SheerQM
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Quantum Mechanic
QM is a AC-drive Honda Accord converted by a alternative fuels class at Saddleback College. The funding for the project was provided by Sheer Pullen, most of the hardware was provided by Metric Mind Engineering and EV Parts.
QM is a testbed for Sheer Pullen's Battery Management experiments. As such, the car has already been through three battery packs, and is likely to go through many more before being replaced.
QM has a entry in the EV photo album. It is car #338.
Battery History of QM
- ) Original pack - the first pack was a test pack of hawker cyclons purchased from All Electronics Corperation for $750. This 250V pack was supremely unreliable, but was good enough to move the car around and onto tow trucks and whatnot. When fully operational, the cyclon pack provided truly impressive acceleration, as it only weighed a few hundred pounds. This pack was charged with 4 individual 12V chargers, moving them from sixpack of batteries to sixpack of batteries. Operating range was approximately 6 miles.
- ) First operational pack - The first pack used for actual driving was a pack of Evercel nickel-zinc batteries. When first installed, these gave the car a operating range of somewhere between 80 and 120 miles (depending mostly on terrain). The batteries quickly degraded, partially due to limits of the technology and partially due to buggy battery management software. These batteries had three different battery management systems connected to them at various points - a Lee Hart style relay balancer, a Rudman Mk2 array, and a MK3 array that is infamous for having exploded. The software failure that damaged the batteries was actually in the charger controller, rather than any of the battery probes.
- ) Second operational pack - The current pack, being used to debug the MK3 v II system, is a pack of 56AH (nominal) lead acid batteries. (PowerSonic PG12V55) I hope that these will only be in the car for a year or so, after which I hope to replace them with another nickel-based battery. Their primary purpose is to provide me a platform for getting all the bugs out of my management software, and also improving the hardware of the high voltage system until I feel completely comfortable with it.
Other modifications of QM
- ) Inverter placement modification - 2004
In 2004 the inverter was moved from being attached to the transaxle, adapter, and motor (and thusly moving with them whenever they moved during acceleration) to being attached to the firewall at the top, and the radiator mounts at the bottom. The new placement enabled me to get more batteries into the front of the car, and also made the entire system more maintainable.
- ) Cooling loop rework - Nov 2006
As part of installing the new batteries, several improvements were made to the cooling loop in the hopes that they would prevent air lock of the loop. They did not, and I'm currently considering what other improvements to make. One option that is looking tempting is the replacement of the cooling system water pump
These improvements include replacing most of the rubber hose with PVC, the addition of a tap at the topmost portion of the loop for 'burping' the system, and rerouting the hoses to remove several of the bends in them.
- ) High Voltage System rework - in progress
This project involves replacing some of the high voltage wiring. Improvements will focus on safety and maintainability. It also involves wiring in a BatMod.
- ) Battery Management rework - in progress
This project involves installing the MK3 networkable battery probes in the car. A prerequisite is having working code for the MK3s that includes a workable and reliable bootloader.
Other resources about QM
The car's original web page can be found at sheer.us. It includes barely sorted links to pictures, half-drawn schematics, and is generally not a very impressive bit of work. I hope that this wiki page will be better able to document the car.
