Electric conversion: Project ForkenSwiift - Page 31

Silveredwings · 01-05-2007, 08:45 AM

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 · 01-05-2007, 08:49 AM

PS - did you get the Healey going yet?

Silveredwings · 01-05-2007, 09:25 AM

No but thanks for asking. BTW, your progress inspires me every day.

Now that I'm nearly done with the holidaze (family-shared illnesses notwithstanding), I expect to get back to it soon.

Silveredwings · 01-05-2007, 11:29 AM

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.

The Toecutter · 01-05-2007, 06:01 PM

Instrumentation is nice and all, and perfect for your application, but I'm going to try to keep it to a minimum in my conversion. I want an EV that will make people's loins ache, and not a rolling science project. Imagine the thought of rolling around in the ghettos of St. Louis in one dope ****ing ride, and that ride also being electric powered.

Silveredwings, you should convert the Healey. It might sound blasphemous, but the car has a lot going for it. It lends itself to extensive aeromods without greatly harming the aesthetic appeal, it's lightweight, and has small frontal area. not to mention, the battery room would be pretty decent with all the IC-related components removed.

Metrompg, I think you might be interested in Peter Ohler's EV palm pilot:

http://www.ohler.com/palm/EVDash.html

Victor Tikhonov simply uses a labtop to take his data, but he has all those fancy Siemens and Brusa components for his CRX.

Just the Siemens motor/inverter is more than 8 times the budget of your entire conversion. 107 HP AC motor/inverter combination, revs up to 9,700 rpm. This gives his CRX 0-60 mph in about 9 seconds or so and a theoretical top speed over 130 mph. He scored a set of Ovonic NiMH that supposedly give him about 150 miles highway range or so.

Silveredwings · 01-05-2007, 08:04 PM

Quote:

Originally Posted by The Toecutter

Silveredwings, you should convert the Healey. It might sound blasphemous, but the car has a lot going for it. It lends itself to extensive aeromods without greatly harming the aesthetic appeal, it's lightweight, and has small frontal area. not to mention, the battery room would be pretty decent with all the IC-related components removed.

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.

The Toecutter · 01-05-2007, 08:14 PM

Battery technology has evolved a huge amount in the past 15 years. Due to politics and lack of automotive volume, EV builders just don't have ready access to an affordable battery capable of providing long range and long life.

I've thought of going to the dark side and lowering a smallblock Chevy into my Triumph, but I want to get off of using gasoline too badly. But the raw power of a V8 in a tiny little British car is something that commands my respect. After all, there's not many cheaper ways to get you down the 1/4 mile in under 11 seconds, while still getting over 20 mpg...