Protect battery when (-30C) -22F

Here's video (with an embedded graph) showing the effectiveness of the battery warmer during that recent polar vortex:

It's very easy to see how effective that is for keeping the pack at the ready, even in extreme temperatures.
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One thing I have noticed about the battery warmer is that it turns on whenever it need it when there is no charging schedule active.

So , let's say you have one schedule active for Monday morning at 6am. If you park your car on Friday night and plug it and leave it until Monday The battery warmer will turn on only a couple of hours before your scheduled charging session. So yeah the battery can go below the freezing point during the weekend.

If you are not using any schedule , then the battery warmer turn on and off as needed to maintain a correct temp.



Posted via the PriusChat mobile app.

 

• What he said @Flaming

Perfect time of year to read this thread for the first time.
NOT! (~ ~).
If only I'd read this sooner, I'd have already tried it to see for myself.

Perfect not since I'm already switching to,
How do I help the car keep the pack temps lower and it's still under
60 F (15 C )
ambient today and pack temps are looking about
10 F (-12 C )?
higher than ambient temps

 

Very nice video!
But a question would be, Was the car in a warm garage at the start of this 5 min. 1.7 mi commute? How much of this battery temp was provided by the built in heaters?

 

The data is in the video. Dashboard shows outside temperature, which is the garage in this case (15°F). And the aftermarket app show battery temperature (41°F).

 

@john1701a please correct me if I've overstepped

Bill
A good question to ask, if the garage was heated. I had to rewatch the video, I had wondered the same.

In the first 22 seconds of the video, the video shows the dash thermometer showing 15 F with garage door closed and battery temp 41 F
and the car was not used for 2 days prior to the trip in the video.

How much of the battery temp was provided by the heaters?
I believe a good estimation would be the difference between 15 F and 41 F at the start of the video, although
the ambient temps were probably fluctuating while the car was plugged in.

at 0:08 seconds in the video the graph shows the traction pack heaters being used Tuesday 3 times between 4am to 6am - 4 times between 9am to 10:30am - 3 times between 8pm to 9pm than Wednesday morning 5 times between 5:30am to 7am while the video was made on Thursday Dec 31st

Stats at the end were 30 minutes driving, 18.7 miles driven and 61.4 mpg show at timestamp 3:05 in the video.

I'm pretty sure I got at least some of the above right. They are all good questions and hard to see unless the video is played in slow mo.

I also hope @john1701a has more to add and corrections to mistakes I may have made.

Looks like it took me a half hour to gather that info
Thanks for verifying John

 

The garage is insolated, but not heated. So in the dead of winter, soda cans will explode (in spectacular fashion) if we forget to bring them in the house. The battery-heater does a very nice job of keeping the pack warm. It is a simple & effective design.

We had a cold snap last month where it dipped into the negatives overnight. So, the garage wasn't as cold but outside daytimes temperatures were barely above 0°F. The following is a capture of that, which shows the battery-temp being kept nicely above freezing then too.