Garage Battery Warmer.. Crazy but works!

[scottm]

Kudos to @jeffdom1978

For playing with notions of pre-heating battery a different way. (If you're not living North of the 49th-ish this probably all seems strange to you. And yes, I HAVE used a blow torch on my engine block before to soften the oil enough to crank the engine...)

Some folks have already chimed in "just heat your garage"... The way I look at this is .... you are heating the garage but in a somewhat targeted way that puts the most benefit of heat closest to where it needs to be. The fact that some heat doesn't transfer to battery is OK, you're heating the garage and that's fine too.

This isn't a unique problem for EV's in cold climates. They call ICE cars ICE for a reason.... they get frozen blocks too.

 

[Brass Guy]

Actually, the battery heater will turn on if you're driving; whether the cabin heat is on or not.

Range mode keeps the battery heater off. (Or quite reduced.) This may apply to using the app too, I'm still not sure though.

 

[scottm]

Actually, the battery heater will turn on if you're driving; whether the cabin heat is on or not.

yep... that's what I meant by this

When you're driving, the demon has a mind of its own and will heat battery whenever it feels, regardless of HVAC settings.

Range mode keeps the battery heater off. (Or quite reduced.) This may apply to using the app too, I'm still not sure though.

This is a good related point! Range mode dampens the heating spike... limits the power.

 

[Snowstorm]

I dunno, I can’t see how an external heat source can warm the battery more effectively than warming the battery from within. If you preheat the car via the app, it would warm the battery to a level such that you get at least some regen.

 

[tga]

You are in a garage, temps shouldn't be dropping below maybe 50.

Says the guy in GA to the guy in Chicago... It has already hit 27 in my uninsulated, detached NH garage. A cup of water I left out there froze solid.

I have an attached insulated garage. The house is well insulted too. My garage is usually about 10F warm than outside, it does NOT stay at 50F like someone suggested

At my old house in MA, I had an insulated, attached garage. Garage doors were insulated/foam-core with gaskets to (somewhat) seal the edges against the frame. I never saw less than 35 on a max/min thermometer.

 

[Nitemare3219]

OP, I think your solution is crazy. Why bother with that garbage? Your best solution would probably be buying some piece of crap $50 Android tablet that's on sale, then using some 3rd party Tesla app (like Dashboard for Tesla) to set a charging start time to use the heat produced from charging the car to warm the battery (assuming you're using 240v) - there is nothing wrong with charging the car every night, and you could at least do it in the winter for the purpose of heating the battery. No waste electricity, and no stupid heating blanket on your garage floor. But for a 10 mile commute, you could also just turn on range mode and deal with 0 regen... not really losing that much in efficiency unless it takes you 30 minutes to travel 10 miles (e.g. lots of stop-go).

Electric Blankets take VERY little power, probably like 20 watts.

Uh, wrong... and you seriously think 20 watts of power would do a damn thing to a 1,000lb brick?

 

[BluestarE3]

Kudos to @jeffdom1978

For playing with notions of pre-heating battery a different way. (If you're not living North of the 49th-ish this probably all seems strange to you. And yes, I HAVE used a blow torch on my engine block before to soften the oil enough to crank the engine...)

Some folks have already chimed in "just heat your garage"... The way I look at this is .... you are heating the garage but in a somewhat targeted way that puts the most benefit of heat closest to where it needs to be. The fact that some heat doesn't transfer to battery is OK, you're heating the garage and that's fine too.

This isn't a unique problem for EV's in cold climates. They call ICE cars ICE for a reason.... they get frozen blocks too.




View attachment 356724

Hmm... a possible new use for the Boring Company Not-a-Flamethrower?

 

[scottm]

It would take about 30 hours of heating at 300 Watts to raise the battery temp from 40F to 70F, that's about 8.7kWh of juice.

Which is equivalent to adding about 10% charge to the battery if you were to do that instead.

A 1000W heater would do the job in about 8 hours, or overnight. Instead of using electricity, you could light about a dozen candles and place them around evenly under the battery to do this same thing.

Or use 1500W heater would do it in just under 6 hours. This is the maximum power you can hang off a typical 15A 120V branch circuit from your breaker box.

And this is "ideal" meaning the car would be wrapped and well insulated against additional cooling from reaching the car as it was being warmed up.

