Hello,

I have a 12vbattery 7.2AH. If I loaded it 7.2A, the battery will run out within 1 hour, is that right?
If so, If I loaded it 450mA, will the battery run out in 16 hours?
Thanks for help

-ken

 

Approximately, but never run it completely out or it won't recharge. Also, if you have a constant resistance, the battery voltage will drop as the battery charge falls. That means less and less current will flow.

 

You might note on your battery that it specifies the 10 or 20 hour rate. You might consider a circuit to disengage the load when the battery reaches 10.5 Volts. Of course, that circuit will consume some energy from the battery, lowering the time available for the load.