Tuesday, December 14, 2010

2009 Mini Cooper Clubman Electric and the Rinehart Motion Systems Controller

This week, we kind of sort of wrapped up the Mini Cooper Clubman and are now driving it. Which is quite fortunate in that it was 9 degrees Fahrenheit here this morning - a bit brisk. Cape Girardeau Missouri is blessed with four full 3 month long seasons and the spring and fall are truly a delight. Summer and winter less so. In July it's 100 degrees F and often 80% humidity and we fat boys suffer terribly in the heat.

But the other end of all that is December. The days are so short it is dark by 4:30PM and it can get quite cold. Not Minnesota cold, but cold nonetheless.

We do love the little sports cars. And in the spring and the fall they are deadly weapons of romantic mayhem. But in July, and again in December/January, they are pretty much useless.

We found the Canadian EV heater assembly almost useless. It seemed like a good idea in July when we installed it and Randy Holmes of Canadian EV assured us that this single element heater would somehow be adequate because it was a "special voltage". We never did get together on what that meant or how it could be adequate, but he IS in Canada after all.

Anyway, in December, it was a joke. The show this week was delayed until Monday, largely because I wound up with a 3 hour show. So we cut the heater section and a thing on the Roving Networks instrumentation and got it down to 2. I'll try to include those sections this next week - or sometime.

In any event, and with any level of heat, the Speedster is a seasonal toy car. Bottom line, top line, whatever line, that's the gig. It's great in Spring and Fall, but air conditioning OR heating a small convertible like this is a losing battle however heroically approached.

The ultimate summer and winter car is of course the Cadillac Escalade EXT. And we do have plans to convert it, but his majesty Mr. Jim Husted has taken our project of twin eleven inch Netgains and made it a career move. We'll get them someday. And I'm not going to disable the car until we do. We already have the transmission. But with new battery announcements just around the corner, and this thing requiring a massive 67kWh pack, we'll do that with nextgen batteries.

That leaves the Mini Cooper. We have made some encouraging progress. I guess it's always easier the second time around. We did revise our adapter to include the magnetic pulse pickup from the original engine, and now have a fully functional tachometer, and this has awakened our DME and more importantly, our power steering. Unfortunately, when the RPM falls below 600, after just five or six seconds the power steering kicks out. The ONLY place I need this electric power assist is in parking - typically when creeping along at about 40 rpm. So I have to put in the clutch and REV the motor to get the steering to kick in. ANd I have to do that every few seconds. But it does work.

And it IS nice to have the tach work. Far from a marginal dial in the corner of the car, this tachometer is quite large and centered on the steering wheel. I found it very annoying that it lay there dead.

I actually had some success getting working with the TIMS600 controller by stealing the encoder signal input to the controller. In trying to get it to "work better" I tried several different circuits, and finally loaded it to the point the controller lost encoder input and blew up an IGBT trying to run the motor with errant information.

We had no idea how to fix it, no support whatsoever from either the manufacturer or Metric Mind, where we bought it. Victor has never actually even run one of these controllers or motors for that matter. And the company is in Switzerland and has no interest in supporting it. I found we could order one from a European EV supplier and have it shipped to the states - 12 weeks later.

So we had seen Rinehart Motion Systems PM100DX become available on David Kois web site in a package with a Ford Siemens motor. This is a 100kW controller with a 300v and 600v versions available. And they are in Wilsonville Oregon - they speak English, and in theory might support their product.

They were not too keen on the project initially. We use an MES-DEA 200-250 motor. While not unheard of, it is expensive, and problematical. RMS support for motors is achieved rather by hand - they have to manually tune the parameters to the controller - somewhat by guess - and check the results on a dyno. So we had to ship them our motor. They had to MAKE an adapter for it to put it on the dyno. And while it does give them known support for another motor, how many 200-250's are out there? Actually a few, but not many.

In any event, incredibly they had us a controller and returned our motor in a WEEK. Not bad. Actually, it was phenomenal in this business. I dont' think we've ever gotten ANYTHING in a week.

In tearing down the system, we found some pretty serious damage to the off end mount, the clutch, and incredibly the shaft coupler. The coupler was actually TWISTED and discolored. This had been machined from a solid 4 inch round billet of 4045 hardened steel.

While we were fixing all that, Matthew Hauber thought little of our mid mount "belly band" and devised a much sturdier one of steel.

We built the car back up and installed the RMS 100kw unit.

