**The**140-minute reserve capacity indicates the number of minutes a**battery**can deliver 25 amps of current without dropping below 10.5 volts. An interesting rule of thumb is that typically if you divide a given reserve capacity by two, you will derive the approximate amp**hour**capacity. The most common**battery**rating is the CCA or "cold cranking ...- Multiply this by 2 to get the voltage of the battery: 36 volts in the case of our example. 125 refers to the number of amps per cell. 13 refers to the number of negative plates in a cell. Take 13, minus 1, and divide by 2. This equals 6. Now multiply the middle number (number of amps per cell) by half the last number (minus 1).
- Ah = 800W / 12V = 66.67 Ah. This means you will need a
**battery**with at least 66.67 amp-**hours**(Ah). Here is the step-by-step procedure**how****to****calculate**Ah of a**battery**:**Calculate****the**electricity needed to power an electronic device. That means you want to multiply the wattage by**how**many**hours**you want the device to run. - CALCULATINg
**BATTERy**CAPACITy The**ampere-hour**rating is the product of the number of**amperes****of**current the**battery**can supply multiplied by the number of**hours**(or fraction thereof) over which the current is supplied to a specified end point voltage. For example, a TEL12-125 series is rated as a 127.2 Ah**battery**at the 8**hour** - *Please note: Some links on this site lead to web pages operated by companies that we have affiliate relationships with. In some cases, we may receive compensation for referring traffic.