Just bought the AA NimH 2500mAh rechargeable batteries. I recharge them fully.
If I use them for only 10 minutes and then recharge them for another 8 hours, will they be overcharged?

 

Hello,

It depends how the charger works.
A very cheap charger will use a current source and not look at the status of the battery.
A good charger will stop charging when the battery is full and swtich to tickle charging.

Greetings,
Bertus

 

But how do I know that whether it looks at the status of the battery?
The instruction manual says to charge 8.5 hours.
Here also says that it is designed with trickle charge.
You meant trickle charge not tickle, didn't you?
What does trickle charge mean?

 

Btw, the manual didn't say anything about overcharging. So I assume it won't overcharge the batteries no matter how long I charge them? Am I right?

 

Hello,

When the battery is full, the charge is kept by the tickle charge.
If no tickle charge is used the battery will go empty again over time.

Here are two links from the EDUCYPEDIA.
1) one on batteries:
http://www.educypedia.be/electronics/componentbattery.htm
2) one on battery chargers:
http://www.educypedia.be/electronics/circuitsbattery.htm

Greetings,
Bertus

 

Thanks soo much for your time.

 

Just bought the AA NimH 2500mAh rechargeable batteries. I recharge them fully.
If I use them for only 10 minutes and then recharge them for another 8 hours, will they be overcharged?

If you overcharge them for 7 hours and 50 minutes then of course they will be overcharged and might be damaged. If the charging current is high then the battery cells will become too hot which will melt internal plastic insulation.
Energizer has an Applications Note for their Ni-MH batteries and say that a "trickle-charge" should be limited to 1/40th of the battery's capacity, 63mA.

You need a "smart" charger.
It will detect that a battery cell is near full charge and refuse to charge more.
It will limit the current correctly.
It will properly detect a full charge then shut off.
It will detect if a cell is shorted and refuse to try to charge it.
It will detect if the temperature of the cells is too high then shut off.