ampere hour, amp hour

amp hours for same battery

One of the questions we regularly get asked is, “What is an Amp-hour?” or they also ask the "AH" meaning in battery. A lot of people get confused about the difference between AH and volts. An “AH” or “amp-hour”, is an abbreviation of ampere-hour.  

An ampere is a unit of measure of the rate of electron flow or current in an electrical conductor. An Amp-hour describes or refers to the amount of energy charge in a battery that will allow one Amp of current to flow for one hour.

In order to define the battery's amp hour rating for lead-acid batteries, manufacturers will drain it down to 0% battery capacity, over a specific amount of time and the level of amperage it takes to get the lead-acid battery to zero over that time is the AH rating.

The standard amp hour rating for deep cycle batteries is 20 hours, which is significantly lower than the average amp-hour of a car battery which is rated at 70 amp-hours. So if your battery has a rating of 100AH @ 20Hr rate, that means the deep cycle battery was discharged over 20 hours battery capacity with a 5 amp load.

The current rating of a lithium-ion battery (rechargeable) and lithium batteries (not rechargeable) is rated at 3,200 mAh, which means it can discharge 3,200 milliamps (3.2 amps) in one hour and then it's done.

A starting battery's amp-hour, on the other hand, is normally rated at 10Hr due to the fact that they’re used faster. 

The faster a battery is used, the more its Ampere hour rating declines. Batteries that get drained more quickly have less overall available amperage, this is known as the Peukert effect.  Draining it frequently will, of course, have a significant effect on the battery life.

Frequently Asked Questions:

How to determine the amp hours in a battery?

You have to determine the watts to be able to calculate the amp-hour at the battery voltage. Assume you want to use an inverter to power a 250 watt 110VAC light bulb for 5 hours. Amp-hours = watt-hours / 12 volts = 1470 / 12 = 122.5 amp-hours

To know more about a battery's storage capacity, check this video out

How long does a marine battery supply power?

The number of charge cycles can vary greatly depending on whether an AGM, Gel, Lead-acid, or Lithium battery is used. Using a battery on a regular basis will help it last longer. If you recharge your batteries on a regular basis, they can last up to 4 years.