I'm looking for cheap rechargeable digital camera batteries online, and 2500mah is the most abundant option. In fact, I haven't been able to find any 1300mah nimh batteries, nor 1600mah(which is what the now-dead ones are). I only have about 6 dollars to spare on this at the moment, as that's all I have in my paypal account, so there isn't much else I can do...

active| newest | oldestThe charger puts out 1300mA, so a 2500 mAh battery will take 2500mah/1300ma = 1.92 hours. (see how the units cancel out?)

Think of a charger as the hose filling the buckets.

The charger is rated in flowrate, how much it can put into the battery. Some chargers say 'quick 15 minute charger' but that's just extrapolated from the flowrate and expected size of the battery. Since you can't have a definitive battery size, that 15 minutes is bunk - it all comes down to flow rate and capacity.

Lemonie says below: Since not all battery(s/packs) are created equal voltage, each charger must match the voltage required by the given battery. Analogy again: Voltage is the pressure in the pipe required to raise the 'head' of water to the lip of the bucket. Not enough pressure, you can only fill the bucket partway.

Again, 'amps' being flowrate, not total quantity, you need another factor, TIME, to extrapolate capacity - flowrate times time. 1 amp for 1 hour is one amp-hour. 2 amps for 1 hour is 2 amp hours. 2 amps for 2 hours is 4 amp hours.

Back to our charger, the charger charges at 'x' speed (amps), a battery of 'y' capacity (amp hours), the charge time will be 'y' A(mp)H(ours) / 'x' A(mps) = 'z' H(ours)