I will NOT say the installation went smoothly or that this is a device for the novice. Just downloading and installing and configuring the sofware on a Windoze notebook was a bit of a challenge. The variables and indeed the thinking behind the Rinehart is a bit different from what we've done before. And it required some changes to the control wiring.

For example, we had to add a separate precharge relay. The Rinehart uses this relay to precharge the input capacitors through our 500 ohm 25 watt precharge resistor. Then, IT switches the contactor on. We had previously just run the contactor from switched 12v.

While a little more complicated, this is certainly a good system and I would rate it as vastly improved over what we were doing.

Kind of oddly, the unit wants a GROUND as a brake signal for when you put on the foot brake. On all cars I'm aware of, the brake switch puts out 12v. In our case, both the throttle voltage and the brake signal derive from the DME anyway, not from the actual brake switch. But it is of course a +12v signal when you apply the brakes.

I had to build a little box with a MOSFET and three resistors in it. Basically, the drain of the MOSFET is tied to +12v through a current limiting resistor. The junction of the resistor /MOSFET is provided as the output and with the MOSFET off this will be +12v.

The source of the MOSFET is tied to ground. The 12v brake signal is applied to the gate whenever the pedal is applied and causes the MOSFET to go into conduction. MOSFETS have very low forward resistance, and indeed this was an 80 amp MOSFET I had laying around that is also quite fast. Gross overkill, but it should last. When the MOSFET conducts, the output drops to ground. And the RMS appears to be sastisfied with this arrangement.

The RMS has a software startup sequence we found a little peculiar. It has the usual FORWARD and REVERSE 12v inputs. But it REQUIRES both to be at ground during startup. It THEN requires a BRAKE signal and the appropriate FORWARD or REVERSE to appear simultaneously to complete its startup sequence.

i normally just wire FORWARD to 12v, leave REVERSE disconnected, and use the transmission to backup. The advantage being that I can cycle the controller while rolling down the road - occasionally a nice function if it trips out for some reason but can be reset to operation. I've done this with the Curtis 1238 and a Kelly controller quite successfully. It also worked with the TIMS600, but the DME has some requirements to do a cycle as well.

In any event, we wired a single pole double throw toggle switch (surprisingly rare to find). But if you switch into forward or reverse in the wrong order, or without the brake applied, it not only doesn't respond But it seems you have to reset it and go through the sequence again. This is NOT natural or OK frankly. If you don't actually "know" to do all this, you'll never get the car going and I rate it a human factors faux pas.

It probably does have some salutory safety merits, but not many.

We did notice that they had some unused digital inputs. And we requested that they do some software changes to let us use this with a switched ground input to disable all regenerative braking. We don't actually have this feature on the Curtis 1238, but did have on the TIMS600. And I liked it. In inclement weather, I'm a little uneasy with regen. It is only applied to the front wheels, and you have less control of your braking, and are actually braking when you take your foot off the accelerator. On ice, this doesn't sound like a good idea. I haven't actually tried it yet, but it would seem even a little braking action on the front wheels on glare ice, performed by the not very active action of REMOVING your foot from the accelerator, is a disaster in the making.

They revised their software to include this feature. If you apply a ground to digital input 4 it will disable regen entirely. In the video, I noted that it only disabled accelerator regen, but I've already gotten a firmware update fixing it.

Along the way, we've had four or five phone calls, a dozen e-mails, and three firmware updates. Chris Brune is very calm, very professional, not at all in the "you guys are a bunch of idiots" camp I run into so often. Very helpful and very professional.

Is this controller ready for prime time? The fit and finish mechanically is just GORGEOUS. We're driving the car and it makes not only good power, but it feels more "appropriate" to the Mini Cooper than what we had, which was probably overkill. We're running 340 volts now at up to 300 amps and generally under 100kw, which is what this is rated for.

My take is that it is kind of in a prototype stage. This is four or five guys, struggling for life in a kind of hostile world, with a limited market. They build few. And so the pricing is very high, and very mercurial. The unit lists for an astronomical $9500. They sold us ours for $6500. And they allude to a deal with Remy that could get them into "production' more in the $4500 mark. So I can't make it out. I don't know what it is or what it might be so it's kind of hard to talk about value. I paid it gladly.

The configuration software is plain but quite well done. It will take a little getting used to and you do have to RTFM. But once accustomed to it, I like it. I found some of the variables a little bizarre and a little immature. We have GREAT configuration options on the accelerator, and almost NONE on the braking regen for example. But it is all software and as I said, we had three firmware upgrades in a month for this project. It will certainly get there.

