I bought this battery pack from a local guy who didn't know anything about it or have any details about where it originated, other than the vehicle was wrecked. The pictures indicate the exact condition I received it in. He says the car drove (mostly) before it was removed. There are 6 cells missing, and these strange aftermarket boards installed all over it. Can anyone explain what's going on? I really only bought it for the cells so I can have spares for my own battery, but if these little boards are useful for anything I'd like to know. Each board has an m430f1232 microprocessor (Texas Instruments), a PS2502-2 opto-coupler, a small reed relay and a few other discrete components. They are very obviously hand assembled. On the back of the board it says "J. Connor M. Himojosa". Each one is hand numbered. -Michael
The MSP430 series from Texas Instruments is a good, auto-grade part. Without tracing everything, it looks like a home-made, charge monitoring and possibly charge topping system. It looks like an evaluation board but I can't be sure. The newer MSP430s are much smaller and can be bought on a daughter board: MSP430 Timer Demo Temperature Recorder NHW11 Prius Temperature Hack It might make sense to see if you can trace back to the owner and find out if they have any more technical details. It is a dandy part. Bob Wilson
The story I was told (if you choose to believe it) was that a local company purchased about a dozen Prius cars of various ages for crash testing as part of some program. They hired a contractor to remove the batteries beforehand for safety reasons. That contractor wasn't instructed what to do with the batteries, and knowing nothing about them, sold them to me. It's unlikely I'd ever be able to find out who owned the car originally. I was told this particular vehicle was "yellow and blue" and "had a fin", but googling hasn't turned up anything helpful. Unfortunately, these batteries all seem to be in pretty bad shape. I'm having difficulty getting any of my chargers to recharge the cells. I need to find something to clamp these things into because they keep swelling up. Everything I've got is geared for working on LiPo batteries, and I'm not familiar with a NiMH system. As for the little boards, it doesn't look like my universal programmer works on these microcontrollers. I might order one so I can see if I can recover a copy of the program and see what it's doing. Worse case maybe I can set them aside and use them for something later. -Michael
Thanks, makes more sense btw, where is "here?" The 'fin' makes sense as they probably had some sort telemetry setup. The NiMH cells are tricky to charge but you'll never get LiON energy densities. If you don't have a NiMH aware, smart charger, at least clamp the maximum module charge to 8V and in cycle-charging, no lower than 6V. Until you see appreciable charge returning, keep it in the 50-100ma range. Later, you can increase the amps. You might contact "ReInVolt" in Summit NC as they are always interested in traction battery shells and electronics. They rebuild them using modern modules and I know they are not interested in the NHW11 style modules. There may be other traction battery rebuilders also interested but I've done business with ReInVolt and have one in our 2003 Prius. TI sell a nice, USB based unit used with the smaller MSP430: MSP430 USB Stick Development Tool - EZ430-F2013 - TI Tool Folder You'll probably have to rig up an adapter cable to fit the 4-wires which includes power. A very nice part and the software 'doesn't s*ck'. I'll be using it for my next project. Bob Wilson
When I'm working with LiPo batteries, I typically use a programmable bench power supply and a quick script to log the charging characteristics and cut power once it believes it's fully charged. I tried to charge the Prius cells the same way, at around 8 volts. The voltage comes up pretty quick, then they just sit there pulling 80-100ma, which for a LiPo signals the battery is done taking a charge. I have an IMAX B6 charger that's supposed to do NiMH batteries, but it doesn't give me a method to enter any parameters, and seems to enjoy charging the cell at 10V+. I didn't know if that was part of the normal method to charge these. Either way, it causes the cell to swell up. Unfortunately, most of the shells and wiring have been cut up. It looks like after a while he got tired of unbolting stuff and used a grinder on them. Even the "good" ones are bent to the point I doubt anyone wants them. I do have a bunch of battery computer modules now, though. I might keep one to play with and sell the rest. If I can get the cells to charge they're more valuable to me for other projects. -Michael
