Preparation needed for extreme cold weather

[Herbknowsit]

I have left my MME plugged in during some 10 degree temps but never saw any message warning to plug in prior. For that matter, there has never been any message on my phone apps telling me that the MME decided it needed to "warm up" and use some juice from the charger. So if it IS doing so during non-charging hours when plugged in, and not on charging schedule-it is unknown to me. I know the temps are raising hell with any/all battery gizmos i have outside now.. Like remote weather guages, driveway alarm, greenhouse temp settings etc.

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[GreaseMonkey]

You all should be aware of and familiar with the turtles. You need not fear the turtles, rather respect and understand them. Here’s what I mean:

I would be cautious driving in very cold temps (0F and below) at low state of charge. Last time we had a cold snap, the energy consumption skyrocketed vs normal and what would typically be a 10% trip under normal winter conditions became 20. I got hit with a yellow turtle on my way home and the car lost most of its power (couldn't overtake anyone and could barely keep up with highway traffic). While waiting for a L3 charger to free up (vehicle parked with heat on), I was losing battery charge rapidly (went from 12% to 8 in minutes), that I got concerned and turned the car off and waited in the cold. This was the time when Teslas were getting stranded at charging stations. And in my situation, I only got a yellow, but there exists a meaner red turtle too.

So moral of the story is not to say: nothing will happen. That would be incorrect. You need to be extra diligent in not pushing the car below 20-30% (not scientific, just my experience) and keep it charged. So if you’re contemplating making another stop to charge, do it! Don’t be lazy. You need to give the car enough energy to warm up the battery. Cause the car cares about its battery more than it does about you.

 

[GreaseMonkey]

Here’s more from the indispensable @Mach-Lee :

https://www.macheforum.com/site/threads/turtle-mode-cold-weather-warning.33148/

 

[dalola]

I believe it's also been determined that battery warming does not happen if you are charging under 36A, something to be aware of. Some one correct me if this is wrong.

Also, don't forget to set your tire pressure to account for the extreme cold, you lose about 1 lb of pressure for every 10 degrees of ambient temp drop.

 

[VindictivePantz]

I've been bumping my target to 90%, leave it plugged in when near a L2 charger, and keeping HVAC to AUTO at 68F.

I religiously set departure times, and remotely start to get the cabin warmed if not plugged in so if I need to sit the heat off to give some hope the heater can warm the battery, I shut the HVAC off.

I've seen such a drop in the GOM when traveling decent distances at highway speed that the extra 10% I put in helps keep the turtles at bay (thus far.)

 

[Mach-Lee]

So with cold weather less than 14ºF/-10ºC, it's important to plug into 240V and charge to 80-90% every night if you have the ability to do so. Plugging in acts like a block heater for the battery. If you can't plug in, the car will still work, it will just be very cold and sluggish (but cold does not hurt the battery). You should also try to set departure times before you leave if possible. Having the battery warmed up with a departure time will ensure you have maximum heat output.

In some cases, you may need to expand your charging hours to allow battery heating at more times of the day. I'm currently using a midnight to 3PM charge window. I also set a battery-only departure time at noon on days I don't have a set schedule, this ensures the battery has always been heated in the past 12 hours.

Also you should avoid draining the battery below 20% in cold weather because of the increased risk of turtle mode with cold temps. Yesterday I got into turtle mode with about 13% left, if I hadn't warmed up the battery first it would have happened much sooner. I did a 0-60 with red turtle and it took a whole minute, so you want to avoid that.

Cold weather plug in warning is still there.

I believe it's also been determined that battery warming does not happen if you are charging under 36A, something to be aware of. Some one correct me if this is wrong.

Also, don't forget to set your tire pressure to account for the extreme cold, you lose about 1 lb of pressure for every 10 degrees of ambient temp drop.

Full battery heating takes 30A from the wall, so you want your EVSE set to 30A or higher for full heating effect. The battery will still heat with an EVSE less than 30A, but the power output will be reduced and the battery won't get as warm.

 

[Ravensfan1996]

In the winter i just leave mine plugged in all the time.

 

[Schwartzcynthia]

This is explained in the manual.

When you're not using the vehicle, it should be plugged in to 240v all the time. That way, when it needs to warm the battery it can.

Will it be harmed just sitting outside unused? No.

I am not at home this week so my car doesn't have a place to stay on a charger. It is going to be low 20's next 4-5nights. Would it help to periodically throughout the night turn on the climate control or just leave it off. By the time I need to drive it should be at least 32-34 degrees..

 

[RickMachE]

I am not at home this week so my car doesn't have a place to stay on a charger. It is going to be low 20's next 4-5nights. Would it help to periodically throughout the night turn on the climate control or just leave it off. By the time I need to drive it should be at least 32-34 degrees..

No.

And you can only do 2 remote starts before you have to physically start it.

 

[ChasingCoral]

Good to know. Thanks yall. I haven't seen that message asking to keep it plugged in yet, even though it has been decently cold here and there. We have a charging schedule set up through our Chargepoint Level 2 to match our electricity providers schedule (we do overnight charging almost exclusively since it is offpeak pricing). Probably will just override the schedule for the next couple days.

Don’t bother. Overnight charging will be fine. Set up a departure time if you haven’t already.

Remember, severe cold in MI = normal winter in Canada.

 

[ChasingCoral]

I am not at home this week so my car doesn't have a place to stay on a charger. It is going to be low 20's next 4-5nights. Would it help to periodically throughout the night turn on the climate control or just leave it off. By the time I need to drive it should be at least 32-34 degrees..

Leave it off. Unlike high heat, severe cold doesn’t damage the HV battery. You just need to warm it back up for use and especially before charging.

12v batteries are another matter.

 

[pepiopee]

I believe it's also been determined that battery warming does not happen if you are charging under 36A, something to be aware of. Some one correct me if this is wrong.

Also, don't forget to set your tire pressure to account for the extreme cold, you lose about 1 lb of pressure for every 10 degrees of ambient temp drop.

Interesting. I'd like to check on this - I'm using just on a 30A circuit netting 24A.

 

[dalola]

Interesting. I'd like to check on this - I'm using just on a 30A circuit netting 24A.

See Mach-Lee's response to this above....apparently it does still warm some, but at a reduced level. I'm only charging at 16A, but my garage is also heated to ~50 degrees, so it's not a huge impact for me.

 

[DK_Min]

I learned a lot today! Haven’t run the full calcs but the reduction in range is given.

What I don’t expect was the power limiter (which makes sense from a protecting the battery and electronics) standpoint.

Are those the jail bars everyone talks about on the power meter? Once I got to around 30% I wasn’t able to use full power anymore (or anywhere past those bars) and then down at 25% I got the other warning. Any details on when the power is reduced?

Parking it in my warm garage tonight and will do a full charge up to 100% (as I have never charged it above 90% and want to calibrate the gauge and do some balancing of the cells.

All good things to learn!

 

[AliRafiee]

I learned a lot today! Haven’t run the full calcs but the reduction in range is given.

What I don’t expect was the power limiter (which makes sense from a protecting the battery and electronics) standpoint.

Are those the jail bars everyone talks about on the power meter? Once I got to around 30% I wasn’t able to use full power anymore (or anywhere past those bars) and then down at 25% I got the other warning. Any details on when the power is reduced?

Parking it in my warm garage tonight and will do a full charge up to 100% (as I have never charged it above 90% and want to calibrate the gauge and do some balancing of the cells.

All good things to learn!

Those are the jail bars. They grow in various levels as you go faster, your battery level gets low, and/or gets cold.

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