On a broader front, I find the 650v AC solutions simply impractical for an EV. None of the peripheral items, DC-DC converters, water heaters, air conditioner compressors, etc can work at those voltages. While Rinehart has a 600v version of this controller, we found the 300v (up to 360v) perfect for this application.

So while it felt a little like we were on the beta team, and while I would admonish that "some assembly is required" and a complete novice probably does NOT want to use this controller. But that said, I'm kind of picturing a package with a Remy or other motor, with the whole gig somewhere this side of $10K, as being quite viable. The 100kw is PLENTY of power for a 3500-4000 lb vehicle if you have no NEDRA aspirations. Obviously in a sports car it WOULD be competitive. A Speedster with this in it would just be over the edge.

I think if these guys has a few installations of this controller and an appropriate motor out there to waive the flag publicly and work out a few of the software issues, it has a GREAT future.

A very interesting aside, and part of the reason I'm so impressed with this device, goes to our heat redux. We had a TREMENDOUS amount of heat from the TIMS600 and MES-DEA motor. It was incredible. We actually used the MINI radiator to cool it and found we had to turn on the radiator FAN to adequately cool it.

Same motor with the RMS PM100DX barely gets warm. Now it IS true we went from a 375v 400AMP system to a 340V 300 amp configuration. But the change in heat was dramatic. I'm guess that in addition to being 25% smaller, this controller is also much more efficient.

And that allowed us a very interesting experiment. We SHITCANNED the Mezzier pump and BUNCH of expensive Summit Racing hose work, along with a complicated fill and bleed procedure. We took the pump output of our 4kw heater, which comes from the heater core, and routed that through the controlller first, the motor second (both are liquid cooled) and thence back to the 4kw heater bottle which feeds the heater core.

This little loop is both interesting, and very unlikely to be effective. The heater core of course has a temperature drop, winter or summer, on or off. So it SEEMS adequate to cool the drive train - of course it does in December. We'll SEE next July.

We rewired the pump to run whenever the ignition is on. But kept the heater elements on a manual switch.

So I can drive down the road and get a very modest amount of heat from the motor and controller - more on the highway of course. And if I need more, I can turn on the 4kw heater element.

Now this is a bit counterintuitive. Our heater doesn't work as well as it did. It is actually HEATING the controller and motor, and the loop is bigger with more coolant in it. So it takes longer to get up to temperature. But at 8F, we are still getting a pretty warm car I would say in five or seven minutes. Previously three minutes. It's very nice after 10 minutes.

The heater is hard set at about 65C. Of course, there IS a pretty good temperature drop across the heater core. The Mini heater is quite efficient at extracting heat from this core. So I would guess the temps coming OUT of the heater core are a good 15C below that or 50C. With good flow, the RMS is rated at an inlet temperature up to 80C. The motor frankly doesn't matter at these power levels. So with the heater on, and after running for a few minutes, I think we're going IN to the heater core at 65C, coming out of heater core and into RMS at 50C, and coming out of RMS and MOTOR into heater back at about 60-65C.

This very unlikely system seems to work very well at this point. It remains to be seen if it can "hold water" in the summer.

Of course, in the summer we would never have the heater element on. But with the heater fan off (or diverter to A/C) we are not going to get as much temp drop across the heater core as well. I'm hoping for 10C. With a 40C ambient, (hot day) whether or not 10C cooling will keep the controller under 80C is a big question. I'm guessing at this point that it will. But we'll just have to test it to find out.

If NOT, we'll have to have a summer rig with a little heat exchanger that can be cut into the loop between the pump and the controller input. This is not a hard "get well" in any event - almost trivial.

So the good news is that the Mini Cooper drives well and that it heats/cools within parameters. And actually the heater, which you would not say "will run you out of here" it is comfortable on very cold days.

And unlike the Speedster, we have all the other creature comforts. Bluetooth phone, HEATED seat warmers, Sirius Satellite Radio, windshield washers, EFFECTIVE windshield wipers (actually I think we even have headlight washers and wipers) all the comforts of home and a modern automobile.

The Mini Cooper has been a much more complicated project than we bought into and a much more expensive one. We undoubtedly have $75K in this car at this point - but I think we did better than BMW on the expense side.

Rate Rinhart Motion Systems and the PM100DX a comer. And better, with Oregon based support in English, and in our case outstanding support at that. That's a BIG issue as we've learned the hard way on the 2009 Mini Cooper Clubman Electric.

