MG ZS EV - MG guidance for charging in Winter months

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J0y

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This is from MGs EU website from 2021, so probably still valid for most other models including mk2.


So far this is the only 'official' guidance from MG I have come across, particularly whether or not to charge the car to 100%.

news.mgmotor.eu

MG Winter tips for electric motorists - MG Motor Europe

Learn how to maintain enough battery energy in your EV, and how to drive safely and without range anxiety in severe winter conditions.
news.mgmotor.eu news.mgmotor.eu
  • Always try to charge the battery to 100% while charging with AC (normal/slow charging). When charging with DC (fast-charging), it’s recommended to charge the battery to 80%.
  • If possible, charge the battery every night to ensure it has enough energy when you hit the road in the cold morning.
  • A low battery level and low temperatures have a negative effect on the remaining driving range. Park the car in a garage as often as possible. This could have a positive effect on the battery temperature.
  • Once the car is heated up, turn down the heater in the car to a more comfortable setting in the middle of the scale, or turn off the air conditioner to maximize your driving range.
  • Don’t drive too aggressively and keep your speed as constant as possible to minimize the average energy consumption and maximize your driving range.
  • Activate the adaptive cruise control when possible. This helps to keep your speed as constant as possible in order to minimize the average energy consumption and maximize your driving range.
  • Activate the strongest setting of the regenerative braking system to regenerate as much energy as possible in order to maximize your driving range. However, on a icy or slippery surface, it’s recommended to set a low regeneration level.
  • Use as many opportunities as possible to heat the battery, such as fast-charging (DC). The temperature of the battery will increase by normal driving and AC charging. At low battery level combined with low external temperatures and a cold battery, you may experience less power than normal. This adjusts when the battery reaches a normal working temperature.
  • Every 100% electric MG has an Eco mode available, if extra range is urgently needed. Be aware that by applying this feature, it will override the climate control of the car (it will turn off/turn down the heater in the interior significantly).
 
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2021 so supposedly for the 1.gen, which surprisingly (to me) uses NMC batteries even though it only has 42KW of capaticy.

Usually EV car manufacturers dont recommend to charge the battery to 100% when using AC for NMC batteries, so either this is a manual that came out late 2021, together with the standard range gen.2 (Which uses LFP batteries that does not degrade when charged to 100%) or MG says something different than "every other EV manufacturer"

LFP = Charge to 100%, not a problem
NMC = Charge to 100% if needed, but only to 80% if the extra range is not needed, and if 100% is needed, time the charge to get to 100% shortly before departure, as NMC really dislikes to be charged to 100% for extended periods of time.
 
The problem is that charging to 80% at home on overnight cheap rate with the Mk1 (NMC battery) is very difficult because it has no programming facility. I can time-limit the charge but that would result in very variable charge values. So in the absence of any other method I charge, whenever a charge is needed, to 100%. The car still shows 165 miles after a full charge in summer, but is down to about 135 miles recently. No one from MG has indicated I should not use this method.
 
Tim Green said:
The problem is that charging to 80% at home on overnight cheap rate with the Mk1 (NMC battery) is very difficult because it has no programming facility. I can time-limit the charge but that would result in very variable charge values. So in the absence of any other method I charge, whenever a charge is needed, to 100%. The car still shows 165 miles after a full charge in summer, but is down to about 135 miles recently. No one from MG has indicated I should not use this method.
Click to expand...
I only know the 2.gen, that has a slider in the battery menu where you can set it to 80%

Is there no such option on the 1.gen ?
 
I treat my EV like every other car I've had, except for I don't fill it up, just charge to 80% unless I'm going on holiday. I my charge it to 100% every so often but after over two years of ownership I've had it tell me to balance the battery. The rest of the time I charge when it's low and always drive in normal mode. I usually ignore the GOM and just go off the % battery, after all it's just a fuel tank but full of electrons not fossil juice.
 
My limited experience is based on fairly new mk2 SR (3 months) we charge to 80% roughly using off peak ohme charger. For example, if my car shows 36%, I could set to ohme app to add 45% .

Occasionally, I find especially during very cold weather spell it may be better to top up to 100% to make up the lost per kwh loss of mileage.
Risk to battery overheating in low temperatures which is the major cause of battery damage.

I agree with most comments here. It seems charging upto 80% for most daily commute/school runs etc is most sensible with occasional 100% as and when required.

hmadsen said:
2021 so supposedly for the 1.gen, which surprisingly (to me) uses NMC batteries even though it only has 42KW of capaticy.

Usually EV car manufacturers dont recommend to charge the battery to 100% when using AC for NMC batteries, so either this is a manual that came out late 2021, together with the standard range gen.2 (Which uses LFP batteries that does not degrade when charged to 100%) or MG says something different than "every other EV manufacturer"

LFP = Charge to 100%, not a problem
NMC = Charge to 100% if needed, but only to 80% if the extra range is not needed, and if 100% is needed, time the charge to get to 100% shortly before departure, as NMC really dislikes to be charged to 100% for extended periods of time.
Click to expand...
I have added the link
You are right the article is from Dec 2021, but MG make no reference to the type of battery this applies to.

