Questions about battery powered device

[ptewright]

I am thinking of using a battery to replace a 12Vdc adapter to power my robot. (My long wires are getting tangled up all the time). My load draws about 1A. I found a cheap 12Vdc 3.5Ah NiMH rechargeable battery. So I guess that means that the battery can last approx 3.5 hours, correct?
Is there any chips out there that can detect the level of battery left and output a signal to a microprocessor to shut off the entire system if it's below a certain level?
I'm also thinking of having a built-in charger for this battery. Does anyone have a circuit? How do I prevent it from overcharging? Do I keep on monitoring the level and interrupt the charging when it reaches a certain voltage?
Thanks a bunch!

 

[akg]

Is there any chips out there that can detect the level of battery left and output a signal to a microprocessor to shut off the entire system if it's below a certain level?

y u need chip for that? , when a comparator can generate an INT to the micro.

I'm also thinking of having a built-in charger for this battery. Does anyone have a circuit? How do I prevent it from overcharging? Do I keep on monitoring the level and interrupt the charging when it reaches a certain voltage?
Thanks a bunch!

lots when i googled.. find the one suited for u.