Jack Rickard


  1. After the fair weather cars get back into use you can send the Mini up to the dyno. :) Possibly do a head to head with a mini E?

  2. Jack - with what you know now, would you do the Mini with this set up again, or use an AC50 or a DC motor?

    Great stuff on the videos: I've caught up to about March 2010 and I shall be recommending to the IPCC that they ask you to deliver a lecture to their staff on the relationship between hypothesis and data

  3. John:

    I kind of like the hard road. We've learned a lot. And we need to get familiar with larger AC systems. The AC50 is simply not powerful enough to move this 3500 lb car. But a Netgain 11 would do so very nicely, and many thousands of dollars of adapter and coupler work would have been reduced to about $1000 total.

    We have no power on our power brakes. So I kind of like regen to make them FEEL like power brakes. But for the additional expense, a vacuum pump would have been much less.

    If we were doing a new one today, we'd probably do a Soliton1 and Netgain Warp 11 in this car and do just fine. We'd have larger cells and less of them for a 170 or 190 volt pack and a lot of things would have been easier. In fact, I think we'd have been able to do a longer range with the larger cell sizes than we can with regen and by a significant amount.

    You can simply deliver the message on hypothesis and data for me as it is very simple. EVERYTHING makes SENSE if you phrase it carefully enough. That doesn't make it so. Data is just data. It stares back at you accusingly until you can figure out what it means. And it feels NO obligation to make sense at all.

    Jack Rickard

  4. Is anyone else having the same scenario with this week's video as I am? I've tried IE, Firefox and Chrome. In non-HD mode, the video is garbled. In HD mode, the video runs fine for about 15 minutes then stops, with the Donate box popping up.



  5. worked just fine for me. Safari on a Mac.

  6. Fine for me too - Firefox on XP in non HD to save Jacks bandwidth.

    Thank you for the full response to my earlier question Jack

  7. I had the same problem on both Firefox and Chrome on my home computer, and on my PS3 browser. When I tried at the office, everything worked just fine.

  8. Jack and crew,

    I am very impressed with all you have done with the mini. I really like how quiet it is while your out driving. The DC motors are not quite so quiet. Impressive acceleration too.

    Looking forward to the next show.

    Now off to work on my new project Black Midge EV

    Pete :)

  9. Hi Jack,
    Congrats on getting the Mini back on the road, and in fine form! Looks like a blast to drive!

    I appreciated the "ballparking" formulas you provided for power of motor needed and predicted Wh/mile for a given vehicle weight. In the spirit of "now what do I do with the information", could you explain how to calculate the power rating of a motor from its specs online? For instance, my conversion plan calls for a ~80kW motor (2835 lbs X 28). When I look at the specs for, say, the Warp 9 ( http://www.go-ev.com/images/003_09_01_WarP_9_Graph.jpg), it's a little hard to figure whether it's well-matched to my needs based on planned current and voltage. The Netgain motors all have specs listed at 72 Volts, which is much lower than where most people are designing systems.

    You refer to certain motors as being a 100kW motor, or a 150kW motor, and I understand that this is the max power it can handle (Voltage X current in the system, within the limits of the max voltage and current allowed). Did you get those figures directly from the manufacturer? I admit, I've only looked at Netgain's site, but they don't designate the max power and current recommended for their motors. How would you rate, say, the Netgain Warp 9 in terms of max power? Or a Warp 11?

    I hope my questions make sense! I'm discovering that I know just enough about electronics to use all of the right terms in the wrong ways and sound really dumb to people who have years of experience. Be kind... :)


  10. Sorry, forgot to mention my "planned current and voltage". Duh. Since I'm just planning this project right now, I've been using the voltage and current of the pack that Jack is giving away as a starting point: 180 Ah and 167 Volts.

  11. Jack,
    You mentioned random controller shutdowns with your Curtis 1238 and I've experienced the same. Have you traced out the cause? Mine seems related to regen, but not the amount nor the pack voltage. Upon shutdown I get a Code 18, (Severe Overvoltage), or a Code 38, (Main Contactor Welded). Since I have not actually gone into over voltage and I don't have a welded contactor I think what is happening is for some reason the contactor opens up during regen and occasionally causes a voltage spike giving the over voltage message. I can go months without problems and then have it happen twice in one week. Cycling the key switch resets everything and I can continue driving. Thoughts?


  12. Alex:

    Your question not only makes sense, it is so common and so WITHOUT a good answer we ought to devote a show to it.

