[eugenebrooks]

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Originally Posted by Venkatesh
I have a question for the electrical wizards out there. How would a charging system be properly designed to charge multiple batteries at one? I would think a nicely setup diode layout would prevent one battery trying to charge another, even if there was a chance for something like that.
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The proper way to do it is to route a suitable supply through a Unitrode 3906 charge controller, set up with a pass transistor capable of handling the charge current and power dissipation requirements. As noted earlier, you can use a common supply and a separate 3906 and pass transistor for each battery. The 3906 has battery charge status indicators that can be set up on leds. We used two of the exide chargers this year with 50 amp connectors attached. We ran into problems with not enough batteries in the finals, and problems with chargers getting unplugged and students not reading the leds on them carefully. We will address the issue with a multi-battery charging bank design over the summer. It would have to be a custom design using a high power darlington pass transistor, the available unitrode 3906 designs on the web run at lower charge currents.