Slow rapid charging on multiple chargers

[mattdav]

Hi all,

This weekend, I took my 2020 ZS EV to the Fully Charged Show. This is a 240 mile each way trip for me so I was using rapid chargers. On the way back home yesterday, I charged at a 150kW Instavolt charger at Banbury, a 120kW GridServer charger at Norton Cane services on the M6 toll road and a 50kW Instavolt charger at Penkridge retail park off the M6. On each occasion, the charging rate never rose above 32kW. The first two charges I arrived with around 20% battery. I thought the ZS could charge at up to 76kW and I'm sure I've seen it charge before at mid-60s.

Any ideas before I take it to the dealer? I don't have a photo of the charger at the 150kW Instavolt but in all three cases, there were no other cars charging nearby so should have been no problems with load.

 

[fatboyfat1981]

Hi Matt,

Apologies if you already know this- There are other factors that determine the charging rate other than the charger & car’s quoted Max rate- the two big ones being battery temp & number of cars charging at from the same site, along with the battery SoC at the start.

To start with, 36kW at 20% on the car sounds about right- the charger & the car talk to each other & limit the charge rate when the battery is cold and/or at low capacity to maintain battery health. If the car & outside temps were cold that wouldn’t help either.

The last one is the charger itself. Regardless of the quoted max rate, if it can only pull x kW from the grid (possibly due to other cars chargers at that site at the same time) then that is another limiting factor.

I’m not saying that you’re definitely fine, but don’t worry yourself about it just yet- try another DC charge on a warm day with about 40% capacity left on the car & see how that works out before going to the dealer.

 

[mattdav]

Hi Matt,

Apologies if you already know this- There are other factors that determine the charging rate other than the charger & car’s quoted Max rate- the two big ones being battery temp & number of cars charging at from the same site, along with the battery SoC at the start.

To start with, 36kW at 20% on the car sounds about right- the charger & the car talk to each other & limit the charge rate when the battery is cold and/or at low capacity to maintain battery health. If the car & outside temps were cold that wouldn’t help either.

The last one is the charger itself. Regardless of the quoted max rate, if it can only pull x kW from the grid (possibly due to other cars chargers at that site at the same time) then that is another limiting factor.

I’m not saying that you’re definitely fine, but don’t worry yourself about it just yet- try another DC charge on a warm day with about 40% capacity left on the car & see how that works out before going to the dealer.

Thanks for this I think it may have been the temperature. It wasn't that chilly last night but probably below 10 C.

I've been looking on other forums and found a post where someone has the same problem as me. Like me, their other experiences were with a Leaf. Looks like the MG battery may be more sensitive to cold than the Leaf.

I'll wait for a warm day and have another go. Thanks for the response.

 

[hmadsen]

Thanks for this I think it may have been the temperature. It wasn't that chilly last night but probably below 10 C.

I've been looking on other forums and found a post where someone has the same problem as me. Like me, their other experiences were with a Leaf. Looks like the MG battery may be more sensitive to cold than the Leaf.

I'll wait for a warm day and have another go. Thanks for the response.

My guess is that this has been an issue, as they added a battery preheat option to the Mk2, where it is possible to preheat the battery if you are going to fast charge it on a cold day.

Cost a bit of range, but will get you in and out of the charger a lot faster.

 

[Kithmo]

Putting the cabin heater on and giving the car some welly just before charging will warm the battery slightly.

 

[Maciej]

My guess is that this has been an issue, as they added a battery preheat option to the Mk2, where it is possible to preheat the battery if you are going to fast charge it on a cold day.

Cost a bit of range, but will get you in and out of the charger a lot faster.

How do you do it?

 

[hmadsen]

How do you do it?

On the Mk2 you go to the battery menu and select to preheat the battery. Simple toggle switch on the screen.

I dont think this is an option on the Mk1 though

 

[JohnInFrance]

..... On the way back home yesterday, I charged at a 150kW Instavolt charger at Banbury, a 120kW GridServer charger at Norton Cane services on the M6 toll road and a 50kW Instavolt charger at Penkridge retail park off the M6. On each occasion, the charging rate never rose above 32kW.

On the plus side, you car didn't get bricked on either rapid charger - every cloud and all that