# Way too Cold!



## TheSGC (Nov 15, 2007)

Well last night is was -15F and this morning was -8.5F and the auto transmission in my EV would not engage! It was so cold that the transmission clutches could not engage and it through a few errors on the computer! This is the first time I have driven the EV below 20F, and usually if the temp is below 32 I can feel the transmission be extremely sluggish and hesitant while consuming 30% more power, but this time I got nothing!

Next EV will be a stick. A nice high voltage EV with a stick.


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## rwaudio (May 22, 2008)

TheSGC said:


> Well last night is was -15F and this morning was -8.5F and the auto transmission in my EV would not engage! It was so cold that the transmission clutches could not engage and it through a few errors on the computer! This is the first time I have driven the EV below 20F, and usually if the temp is below 32 I can feel the transmission be extremely sluggish and hesitant while consuming 30% more power, but this time I got nothing!
> 
> Next EV will be a stick. A nice high voltage EV with a stick.


That's odd, this winter we've had -22F a few mornings (colder with the wind chill) but both of my gas automatics started and drove just fine, they've also been fine below -40F with a block heater which I'm sure doesn't give too much heat to the tranny. Perhaps it's just a sign you need some transmission work.

I guess that raises the point that in the winter EV drive train is going to stay cold and not warm up to the same extent from the engine. On the other hand might be better for the parts not to be heat cycled all the time.


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## TheSGC (Nov 15, 2007)

rwaudio said:


> That's odd, this winter we've had -22F a few mornings (colder with the wind chill) but both of my gas automatics started and drove just fine, they've also been fine below -40F with a block heater which I'm sure doesn't give too much heat to the tranny. Perhaps it's just a sign you need some transmission work.
> 
> I guess that raises the point that in the winter EV drive train is going to stay cold and not warm up to the same extent from the engine. On the other hand might be better for the parts not to be heat cycled all the time.


Bingo, the engine really does heat up the tranny, at least it does in my Civics. The transmission and the engine share the same radiator and heat up to over 35F real quickly, like 10 seconds after turning on. 

The transmission is new and my dad just tested the EV and it's 15F now and it works, so there is a limit to what it can handle for temps. I lose at least 30-40% of power through the slush box in this weather so it really has to go, or i need to find some sort of ATF heater I can have come out like 30 minutes before I leave.


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## Jimdear2 (Oct 12, 2008)

SJC,

If I remember correctly way back when I think you said that your trans oil never showed any real temperature. Or it could have been one of the other auto trans people.

When things warm up a bit you might want to check and see if your trans oil isn't contaminated with water from condensation that never got boiled out when the oil heated up. There is a lot of detergent in Trans oil to mix with that water and make pink foam.

You might not have cold stiff oil it might be frozen oil foam

Just a thought off the top of my head.
Jim


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## Coley (Jul 26, 2007)

I have always heard of trans fluid having detergents and wondered what for.

There is no combustion, as in an engine, so what needs the detergent??

Just wondering.....


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## ruckus (Apr 15, 2009)

Yes, preheating tranny will help greatly.

no, you don't want water in your tranny, especially at low temps.

Why it threw a code? tell us more about your setup...


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## TheSGC (Nov 15, 2007)

It's a 1996 Civic LX with a 1998 Civic Auto transmission B4RA. It through a P0730 "Incorrect Gear Ratio" code which means gear slippage and solenoids weren't engaging. It has fresh Honda ATF and everything did check out when I removed the solenoids to test. 

I did some tests a few years ago before I EV'ed the Civic and I found little temperature difference between the outlet and inlet lines from the cooler (like 2-5 F) but it was always warm the lowest being 35F after a minute and usually 95 to 150F depending on terrain and outside temp. 

I'll have to check for water in the tranny, but now it has been working since it got above 0F. Maybe I shouldn't have idled my motor longer? It was only one or two minutes before I tossed in the towel and took the ICE (which didn't start cause the battery was an ice cube, i had to be jumped at home, the gas station and at school, Sears is going to get an earful for that one).


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## jeremyjs (Sep 22, 2010)

I wonder if you could find an oil plug heater that would fit in the transmission. Or maybe you could get an oil pan warmer and afix it somehow.


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## DIYguy (Sep 18, 2008)

Yes, we had -27 yesterday morning.

I'm a big fan of synthetic trans fluid. It doesn't thicken up like mineral oil in severe cold. 
Perhaps more importantly, when it is running under load, studies have shown a 50 degree F reduction in temps with synthetic Trans fluid. Hi temps kill auto trans.... this is a big deal... 

Cheers.


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## Anaerin (Feb 4, 2009)

Thickening fluids is often a problem, especially in cold weather. Diesel can also gel and solidify in extremes of temperature.

Thinking of battery warming, has anyone tried using a mains heating pad (Just your basic home unit) for warming cells? How do they do with the excesses of temperature in colder climes? And will they run off DC as well as AC?


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## gdirwin (Apr 7, 2009)

Love to see the Canucks all checking into a cold weather thread!

We had a solid week of -30C last week - I was out of town and the car was not plugged in - came home, plugged in for about an hour (battery warmers) and went for a drive. My Zilla gave an odd error during startup (1131 - Shorted/Loaded Controller during precharge) - had to stop/start/stop/start a few times, then it went away.

While driving, I got another error (1122 - Controller Desat error) but the car kept running. Stopping/restarting and everything was good again.

Still checking with Otmar to see if he has any ideas.

After plugging in, no more problems (it is also a bit warmer).

