Installation of an auxiliary heater to improve electric range

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Star63

Active member
Joined
Sep 10, 2018
Messages
43
Location
Finland
We've had a fairly cold winter this year in Finland. Even in the southern part of our country the temperature has occasionally been -25 deg Celsius. This has resulted in clearly reduced range and I found myself putting more clothes on when trying to minimize the need for the electric heating.

I finally decided to install a fuel burning auxiliary device to heat up the water in the heater loop.
This Eberspacher unit is located behind the frunk box:

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It could burn ethanol which would be more sustainable. I use fuel oil (diesel) instead because I think it is safer.

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The operating switch:

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I can use this heater instead of eletric heating while driving and I don't have to lower the temperature anymore to save electricity.
I can even pre-heat the car using the connected drive app. The fuel heater takes a signal from the original water circulation pump. The electric heater also kicks in but the PTC resistor will soon turn down the power consumption when the auxiliary device heats up the water.

It seems that the electric range is now about 30% longer. Very happy :cool:
 
Mitsubishi i-MiEV owners who live in cold climates also installed auxiliary heaters powered by diesel or alcohol. By their accounts, this worked very well and did not burn much fuel.

I've been surprised that an auxiliary heater hasn't been an option in early EV's with limited battery pack capacity. This makes so much sense rather than using limited battery pack energy to heat the cabin.
 
The old air-cooled VWs used gas powered auxiliary heaters like that.... it was an option. A friend had it in his VW Thing and it worked extremely well. I think of my Rex as a gas heater... as the need for heat on our 65~mile round trips for groceries etc is main reason I have one. The secondary reason is more flexibility for planning longer trips.
 
Great solution! Is there separate pumps for interior heating and battery thermal management? have you checked the battery temperature, to make sure it does not get too warm? Inspirational post!
 
The battery is heated using electrical resistance heating elements and cooled using a refrigerant loop from the A/C system. This water loop is only for cabin heating . It connects the cabin restive heater and the optional heat-pump to the cabin heater core.
 
alohart said:
I've been surprised that an auxiliary heater hasn't been an option in early EV's with limited battery pack capacity. This makes so much sense rather than using limited battery pack energy to heat the cabin.

A diesel air-fuel heater is a factory option on the Renault Kangoo Z.E. van.


British Gas retrofitted Eberspacher heaters on their fleet of 24kWh Nissan eNV200 vans. The BG vans are showing up on the used market now. I thought about getting one but decided the asking prices were too high.
 
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