backup battery charger

[Al Skierkiewicz]

Originally Posted by eeeeweeezeee

yep, the circut is more than a little flawed. using about 1/3 of the parts in the schematic, I made a small variable power supply today that I am a lot more happy with. now, i just charge that battery however I want (within the margins of ni-cad common sense)

Please note my emphasis in the following rule...
<R49> The 7.2v backup battery may be charged on or off the ROBOT. When off the ROBOT, the battery is to be charged with a 7.2V backup battery charger. When mounted on the ROBOT, the backup battery may be charged from the 12VDC primary battery by using the custom charging circuit available from Innovation First Inc. or any similar charging circuit (note: IFI will provide the design for this circuit on the IFI website, however teams must obtain the parts for this circuit and assemble it themselves). The use of this circuit is strongly encouraged.

NiCad battery technology requires some method of limiting charge current to prevent battery failure. Don't fall into the trap that you need to charge the battery on the robot from the main battery. A few extra battery packs and the IFI wall charger will get you through any competition.