Can You Quickly Warm A Cold EV Battery On A Chevy Bolt? Video


Electric car range drops dramatically in the cold.

Yes, we are all well aware of the fact that cars don’t like the cold. But not as well known is that charging a cold battery is slower than when warm, too.

The easiest method for warming a battery is either a DC fast-charge session. Even better is to never let the battery cool. The latter can be accomplished by parking in, say, a heated garage. However, the DC fast-charge scenario isn’t so easy. Who owns one at their residence? Put your hands up to indicate yes.

With no hand-raisers out there, is there some over method to quickly warm a battery so that it can charge fast? Or maybe just so efficiency and range increases?

If you own an EV, then you’d likely know that highway driving heats the battery quickly. And that some brief, but strong, regenerative braking does too. So is this the key to the battery warm-up for charging faster?

The video focuses on a Chevy Bolt, but the method would apply to other EVs too.

Video description:

Can you quickly warm up the high voltage battery of an electric vehicle in the dead of winter? More specifically, can I make it happen on our 2017 Chevrolet Bolt EV?

Following cold and warm battery charging sessions that show either end of the DC fast charging spectrum, I wanted to test a viewer suggestion to hit highway speeds and then pull back with maximum regenerative braking.

Hopefully, this would provide sufficient action for the battery pack to warm up and be ready to accept a charge rate closer to that of the second session (43kW), rather than the piffling 15kW rate we saw in the cold session.

Cold battery DCFC link
Warm battery DCFC link

This video covers mainly my first attempt to make that happen but also references a subsequent test with more extended highway driving towards the end. Both yielded similar results and should provide useful insight for Bolt EV drivers – or potential owners – considering how they’ll use the car. There’s also a reminder that Tesla owners aren’t immune from this issue, as my Model 3-owning in-laws experienced on their way over to Boston from Cleveland, OH this past Christmas!

Let us know about your experiences with cold battery charging in the comments and thanks again for watching.

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21 Comments on "Can You Quickly Warm A Cold EV Battery On A Chevy Bolt? Video"

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“is there some over method to quickly warm a battery”…
You could trying plying it with a few drinks.

There is definitely some “under method” that can “quickly warm a battery”.

The “over method” for the Bolt, might be a tough Nut to crack.

Yep, just ply your Bolt with some good old Yukon Jack and away it will go!

But alcohol intake reduces core body temperature soon after the initial heat-hit.
A brisk walk or a pub with its own running-machine should sort the problem.
A Bolt-like Olympic 100m sprint would also work.
(Am I hilarious or what ?)
Cheers – mine’s a double whisky, mate.
Paul G

Seems like the most efficient charge would be if the car immediately started to warm the battery after being plugged in, since at that point it has the power to do it.

Video is noisy

Thanks for sharing, but note the currently embedded vid isn’t the one described in the article. The latter is here:

Fwiw, none of the ideas tested for quickly heating up a cold-soaked battery have made a significant improvement. Driving at highway speeds for an extended period of time, as in the December warm battery session, was the only way to achieve normal DCFC rates right from the off.

As I understand it both Kreisel and Tesla have active thermal management but the strangely quiet Austrian company Kreisel claims to really have cracked the cold/hot “problem”(quote): “The cells inside a Kreisel Battery Pack are constantly flushed with a special liquid so the battery has the perfect temperature at all times. Even at high load, e.g. during acceleration or fast charging, the cells remain in the optimal temperature range. This also increases the life span of the battery.” ( From: ) That aside, it’s no surprise that no solutions – simple or more complex are mentioned by any of those anti-EV, eco-hostile, er, “ICE”-addicted media entities and trolls that have been keenly synchronizing their latest assault on EVs. Rush Limbaugh was one of ’em. Tells you all you need to know.(eg. see Iraq “WMD lies-for-oil”) And as I’ve pointed out elsewhere – it’s odd, innit, how we’ve never heard complaints from Norwegians…their homeland can be as frigid as Canada or Alaska for 8 months of the year. Funny too how said anti-EV assault-squads only specifically mention Tesla and Hyundai who produce the longest range – ergo potentially most threateningly disruptive – EVs available. I guarantee that you’ve,er, strangely never… Read more »

While I would have liked getting a Fully electric I ended up getting a (now discontinued (boo!)) Volt. for cold weather the car fires up the gas engine for long enough to heat up the (shared) cooling system. It has made it practical to use the car in really cold weather, but of course the charge rate is stupidly slow even in warm weather (what were they thinking???)

The 2019 Volt finally went up from level 2 charging rate of 3.6 kW to 7.2 kW.

As of 06/28/18 – New GM Volt

“Headlining the new feature set is an improved 240V charging system that will up the rate of charge from 3.6kW to 7.2kW or 16A to 32A. The move, which matches the charging rate of Chevy’s Bolt on Level 2, will give the Volt a full 53 mile EV charge in 2.3 hours”

It’s the GM “too little too late” death knell strategy, once again hard at work.
R.I.P. GM Volt.

For Click-Bait, ( AAA ) you can always make the electric range statistical outlier worse, by running the car like you stole it and putting cabin heat at 80 degrees.

As for BMW i3, you can setup morning precondition of the battery to warm it. up before you leave the house, raising your on the road miles perk kWh range and efficiency.

Yep, this is a very solvable problem. BMW did it years ago with the i3. Only inconvenience is it takes about 3 hours to heat up the whole battery. I can testify that winter EV driving in an i3 is better than a Prius.

Me too – my 2018 i3 has heat in 30 seconds and usually I have full range without 3 hours of preheating (except on the very coldest of days).

It really is a great car, especially in these later longer range iterations. If you can pick one up on USAA or a utility discount, it can be cheaper than a prius (the tax incentive is still in full effect).

Seems odd that that charging itself doesn’t start to warm up the battery. Is that something that could be changed via a software update for EV’s?

Charging via L2 (220v) does put some heat into the battery but not very much.

Charging via L3 (DCFC) puts more heat in but if the battery starts out cold it can’t safely handle the current needed to warm the battery quickly, it’s a chicken and egg thing.

The Bolt at least has a decently powerful battery heater but it draws a LOOOT of power so it doesn’t use it very much, the only time the Bolt feels free to heat the battery to what it considers “optimum” (about 25C) operating temperature is if you’re plugged into an L2 charger and not currently charging (charge is complete or charge is not needed).

What would driving while holding pressure on the brakes do?

We are well aware that battery electric vehicles don’t like the cold, not other technologies. Fuel Cells, for example, are totally fine with temperatures down to -40°. A fuel cell vehicle loses about 15% of it’s range in -20° vs 45% for a BEV. Stop trying to tar other technologies with BEVs flaws. Oh and a fuel cell requires zero parastic energy overnight, the fuel cell can freeze and is able to self start without issue.

My sure fire method is to own a Volt.

This is a simple heat capacity problem. Given the large mass of the battery pack there’s no way just driving a short distance and using regen is going to heat the battery sufficiently. Didn’t really need the experiment to show that.

Watching the Weber Auto teardown of the high voltage components of the Bolt gave me the idea that it should be possible to make and install a self-contained low wattage (maybe 100W or less) heater that could be installed in series with the battery heating/cooling loop that one could plug in to a 110V outlet just like many people plug in engine block heaters on their ICEVs today.

Basically all you’d need is a small heating element and a low volume pump that would circulate warm coolant through the battery and keep it warm on very cold nights.

“Basically all you’d need is a small heating element and a low volume pump that would circulate warm coolant through the battery and keep it warm on very cold nights.”

You would also need to insulate the battery pack.