Electric car conversion: Project ForkenSwift

[MetroMPG]

Got the EV-1 controller to work.

Couldn't have done it without help - a couple of basic mistakes in my wiring (no surprise there). More to come...

(And feedback from the group...)

Originally Posted by SW

Excellent.

Attaboy, Metro. I knew you could do it. I have been sending you good luck telepathic messages for 2-3 days.

SWEET!

[MetroMPG]

Some more excellent controller news: I got the Cursit to work!

More correctly, someone who is smarter than I am looked at the Club Car golf cart wiring diagram and suggested a way to connect the potentiometer successfully using all 3 wires (normally you just have to use 2 pot wires for motor control).

So! I spun the motor up (and down, and up, and down... ) with the Cursit. So smoooooooooooth. So golf cart-ish. It made me want to pile the batteries on the passenger seat and head for my tee off.

So now the question is: which one to use in the car (they each have their own advantages/disadvantages). Still, it's a good problem to have.

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Testing the EV-1 controller:



Above - laid out in the basement on a piece of cardboard is the entire forklift wiring harness and all its connections & switches, connected to the complete Baker control panel on the desk.



The output was fed into a 36v light for testing. The rod I'm pushing activates the pot, making this the largest and most complicated dimmer switch I've ever used.

[MetroMPG]

Just scored this new old stock 600A DC ammeter on eBay for 18 bucks plus shipping. That's an awesome deal! Ivan priced a similar gauge through his work and it was around $75 CDN - and didn't include the needed shunt.

This thing will basically be the Forkenswift's Game Gauge. The goal is to keep the needle as close to 0 as possible.

You can actually get ScanGauge-like monitors for EVs, but they cost a significant portion of what we already have invested in the car

I'm thinking one (difficult) way to get useful trip data for testing will be to video tape the meter while driving, then playback the tape and note the reading every N seconds for some period. Then average the results. This could be useful for comparing the efficiency of the 2 electronic controllers.

[MetroMPG]

SW replies...

Maybe you could modify the meter with a heated needle and then run some thermal paper past it while driving... j/k

But seriously, if you had a way to make periodic voltage readings with your laptop, you could effectively record the current at intervals by reading the voltage across the shunt (that's what the meter does). Depending on what other measurements you recorded at the same times, you could build some interesting data to play with (like vehicle speed, braking, battery voltage, SOC, etc).

There must be a cornicopia of A-to-D devices you can plug into an RS232 port with which you can take voltage recordings.

[MetroMPG]

Good ideas. Something like this?

http://www.rentron.com/Volt-Meter.htm

It would satisfy the nerd in me to drive both the cheapest AND most instrumented NEV in existence.

Or a DMM with an RS232 output:

http://cgi.ebay.com/Mastech-PC-RS232...QQcmdZViewItem

Too expensive for Project Forkenswift, but I didn't even know they existed until you suggested it.

[MetroMPG]

SW again:

That looks like it would work for a single channel metric.

I'd be very surprised if you'd want to stop there with only the amperage over time w/o reference to what else is simultaneously going on. I was thinking of maybe a 4-channel or 8-channel multiplexed A/D. I'm sure I've tripped over things like that but now that I want one, I'd have to go digging.

EDIT (second try): the example above uses the ADC0831 single-channel 8-bit A/D converter chip. Also in the same family are ADC0834 (4-channel) and ADC0838 (8-channel). The 8-channel can be configured as either 8 directly addressed inputs or 4 differential inputs. That latter may become necessary if you want to measure things on both the high voltage side as well as the 12V system. You definately don't want to make the grounds of those 2 systems common to each other.

[MetroMPG]

More SW smartness:

That site also has an example using the chip for which they're selling the firmware & tools that implements a 4-channel A/D voltage logger. That chip is actually an 8-bit microprocessor with the A/D, and a small amount of program memory built in. It may even have voltage conversion buffers required to convert serial communication to true RS232 (I'm not sure).

In contrast, the 8051 is the chip used in many ECUs (like Honda) and is powerful enough to be useful independent of a PC. It's a faster 8-bit microprocessor, with 4 built-in 8-bit I/O ports but no built-in A/D chip. For that, you'd probably use something like the ADC0838. Serial I/O would be optional but you'd probably want to use one in order to program/debug/data-dump the thing.

[MetroMPG]

Someone suggested SW should consider converting a car... he has a vintage Austin Healey...

I've thought of that. In fact I think it would be too cool to convert one of the AHs I've seen with blown engines (though most of them end up modified with V8s).

I also know the racing history of Donald Healey's cars, and how successful of a roadster icon it became in America. I see both sides of it. I think I'd end up trading my time off between swapping in new running hardware into very very old rolling hardware vs. updating everything between the frame and the pavement. Even a GT6 is atleast a decade more advanced than the Healey whose running gear was designed in the early 1950s.

I'd actually rather send the Healey off to a good home and use it's accrued value to hack up something much easier to provision with parts and will handle as if it was made closer to this century. Maybe a Miata or Z3. I've gotten very spoiled with the handling and reliability of modern cars. Then the biggest limiting factor is battery technology, as it has been for the past 150 years.

I know what you mean about that Siemens AC drive system: the ProEV Impreza has 2 of them in it for 270hp 4wd plus 35+ kW worth of Kokam Li-Ions.

[MetroMPG]

Someone discussing the merits of choosing a more desirable host car...

I want an EV that will make people's loins ache

I want an EV that'll get me to the grocery store and back. So I could buy, um, strip loins. (Oh dear. Does that mean I want an EV that will make cows' loins ache?)

[MetroMPG]

weekend update ...

1) Fixed (epoxied) the speedo cable boss I fubared earlier. Installed the replacement cable from the red car (getting the cluster out was a bit of a pain). Then tested it: made the wheels go 25 km/h

2) Put oil back in the tranny ("previously enjoyed" 5-20 synth from the Blackfly ) ... then noticed it was seeping around one of the axle seals. Crud. Last thing I want is an EV that leaves oily spots on the driveway. That's just too ironic for my tastes.

3) Dug up Jerry's nice clear circuit schematics over at http://evconvert.com. They're so easy to read for an electrical newb like myself. Got together with Ivan and we drew up the Forkenswift's schematic, v 1.0. I'll post it sometime.

4) Tranny & adapter plate are now properly fastened with good size nuts & bolts (no more wing nuts).

5) A friend donated about 20 feet of used 2/0 welding cable - it'll be great for making battery connections.

6) This week: want to pick up a battery load tester, and start looking for 6 or 8 surplus/used batteries. Starting with the forklift co that sold us the Baker.