go up if the discharge rate was lower.

kitestrings

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Re: Watts per cell to Amp Hours
« Reply #2 on: January 11, 2015, 03:37:28 PM »
Isn't a 20-hour capacity rating more common for deep cycle batteries?

mab

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Re: Watts per cell to Amp Hours
« Reply #3 on: January 11, 2015, 03:48:32 PM »
20 is sort of standard, but for deep cycle types 10hr and 5hr are also often used.

Based on the weight of your batteries and assuming they're GEL/AGM (they're clearly aimed at UPS use) I'd hazard they'd be 130Ah at 10hr rate; 150Ah at the 20Hr rate - but that is a guess rather than anything scientific.

if you can find a spec sheet for something similar online they sometimes have a table or graph of Ah vs rate of discharge.

dnix71

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Re: Watts per cell to Amp Hours
« Reply #4 on: January 11, 2015, 06:53:03 PM »
I just looked at the spec sheet. The short circuit amps is over 4750. The battery is a jumbo UPS battery. It's made to last 15 minutes, then recover slowly.

PDF: http://www.jantechups.com/userfiles/files/Battery/GNB%20Exide/VRLA/Sprinter%20S/S12V500%20datasheet.pdf