I have a plain old mobile DVD player (Apex model PDVD-937). It runs on a single rechargeable battery supplying 1600mAh at 7.4V. I would like to augment it so that it can work for a longer period of time.
I've recently purchased an additional battery that is compatible with the original, albeit supplying only 1000mAh. I would like to wire the two batteries together so that I can enjoy a larger charge (2600mAh?) and longer time for playing DVDs on the device.
Being a complete electronics newbie I am guessing I need to hook the batteries in a series, but I've run into a problem. Each of the two batteries have three wires coming out of it: Red, Black and Yellow/White. Here's what it looks like:
Assuming Black for negative and Red for positive, what is the Yellow/White wire for? How should I setup the two batteries to get the longer operating duration for the device?