MG4 Trophy Preheat Battery Help

[the briggie]

I was thinking about the advice Tesla gives in their manual about fast charging when the battery is cold: basically, don't do it! Here is what the manual says:

"You can minimize the amount of charge time by using Trip Planner (if available in your market region) to warm the Battery while driving to a Supercharger."

Which I interpret as meaning that driving the car warms up the battery. See also post by Ayoull above.

My car recommends that but only for rapid charging not necessarily for day to day driving. Mines is auto set for -5 on 10 off but can be adjusted to 5 on 10 off for DC rapid charging. As you can see it is temp dependent measured at the battery. More useful in Nordic countries but given what we are experiencing

The normal driving efficiency is probably no battery heat effectiveness for short hops ( battery usage v benefit) but longer you may see more benefit imo by preheating

 

[Ayoull]

Good point so by warming up we mean the "electrons and ions" are moving more freely increasing efficiency

When a battery is used (discharged or charged) it naturally produces heat through the transfer chemical reaction that occurs inside the battery via electron flow, it will heat the battery slightly but not to summer temperature levels, but this will inevitably improve battery performance slightly.

This is why battery thermal management is geared more towards cooling a battery opposed to heating as a battery will naturally warm itself up but not cool itself down, hence issues with battery life in cars without thermal management like the nissan leaf

 

[PeteC]

If you are on a journey, and need a rapid charge, I assume you will have been driviing for some time. In this case, my understandiing is that the battery will already be warm, so no extra heating is necessary.

Pre-heating is exactly that: heating a cold battery before you start your journey.

I wasn't meaning pre-heating before a journey. I was talking about the intelligent battery heating that is available in the battery menu. It's shown at about 1.30 in the following video and is being used on the way to the charger to help with rapid charging. I've also seen mention of it being used in the same way in the MG5 forum. What I can't find is how long before charging I should turn it on.

 

[Ian Key]

Looking at the time on the infotainment screen it appears he switched it 35 to 40 minutes before charging.

 

[PeteC]

Looking at the time on the infotainment screen it appears he switched it 35 to 40 minutes before charging.

Oh, why didn't I think of that!. Thank you Ian!

 

[Tigger]

Thanks for posting that video, Pete, brilliant! Please let us know what happens with rapid charging when you try battery preconditioning . . .

 

[SEastEV]

Note* Preheating the cabin will NOT work via the app if the car is plugged in but not charging. MG are aware of this and investigating

Does that include the situation where it is plugged in but finished charging to 100% and so has stopped because of that? Can I still pre-heat the cabin in that situation?

 

[PeteC]

Does that include the situation where it is plugged in but finished charging to 100% and so has stopped because of that? Can I still pre-heat the cabin in that situation?

If my Trophy is plugged in but no longer charging, I can use the app to start pre-heating. It will start charging at the same time, but I'm usually only charged to 80% and I don't think I've tried it at 100%. I might get a chance to try that this weekend as I'll be taking it up to 100%. However, I know that some people have found that they can't start preheating when plugged in unless they start charging manually first. Again, I don't know if this is at 100% charge.

 

[SEastEV]

If my Trophy is plugged in but no longer charging, I can use the app to start pre-heating. It will start charging at the same time, but I'm usually only charged to 80% and I don't think I've tried it at 100%. I might get a chance to try that this weekend as I'll be taking it up to 100%. However, I know that some people have found that they can't start preheating when plugged in unless they start charging manually first. Again, I don't know if this is at 100% charge.

Thanks Pete. Let me know if you do get a chance to test. Seems like the issue might only be affecting some people then?

 

[siteguru]

Does that include the situation where it is plugged in but finished charging to 100% and so has stopped because of that? Can I still pre-heat the cabin in that situation?

It may depend on the charge point. In my case the wall box goes into standby mode when the car has told it that charging has finished. In that situation I can't start cabin preheating (or battery heating) via the iSMART app - I have to unplug the the charge cable first. (I also can't set the car to start charging because it starts and then tells the app very quickly that it is fully charged and so sends the Stop signal before I can do anything like start preheating).

This is an iSMART app/car firmware issue which MG are aware of (but no ETA as to a fix).

