9v rechargeable battery
 

I bought one 9v 280mah rechargeable battery & charger and now I need to know in how much time I can fully charge it with the included wall charger here the info of it :

Input:110-240V 50/60HZ
Output:1.5V===350MA
9v===30MA

The wall "charger" is likely just a transformer and recitifier. The charge rate is determined by the battery hooked to it and the charge level. Since the output resistance is pretty high (judging by how far the output v drops as the current increases. As such, the actual charge rate varies. But, for a rough estimate, use the 30mA figure. So, 280mAh at 30mA would take over 9 hours. Really though, I would terminate the charge when the battery temp gets over 100*F...

ok thanks for the explanation! do you think I can charge 9v battery with my hobby grade charger ?

How fast do you want to charge them? The cells in there probaby wont take kindly to a very fast charge. If you can adjust your charger to an output of about 600mA then that would be OK and would be about a 30 minute charge. Keep an eye on the temperature of the battery. If it starts to get VERY warm then stop, let it cool, and charge at a slower rate.

I wouldn't even go that high. set the charger as low as it will go...

Yeah, for a 280mAh battery, I'd go as low as 100mA (0.1A) if possible. Even 0.5A is too much IMO.

Really? By fast charge I meant like 5-10 minutes... I used to do that with the older NiCd-celled ones 'cause they can usually handle higher temps. I'm assuming his are NiMH, so I suggested a lower rate.

im back from charging it only 149mah goes thru it and on the battery its say 280mah maybe fake ?

Old?

no brand new

What rate did you charge at? And was it at 0V when you started?

when I started to charge the battery was around 4v I used it to discharge it all the night with my rc car led light and I charged it at 0.10a

Try cycling it a few times. It shouldn't be that far out of spec.