[Thewhirlwind]

Seen a few posts stating how much the cold in winter reduces range. Will the heat pump in the new M3 mean that the winter range is much closer to the summer one?

 

[cah197]

No, not really.

 

[reserves]

Seen a few posts stating how much the cold in winter reduces range. Will the heat pump in the new M3 mean that the winter range is much closer to the summer one?

It will be closer...

 

[Thewhirlwind]

It will be closer...

How much closer?

 

[dk6780]

It depends on how cold it is, how fast you drive and how you charge the car. There's no straight answer even once people actually have them.

 

[dwl99]

I shouldn't think it'll be anything remotely near the range you would get during the summer. This article claims a 20% reduction in the cold weather loss but I would take the manufacturer's claims with a large pinch of salt.

 

[mrdr_ev]

It only makes a difference if you use the cabin heating. This means that the cabin heating portion of power budget for winter journeys will be about 50% better efficiency. If you don't use cabin heating, or you drive like a nutter and cabin heating is a small part of the power budget, then you're unlikely to notice the difference.

 

[ringi]

A heat pump can make a large difference to a taxi driving that is heating a car while waiting for the next job, it makes little difference to someone doing 85phm none stop on a moterway.

 

[Thewhirlwind]

Just seen on the Tesla site they have new 2020 version M3s for £1300-£1500 off... I would have thought the upgrades are worth more than that?

 

[Thewhirlwind]

Just came across this post when looking into heat pumps:-
My car has the heat pump. I enquired to VW about its effectiveness, and they emailed me the following. I hope it helps you reach a decision:

"The heat pump reduces the energy demand needed for the air conditioning to climatise the interior by about 36% compared to the electric auxiliary air heater.


This reduction will benefit the road performance which will increase the real world range and will be reflected on the range monitor in cold conditions.


In the best conditions the e-Golf reaches a 190 km (118 miles) range. But normally the range is between 130 – 190 km (85 – 110 miles), but in cold temperatures the heat pump helps to increase the range (by a maximum of 36%) to reach a range in the region of 190 km (118 miles) again, which would be reflected on the car’s range monitor, so the car does know that a heat pump is installed."
Seems from this a heat pump negates the effects of cold weather on range?

 

[cah197]

Seems from this a heat pump negates the effects of cold weather on range?

Yes, but it's not free.

And the COP on a heat pump drops quite a bit once you're dealing with very cold temperatures. Almost to the point that it's equivalent to using an electric heater.

So it depends.

 

[firetrax]

Anything down to around 0C the heat pump will have big benefits on the energy used to heat the cabin. I saw this when moving from a Leaf with no heat pump to one with a heat pump. The heat pump will always be at least as energy efficient as a resistive heater and usually quite a bit more efficient especially in UK type winter temperatures.

 

[dk6780]

The reduction in range in cold weather is not just due to the use of charge in heating the car, but also due to lower efficiency in releasing energy from the battery and a reduction in the amount available for release. So even if you drove without the heater at all you get reduced range, and this is reduced further by using the heater. The heat pump reduces that final reduction by up to 80% but cannot touch the other reductions so will not get you back the full heater off range let alone to full Summer range.
Trust me, I know this from pushing the range limits in a heat pump equipped LEAF and having to drive without even the heat pump to have sufficient range in a car that could achieve the range on 80% charge in the Summer.

 

[Thewhirlwind]

The reduction in range in cold weather is not just due to the use of charge in heating the car, but also due to lower efficiency in releasing energy from the battery and a reduction in the amount available for release. So even if you drove without the heater at all you get reduced range, and this is reduced further by using the heater. The heat pump reduces that final reduction by up to 80% but cannot touch the other reductions so will not get you back the full heater off range let alone to full Summer range.
Trust me, I know this from pushing the range limits in a heat pump equipped LEAF and having to drive without even the heat pump to have sufficient range in a car that could achieve the range on 80% charge in the Summer.

So the info quoted above from VW is incorrect?

 

[dk6780]

IMO, Yes.

 

[Odinias]

So the info quoted above from VW is incorrect?

Even with petrol cars, the MPG is massively reduced during winter temperatures due to simple physics. In addition to what dk6780 said, the cold air is also a lot denser than warm air, which results in more resistance. So the battery/engine has to work harder to move the car. This is a known fact about cars operating in Winter.

So yes, even without the cabin heater on, you will never get the same range as you would in the Summer.

As for the quote from VW - consider the source, they're trying to sell or promote their own car so of course it's biased. Unless they have a car that can defy the laws of physics, to suggest that they can achieve summer ranges just because they have a heat pump is ridiculous. Not even Tesla would make such a bold statement. VW are definitely talking out of their backsides.

 

[cah197]

Even with petrol cars, the MPG is massively reduced during winter temperatures due to simple physics.

In ICE the heating is always 'free', so there's no difference in using the heater. In an EV even with a heat pump this could be 1-2 kW, which might be 10% of range in a smaller battery car.

With an ICE, colder, denser air improves the cycle efficiency a little bit.

 

[Odinias]

In ICE the heating is always 'free', so there's no difference in using the heater. In an EV even with a heat pump this could be 1-2 kW, which might be 10% of range in a smaller battery car.

Of course and I completely agree. I never said otherwise

With an ICE, colder, denser air improves the cycle efficiency a little bit.

That's not true. Can I ask where you got this information from? Can you provide a source?

All cars have a reduced fuel economy during Winter versus Summer regardless of whether it's an electric car (heat pump or no heat pump) or an ICE car (cabin heater on or off).

Colder and denser air does NOT improve the cycle efficiency in an ICE car, quite the opposite in fact.

 

[RobM]

Cold air is more dense. So you get more oxygen in the same space. More oxygen, bigger boom! This is also why altitude has an impact.

I dont have any sources. Its just what I rekon tbh.

 

[cah197]

Colder and denser air does NOT improve the cycle efficiency in an ICE car, quite the opposite in fact.

I see you must have failed your thermodynamics course.

So what are Inter-coolers all about then?