July 23, 2009
I have been toying around with different power sources, and in my travels have made a few battery packs recently... The problem is, I havn't bought a charger. Awhile ago i got a few samples of Maxim IC MAX712/713 NiMih/NiCad battery charger ic's. I downloaded the datasheet for it here, but I have a few questions.
First, i'm having trouble understanding in the schematic what exactly the "Battery" is for. I'm assuming that the "Load" +/- is where i would actually be placing the battery to be charged, but why the other "Battery" when the whole system will be powered by a wall unit?
Also, it talks about the RSense resistor, "Since V+ shunt regulates to +5V, R1 must be small enough to allow at least 5mA of current into the V+ pin."... Now does this mean that the charger would be trying to trickle charge @ 5mah? Wouldn't it be more efficient to charge for a few hours at 150-300mah?