    Electric motors are just not like the ICE engines we are accustomed to. They DO often have an RPM limit and I'm a little shy of overrunning those as the results are somewhat similiar to stepping on a land mine if you err. But the specs usually have a bit of pad in them.

    As to power, let's start with the basics. Electric motors are CONVENTIONALLY rated on a 1 hour rate. That is, they can sustain that level of power for 1 hour continuous operation without letting the smoke out.

    The Netgain Warp 9's one hour rating is 32 horsepower at 72 volts.

    Now it gets a little interesting. Nominally 746 watts per horsepower or 23,872 watts. So the Netgain Warp 9 is conventionally a 23 kw motor. And that, I rather insist, is THAT.

    In recent years, a lot of new blood on the vendor side, and some very enthusiastic people in companies such as Tesla, of course want to purvey the largest number possible. And so, they began to talk about PEAK power ratings of 150kw or 200 kw. Technically, and by convention in the industry, there really isn't any such thing.

    The one hour rating of the motor is a function of it's ability to handle CURRENT primarily and that current is of course the result of the applied voltage. And so it can handle that amount of POWER, expressed in watts usually but sometimes horsepower, for an hour.

    The main limitiation is it's insulation. If you burn the insulation off the windings, the windings short, and you quickly melt the motor - sometimes in a fiery display.

    But what we are REALLY talking about is its ability to dissipate heat. You are saying that this motor can dissipate heat at such a rate, that at this current load, which causes x amount of heat, the difference between the heat generated and the heat dissipated is such that it will take one hour or more to reach that point of destruction.

    Heat is really quite cummulative. So if we could handle 320 amps at 72 volts for an hour, we could handle twice that amount of power for 30 minutes. (Not quite that linear in reality, but give me a a little room here guys). This line of logic would indicate that we could handle FOUR times that amount for 15 minutes. And of course EIGHT times as much for 7 minutes.

    As I alluded, it's more of a square of the diameter of the wire function than a linear one. So it's not quite that good. But you get the concept.

    But in practice, you really can quite realistically run 3 to 5 times the power in a motor as its one hour rating - for short periods. Shorter being better.

  13. Starting with the Warfield forklift motor basically, George Hamstra has incorporated certain design changes over the years in the Netgain series of motors from his perspective, where he started as an electric drag racing enthusiast. And so for the 12 seconds of life he was concerned with the Warfield was quite robust, and he worked on that since then from there.

    Since a zero to 60 in an electric car rarely goes over 12 seconds, this leaves some wiggle room.

    A safe bet would be 115kw or five times the rated power for a normal acceleration for this motor. In practice, it's done 300kw routinely. A zilla 2K puts out 2000 amps and 156 volts is a very popular pack size among those guys.

    Which gets us to what we were REALLY saying. And that is, you take what your PACK and your CONTROLLER can do, and realize that the actual power in the motor will not be based on your NOMINAL voltage, but rather on your real voltage at that current level. And I can't give you those numbers because I don't know which size cell you are using or what size controller.

    But let's say you were using a Soliton 1 which is rated for 340volts and 1000 amps. And let's say you used CALB 180 AH cells. They will probably actually DO the 1000 amps. But the Netgain traditional experiences commutator arcing above 170 volts. The NEW Netgain 9 just released has some newer brushes that the BRUSH VENDOR swears will do 192 volts without this arcing. George won't sign up to it. But it probably would.

    If you DID have a 192volt pack, and you DID take 1000 amps out of it, you are no longer going to have 192volts. I would GUESS at that level - over 5C, you would be looking at 140 volts on a freshly charged pack.

    And that gets you to 1000 x 140 = 140 kw. And the Netgain Warp 9 will undoubtedly do it for 12 or 15 seconds with no serious harm. 140,000 / 28 is 5000 lbs. I've heard of it done. But you're pushing the limit there guy.

    So the power calculations we use are all about sagged voltage and current. The motor almost doesn't get to vote. But the rule of thumb for DC-series is 3-5 x rated for peak. AC induction motors tend to be more conservative at 3 x rated for peak. I don't know why.

    If I was at 5000 lbs, I would of course use a Netgain 11 - longer arm, more leverage, more torque for the same power input. But its true, motor sizing is a guess.

    Controller and pack sizing less so. We can calculate them. So the order of precedence would be to determine roughly what size pack you are going to use and how much the vehicle will weigh. That gives you your pack voltage and current, and you are into controller limitation.

