DBGator

Now that it is cold outside, it has become obvious that our car does not put out any hot air. The air coming out of the vent is very cold.

How do other people find the heater? Is your air warm when it is cold outside?

Old Rocker

The mornings and evenings started getting into the 40's recently and I used my heater. It worked as expected. I happened to have the driver screen set to display watts per mile and seen a large number (from memory) about 1000 or more which is much higher then I ever seen from using the air conditioner. Never have any of the accessories (climate, massage, audio) caused enough draw for me to alter my driving habit or charging plan.

hlothery

My heating works just fine. It is almost immediate on a cold morning. I generally keep the temp setting on 72-74 for AC in the warm months (ambient temps in the 80s-90s), and reduce that to 70-68 when I need heat. Today it was 45 outside and I had immediate heat and had to reduce the temp setting to 68.

DBGator

That does not sound like how my car feels. I check the energy efficiency settings and the climate control is not turned off for extended range.

Any other clues?

dharrar

I discovered the climate settings and have mine set for each weekday morning about the time I leave for work, then again in the afternoon when I expect to go home. Works great and automatically switches from heating to cooling if a warm day outside. I love the feature!

Do have my AMG EQS in for service where the two AMG controls incorporated in the steering wheel went blank and no longer function! Dealer will have had the car a week tomorrow so obviously have difficulty with the service.

AppleFan1

Same for me. It has gotten unseasonably cold here with lows in the upper teens and low 20s and highs in the low 30s lately. The heater works perfectly. However, I find that the range is reduced a lot.

DBGator

We have been told that the heater control module has a fault in it. Dealer having to contact Mercedes, as they have no experience with this. Probably will be several days in the shop.

c4004matic

DocBrown

Just before Christmas my EQS heater failed. It's not a good thing in Canada to have no heat. Basically, it's like a hair dryer somewhere under the dash, but alas there are NONE in North America. So I have a loaner until it's fixed. ETA on the part from Germany is February 20.

c4004matic

I can commiserate. A tough one in the tundra!

Diesel Benz

I cannot find any "hair drier" like part for the EQS within the HVAC box. I assume you are referring to an electric heater like the heater booster on MB diesel cars (a few small petrol cars too).

The main heater element on the EQS is a PTC heater in the low temperature coolant circuit. This is a high power resistor, a bit like the one some houses have for hot water heating. In addition the EQS has the heat pump, the HVAC system working in reverse. I guess this is a market area dependent option even in the EQS.

The PTC heater element seems to have failed on other Mercedes EVs more often than reasonable. Perhaps the same issue here.

finlayson

I had to look up "PTC"; I think this is what the previous poster was referring to:
https://en.wikipedia.org/wiki/Thermistor#PTC

Tjdehya

I am 1000% sure that the EQS does not have a heat pump. This was a big debate when the EQS launched. The entire EV industry was wondering why MB would launch such a vehicle without a heat pump.
That plus the fact that the EQE SUV will be the FIRST EQ to have a heat pump. (From what I understand, It is still not a true heat pump)
The lack of a heat pump is why the EQS losses a large percentage of range in cold temps.
It’s definitely in the top 5 of the poor engineering decisions list for this EQS.

Diesel Benz

Thanks for clarifying that. I guess the initial info has mislead me to assume all MB EVs would have a heat pump. Also mislead as pretty much all other EVs have a heat pump, even the small VW ID3 (on cold countries). Even some old ICE cars have a heat pump.

No wonder the EQS has no heat if the PTC heater is broken.

Can you share more details about the EQE SUV heat pump, why is it not a true heat pump?

Tjdehya

Exactly, it is one of the many engineering fails by MB in the EV venture.
Just my opinion based on my reading. It is not something I know for sure but judging from MBs description it doesn’t sound like a real heat pump.
​​​​​​​

c4004matic

​​​​​​​Mercedes does not use a heat pump, and its not necessary. In really low temperatures a heat pump is useless, thus, cars with heat pumps also use resistive heaters. The Mercedes' EV heating system approches the efficiecy of a heat pump at less extreme temperatures without the complexity or cost of a heat pump. It also has the additional benefit that its ICE inspired radiator type system is equally adept at cooling so power limiting due to excessive battery overheating is almost unheard of.People hear some new term that they don't understand and suddenly every one just walks like a lemming off a cliff.

Diesel Benz

A proper heat pump works well below -20 degrees Celsius (decent efficiency). One might claim EQS does not need it because it has a big battery and the range is still sufficient at low temperatures.

Considering how owners at this forum talk about savings with ECO+ modes etc. I'd say many would still like to have the efficiency improvement from a heat pump if they often drive at temperatures below +10 degrees Celsius (50 F).

Heat pump would not cool the battery, might be used for heating the battery but I would not consider that necessary. Just heating the interior makes sense (for some of us).

c4004matic

Absolutely incorrect. We are not talking about a house. A heat pump works by differential in temperature (its an AC compressor in reverse). The pipes on a home installation are buried under the frost line, thus maintaining efficiency at very low temperature, thats nowhere similar to the situation in a vehicle. In an EV, nothing makes significant heat. Thus, as the temp gets colder, the pump has no gradient in temperature to work with. Below 20 degrees in starts to struggle, and below zero its just dead weight.

Diesel Benz

Are you not familiar with air-to-air heat pumps in houses? The exact same scenario as on a car. The air outside the house can be -20 C and the air inside the house some +22 degrees C like inside the car.

c4004matic

Again, there has to be a temperature differential....My daughter has heatpump AC in Seattle. It works great till around the 20s below that they also have resistive elements. Just like a normal AC cant cool air at low temps! It just turns off the compressor!

ua549

Normal AC can cool at low air temps. I cooled a mainframe computer in my garage and the AC kept cooling even when the outside temps were in the 40°F range. At that time I maintained a 65°F temperature year around in the garage. If the AC stopped working the temperature would soar into 3 digit territory within 5 minutes during the overheated shut down. (I didn't have 3 phase battery backup.)

c4004matic

In the 40s....​​​​​​​

ua549

The AC worked with a 60°F differential in both heating and cooling modes. The specs indicated that the 8 ton unit had a ±90°F range.

Prago

The EQA and EQB have heat pumps actually. No idea why the more expensive EQ vehicles do without.

https://group-media.mercedes-benz.co...l?oid=51162885

Diesel Benz

Which temperature differential are you referring to? Theoretically a heat pump works as long as it cools the gas/liquid down to a temperature lower than outside air (assuming a pump heating the cabin or a house from outside air). In practise one needs to take care of water freezing etc. but commercial products do that.

The example video above shows a heat pump that works (efficiently enough) at -13 F. This pump is intended for house heating but what would prevent the same technology being used in cars? Perhaps these are not common in the US but it does not mean they do not exist or would not be common elsewhere (like northern Europe). My understanding is that the main thing is the type of gas used. The cheap and traditional ones may not work but those are not allowed any more (in Europe). ICE cars run on CO2 even if only for cooling.