Battery Capacity
- Thread starter PiKe
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If I was really concerned about it......measure the volts across the terminals - prob 1.2v for NiMH AAA or AA - put the battery into a torch (or other appliance) with a known power bulb, and time how long it takes to run out of power
2 batteries in series (as in inside a torch) will give you 2.4v. Say the bulb is 0.5 watt
P=V x I
0.5 = 2.4 x I - so amps = 0.21
Say the torch lasts for 6 hours, amp hours = 6 x 0.21 amps = 1.26A =1,260mAh, but that's for 2 batteries so half that for one
Trouble is that there are not too many single battery appliances - that's the reason I used 2 as an example
Dunno if that helps - I'm sure someone will correct my O level physics if I'm wrong - and if I am, I can always write articles for Wiki
2 batteries in series (as in inside a torch) will give you 2.4v. Say the bulb is 0.5 watt
P=V x I
0.5 = 2.4 x I - so amps = 0.21
Say the torch lasts for 6 hours, amp hours = 6 x 0.21 amps = 1.26A =1,260mAh, but that's for 2 batteries so half that for one
Trouble is that there are not too many single battery appliances - that's the reason I used 2 as an example
Dunno if that helps - I'm sure someone will correct my O level physics if I'm wrong - and if I am, I can always write articles for Wiki
A NiHM battery is considered flat when its putting out about 80% of its stated output voltage. They discharge slowly and then the voltage will drop right off suddenly.
What you could do is buy a resistor that would cause the battery to output its rated mHA. You then put the meter across the resistor and monitor the voltage. When the voltage drops to 80% of its rated voltage the battery is considered flat.
You then work out the batteries capacity rating as a percentage against an hour I.E. if it reached 80% voltage after 45 minutes it would be working at 75% capacity.
What you could do is buy a resistor that would cause the battery to output its rated mHA. You then put the meter across the resistor and monitor the voltage. When the voltage drops to 80% of its rated voltage the battery is considered flat.
You then work out the batteries capacity rating as a percentage against an hour I.E. if it reached 80% voltage after 45 minutes it would be working at 75% capacity.
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