    Our latest Speedster uses a pack of 38 CALB 180's. The 4C rating for continous on the CALBS is 720 amps and we wind up with a base voltage of 120. But our controller is limited to 550 amps. At that rate, I would look at a 12% voltage drop and so 108 volts maybe at 550 amps. That's 59400 watts into a motor that claims to be rated for 50 kw. It's not even breaking a sweat. And indeed, our motor temps have been actually trivial. I see 40-70C on a motor that can do 170Centigrade. We could easily drive this car with a 30kw motor because our limitation is really our controller.

    The good news is, Curtis is going to up the ante to 650 amperes, I'm told, this month.

    Hope this helps. The motor really is always a wag.


  14. JRP3:

    I most commonly have the dropouts with the Kelly Controller on the original Speedster. But I HAVe had a 38 code come up very occasionally on the Curtis in Speedster Part Duh.

    I chalk it up to a quirky controller from Curtis. The cure is pretty easy, and it comes so rarely, I haven't pursued it. But it's real and it is curious. As we are on liquid cooling and hardly ever get above 45C, it's not thermal. It looks pretty random.

    If you come up wiht something more concreted as to when it happens in the driving regime, I'll try to duplicate it if you like.


  15. JRP:

    One thought. A lot of you guys like a voltage limit on the high side from a concern about overcharging your cells with regen. First, that won't happen. But there IS a setting in there for max voltage as an error. Please check to see what that is and how it compares to your pack voltage.

    jack Rickard

  16. Jack,

    Thanks for your answer, that was a very helpful walk-through of the thinking behind matching motor to controller and pack. Or at least an honest admission of the need to approximate motor capabilities. I think what I'll end up doing is stockpiling the cash (or winning the contest!), and then see what's the latest, greatest in controller/motor/pack options for my vehicle's weight class. Seems like there are a lot of possible combinations, and you really can only end up buying what's available when you're ready to purchase, right? I'll definitely shoot you my plan when it's time to break ground (pun intended).


  17. For anyone else having the same garbled lo-res Flash video problem I asked about a couple days ago, the following steps fixed things for me:

    1. Right-click on the video
    2. Select Settings
    3. Select the first tab
    4. Uncheck 'Enable hardware acceleration.'
    5. Close dialog
    6. Refresh page


  18. Jack's ballpark figures work out pretty well for my conversion. At 2200 lbs., the EV uses around 240 Wh/mile at a cruising speed of 60 mph on flat ground. When building the car, I employed a similar rule of thumb for sizing my pack. At that 60 mph, the car pulls around 12 kW from its 120V pack. So my rule was to put in 3x that size pack of lithium cells in kWh, i.e., 36 kWh. This gives me good acceleration up to 3C and allows for about 2.5 hours of freeway driving at 80% DOD.


  19. Jack,
    That's part of the mystery of the shutdown, I can regen up to 128V on a cold morning going down hill with no problems, but have a shutdown when regen is only pushing me to 126 volts or less. Shutdown is usually on strong regen but it's also happened on weak regen, but I think the common factor on the weak regen shutdown is going over bumps. The car is a bit stiff. It's happened a couple of times during light regen crossing rail road tracks, so maybe the shock of the bump plus the regen is kicking the contactor off. When it's shutdown on strong regen it's usually been on a smooth section. I might try mounting the contactor differently to better isolate it.


  20. jRP3:

    Do you have a 24 volt contactor on that beast?

    Jack Rickard

  21. Jack,
    Yes, the one HPEV sent me. Second one actually since the first buzzed quite loudly from the PWM.
    I was thinking I could have a problem with the key switch relay to the controller dropping out. Both it and the contactor are mounted to the heatsink plate the controller sits on which is mounted to the transmission and motor. Maybe the force of regen and/or bumps moves the motor enough that either the contactor or relay disengages.


  22. On second thought it can't be the key switch relay since I don't lose power to the 840 display.


  23. Dear Jack,
    I think you can solve your power steering problem by making a small Arduino circuit, adding extra pulse when the motor is not rotating or rotates too slowly.
    Algorithm is very simple: wait for a pulse for 1/10 sec. If there's no pulse - make one. If there is one - start waiting for another 1/10 sec.
    It would make "artificial idle" on RPM meter, but it shouldn't be a problem.

    Second thing - since you control your brake signal with MOSFET anyway, why not switching it when you want to disable regen on breaking?

    Third thing - Merry Christmas from snowy Poland (chilly -15C).