 

[SEastEV]

It may depend on the charge point. In my case the wall box goes into standby mode when the car has told it that charging has finished. In that situation I can't start cabin preheating (or battery heating) via the iSMART app - I have to unplug the the charge cable first. (I also can't set the car to start charging because it starts and then tells the app very quickly that it is fully charged and so sends the Stop signal before I can do anything like start preheating).

This is an iSMART app/car firmware issue which MG are aware of (but no ETA as to a fix).

Thanks. May I ask which charge point you have?

 

[siteguru]

Wallbox Pulsar Plus

 

[kelloggs]

Please excuse me if this is not valid but I tried turning on battery heating and cabin heating yesterday morning while plugged in, no chance. Tried it today with 90% battery, turned on ohme charging and it all worked as described above. So work around is charge to 99% then turn it on?

 

[the briggie]

Its all about having an active charger..anything below 100% will create a demand if you manually ask it to

 

[Chr1sB]

Very interesting. I have now repeated my experiment of yesterday without pre-heating the battery, and got much the same result as I got yesterday. I started off getting 2m/kw, but this cranked up to 2.6 by mile 3, then up to 3.2 by mile 4. I was going to post that pre-heating didn't seem to be much help, but your experience could well contradict this.

A couple more variables to add to the mix:. First, I suspect that just running the car warms up the battery. But if you are driving fast, cold air flowing under the car could cool it. My maximum speed today was 50mph (lots of traffic) which might have helped my figures. I look forward to your results with pre-heating with interest - your trip of 120 miles is a much better test than mine.

P.S. For the record, the temperature here this morning was -1.8C.

I pre heated the battery about 30 mins before I drove off and also pre-heated the cabin too today before I set off on a 15 odd mile journey. Similar temps and setting to the last journey I took.

Interestingly the m/kw this time was very different to last time when I didn’t pre-heat the battery or cabin (stayed at 2 m/kw for 40ish miles) as car started at 2.4 m/kw and then continued to go up until it peaked at 3.2 m/kw when travelling stopped after about 15 miles.

So whilst immediately better m/kw with pre-heating, the pre-heating did take 5% out of the main battery ie reduced range by approx 12 miles, before I started off, so it just seems swings and roundabouts re whether to pre-heat or not given the bottom line effect on range is similar.

 

[PeteC]

If my Trophy is plugged in but no longer charging, I can use the app to start pre-heating. It will start charging at the same time, but I'm usually only charged to 80% and I don't think I've tried it at 100%. I might get a chance to try that this weekend as I'll be taking it up to 100%. However, I know that some people have found that they can't start preheating when plugged in unless they start charging manually first. Again, I don't know if this is at 100% charge.

I just tried pre-heating my Trophy when it was at 100% charge and it failed, which is what I thought it might as it wouldn't be able to take any charge. I turned the power off to the charger from our consumer unit and tried again and it pre-heated even though the cable was still plugged in as the charger wasn't on, so at least I didn't have to trudge through the snow to remove the cable!

 

[SEastEV]

I just tried pre-heating my Trophy when it was at 100% charge and it failed, which is what I thought it might as it wouldn't be able to take any charge. I turned the power off to the charger from our consumer unit and tried again and it pre-heated even though the cable was still plugged in as the charger wasn't on, so at least I didn't have to trudge through the snow to remove the cable!

Useful info Pete. What charger do you have? I am trying to find out whether the choice of charger would help for this (I don't have car or charger yet).

 

[PeteC]

Useful info Pete. What charger do you have? I am trying to find out whether the choice of charger would help for this (I don't have car or charger yet).

It's a pod point charger that's about 4.5 years old.

 

[Ian MG4 Trophy]

If you are on a journey, and need a rapid charge, I assume you will have been driviing for some time. In this case, my understandiing is that the battery will already be warm, so no extra heating is necessary.

Pre-heating is exactly that: heating a cold battery before you start your journey.

P.S. Pete, you talk about 'intelligent battery heating' - is this available on UK models? I was under the impressioon that it was sold in places like Norway. My app only gives me 'Scheduled Battery Heating' (or is Scheduled Battery Heating 'intelligent'?).

Intelligent battery heating is available on my trophy, and I'm in the UK, it's on the battery settings on the car not the app

 

[SEastEV]

It's a pod point charger that's about 4.5 years old.

Thanks. Anyone with a Zappi and MG4 out there who can confirm whether or not they can pre-heat cabin when the car is plugged in and at 100% charge (i.e. not charging)?