I could not find any other official guidance from MG. One reason may be they want end users (us) to use it as we see fit. If they don't want to charge battery to 100% each time they must have mentioned it.
 
J0y said:
My limited experience is based on fairly new mk2 SR (3 months) we charge to 80% roughly using off peak ohme charger. For example, if my car shows 36%, I could set to ohme app to add 45% .

Occasionally, I find especially during very cold weather spell it may be better to top up to 100% to make up the lost per kwh loss of mileage.
Risk to battery overheating in low temperatures which is the major cause of battery damage.

I agree with most comments here. It seems charging upto 80% for most daily commute/school runs etc is most sensible with occasional 100% as and when required.


I have added the link
You are right the article is from Dec 2021, but MG make no reference to the type of battery this applies to.

I could not find any other official guidance from MG. One reason may be they want end users (us) to use it as we see fit. If they don't want to charge battery to 100% each time they must have mentioned it.
Click to expand...
Maybe its a tradeoff, the 1.gen only has a 42 kWh battery so if they tell you to only charge to 80% you only have about 35kWh of usable battery (Plus if you don't want to go below 10% it's only 70% usable battery so only about 30 kWh, which will give a pretty low range, especially in winter)

So they say "Just go to 100%" because they know the battery is not likely to degrade to 70% before the battery warranty runs out, even though the degradation might mean you end up with 75% SoH instead of 85% if you treated the battery "well".
 
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Li-ion, NMC etc. batteries don't like charging when very cold, but according to this link on SpeakEV, the later MG's have a battery heater. Which EVs have battery heating? In theory you could retrofit one inline with the cooling cct. to keep it toasty on cold mornings... Garage is good, heated garage is even better! 😊
Those of you who have remote control via the app, can turn on the car to heat up, and then off 20min later, and let it recharge whilst you have a shower and breakfast... Then it'll be warmer inside and out!
Those of you who don't have, could always put a couple of parafin heaters under the battery, that 1.5m aluminium machining will spread the heat out.... 😄
 
Last edited by a moderator:
PVperson said:
Li-ion, NMC etc. batteries don't like charging when very cold, but according to this link on SpeakEV, the later MG's have a battery heater. Which EVs have battery heating? In theory you could retrofir one inline with the cooling cct. to keep it toast on cold mornings... Garage is good, heated garage is even better! 😊
Those of you who have remote control via the app, can turn on the car to heat up, and then off 20min later, and let it recharge whilst you have a shower and breakfast... Then it'll be warmer inside and out!
Those of you who don't have, could always put a couple of parafin heaters under the battery, that 1.5m aluminium machining will spread the heat out.... 😄
Click to expand...
I think i read that a Tesla will not charge its NMC batteries if the battery pack temperature is below 0°C, if this occurs and you start a charge, all of the energy from the wall box goes into heating the battery, and the actual charging does not take place until the battery is above 0°C, I would imagine the ZS EV is not that different, it uses the same battery chemistry so probably somewhat the same chemical / temperature constraints apply.

When I navigate to a supercharger the car will heat the battery to atleast 40°C if it is left to control the heating itself, this is of course to make the battery warm enough to accept 250kW, i would imagine the ZS EV does not need the batteries to be heated to quite that temperature to accept 90kW and another thing is.....Charging the batteries at a SuC will also heat the batteries, as evident on a hot summers day where the cooling fan comes on pretty quickly when starting a charge, to expel heat from the battery pack, the battery does not like getting too hot either.
 
Last edited by a moderator:
That is interesting. I think MG mk2 has a battery heater. In the MG app it suggests to use scheduled battery heating an hour before using the car. No other info or context. Did experiment a bit but no conclusive results. Also if do schedule it from thd app, there's actually no way to know if it had done anything.

Have not tried DC charging yet, but will do soon after a longer journey by which battery would naturally be warmed up.
 
J0y said:
That is interesting. I think MG mk2 has a battery heater. In the MG app it suggests to use scheduled battery heating an hour before using the car.
Click to expand...
Really? I have a Jan '24 Trophy Connect and can't see such a setting in the app. I can start the window demister or the A/C but can't see anything about battery heater or even battery temperature.
 
Click on the battery button on main screen, takes you to another screen, on top right corner you will see a very tiny hexagon symbol, click on that you will see those options.

Not sure why the have made those hard to find.
 

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J0y said:
Click on the battery button on main screen, takes you to another screen, on top right corner you will see a very tiny hexagon symbol, click on that you will see those options.
Click to expand...
Thanks for that - I'll use it in future when it's a cold morning.
 

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