Heating in a EV car

Hi Everyone,

I am looking for advice on how to heat a car that doesn't have an engine. I need to heat a vehicle using electrical technology and not sure what the best practice would be.

I know that all electrical heaters are 100% efficient in theory, and that fan assistance is probably nice to get even distribution.

But I'm not sure about what battery technologies would be best: lead acid, leisure battery, LifePo, etc?

I'm fairly happy with basic circuitry and a soldering iron, so making something with a thermostat is no problem, but perhaps an off the shelf product could be a good start?

The vehicle has plenty of room for batteries, so space is not a problem.

Perhaps the answers are obvious, but I'm not particularly well versed in these areas Thanks anyone for any advice.

Ben.

Heat pumps can use your packs power to transfer in about 5x more heating energy from the outside environment to the inside of your car to heat you. If a normal heating element is 100% efficient, they are ~500%.

That said, heating the whole inside of an EV if you on lunch wanted to heat your body is quite poor efficiency.

A good heated seat pad, and heated steeering wheel cover can do a surprisingly good job at keeping the driver warm while not wasting energy heating the entire vehicle interior.

As someone who rides eBike through winter in NYC - electric clothing seems to do the trick. Similar to what Luke suggests using a heated seat and perhaps control surfaces? Nichrome wire stuff but fairly efficient application of battery capacity. Basically keep chest/core blood warm, arms/legs generally follow.

ICE vehicles waste so much engine heat it’s relatively easy to heat an entire passenger compartment for hours on end. Unfortunately, EV’s can’t afford that luxury yet so we must look at and explore different and/or more efficient approaches.

Thanks for your input folks.

I agree, keeping your core warm is nice and efficient and warm clothes, wooly hat, heated seat pads are a nice idea. My only problem with that approach is my poor old passengers

I didn't know heat pumps had made it into vehicles, that sounds really interesting. I see the Nissan Leaf and Renault Zoe have adopted one: http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/heat_pump_cabin_heater.html

A bit of a rant on the Tesla forums about the pro/cons (a Tesla does not use a heat pump) https://my.teslamotors.com/en_GB/forum/forums/why-not-selfcontinaed-heatpump

Looks like a fun area to research, cheers all.

If you look around on DIY Electric Car forums, there've been some discussion about that sort of thing, including heated seats and steering wheels, to minimize the amount of heating needed, and thus power wasted on that.

Also have been discussions about DC powered air-conditioner units, which may also be usable as heatpumps (or may be reversible by design).

We put a 500 watt 110volt out of a fan heater in my mates Toyota hilux conversion with the same thermostat he runs 144 volt system and heats the car in about 2 minutes in a -8 degree frost. And doesn't seam to effect the battery pack, he only has a 50km range. The PITA job was getting to the heater box to pull out the water coil.
Cheers Kiwi

Propane heaters are quite small and efficient.
I have converted old soviet car kerosene heater to propane. I used 12V digital thermostat and 12V solenoid valve from ebay.

I built a operator cab for a crane I had a few years ago. I used an ESPAR diesel heater. These are what the truckers use to keep their cabs warm when the engines are shut down. Not cheap, but incredible efficiency, with extremely low burn rates. The crane I now have came equipped with the same heater. i gallon of diesel lasts for days, one number that sticks in my head was .07 gpm on high (I think, really low). Thermostatically controlled, and lots of heat almost instantly. Sure it's using diesel but so little for so much heat..... quiet also. German built I believe.

vax said:

Propane heaters are quite small and efficient.
I have converted old soviet car kerosene heater to propane. ]

Click to expand...

is that a direct space heater ? Or an indirect unit that heats air or water ?
The thought of having a direct propane burning space heater inside a car is perplexing