Parts, Trade Show
11/11/95Two things are happening at this point, neither of which make for good pictures or diagrams. I'm ordering some miscellaneous parts and next week I'm going to the NESEA Sustainable Transportation Show in Rhode Island. At the show I hope to see all of the EVs produced by the professionals (many of whom do it for a living) as well as the latest technology and parts being offered.
I've ordered the E-Meter, an electric heater kit, and a vacuum assist pump (for the brakes). Most of the new parts I've ordered will help me get the dash back together and finish any other wiring in that area. Unfortunately the nice little spot I had pegged for the ammeter didn't work out (too little), so I'm back to trying out other areas. While I was in the neighborhood I removed the fuel and engine temperature meters and replaced them with a perfectly matched, highly precise, black plastic cover (a cut up 5 1/4 inch floppy): very elegant.
The old fuel and engine temperature meters are pretty interesting in that they use bimetal, a metal which has a memory. The more you heat up this metal the more it bends back to where it "remembers" it used to be. To use it as a fuel gauge, for example, you put a sensor in the fuel tank that varies the resistance in a circuit: the more fuel in the tank the less the resistance. This resistance is in line with some special wires that are wrapped around the bimetal; when the resistance is low, the wire heats up and causes the metal to bend more. At the end of the bimetal is a mechanical linkage so that any movement on its part causes the red fuel gauge needle to move up or down.
Here's the fun part: the bimetal doesn't care where the heat comes from so I can now hold this fuel gauge over my wood stove (or a hair dryer) and read up to a half a tank! This would probably explain why sometimes your fuel gauge reads one thing when you get home and then something lower when you go out to start the car the next, cold morning.
I also ordered some parts from an electronics supply store. During my spare time I'm going to futz around with building a key-less control console. Here are the specs for it so far:
In my old truck I developed a remote control starter circuit, which allowed me to arm and start the vehicle from a hundred feet or so. This was great to warm up the engine on cold mornings, plus I built in a timer so it shut down automatically after a few minutes: in case I got delayed. The EV won't need this, but it might be nice to have a similar circuit to momentarily turn on the heater. Since the EV's heater is instantaneous the timer could be set for a much smaller on-time.
12/5/95Went to the show, ordered a controller, took time off during the holidays, got some parts. But let's cover all of this in order:
trans2: personal multi-use EV
The Show: The NESEA show was fun, but not very big. I got a chance to meet a few folks and to see some of the EV offerings. I also drove Ford's EV, a mini-van/station wagon type of thing that runs off of Sodium-Sulphur batteries (operating temp: 600 degrees!) and easily drove the guy from Manchester, NH to Providence, RI (about 120 miles?) with juice to spare. Saw some nice EVs from Solectria, a cute little EV-let called the trans2 (picture above), as well as some of the high school/college vehicles. Gary Flo was there, from Mendomotive in CA, and had the Zapi line of controllers on hand so I got a first hand look.
The Controller: Shortly after the show, after exchanging some email with Gary Flo, I placed an order for the ZAPI H3 controller. The H3 is a regenerative controller as well as supporting a higher current flow. The regen option costs extra in two ways: extra contactors and extra complexity (more connections, pieces, etc..).
The Turkey: was cooked by someone else! We went to a Bed & Breakfast for the holiday and even found enough snow to get in some Cross-Country skiing. Nice break from EVs and Programming.
The Parts: Yesterday I got the parts I ordered from EcoElectric: E-Meter, Ceramic Heater, and Vacuum pump. The ceramic heater is neat, in a geekly way. It has the characteristic that the hotter it gets, the higher its resistance. So it is self regulating: if your fan fails to blow air through the heater core, the heat goes up, resistance goes up, and the heat stops going up. The E-Meter is a nice unit too and the best news is that it FITS (and looks good) in the spot I picked out for it. My only complaint about the E-Meter is that it's primary market probably isn't 100-144vdc EVs, thus you need a few extra parts to make it work which drives up the cost and complexity.
Next: Battery Box Build
© Copyright 1995-2002 Jerry Halstead