 

[mswlogo]

OP, I think your solution is crazy. Why bother with that garbage? Your best solution would probably be buying some piece of crap $50 Android tablet that's on sale, then using some 3rd party Tesla app (like Dashboard for Tesla) to set a charging start time to use the heat produced from charging the car to warm the battery (assuming you're using 240v) - there is nothing wrong with charging the car every night, and you could at least do it in the winter for the purpose of heating the battery. No waste electricity, and no stupid heating blanket on your garage floor. But for a 10 mile commute, you could also just turn on range mode and deal with 0 regen... not really losing that much in efficiency unless it takes you 30 minutes to travel 10 miles (e.g. lots of stop-go).


Uh, wrong... and you seriously think 20 watts of power would do a damn thing to a 1,000lb brick?

He's the one that said it works. But it looks more like blankets are around 60 watts. And I agree that's not much. I would think you'd need like 200 watts minimum (constant over night) and it would have to be well connected. I thought he said he used 2 blankets, I forget.

EDIT: Just looked it up Electric Blankets are roughly 200 watts.

 

[ReddyLeaf]

@jeffdom1978. Yes, something similar was done by a Nissan Leaf owner in eastern Canada several years ago. He used industrial heating pads, stuck directly on the bottom of the battery. They are thin, with one side that has a super sticky coating. The setup kept his normal summer range (70 mi) even in -20C winter temps. For him, it was absolutely mandatory since his commute was more than 40 mi and he wasn’t able to plug in at work.

 

[SSedan]

Charged for 1hour 40minutes at 60amps outdoors at 20f after having sat for 10hours before charging began and was a short drive with Regen limiting then.
That charge rate/duration gave me no regen when I left this morning. Battery needs to be warm to charge so letting it.preheat while driving is not all waste, keeps the battery temp from dropping too low and just having to warm more before charging.

 

[mswlogo]

Charged for 1hour 40minutes at 60amps outdoors at 20f after having sat for 10hours before charging began and was a short drive with Regen limiting then.
That charge rate/duration gave me no regen when I left this morning. Battery needs to be warm to charge so letting it.preheat while driving is not all waste, keeps the battery temp from dropping too low and just having to warm more before charging.

I don't believe the car will pre-heat while driving. Other than it's natural heat generation in the motors and getting recirculated to the batteries and some heat from charging due to regen. There is no extra battery heating going on while driving.

 

[Brass Guy]

I don't believe the car will pre-heat while driving. Other than it's natural heat generation in the motors and getting recirculated to the batteries and some heat from charging due to regen. There is no extra battery heating going on while driving.

Oh yes, the battery heater definitely is in use while driving. I've seen my energy draw at near 10kW while stopped. I usually switch to range mode when this happens since (usually) before the battery has warmed I'm at my destination; making it a waste of energy. The energy draw then drops to its normal sliver.

 

[tga]

I don't believe the car will pre-heat while driving. Other than it's natural heat generation in the motors and getting recirculated to the batteries and some heat from charging due to regen. There is no extra battery heating going on while driving.

Drawing power from the batteries heats it, due to the pack's internal resistance. P=I^2*R

 

[Rocky_H]

I don't believe the car will pre-heat while driving. Other than it's natural heat generation in the motors and getting recirculated to the batteries and some heat from charging due to regen. There is no extra battery heating going on while driving.

It sounds like you are describing the Model 3.

Oh yes, the battery heater definitely is in use while driving. I've seen my energy draw at near 10kW while stopped. I usually switch to range mode when this happens since (usually) before the battery has warmed I'm at my destination; making it a waste of energy. The energy draw then drops to its normal sliver.

It sounds like you are describing the Model S/X.

This post is in the Model S section.

 

[mswlogo]

It sounds like you are describing the Model 3.

It sounds like you are describing the Model S/X.

Sorry, you are correct. Thanks for the correction.

 

[Brass Guy]

I never realized the 3 BMS behaved that differently from the S/X.

 

[SSedan]

It is the lack of a resistance heater on the 3 battery that creates the difference.

 

[⚡️ELECTROMAN⚡️]

then using some 3rd party Tesla app (like Dashboard for Tesla) to set a charging start time to use the heat produced from charging the car to warm the battery

You can select from the main touch screen a specific time to start charging.

Is Dashboard not available for Apple users?

 

[Don85D]

Even in an ICE the acceptable way to deal with very cold temperatures is a small electric heating element placed in the coolant circuit. This heater can be on a timer to start up a few hours before departure. If it works to heat oil it should work to heat battery cells which are in the same antifreeze solution. I'm sure that Tesla can add the feature as all of the components (heater, fluid and pump) are already in the car. Someone just needs to ask.