Originally Posted by Cubytus
Second thing, I have 2 batteries for the NP4750. Is anyone familiar with Li-Ion technology so I can link them together without harming any of the components ? Contrary to certain 'smart batteries' manufacturers, the NP4750 ones do deliver current even if the controller is not powered. However it may play a role while charging the battery. Not having any further information, I tought about some strategies:
First, just link the positive and negative leads in parallel, and, for recharging, a circuit that just flips the controller on on the "slave" battery
Second, let a more sophisticated circuit "sense" "master" battery level, then connects the second one to the motherboard whenever it reaches a predefined low level. The level could be sensed by detecting wether the battery LED starts flashing.
If this one seems the best solution to me as the function of the batteries are not altered, I don't have enough electronics knowledge to design a flip-flop circuit that would be able to let pass the numerous amperes from the batt. The kind of circuit I'm searching for is a kind of bi-stable relay that would draw only a negligible amount of energy to keep its state, different from a normal relay that needs to be fed electricity to keep on of its states.
Unfortunately... and from my experience, what you propose may involve alot more than just a collection of flip flops and op amps. All in all, it would perhaps be a good exercise from an academic perspective