What do the EV guys do in the winter?

[MetroMPG]

Heated/insulated battery boxes are pretty common in northern EV conversions.

Regular use will also keep the batteries warm, especially if you use a timer so the car is topping up just before you're ready to use it. Charging generates heat (as does discharging), and there's a lot of mass in your battery pack -- esp. floodies!

I rarely drove/drive the ForkenSwift in the winter, but the hair dryer pre-warm was my preferred method for cabin heat. I was never going very far, so it never cooled down enough to be an issue before the trip was done.

Mainly I avoided winter driving to prolong the cars life (salt/rust).

[NeilBlanchard]

Wearing a heated vest, used by motorcyclists, answers one heating issue. The defroster is a bit more complicated to solve, but we know how to do direct heating on the windshield, without the lines that are on the rear window.

[hat_man]

Thanks for the info. I guess I was wondering a little more along the lines of what do you all do with the batteries IF they aren't being used on a regular basis. I can see where if they are being used they would only have diminished capacity but if you weren't able to use them for an extended period of time how do you maintain them after they are fully charged?

I know the answer is probably a given for folks that have or have investigated EV's. Maybe someday I'll give it a try, but for now I need to try and finish my projects on the Ranger. So much to do and so little time.

[MetroMPG]

Just how extended a period are you talking about?

If you're talking weeks, then you'd want to do a top-up charge before using the vehicle anyway (to replace capacity lost to normal self-discharge). That would warm the batteries some.

[oil pan 4]

Originally Posted by MetroMPG

Heated/insulated battery boxes are pretty common in northern EV conversions.

Regular use will also keep the batteries warm, especially if you use a timer so the car is topping up just before you're ready to use it. Charging generates heat (as does discharging), and there's a lot of mass in your battery pack -- esp. floodies!

That will work well for lead acid.
The LiFePO4 cells put off surprisingly little heat.
I had my LiFePO4 pack almost get drained from leaving my running lights on at work one day (LED running lights all around saved my LiFePO4 batt from a deep discharge). So I pulled the Anderson connectors and threw them on our "big 12v battery charger" and brought them from nearly drained to full charge with about a 4C charge rate.
There was very little detectable heat build up and I only know this because I was afraid of too much heat build up so I kept checking them every few minutes. Then after about 20 minutes they were fully charged and barely any warmer.

On a side note I read that any charging done when the lithium battery stack its self is below 20'F can cause you to permanently lose up to 20% of your capacity in one charging.
I don't know if this applies to LiFe or LiCo, the article I read just said "lithium".

[Ryland]

I put my 32 year old electric car in storage once there is snow on the ground, once every month or two I plug it in to top the batteries off, my batteries are about 5 years old and still in good shape.

On my lithium batteries on my motorcycle I have a thermosensor on each cell in the pack that is part of the battery management system, charging the cell (GBS brand, 100 amp hour cells) I do notice that they get warmer by a few degrees, so far that has just been to top them off, so I'm not sure how warm they would get from a full charge, I'll know in the next few weeks when I get the license plates in the mail.

[Daox]

EVTV did a test on that. Most of the heat is generated in the last ~10% or so of the charge. Basically the constant voltage part of the charging, not the constant amperage. This is just one more reason to limit charging to less than 100%.

[thingstodo]

Does anyone know from experience what the low temperature on their BMS is programmed to? Where the BMS refuses to charge the batteries until they warm up.

I have read 0C (32F), -20C (-4F), but as seen on EVTV (that`s why I looked) the battery spec sheets don`t seem to match the advertising, or sometimes even other spec sheets for the same chemistry but a different amp-hour capacity.

I am going to have to heat my pack, and insulate it. Saskatoon, Canada gets down to -40C (-40F) a few days a year. That may cause me some issues in summer when I may need to cool the pack ... we also get a day or two that hits 35C (95F).

[Daox]

I haven't seen any testing on that, but I've heard 0C is the lower limit as well.

[fidalgoman]

I also wondered about electric vehicles in extreme weather conditions be it 114 F in Phoenix or -25 F in the winter here in Montana.

Don't get me wrong I'm not dissn' electrics. I like the idea. It's just that when you have to run a heater in the winter or an air conditioner in the summer what does that do to your range?

If you take your car skiing and park it over night in minus ten or so and head back to the city an hour and a half away without being able to plug it in, is it practical or do you need another vehicle for when times aren't optimal.

I'm not talking about a couple of lead acid batteries and a golf cart motor but a sophisticated vehicle like the LEAF or Tesla?

Just curious how that works out.