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What's up with the cold battery limit?

What's up with the cold battery limit?

Last week it was pretty cold here in Orlando, and the dash indicated that regen had been limited to half. Why is this? The battery can still output the full 200 kW, and the normal 40 kW of regen seems like it significantly below what the battery should be able to handle ( superchargers can pump in 160 kW ), so why is it lowered even more when cold?

Also isn't it supposed to heat the battery up to fix this? It was still limited after my 30 minute drive to work.

burdogg | January 10, 2018

I am not sure on all the logistics as I am NO expert, but one thing I have learned from someone on the 3 forum, batteries in general can be damaged if they are charged while cold. So the output is less of an issue, but the input. Note that yes, even after 30 minutes of driving, especially if you keep the heat off, the battery still may not be warm enough to do full regen - all in the name of preserving battery degradation or significant damage. Supercharging the same thing can actually happen - ie if it is extremely cold/ battery is cold soaked, it takes a bit to ramp up the charging speed - my understanding is that the battery needs to warm up, but it does so much faster because you are supplying energy to the car that can in turn heat up the battery much faster than you just driving it around.

Again, i am no expert, some are things I have gleaned from the forums from others. I am sure someone with more knowledge can pipe in and give you much better info that I :)

Rocky_H | January 10, 2018

There you go. To @burdogg do you listen! (/yoda) Yes, permanent damage to lithium ion batteries from charging fast while they are cold.
If only the manual said something about this. *hint hint*

burdogg | January 10, 2018

:) Yoda, it is so hard though, I just can't... I mean, have you read the forums lately, it is so hard to listen :)

Manuals? Manuals! Are you trying to tell me I should read the manual? I don't read no stinken manuals.

burdogg | January 10, 2018

Oh and sorry - I just read my post and should have been more strong on the permanent damage to lithium ion batteries from charging while they are cold, as i did know that one :)

lilbean | January 10, 2018

Manual? I thought the thing was automatic. Shoot!

agigngright | January 10, 2018

If you pre-heat the interior, will that heat up the battery before you try going out in the cold? I have read we should always pre-heat, but the only option I see on my app is the interior climate control. Am I missing something?

burdogg | January 10, 2018

You aren't missing anything - it is the interior climate control on the app. This will also heat the battery through natural use and heat. Now they supposedly updated the app to also pre-heat the actual battery when plugged in and there is supposedly a red battery icon right between the seats that shows the battery is being heated - I have yet to see it though, so don't know if it truly has been rolled out or not yet. But as far as I know, there is not an actual Pre-heat Battery button - it is just done by turning the interior heat on.

burdogg | January 10, 2018

Also the best thing to do is to time your charging so it is finished as close to the time you leave as possible - this will give you much better wh/mi and full regen.

bhoskins | January 10, 2018
burdogg | January 10, 2018

Thanks bhoskins - I have yet to have that show up - is it only when you are plugged in and temps are certain degree? What is the situation that you have that show up? or does it show up all the time?

LTO2 | January 10, 2018

@burdogg: Same, same: I have yet to see the battery-is-being-heated icon, even when outside temps were single digit (garage doors insulated, two walls with exterior sides not), lthe X connected to charger, and interior heating turned on.

Triggerplz | January 10, 2018

@burdogg battery preheat video

https://youtu.be/vE_0IU3Fexw

Triggerplz | January 10, 2018

It shows up on mine

Model_D | January 10, 2018

@psusi Do you have range mode on? Range mode doesn’t heat up the battery with electricity and it takes a long time for the X to warm itself up without the electric heat.

obiwin | January 11, 2018

Just here to re-iterate that the key thing is to have Range Mode turned off to allow for battery preheating. I finally got mine to preheat when I read in another forum posting to turn off Range Mode. The preheat icon on the phone app does not immediately show up, nor is it always on, so if you're not watching the app, you'll likely miss it. The battery preheat icon usually does not show for me until the cabin temperature had reached almost 50 degrees (a few times it has come on in the high 40s) It also seems to turn off when my cabin reaches 75 degrees, sometimes sooner. (I usually like to preheat to 76 or 77). The most preheating I've noticed is about 1/3 rd regen range, so don't expect full regen from preheating.

psusi | January 11, 2018

I work with li-po batteries and have never heard of "damage" from charging while cold. Only the internal impedance going up which in turn limits the maximum current both going in and out of the battery. If it can take 190 kW at normal temperature, I can't see a little cold cutting that nearly to 1/4th... unless it was below freezing maybe.

I did have the cabin heat on and don't *think* I had range mode on, but good to know that affects it.

johnse | January 11, 2018

@psusi

Li-PO batteries are a very different chemistry. They have some advantages, but energy- and power-density are not as good, IIRC.

Vawlkus | January 11, 2018

Burrdog: even timing my charge to end when I leave in the morning does not give full regen. The one and only thing that gives me full regen is if the outside temp is above 10 C.

burdogg | January 11, 2018

Vawlkus - you need to find somewhere warmer to charge your car :)

Vawlkus | January 11, 2018

This is Canada burrdog, it doesn’t GET warmer. }B)

burdogg | January 11, 2018

Guess that is why I get two r's - to emphasize the burrr, its cold here in Canada :)

psusi | January 11, 2018

Wait, I thought the Tesla batteries *are* lipo?

MXFan | January 11, 2018

No, Li-Ion

psusi | January 12, 2018

Interesting... that link says:

In short, it means that so-called “lithium-polymer” batteries are almost exactly the same as lithium-ion batteries, but they are instead contained in a flexible polymer casing. It’s basically just a repackaged lithium-ion battery.

Which is pretty much what I thought, despite what johnse said.

Rocky_H | January 12, 2018

Yeah, "lithium ion" is the overarching general category name that includes many different types of chemistries, so li-po and many other specific types are all forms of lithium ion batteries.

Regarding "won't charge when it's cold", my Zero motorcycle doesn't have a battery heating system, so if it's below freezing, it just _won't_ charge at all until it can get warm enough from being in the garage.