Also I found that my PID interior temperature controller (which regulates two SSRs for ceramic heating elements) does not work went it gets too cold - I had to aim an interior heater at it until it warmed up enough to work.

If I plug in (battery heaters and an interior warmer) then everything works well...

Just installed Nokian Hakka snow tires - those and AWD gives awesome handling, traction and stopping power...

Lets here some more cold weather stories...


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## Tesseract (Sep 27, 2008)

gdirwin said:


> ...My Zilla gave an odd error during startup (1131 - Shorted/Loaded Controller during precharge) - had to stop/start/stop/start a few times, then it went away.
> 
> While driving, I got another error (1122 - Controller Desat error) but the car kept running. Stopping/restarting and everything was good again.
> 
> Still checking with Otmar to see if he has any ideas.


What a coincidence... we've had three Soliton1 customers this winter - but not last - report occasional desat errors when the temp was below 0C. I have yet to duplicate the problem (by putting a controller in a deep freezer at -24C) but Qer found a minor bug in the code dating back to when Quiet mode was introduced so maybe fixing that will do the trick? 

Anyway, I just found it very interesting that two very different controllers have experienced the same problem - desat error - when it is bitterly cold outside.


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## DIYguy (Sep 18, 2008)

Interesting read. I think this is very useful information. (BTW Garth awesome build there...been meaning to tell u that). I have the Soliton, but haven't been driving it in this recent cold.... it's soon to get some upgrades. So,... I'm of little help here.

Cheers,


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## gdirwin (Apr 7, 2009)

Interesting about the Zilla and Soliton - occasional Desat errors when it is cold - possibly frost build-up creating a one-time conductive path? \

Any more possibilities?


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## Tesseract (Sep 27, 2008)

DIYGuy - if it is below 0C up there it'd be great if you could just quickly test your controller one day. All you need to do is apply throttle until motor amps exceed 175A or so and see if desat trips. Whether it does or doesn't, updating to 1.3 is a really good idea since it fixes a minor bug in Quiet mode that Qer found (and which we *think* might be the cause of the cold weather desat problem). Unfortunately, we don't know for sure since none of those affected has reported back to us and we can't duplicate it ourselves.

gdirwin - my first suspicion was frost, too - and that may be the cause for the Zilla because it isn't really sealed at all, but the Soliton1 is fairly well sealed (if the ethernet cap is on, anyway) and the desat error goes away as soon as the heatsink temp exceeds 0C (as reported by the thermistor). If there was frost inside the controller it would take a long time for it to first melt and then evaporate, especially at just above freezing, so I don't think that's a likely cause.

A much more plausible explanation, - besides that bug in Quiet mode - is that a substitute for a part we could no longer get (this happens all the time and it is probably the most frustrating part of my job) isn't behaving quite right at cold temperatures. Once again, that it goes away once the temperature gets above 0C kind of argues against that, but, well... stranger things have happened.


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## DIYguy (Sep 18, 2008)

Tesseract said:


> DIYGuy - if it is below 0C up there it'd be great if you could just quickly test your controller one day. All you need to do is apply throttle until motor amps exceed 175A or so and see if desat trips. Whether it does or doesn't, updating to 1.3 is a really good idea since it fixes a minor bug in Quiet mode that Qer found (and which we *think* might be the cause of the cold weather desat problem). Unfortunately, we don't know for sure since none of those affected has reported back to us and we can't duplicate it ourselves.


It's sunny and -8 C here today... I keep my EV in a heated garage though . Not that I couldn't put it outside for a while... .but if you had of asked yesterday, it would have been a lot easier. I have just started my mods/upgrade work. I expect I will have it drivable soon after getting my new batteries though...even though I plan a number of changes. Were you interested to test before software upgrade? Did you do your tests in deep freeze with different software revs?
I will definitely upgrade to 1.3, just no need to mess with it now. If you want me to keep this in mind for when I put it back together and test before and after upgrade I could do that. I assume minus temps will be around for quite a while here yet.


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## Tesseract (Sep 27, 2008)

DIYguy said:


> ...but if you had of asked yesterday, it would have been a lot easier.


S'alright. This problem is more of an annoyance than a fatal error. If you can run the motor at about 100A (ie - put the transmission in neutral and barely touch the throttle) until the controller warms up above 0C you can drive normally. Still, a bit embarrassing regardless.



DIYguy said:


> Were you interested to test before software upgrade? Did you do your tests in deep freeze with different software revs?


Before and after software upgrade would be best. I tested just the versions of code that the customers reporting the problem were running on a controller in a freezer at -24C and couldn't get it to happen, which is why I suspect it is a perhaps a subtle problem that depends on both the code and a component. In the log files received so far it shows the desat always occurring at ~167A and with temp below 0C and duty cycle below 6%. Oh, and it appeared to only affect Quiet mode, but one customer blew that theory out of the water (still, Qer did find a minor bug in it, so, hope springs eternal and all that).


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## gdirwin (Apr 7, 2009)

My Zilla has been fine all week, with temps around -20 to -25C (-4 to -13F). Tonight will be -32C (-25F) - so far only that one DeSat error...

I don't think anyone has tested controllers at such cold temps (who would be foolish enough to drive an electric car in such temperatures?), so any experience gained is valuable to trouble-shoot and improve designs...


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## Coley (Jul 26, 2007)

When I got to town the other day when it was -22F, my truck wouldn't start from setting outside all night.

The guys in town got a kick out of seeing me jump start the truck, with my EV.


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## DIYguy (Sep 18, 2008)

Not too cold...but another 10" of snow last night. . . lol

Just to give you an idea of the snow, the white fence is a little over 4' high....


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