Fri 31 Jul 2009
Here is a charging fixture that I made today to charge 10 A123 cells at the same time. I machined slots into the wood to keep the copper plates from rotating. There is also a 1/2 inch wide slot under each cell to hold them in place. The power supply is set to 3.70v. Each cell can reach its finishing voltage separately from the others due to a one ohm resistor feeding each cell. The other important thing the resistors allow is that a drained cell can be put into the fixture next to a fully charged one. The charging takes a little longer with the resistors, but it gets them all fully charged equally. Then I can load test them one at a time to see what their capacity really is with a 50 amp load. There are currently 30 cells awaiting testing. A group of 10 cells in parallel will eventually find its way into a module that will replace a nicad cell in the #1 truck. A complete pack will only take up the driver’s side half of the battery box. The trick will be to make a BMS board that will fit on top of the closely spaced cell posts like the nicads have.
Leave a Reply
You must be logged in to post a comment.