Battery power

[camioneur]

Any physics buffs tell me why new cheap batteries that measure 1.5V output across my voltmeter will not run my digi camera but expensive ones that measure exactly the same acrooss my voltmeter do? On the same subject, my Uniross rechargeables don't recharge to 1.5V, they come out of the charger at 1.4V to 1.45V but never 1.5V and they're all the same so it can't be battery age. Could it be the charger and what voltage should they come out of the charger after a 12 hour charge? thanks

[OBonio]

You shouldn't be looking at the voltage as a measurement for how long a battery lasts. Milliamps per hour I think what should be looked at. The latest NiMH batteries are about 3500 mA/h. The old alkali based one's will be a LOT lower than this.

[Space]

most rechargeable batteries have a voltage of 1.2V, although they have the same size and denomination ( "AA" , for example ) as the 1.5 V non-rechargeable ones.

[qapmoc]

The problem is due to the internal resistance of the different types of batteries, the internal resistence on cheapo batteries is higer than on good ones, you are measuring them without load and the voltage is the same, but when you load them the voltage will drop more on the cheapo batteries than on the good ones.

Volts (drop in this case) = Amps X Ohms so the higher the int res of a battery the higher the internal volt drop and the less voltage that appears at the terminals.

[wilsarnie]

I was a tight @rse once and bought Tesco Value batteries. I used them in my digi camera. They lasted 9 1/2 minutes. I won't be so cheap next time.

[tony1941]

The best value non-rechargable AA size batteries around are the IKEA branded ones (made by Varta, a serious maker of industrial batteries). A pack of ten costs well under �2 and I find that they will run my digital camera and also a large professional flashgun almost as long as a single charge of some NiMH ones