Auxilliary Heater

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i3maybe

Member
Joined
Jan 13, 2020
Messages
17
Apologies if this has been asked before but I am trying to get my head around the heat pump option and am getting mixed messages from the BMW dealers.

I understand that the heat pump has an optimum temperature operating range and as I am in the UK where the temp is commonly around 10 degrees that is a positive.

I also understand the process of pre-conditioning the battery by setting a 'switch on' 3 hours before intended departure.

What I am a little confused about is whether the heat pump is operational and therefore adding to range during normal driving?

So if you didn't pre-condition the battery / cabin before leaving (and while connected to the charger) would there actually be any benefit to range on a car with the auxiliary heater?
 
Thanks for that.

Most dealers in the UK - (where it is a £500 + option and rarely specified) - say it is only for pre-heating !!
 
i3maybe said:
What I am a little confused about is whether the heat pump is operational and therefore adding to range during normal driving?

So if you didn't pre-condition the battery / cabin before leaving (and while connected to the charger) would there actually be any benefit to range on a car with the auxiliary heater?

Yes and Yes.

The heat pump takes the "waste heat" being created by the battery under load, and re-purposes it as cabin heat, though a heat exchange process.

During normal driving, if the heat pump has sufficient temps to work with, it will work in lieu of the resistive coil pack.

If you don't pre-condition the battery, it will take longer for the battery to "come up to temp," but once the battery is producing excess heat that needs to be removed, the heat pump will then utilize that heat to warm the cabin.
 
Thanks for the responses.

Am I right in saying the Aux Heating was fitted as standard to US spec cars?
 
eNate said:
The heat pump takes the "waste heat" being created by the battery under load, and re-purposes it as cabin heat, though a heat exchange process.
The heat pump plumbing is quite clever. It could operate in a mode in which heat is being transferred from the battery pack to the cabin. However, in colder climates when cabin heating is on, the battery pack likely needs to be warmed by its electric resistance elements rather than cooled by its A/C refrigerant coils. If the battery pack isn't being cooled, the heat pump would be transferring heat from ambient air to the cabin via the heat exchanger behind the air intake grill below the front bumper.
 
i3maybe said:
Am I right in saying the Aux Heating was fitted as standard to US spec cars?


Just so we're using consistent terms to avoid confusion:

North American BEV i3 models include the heat pump option. You can double check the heat pump installation in your car by entering your VIN in http://www.mdecoder.com.

All i3's (REX and BEV models) have the resistive coil heating. (When I hear "aux heating," this is what I think of, because some internal combustion cars come with similar coil packs -- also called "aux heat" -- to provide instant cabin heat while the motor is coming up to temperature.)

Lastly, all i3's have battery preconditioning -- the "dealer pre heat" you referenced in an earlier post -- that uses the car's high-voltage battery to operate a coil pack that in turn gets heat to the battery tray. This necessitates a pre-set departure time and also requires the car to be plugged in.
 
alohart said:
The heat pump plumbing is quite clever.


Agreed, Quite!

I saw a breakdown of the battery temperature management in a video Jalopnik posted, comparing the i3 to Tesla. Very interesting and worth a watch.

https://youtu.be/pgu6mkKZwNg?t=329
 
eNate said:
i3maybe said:
Am I right in saying the Aux Heating was fitted as standard to US spec cars?


Just so we're using consistent terms to avoid confusion:

North American BEV i3 models include the heat pump option. You can double check the heat pump installation in your car by entering your VIN in http://www.mdecoder.com.

All i3's (REX and BEV models) have the resistive coil heating. (When I hear "aux heating," this is what I think of, because some internal combustion cars come with similar coil packs -- also called "aux heat" -- to provide instant cabin heat while the motor is coming up to temperature.)

Lastly, all i3's have battery preconditioning -- the "dealer pre heat" you referenced in an earlier post -- that uses the car's high-voltage battery to operate a coil pack that in turn gets heat to the battery tray. This necessitates a pre-set departure time and also requires the car to be plugged in.

I agree Aux heat makes me think resistive heater.

The heat pump was standard until model year 2019 for the BEV in the US and never installed on the REx due to space constraints with the REx equipment. Now, sadly it is an option and I think a rather unpopular one so far due in part no doubt to the lack of educated sales people.

I love the heat pump it makes a huge difference in the winter and keeps the resistive heater from running down to 22f in my experience. It is the primary cabin and battery thermal management system when installed.

The heat pump is completely different than the battery heater often called the battery blanket. The heat pump does not pre heat the battery the battery blanket does that. In order for the battery blanket to pre-condition the battery, a few conditions must be met. The car must be plugged in ( on 110v the battery might deplete some) a departure time must be set, and that departure time must be programed at least 3 hours prior to the desired departure.
 
tjsean0308 said:
The heat pump was standard until model year 2019 for the BEV in the US and never installed on the REx due to space constraints with the REx equipment. Now, sadly it is an option and I think a rather unpopular one so far due in part no doubt to the lack of educated sales people.
It's such an inexpensive option in the U.S., just over $100 if I recall correctly. Every BEV sold where cabin heating would be used should have this option.

However, I wouldn't order this option because I've never heated the cabin in over 5 years of 2014 BEV ownership because Hawaiʻi, so I appreciate this being an option (I avoided the heated seat and battery pack option in our i3). However, our only BMW dealer stocks almost all REx models despite the distance to circumnavigate our island is only 100 miles, well within the range of a 94 Ah or 120 Ah BEV. So I assume that the few 2020 BEV's that our dealer will stock, if any, will have the useless heat pump option just to pad his profits.
 
Again - thankyou for your comments.

I am better educated on the subject now than if I had rung 25 UK BMW dealers at random - and I suspect - got 25 different versions of B/S for my troubles!!
 
The heat pump outputs in the order of 3-4 W of heat for a one watt input, so, when available, and when heating is required, it can maximize your range versus with the REx, which only has the resistance heating. When it's cold enough outside, the BEV will revert to using the resistance heating, though, and in really frigid conditions, would be similar to the REx, except for the extra weight it is carrying around.
 
Just on that last point, where I live the temperature is generally in the 5-15 degree centigrade range. My understanding is that this is a good range for heat pump efficiency - not too cold and not too hot. Am I correct?
 
i3maybe said:
Just on that last point, where I live the temperature is generally in the 5-15 degree centigrade range. My understanding is that this is a good range for heat pump efficiency - not too cold and not too hot. Am I correct?
I've read in the BMW Training Manual series that the heat pump is used for cabin heating until ambient temperature drops below -10º C.
 
Never gets that low where I am so it will be used all the time. Glad that I have specified it.

I noticed that in the UK the used i3's that seem to have the heat pump fitted are usually the ex BMW UK cars that are used for press events. (I guess they like to show the absolute maximum possible range for the press).

Ex-demo dealer cars never have it - no showroom appeal!!
 
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