[Aaron Cake]

I've looked around for references to this behaviour, but have not found it.

Over the last few days it's been pretty cold here. -30 or so at night. In the morning when I head off to work, the car has been sitting for about 15 hours. For the past three days, I have turned the key and expected the IMA to kick over the gas engine as it normally should. However, this has not happened. Instead, I must hold the key in the "start" position as the starter and 12V battery turn the engine over...

Now, I don't necessarily believe this is a problem. More then anything, I assume that the ECU is deciding the traction pack is too cold to draw sucha large current. But what confuses me is that when I leave my driveway (10 seconds after starting the car) I am under assist. If the traction pack is truly too cold, the much higher currents drawn when assisting should be more of a problem then just kicking the engine over...Can anyone prove this behaviour?

 

[Armin]

limited IMA

Aaron,

while it hasn't been that cold here in the Boston area ("only" -20 C on the weekend), and I have never had the 12V starter engage, this is what I found the IMA to do:

On the -20C morning, assist and regen were limited to about 15 Amps. The car was force-charging the battery while cruising. I estimated the internal resistance of the battery pack to be about 1.5 Ohms (at normal operating temperature it's about 0.3 to 0.4 Ohms). The increased resistance is the key reason for problematic cold-weather performance.

The force charging continued, even after the SoC did and upper -end recal. It continued even after the SoC showed the rare 20 bars. But I did still have assist and regenerative braking available (no "burp-I'm full"). The highest voltage I saw during the force-charging was 190 V, more than I had ever seen on that battery!

As the pack warmed up, available assist gradually increased.

 

[LAinsight]

Seems normal. I noticed the same thing, but realized I got only minimal assist even with the foot to the floor. It's must be using either minimum forced charge or assist to warm up the battery pack.
What I found interesting was that I also have a block heater, and even though the engine was warm, it still used the 12Vstarter/battery when the car interior was very cold. I was debating adding a 115V outlet inside the car that is wired to the block heater power and add an internal heater which will come on with the block heater power.

...Leo

 

[Tim Maddux]

http://www.insightcentral.net/KB/faq-performance.html
"The Insight has an auxiliary starter motor that is used to start the gasoline engine in cold weather..."

I also noticed force-charging (3-4 CHRG bars lit) in sub-freezing AM temperatures last winter on Cape Cod. That was the only time I ever saw my battery state of charge report 100% full, as well.

 

[Armin]

I was debating adding a 115V outlet inside the car that is wired to the block heater power and add an internal heater which will come on with the block heater power.

I'd second that idea, but mostly for comfort. If the 12V starter is used in cold weather to protect the 144V battery pack, then I'd assume it's the temperature of that battery that detemines which starter gets used. So unless you put a heater in there, it won't help with avoiding the 12V starter...

 

[Guest]

I'd second that idea, but mostly for comfort. If the 12V starter is used in cold weather to protect the 144V battery pack, then I'd assume it's the temperature of that battery that detemines which starter gets used. So unless you put a heater in there, it won't help with avoiding the 12V starter...

You could add a cabin heater and a small fan pointing into the vent behind the passenger seat to blow the warmer cabin air through the magic box in the rear.

 

[Rick]

You could add a cabin heater and a small fan pointing into the vent behind the passenger seat to blow the warmer cabin air through the magic box in the rear.

It wouldn't be too hard to just power the onboard blower motors in the box. They are after all just 12 volt anyways. There's the one that circulates air in to the box and then there is a fan that sucks air through the batteries. Whats already there will move a significant amount of air as it is. I'd imagine you could get them up to a suitable temperature in 15 20 minutes or so. Though thats just a guess. You'd also get the side effect of cabin pre heating as well.

 

[Aaron Cake]

Figures, it's in the FAQ. I must have missed that. Sorry for the wasted topic.

However, I have noticed the force charging as I head down my street in the cold weather. Normally 3 to 4 bars. I can only assume this is done to heat the pack.

 

[AbCaRed00]

Battery Internal Resistance, Fully Charged Regen, Low Assist; Auxiliary 12V Starter M

I've got the exact same 12V starter and IMA regen/assist symptoms combined as Aaron, Armin, LAInsight and Tim in the less than -20's Celcius temperature where I am located. Windchill factor is making it very cold in the last few days. Thankfully it's getting a bit warmer.

I've fallen short of adding a power consumptive interior electric heater with fan, though that would be nice... but wonder if the OBDIIC&C, [once installed], would help out to a point warming if the IMA fan was turned on at low temperature to draw warmish cabin air.
.
I suppose I should check the two vents in front of the sides of the rear bumper are not frozen over as well. Seems that I heard them before open suddenly at highway speed.
I've been running without fender skirts, and left the hatch open in the rear which may have contributed to some degree in chilling down the IMA battery. I'll close the foam hatch and maybe conserve a little more heat.

It's great having 20 bars for days on end, ...but is 190V as reported something to worry about in these subzero temperatures?

____________________

[EDIT: ..... got the car warmed up taking it out for a run and IMA function is returning closer to normal.
Had it plugged in and block heater raised coolant temp from -3 Celcius indicated via ScanGauge to +23C in a little more than 2 hours to get the engine and indirectly the interior warmed up faster. Used an aluminum roasting pan stuffed around the catalytic converter to draw warm air a bit better. Moved the passenger seat forward to try and help allow more heat circulation/flow back to the IMA via the square vent behind the seat. Climate control/heater on full. Drove 50km mixed highway and city.
Eventually got all but two bars of full assist and regen on flooring it or braking; up from only 4 bars either way for the last few days.

Lowered charge down to 18 bars from pegged out and taking regen. 12V battery reading 14.1V, car starts with IMA now. Ambient Temperatures were -18C to -20C / Zero F to-4F]

 

[Eli]

The two days so far this winter that my battery has been at or below 32 degrees, I noticed that the battery fan came on(at the low setting) without any input from me. I assume this is normal and that the system does this because it is assumed the human will have the heat on.

 

[AbCaRed00]

The two days so far this winter that my battery has been at or below 32 degrees, I noticed that the battery fan came on(at the low setting) without any input from me. I assume this is normal and that the system does this because it is assumed the human will have the heat on.

Good to know that IMA fan operation is automatic at lower temperatures. [<32F/ <0C]
I can't hear the fans running at all, as is reported elsewhere, which will make the OBDIIC&C all the better to detect that stuff.

fwiw: the block heater is best heard inside the vehicle in my case, than outside in ambient city noise and wind. Couldn't hear the 'percolation' going on either at first, so cleaned the dull oxidized prongs shiny on the block heater plug with steel wool for a better connection. Maybe that helps, or maybe it just took time.
Also may put on a thermostatic control for the block heater if it isn't already self regulated to save energy.
With that, and a reliable outdoor-type power timer it would hopefully take out some of the bite of winter operation.

 

[Eli]

Yeah, that's what I've done.. just have it on a timer. It's not self regulated, it's full tilt as long as it's plugged in. I've noticed the percolation noise too, can only hear it with the hood open though. What sucks is that it's obvious the block dissipates a lot of heat, as the final coolant temperature depends entirely on ambient temperature, not how long the heater is on. When ambient temp was 40F, anything over ~3 hours was just wasted. This resulted in a coolant temp of ~140F.

With ambient temperatures in the upper 20s and lower 30s, coolant temp peaks at about 130F after 3 hours.

I've had my IPU cover off for so long, I'm quite aware of every relay click and the fans operating etc. It will be interesting to have the cover back on, as like you say it's difficult to tell if the fan is running. Will be nice when Peter adds a "fan on" display to the OBDIIC&C Gauge.