[ewdysar]

Originally Posted by Tesseract

...Oddly enough, I totally agree with you. Most conversions do come off as science experiments, mainly because the people are so obsessed with doing them as cheaply as possible. We sorta sidestepped that entire mentality with the Soliton1 and concentrated instead on performance (trying to compete with the Kelly's of the world is a sucker's game).

Now, back on topic... cruise control was considered a luxury option on many vehicles until just a couple years ago, so your surprise that it isn't included in EV motor controllers is what struck me as a bit disingenuous. Sure it only requires adding lines of code to the software that, e.g., runs the Soliton1 to implement cruise control, but the code is already over 5500 lines long and that is quite an achievement for a single man (Qer) to accomplish in about 2 years while working full time at a "real job".

All that said, we were thinking of offloading cruise control into a separate box that also expanded the auxiliary I/O, so that only people that really wanted CC had to pay for it. Interfacing with the existing CC system, though, is pretty much not an option. There's just too many variations on that theme from brand to brand and even model to model within a brand. Also, we have learned the hard way that just getting a modern vehicle to still behave properly after the engine has been removed is sometimes extremely difficult. Once again, rebirthev.com has quite a bit of experience with those sorts of problems - probably more experience than they ever wanted to acquire.

Bottom line: it's not trivial, it's not easy, and the market is way too small (but that was true for motor controllers in the first place... )

Tesseract,

Thanks for taking the time to write the explanation(s) in this post. I now have a better apprieciation for how much effort a CC module would be. The funny thing is that I sold my '90 Geo Metro, which I had bought new, primarily because it didn't have CC or power windows. The car was in great shape, 6 years old with 130,000 miles with no major repairs and a lifetime gas mileage average of over 52mpg. I had no idea that 20 years later, there would be zero new cars available that would deliver the same mileage.

Like I've said in other posts, I use CC all the time, so if I do build an EV in the near future, CC is one of the features that I'll try to work out. Because I've got a full time job and a number of other hobbies, sailing (including offshore racing), blacksmithing, woodworking, medeival research, camping, etc., I don't want my conversion to be a science experiment. I want off the shelf parts and fully expect to spend $20k in the conversion, more than half would be the batteries. I'm not afraid of some general fabrication, but I don't have a thousand hours to spend dicking around with little issues. I know from working on a half dozen EV conversions back in the '90s and a few race car builds that the big issues are time consuming enough.

Anyway, thanks again for the answers. I couldn't find anything with as much value on this topic in hours of searching previous posts.

Eric

[coulombKid]

Originally Posted by ewdysar

Tesseract,

Thanks for taking the time to write the explanation(s) in this post. I now have a better apprieciation for how much effort a CC module would be. The funny thing is that I sold my '90 Geo Metro, which I had bought new, primarily because it didn't have CC or power windows. The car was in great shape, 6 years old with 130,000 miles with no major repairs and a lifetime gas mileage average of over 52mpg. I had no idea that 20 years later, there would be zero new cars available that would deliver the same mileage.

Like I've said in other posts, I use CC all the time, so if I do build an EV in the near future, CC is one of the features that I'll try to work out. Because I've got a full time job and a number of other hobbies, sailing (including offshore racing), blacksmithing, woodworking, medeival research, camping, etc., I don't want my conversion to be a science experiment. I want off the shelf parts and fully expect to spend $20k in the conversion, more than half would be the batteries. I'm not afraid of some general fabrication, but I don't have a thousand hours to spend dicking around with little issues. I know from working on a half dozen EV conversions back in the '90s and a few race car builds that the big issues are time consuming enough.

Anyway, thanks again for the answers. I couldn't find anything with as much value on this topic in hours of searching previous posts.

Eric

When I put cruise control on my 1964 pick-up I got a dirt-simple vacuum servo unit from JC Whitney. I had to put two magnets on the drive shaft and mount a pick-up coil. If you have a vacuum pump and tank for your power brakes then the vacuum-servo pull cable could be attached to your hall effect accelerator fairly easily. The rest would be all the same.

[drgrieve]

An idea I picked from somewhere.

By using regen on the throttle and the in built CC module controlling a drive by wire throttle output in theory you shouldn't have to do anything and as a bonus it would be better than stock CC as you'd be kept to speed limit on downhills.

But at the moment since EV's are not usually long range cruisers CC would be a low prority feature for me.

[charliehorse55]

rebirthev.com seems to be down for me...

[Tesseract]

This is an old thread and I think the site has changed since then - try http://rebirthauto.com/

[charliehorse55]

Originally Posted by Tesseract

This is an old thread and I think the site has changed since then - try http://rebirthauto.com/

I see nothing but a store. Where can I read about their experience with vehicle computer systems and the like?

[Tesseract]

Originally Posted by charliehorse55

I see nothing but a store. Where can I read about their experience with vehicle computer systems and the like?

That isn't posted to the web. Where did you get the impression that it was?

[Jamie EV]

Why is it not possible to simply utillize the second cruise control servo wire and run it into the pot box along side the regular pedal cable?

My Elantra has a servo actuated cable that opens the butterfly valve...I'm thinking that if it takes speed and throttle readings from the existing tranny, and it is able to actuate the caBLE...IT SHOULD mate to the pot box the same way as the pedal cable does.

Am I way off base on that? Might take some figuring out but it would be a shame to reinvent the wheel when the car already has it...in my case.

[Tesseract]

Originally Posted by Jamie EV

Why is it not possible to simply utillize the second cruise control servo wire and run it into the pot box along side the regular pedal cable? ...

It is possible, as long as the ECU (engine control unit) is still happy after you've, you know, yanked out the engine...

Also, your EV motor controller needs to use a 0-5V signal for the throttle, and the signal from the original TPS (throttle position sensor) needs to increase with the opening of the butterfly valve (often there are two channels on the TPS and sometimes one of those channels goes down as the valve is opened up - that won't give you the expected results, to put it mildly).

[Jamie EV]

Originally Posted by Tesseract

It is possible, as long as the ECU (engine control unit) is still happy after you've, you know, yanked out the engine...

Also, your EV motor controller needs to use a 0-5V signal for the throttle, and the signal from the original TPS (throttle position sensor) needs to increase with the opening of the butterfly valve (often there are two channels on the TPS and sometimes one of those channels goes down as the valve is opened up - that won't give you the expected results, to put it mildly).

well failing that, a simple comparator circuit could be used to store the pot position and then lock it. Sort of a "sample and hold" type deal that you could hit with a button, freeze your pedal position, it would disengage the moment you hit the brakes.

Alternatively, if you were to create an encoder wheel on the speedometer, you could create a more sophisticated logic gate that increases throttle when speed drops below the sample and throttles back when speed drops below the speedo sample....

much easier to program this on a small computer than it is to build a gate from scratch either way it's not my forte... I have programmed simple sample and hold...maybe there's a simpler way with ttl or cmos gates.