As far as the diode is concerned, you need to test any given charger to see if it has been included as part of the design. Some chargers include it and some don't. Some will have a diode but will have a resistor divider so they can measure the battery voltage after the diode. You will need to test. Put an amp meter in series with the battery and watch what happens when you unplug the charger. It may begin to drain the battery or it may not... if it doesn't then you don't have to worry about it. Charge time depends on how deep you let the battery discharge. You are correct with your math(s)! Let us know how you work things out... Josh Koffman wrote: > On Wed, Nov 25, 2009 at 1:50 PM, M.L. wrote: >> It depends on how "smart" the chargers are. If they have any smarts >> at all, they will cut out at a voltage somewhere close to 14 volts. >> So no, your batteries will never get fully charged if you put a >> diode in series with the charger. > > Ok, no diode. I'll work something out with a switch for this > prototype and we'll see what happens in the final. > > These chargers seem somewhat smart, so they'll switch from fast > charge to float when the battery is nearing capacity. If that's the > case, how can I estimate charging time? My pack will be 7AH. Given a > charger of 750mA should it take roughly 10 hours to charge? If I went > with the 1.25A model would it then take about 5.5 hours? > > Thanks! > > Josh -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist