Benefit of heated battery and heated garage

[fnegroni]

I slow charged my Mg4 SE SR to 100% today, including equalisation, while I was working from home.
I’m lucky in that for a couple of weeks every month I have access to a heated underground parking space with free charging, albeit slow at 3.6kW.

Loaded car with my luggage, ready for a trip from east London to Wokingham, setting off after work at 5.15pm

Car and battery at a balmy 19° Celsius.

Outside the temperature was around 3C at 5pm and got to 0C at 7pm when I arrived.

End result: in Normal mode, adaptive regen, auto A/C set to 22-23°C and using TJA for the most part on the motorway and couple of dual carriageway:

81.1 mostly motorway miles at 3.9 miles per kWh.
Average speed 37mph - journey time 2h 8 minutes exactly as predicted by Apple Maps when I set off.

Arrived with 58% and 124miles remaining on the GoM - essentially a total range of 214 miles.

Important to know the tyre pressures were at 2.5 bar at the front and 2.5 to 2.6 at the rear during the journey.

Oh, forgot to mention, intelligent battery heating was on from the start.

 

[dsimpkins]

So will the battery heat from the mains while plugged into charger?

 

[fnegroni]

So will the battery heat from the mains while plugged into charger?

It will, although because the garage is heated, there’s no need to use the on board heater.
The whole car, tyres, battery pack, the interior, is all in perfect condition

Tomorrow morning I have a 36 miles journey to the office and I am now charging from a granny lead at 2kW. It is currently -2°C outside. If I start the battery heater, it sucks up 1.5kW leaving me with 0.4 kW to charge the battery. So I will wait until it’s fully charged in the morning before starting the heater. Hopefully it will be fully charged and equalised by then.

I also put on a windscreen cover to prevent ice from forming hopefully it will benefit the cabin preheating too.

 

[JonnyG]

EV Luxury ... and great mls/kwh as a result

 

[okohll]

After a bit of searching found this

The state of the art on preheating lithium-ion batteries in cold weather

Preheating batteries in electric vehicles under cold weather conditions is one of the key measures to improve the performance and lifetime of lithium-…

www.sciencedirect.com

which says

'Charging at low temperatures can lead to undesirable anode lithium plating [21,22], and hence a reduced battery lifespan'

so I think I'll try turning on the battery heating at least while charging and see how it goes. Of course everyone's free to decide on trade-offs with other things (or just not to worry) but in my case that's what I'll go for, starting tonight.

 

[Martinonline]

It is unfortunate that there are only a few numbers in the summary paper. It would be interesting to know how the specified battery degradation varies with low temperatures.

I agree with your decision to heat whilst charging and will follow suit during these cold snaps.

 

[dsimpkins]

I usually charge at work, so by the time I arrive, the battery will have warmed up through use I believe.

However, useful to know for if I need to use granny charger at home.

 

[siteguru]

Don't heat the battery whilst charging using the granny - you'll likely get next to no charge going into the battery.

 

[fnegroni]

It was not really needed either. It heated the battery for maybe a minute from what I could see.

 

[Ian Key]

As @Mike80 has posted in another thread AC charging and driving warms up the battery. You only need to preheat the battery when using a rapid DC charger in cold weather.

 

[JonnyG]

As @Mike80 has posted in another thread AC charging and driving warms up the battery. You only need to preheat the battery when using a rapid DC charger in cold weather.

What about when setting off in sub zero temperatures with a very cold battery. How would the range and power delivery coming out of a 19°C garage with 19°C battery temp compare to 0°C ? Seems to have improved range for the OP.

 

[KH11]

Can you switch the battery heating on in the app or do you have to do it in the car? On the last podcast Miles was saying it’s not really necessary in this country as we don’t get it as cold as Finland for example. Unless you are going to a rapid charger that’s not far away from a cold start then the battery should soon get warm once you are on your journey.

 

[KH11]

I have found it, just had a thought that I had seen Burl Solomons talking about battery heating in one of his videos. So if I should require to use it I know where it is.

 

[tsedge]

Battery heating will help both range and power delivery - it has to due to the laws of physics.

I believe what Miles meant is that often in the UK it isn't worth it - but it will depend where you live and how cold it gets. It is particularly likely to be an issue if the car has been left for a long time in sub-zero temperatures.

 

[Waterstoney]

3.9 miles/kWh does is not high with heated parking compare with my outside parking.

My short trip is with low 2miles/kWh.

My 10 miles trips are around 4.0 miles/kWh (3.8, 4.1, 4.0, 4.0) in London with freezing weather in last two days of November:

• battery heater off
• Park outside with top cover for avoid frost
• 0°C to 3°C temperature according to car
• minimum heater A/C usage for removing frost and mist only
• 2.7 or 2.6 bar tyre pressure according to iSmart.
  [*]route speed: 20, 30, mostly with slow moving traffic on 50 miles/h road
  [*]ZS EV LR

I think MG4 is more efficient than ZS. I expect higher efficiency with heated parking. Maybe longer trip makes the battery warming up?

 

[fnegroni]

3.9 miles/kWh does is not high with heated parking compare with my outside parking.

My short trip is with low 2miles/kWh.

My 10 miles trips are around 4.0 miles/kWh (3.8, 4.1, 4.0, 4.0) in London with freezing weather in last two days of November:

• battery heater off
• Park outside with top cover for avoid frost
• 0°C to 3°C temperature according to car
• minimum heater A/C usage for removing frost and mist only
• 2.7 or 2.6 bar tyre pressure according to iSmart.
  [*]route speed: 20, 30, mostly with slow moving traffic on 50 miles/h road
  [*]ZS EV LR

I think MG4 is more efficient than ZS. I expect higher efficiency with heated parking. Maybe longer trip makes the battery warming up?

Mine was mostly motorway and none of those adjustments you appear to have to make: I wasn’t using any ECO settings and my A/C was on full AUTO. Which means I was using the heater and the a/c the whole journey. I also had intelligent battery heating enabled.
I’m just saying that if the car starts fully warm, the cold air outside has little impact on energy consumption. On that trip in milder conditions I would have probably got 4 mi/kwh or maybe a little more, but then I would have used hardly any heating and air density at higher temperatures is lower which impacts consumption at higher speeds.

 

[Tigger]

Can you switch the battery heating on in the app or do you have to do it in the car?

I can't see it in the app. Anyone disagree?

 

[Jeroen]

I can't see it in the app. Anyone disagree?

You can to it in the app, the setting is hidden under scheduled charging

 

[Waterstoney]

Mine was mostly motorway and none of those adjustments you appear to have to make: I wasn’t using any ECO settings and my A/C was on full AUTO. Which means I was using the heater and the a/c the whole journey. I also had intelligent battery heating enabled.
I’m just saying that if the car starts fully warm, the cold air outside has little impact on energy consumption. On that trip in milder conditions I would have probably got 4 mi/kwh or maybe a little more, but then I would have used hardly any heating and air density at higher temperatures is lower which impacts consumption at higher speeds.

Well. Normally I drove with normal mode. I sacrificed comfort just to see how the performance is in cold with ECO mode.

I traveled from London to Cambridge with ECO drive mode on ZS LR today.

London to Cambrdge: 4.1 miles/kWh
4°C, one driver no paasenger, almost no heating and A/C, 40miles/h average speed, 18% battery capacity was used.

Cambridge to London: 3.7 miles/kWh
7°C, picked up one passenger +100kg luggage, 21°C auto climate control (all the way) and adaptive cruise control in very wet foggy weather. 33miles/h average speed including the first leg. 23% battery capacity was used for the 2nd leg.

My conclusion: heating, ACC and load reduce range and efficiency.