More On HEAT

[bennelson]

It's getting cold again.

All summer, I don't bother a bit about heat in the electric car. Today, I was working on location out of the trunk of my car. I had to wait a while for someone else, and don't have a heater in the car for the moment.

It was pretty cold. Which gets me back on the topic of heating an electric car.

My car has mostly just been a 72V system, running on used batteries.
I have a 150 watt heater UNDER my batteries in the rear box to warm them a tad. I ran that for maybe an hour this morning before I had to leave.

Last winter, I just set a household (120V AC) heater in the car behind the passenger seat. I ran that on a timer to heat up in the morning, running off wall power. When I would drive off, the whole inside of the car was already warm, and the heater would stay warm for about 10 minutes or so.

The only down-side to that is the heater takes up some space.

Other ideas that I have had include:

Reusing the original heater core, but with a small dedicated coolant tank rigged up to it with a "pumping-type" block heater rigged up to it.

Removing the heater core, and replacing with an electric heating element.

12V electric blanket.

Motorcycle-style heated jacket and/or gloves

Heated seat cover made from heat-tape sewn into cloth material (removable for summer!)


Ideally, you want to put the heat where you need it, to be most efficient. A heated jacket is more efficient than a heated car, if you just need to keep the person warm.

Maybe a two-part approach is best - I want to heat me AND the windshield (to keep from fogging up), and ideally, pre-heat the car cabin from wall power (rather than the batteries) when parked in my garage.

I guess a cabin heater that could run on AC OR DC would be nice. Relays could be used to connect/disconnect it from/to one circuit or the other when the charger is plugged in.

Maybe a heated seat cover would be the best way to heat a person. Heat tape isn't that expensive, but it IS designed for 120V AC. I wonder how well it might run on 72V? My under-battery box heater is about 130 watts of heat tape. Sure sounds more efficient than running a 1500 watt electric heater!

Anyways, throw out your winter electric car heating ideas!

-Ben


PS: I am also considering upgrading the car to 108V. That would be three more batteries. It all depends on the EXACT spacing of items under the hood for if I could cram them under there or not. My charger is variable, and goes up to a maximum of a 108V system. I would imagine that many 120V heaters would work fine on 108V DC.

[vpoppv]

Actually I do what you do and it works great: I turn on a little 1500 watt ceramic space heater and the car is super toasty by the time I get in. But I also have a heated/massaging pad, and although the massaging will rumble you right out of the seat, I don't feel hardly any heat from it at all. For the windshield, I have one of those little plug in the cigarette lighter defrosters which gets me by ok. Of course we don't get much colder than single digits in Oklahoma, and only dipped in the negative once in the last 6 years I've lived here.....

[Ryland]

You can get 75 watt heated seat covers pretty cheap from places like Speedway Motors, drug store heating pads tend to be 50 watts and get pretty warm (we use one at work for keeping granite slabs warm to cure epoxy) so a 12v 75 watt seat cover is going to keep you warmer per watt then any other option that I can think of, otherwise a 5 gallon 110v tank style water heater hooked to your heater core would work well when you could plug it in and should last a number of miles to keep the windshild clear, using battery power however to keep that tank warm is going to be a big drain so a ceramic heater added inline might be a good idea.
If/when I get around to putting heat in my electric car(s) I'm going to go with Peltier junctions and pull heat off the motor with them, thinking a closed loop to keep dust out of the motor, stacking them to get the most out of them.

[bennelson]

I saw a heated chair cover at the thrift store a while back.

I was mostly a back massager thing, but also heated. I thought it was slick, because I noticed the power supply for it was actually 12V. The heat feature on it was real low though - I could BARELY feel the thing get warm.

About 5 minutes ago, I just threw the electric-oil radiator back in the car.
With that AND the car seat in the back, my wife and I in the front, the car gets full pretty fast...

Maybe I will keep an eye out for heated seat covers.

[Tweety]

Why not re-use the heater core like you mentioned but run it on wall power? Isolate the watertank & lines and you'd get all the heat where you can use it... A smaller warmer for running of battery would probably be enough to keep the heat decent for a good while once it's already preheated as well...

