MK3EB

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Why MK3EB?

(todo: provide links to web sites for the individuals in this list who have them)

Well, first of all, once upon a time I decided I was going to make a battery management system. That was many years, several battery packs, a drug addiction, two girlfriends, one album, about forty thousand lines of code, and many other things ago.

For some reason even though I know the major automakers are going to come out with the perfect electric vehicle that already has all this done, I feel the need to play with it anyway. At this point, here is my stated goal:

I want to log data into mysql, including amperage and voltage and temp of all the batteries in the car at least once a second.

At some point, Lee Hart created this wonderful optically isolated bus that came to be known as the EVILbus. I'll try and do a write up and schematic of it at some future date, but it's basically RS232 carried over a optically isolated system - it's a two wire bus, and any member of the bus can 'step on' it, kind of like how telephones work. Obviously, any member who wants can jam the bus just by holding it low.

For a long time I just referred to my regs, charging system, etc as being EVILbus hardware. However, as far as I know, no one ever came up with a unified standard for what *data* would appear on the EVILbus - there would seem to be several competing standards. Because the bus is so simple and making glue is so easy in today's world, I no longer think it's that important to have a interoperating standard. Instead, i think the many different implementations are helpful in encouraging creativity.

Even though I named the EVILbus (Electric Vehicle Instrumentation by Lee) I do kind of share Lee's once-offhand-mentioned concern that it might worry some people. As far as I know, I don't promote or support evil. (Actually, there are those that would disagree with me on this, but my definition of good is bringing as much happiness to as many people as possible while hurting as few people as possible. That's what I try to achive. My particular reason for getting involved in EVs is that it seems clear that if some technological changes aren't made, we will have many bloody wars over oil. I am very strongly opposed to war.

Originally, I wanted to make a totally decentralized peer-to-peer kind of system that was collision based. However, various experiences with Rick Woodbury and the Tango battery chargers have taught me that doing peer-to-peer with microcontrollers is prohibitively code-expensive. So, I'm settling for call-and-response.

Because I was supposed to help design Rich Rudman's mk3 battery managers, I continue to call this system 'mk3' even though Bruce Sherry has done a fine job of building those and writing software for them.

Here is a list of all the things I have tried - totally unsuccessfully, so far - in my quest:

  • A system that used a basic stamp, held the packets in shift registers, and used transformer isolation
  • A system that used relays, basically designed based on Lee Hart's relay battery management system, but with all of the safety features removed.
  • The 'mk3' - transformer isolated, based on one of the 44xx-series atmel parts.
  • The 'pk3' - similar to the mk3, only using microchip's PIC instead

This time I've gotten Bruce Sherry to do all the hardware design - it's loosely based on Rudman's mk3 regulators, only it includes a expansion header that will allow me to do other things with the boards than just be battery regulaters. Eventually I hope to convince Lee Hart to build a expansion board (or help me build one) that uses his nifty flying-cap trick to move power around, so that I will have a N-way-to-N-way power shuttling system.

I don't deny that there are many fine systems out there that beat the pants off of mine, including Victor Tikhonov's. However, at this point I'm really frustrated with my inability to complete this project for so many years, and I'm determined that I'm going to do it even if it is basically completely without commercial value.

Someday I would like to revisit this problem using transformer isolation again (ethernet transformers come to mind) and CAN. However, I figure it's a good idea to walk before I run.

Anyway, to bring this back to the original topic - mk3eb is a MK3 style reg with EVILbus. MK3EB just doesn't set off my heckles concerning good and evil as much, so I'm calling the project that.

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