Getting 22kw charge on MG ZS

billybonfire3

billybonfire3

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Hi Am I right in thinking that, due to the car, any type 2 charger I use, even a 22kw one, will only deliver 7kw as the the fastest AC the car will convert. To get faster it would have to be a teathered CCS?
 
billybonfire3 said:
Hi Am I right in thinking that, due to the car, any type 2 charger I use, even a 22kw one, will only deliver 7kw as the the fastest AC the car will convert. To get faster it would have to be a tethered CCS?
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Yep - it's all to do with the car supporting single phase AC (1 x 7kW) rather than three phase 22kW AC (3 x 7kW). As mentioned above, even 11kW will only give 3.5kW (3 x 3.5kW => 11kW).

You might see some of the cars sold in Europe supporting 11kW but apparently three phase supply to the home is more common there than in UK, so UK models have single 7kW rather than three phase 11kW
 
biffo said:
Yep - it's all to do with the car supporting single phase AC (1 x 7kW) rather than three phase 22kW AC (3 x 7kW). As mentioned above, even 11kW will only give 3.5kW (3 x 3.5kW => 11kW).

You might see some of the cars sold in Europe supporting 11kW but apparently three phase supply to the home is more common there than in UK, so UK models have single 7kW rather than three phase 11kW
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The same applies if you have the onboard 11kw charger if you use a single phase cable
 
pjmuk said:
An 11kw charger will only charge the MG at 3.5kw, as it's 1/2 the current!
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Actually, it may only be 1/3 - single phase from 3 phase? If right - that would mean 3.66kW from an 11kW 3 phase source and 7.66kW from a 22kW 3 phase source. I have read though that the maximum power accepted by the ZS type 2 socket is 6.6kW. (Not sure about that.)
 
This info from EV Database can help.This is for LR but same applies for SR as well.Check the last entry in the table and the note below it:
Screenshot_20220227-161547_Chrome.jpg
 
So a if you have a 11kw car charging at a home point in the UK on a 7kw charger you will only 3.7kw? As it will only use 1 of the 3 phases
 
N2STY said:
So a if you have a 11kw car charging at a home point in the UK on a 7kw charger you will only 3.7kw? As it will only use 1 of the 3 phases
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No - if your car is capable of charging on 3 phase at 11 kW and you connect it to single phase 7kW you will get 7kW. If, on the other hand your car can only accept single phase and you connect it to 11kW three phase, it will only be able to use one of these phases so will only charge at 1/3 of 11kW.
 
Harry said:
No - if your car is capable of charging on 3 phase at 11 kW and you connect it to single phase 7kW you will get 7kW. If, on the other hand your car can only accept single phase and you connect it to 11kW three phase, it will only be able to use one of these phases so will only charge at 1/3 of 11kW.
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So a 11kw car is not 3 x 3.7kw more like 3.7/7/3.7kw?
 
N2STY said:
So a 11kw car is not 3 x 3.7kw more like 3.7/7/3.7kw?
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An "11kW" car is simply one enabled to accept 3 phase 11kW input. One which is not enabled - can only accept single phase - if at 7kW, then 7kW - but if offered 11kW - but 3 phase, can only see one of these three phases, so 1/3rd of 11kW. Each of the three phases is at 120 degrees to the others. Hope that makes sense.
 
The AC to DC bit is in the car.

For the new ZS EV :

In the UK the car has a single 7kW AC to DC converter (or thereabouts).

In Europe and maybe other regions, the car allows charging at 3.5kW for each of the three phases.

At the home I have a single phase 32Amp supply to the charger. This allows for 7kW charging.

At the office I have a 3-Phase supply and charger with 32Amps on each phase. This would cater for up to 7kW on each phase.

When I plug my MG into the charger at the office (using a 3-Phase cable) it only uses one of the phases so still only charges at 7kW.

If I were to plug a European version of the car into my office charger it would take 3.5kW off each phase and charge at 11kW.

If I took my car to a friends house in Europe and plugged into his 3phase supply which has 16Amp limit on each phase, my car would charge at 3.5kW.

When I had the BMW i3 it charged at 7kW on my home charger on a single phase. At the office it charged at 11kW. My assumption here was it had 3 AC inputs into the converter: 1 capable of 7kW and 2 capable of 3.5kW. When charging on a single phase it used the maximum 7kW capability available on a single phase. When charging on a 3-phase charger it limited all 3-phases to 16Amp (3.5kW), giving a maximum of 11kW.
 
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Dave said:
When I had the BMW i3 it charged at 7kW on my home charger on a single phase. At the office it charged at 11kW. My assumption here was it had 3 AC inputs into the converter: 1 capable of 7kW and 2 capable of 3.5kW. When charging on a single phase it used the maximum 7kW capability available on a single phase. When charging on a 3-phase charger it limited all 3-phases to 16Amp (3.5kW), giving a maximum of 11kW.
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That's possible. But I think it's more likely that there are three identical 3.5 kW chargers. Since 3.5 kW is so low and 7 kW is tolerable, they do some tricky switching on one of the chargers, say the B phase one, so it can operate on its own phase (B), or if there's no voltage there, switch to parallel with phase A. Of course, all considering the maximum current that the EVSE declares via the pilot signal.

I don't know why they don't do the same for the C phase charger, but probably that relay is a bit expensive and tricky to get safe, foolproof, and reliable (high current relay contacts tend to pit and wear out). Also, more than 32 A per phase is uncommon, except perhaps in the USA, where it's nearly all single phase anyway.
 
N2STY said:
I was thinking only a 22kw on board charger would charge at 7kw on single phase? Every day's a
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Coulomb said:
That's possible. But I think it's more likely that there are three identical 3.5 kW chargers. Since 3.5 kW is so low and 7 kW is tolerable, they do some tricky switching on one of the chargers, say the B phase one, so it can operate on its own phase (B), or if there's no voltage there, switch to parallel with phase A. Of course, all considering the maximum current that the EVSE declares via the pilot signal.

I don't know why they don't do the same for the C phase charger, but probably that relay is a bit expensive and tricky to get safe, foolproof, and reliable (high current relay contacts tend to pit and wear out). Also, more than 32 A per phase is uncommon, except perhaps in the USA, where it's nearly all single phase anyway.
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View attachment 7188
 
N2STY said:
I was thinking only a 22kw on board charger would charge at 7kw on single phase? Every day's a school day 🏫
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The Renault Zoe is unique in using the motor windings as part of the charging circuit, allowing it to charge at 22kW on a three phase charge point, and anything in between down to about 1.5kW. They call it a "chameleon" system, as it adapts to its environment.

Whilst it is a very cleverly engineered system, the negative side is that a charging fault can be very, very expensive to get diagnosed and repaired, four figure sums being common.

I'll miss 22kW AC charging when I get my MG ZS, but it will be more than compensated for by the rapid DC facility of CCS!
 
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