Add the seat cover ans you'd be set for real cold...

[Frank Lee]

As a Beetle, Microbus, and Corvair owner, I know all about driving in stupid cold w/o heat.

For my body, it's no big deal: being winter, I'm already dressed appropriately with hat, gloves, etc., although when it gets extreme I go old school (ever seen pics of people on horse drawn carriages in the winter?) and I use a lap blanket. That does wonders.

The big problem is window defrost/defog. I try to remember to leave the driver's door window cracked open ever so slightly so it doesn't freeze shut, and so I can open it a bit more for the first trip of the day and exhaust all that hot steamy breath of mine out the window. Sometimes I will only close the door latch to first click so the whole door vents better- but that one is for my vehicles that do have heat, I shut the door all the way when the heater starts blowng warm a few miles down the road. The VWs need windshield scraping outside and inside, so a small scraper is kept in reach. It's kind of a pain but it hasn't been so bad as to motivate me to rig up heaters/defrosters/whatever, except that I have put a propane sunflower heater between the front seats in a microbus before.

[Weather Spotter]

Might not be room in the metro, but I did this in my s10 when it got cold out. I would take my hunting heater (propane) and fire that up. Nice and warm both air and radiant heat One 16 oz bottle lasted me more than a month of using it to work in the mornings. I would run it for about 5 min before I was too hot then let the heat slowly die off till I got to work. Aimed at the window it melted the Ice very fast

[bennelson]

If I end up adding more batteries under the hood, there may not be room up there for a water tank and heater to run to the heater core.
I like the idea of reusing the heater core, just because it's already there, and that is what it was designed for.

Typically, even if I don't have heat it usually isn't a big deal. Like Frank said, just cracking the window does a lot to prevent fog and frost.

I'd rather NOT use a propane heater, as half the fun of an EV is from NOT USING FOSSIL FUELS. I have toyed with the idea of converting it to a plug-in hybrid with a propane-powered generator. In THAT case, a propane heater might make a lot of sense. I know guys used to use propane heaters in the old VW's.

The other thing is that the heat isn't just for me.
Tonight, my wife suggested we go out to dinner (to the local mom & pop restaurant.) This would be the first time we have been out together since we had the baby. (A two-week-old!)

So..... I put the heater behind the driverseat, and plugged it in. I moved the baby car seat from her car to my car. It was maybe 10 or 15 minutes from the time that I plugged in the heater 'til we left for the restaurant.

I forgot how nice it feels when you open the door and get hit by a wall of heat - all without ever having an engine run!

Anyways, no complaints from the wife or cries from the baby about being cold!

On the drive back home, the heater was cold. Having at least a little something at that time would have been nice. My wife did say that she thinks the baby likes my electric car better than her car.

[Ryland]

Draw back of propane heat is that is produces water vapor and Co, so it can contribute to moisture issues inside the car.
My parents have offered to let me us their VW gasoline heater that they have left from a VW bus they used to have and I passed it up for the same reason as Ben.
Another thing to think about is a slip cover for your radiator heater that you stick behind the seat, if you can keep the mass of it warm then when you pull the slip cover off it goes back to heating the car.

[DonR]

I'm sure your well aquainted with the use of Rain-x antifog & a squegee(sp?). I have heard that making a fresh cut in a potato & rubbing the windshield with it works like anti-fog. At least it does on the inside of a helmet visor.

I will second Frank Lee's use of a fleece lap blanket & good boots.

Here is a link to some seat heaters. I'm sure you can find out more specs.
Carbon Fiber Seat Heater by WarmSeats? and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware-RH2

Is it possible to put defrosting elements onto a windshield yourself?

As for the heater systems, you could make an regulator/rectifier to convert from 110vac to 12(?)vdc. This would alloy you to use the same heating element from the wall or the batteries.

Could you make a heat exchanger to extract heat off of the traction motors & give it to whatever storage system you have, assuming coolant? Only have a pump move this coolant if it is at a certain temp. or temp. difference.

Good luck
Don