Winterize your Electric Car

What does it take to winterize your electric car, and keep it running well (and far) in the cold? Your gas-guzzler's battery might be dead when you wake up on a snowy morning, so how much worse might it be for a car that runs on nothing BUT batteries??

I thought I'd ask some of those happy folks in Canada standing hip-deep in snow next to their electric pickups. I figured if you can dress your EV for an Ontario winter...

...there's pretty much nothing my Seattle sky could dish out that it couldn't handle!

Here are the tricks to winter-proofing your EV.

Winterize your Batteries

Cold slows down the chemical process that goes on inside the battery, so that your batteries don't take a charge like they do in warmer weather, and they don't give out power like they did in the summer, either.

A car with a large battery bank is less vulnerable to cold than the small NEV. You're more likely to be suffering from cold batteries in your Zenn than in your S-10 conversion, because that big wad of batteries huddled together for warmth behind the cab of your S-10 does a lot better job at retaining its heat through the winter than your little Zenn, which splits its battery bank fore and aft under the floor (surface area to volume ratio).

Do you have to worry about batteries actually freezing overnight? Usually, no. Lead acid batteries won't exactly freeze until they get very cold (-40F) because of all the stuff in the battery water. If it gets that cold where you live, you'll have to do something to help them. However, at freezing temperature (Zero C), you've lost 40% of your batteries capacity.

Recommendations for winter-proofing your battery pack

• Drive.
  Keeping the car moving during the winter, keeping the batteries charging and discharging, keeping the motor running, keeping the cabin heater heating...all these things contribute to keeping your batteries warm.
• Charge.
  Charging warms up your batteries. Most of the time, with large battery banks well insulated and garaged, this is enough, because it does generate a good amount of heat! The trick is to not let the heat out, which leads to the next point...
• Insulate.
  Cheap, easy-to-find styrofoam insulation (try the home improvement store) works just fine! Alternatively, there's that fluffy fiberglass batting you can use as a battery-blankie. I've heard of people using spray foam, and even (I thought this was cute) packing peanuts.
Keep these insulation requirements in mind:
• Not flammable,
• Doesn't give off toxic fumes if it gets acid spilled on it,
• Flexible enough to fit in the spaces, and
• High R value (measurement of how well it holds in heat).
• Note: Don't neglect the ventilation. It's easy to tuck the batteries in so snugly that there's no place for the charging gases to go. Don't forget to leave them an exit!
• Add heat.
  Some people use electric blankets to keep their batteries warm, others use heating pads or heat tape under the insulation. Generally, these are "plug in to the wall" arrangements, used overnight when the car isn't running; however, these come in 12-volt versions, too (check the marine supply shops) that you can run off your batteries using your DC/DC converter. (Um, check your ventilation again if you use something like this. 'Nuff said?; )
• Garage.
  Not everyone has access to this, of course, but it helps a lot to keep your EV in a nice, insulated garage overnight.

One more thing about those expensive EV batteries: Don't overdo the heating thing. It reduces your range to let your batteries get chilly, but that doesn't hurt them. It's just annoying. But even a little excessive heat? That'll reduce their cycle lives, and you'll wind up replacing them ahead of schedule.

How do you winterize the non-battery components?

Simply? Think about pancake syrup or olive oil in the fridge. It doesn't like to move when it's cold, right, kind of sits there in a blob? That actually means it takes a lot more energy to spread it where it needs to go. When you heat it up, it's runnier, and it flows easily.It's easy to forget, but lots of things in your car move freely because of liquid helping it along. In the summer, that liquid is free and loose and it takes little energy to get it flowing. In the winter, that friendly puddle of oil turns into margarine, and it takes half your battery juice just to turn your wheels around. That drains your batteries in a hurry, even if they're well insulated.

Fortunately, they make lubricants that stay runny even when it's cold.

And what about winterizing YOU?

So what are your options for keeping yourself warm through the winter in your electric car?Well, some folks just bundle up - wear a coat, thermals, alpaca wool...whatever it takes to keep alive without spending one drop of battery energy on silly little luxuries like cabin heat. You know who you are. You could do that. Or...

...the rest of us will be installing a small ceramic heater to keep the chill off the cabin, either powered by your main battery pack using a DC/DC converter (something like your gas-gobbler's alternator), or powered by a completely separate auxiliary battery. Those little electric heaters do a pretty good job, so you won't even miss all that heat-waste from your old ICE car. (...much. Sigh.)

If you're building a conversion and you live in a cold climate, the best thing to do is build it cold-proof from the ground up; it's much easier to do that than to try to retrofit later on.

Need some more help with cold-proofing your electric car?

Many thanks to:
REV Consulting Ltd.'s owner Richard Lane for a wealth of information (if I messed it up, it's not his fault, though; )
and to the EV Discussion List, especially this thread on insulating your battery boxes and this one, also having to do with how to winterize your EV.

To live outside the law, you must be honest.
- Bob Dylan

Enough of the Cold Already, Return to Homepage