What's the MG ZS EV fast-charge time with the different battery types: LFP (SR) 20-100% vs. NMC (LR) 20-80%?

[tsedge]

I'm new here but have been reading the forum and following the last few podcasts. I'm thinking of purchasing an MG EV early next year (assuming we can order again and get a delivery by then!).

My question is about the LFP (SR) vs. NMC (LR) battery in the MG ZS. It has been mentioned on the podcast that the difference in real-world range for most journeys is about 35 miles because the LFP battery is normally charged to 100% and the LR typically only 80%.

But, what about the fast charge time? How long does the LFP (SR) take to charge from 20%-100%? Does it slow down a lot towards the end? While I can see home charging giving me 100%, if I charge en-route I don't want to have to wait forever to get a 100% charge. Has anyone tried this?

Many thanks,


Tom.

 

[Jomarkh]

On a rapid CCS DC charger most charge rates drop off above 80-90% so it's quicker to charge to 80% drive then stop again rather than try and get it to 100%. So the only gain is having a higher range at of start from home with 100%, so you don't gain as much as you think by having a LR.

 

[tsedge]

Thanks. I was wondering if the LFP/SR was quicker from 80-100% but would understand if it is the same across both types.

 

[hmadsen]

My LR, seems to charge at 80-90 kW from about 10% up to 80%

From 80% to 90% the charge speed drops to about 20 ish, and when it gets to 90% it drops even further. (I stopped it at 90% as i did not want to spend any more time there, even though it was a free charge with the bonnet app)

 

[drmcw]

LR should charge faster than SR but being a bigger battery will take a little longer. See this thread.

 

[tsedge]

Thanks and thanks for the link.

If I'm understanding it all correctly:

• Using the WLTP figures, LR is 273 miles and SR is 198 miles. Obviously real-world is less than this but good enough to compare.
• 80% of 273 is 218 miles, so small difference of about 20 miles effective range from home (assuming normal 80% charge for LR, 100% for SR).
• But LR can obviously be home-charged to 100% when needed for longer trips, which is significant range advantage.
• LR can fast-charge more quickly than SR (94kW vs. 75kW) but as battery is bigger charging can take longer, depending on percentage.
• Both batteries will slow down >80% on fast charge, so going beyond this means lots of waiting around.
• Therefore normal en-route SR range with quick re-charge is probably 20-80% or 120 miles WLTP (100 miles real world?). 60% is about 30kWh which (depending on charge speeds) could be done in about 30 minutes(?).

So.... boiling it down (if I have it right). Long journeys (>150 miles) with the SR would likely mean stopping every 100 miles for 30 minutes, e.g. 250 mile trip == 150 miles + 30 min recharge + 100 miles.

Apologies if I am making it complicated but I'm trying to get my head around what the practical life with SR would be. I think it would suit me as very rarely do a long trip and it looks like charging would be fast enough with the small battery to top-up, but I'd love to hear owner's experiences.

Thanks again.

 

[Gadget Geek]

My LR, seems to charge at 80-90 KWh from about 10% up to 80%

From 80% to 90% the charge speed drops to about 20 ish, and when it gets to 90% it drops even further. (I stopped it at 90% as i did not want to spend any more time there, even though it was a free charge with the bonnet app)

Shouldn't that be kW?

 

[rpannell]

Thanks and thanks for the link.

If I'm understanding it all correctly:

• Using the WLTP figures, LR is 273 miles and SR is 198 miles. Obviously real-world is less than this but good enough to compare.
• 80% of 273 is 218 miles, so small difference of about 20 miles effective range from home (assuming normal 80% charge for LR, 100% for SR).
• But LR can obviously be home-charged to 100% when needed for longer trips, which is significant range advantage.
• LR can fast-charge more quickly than SR (94kW vs. 75kW) but as battery is bigger charging can take longer, depending on percentage.
• Both batteries will slow down >80% on fast charge, so going beyond this means lots of waiting around.
• Therefore normal en-route SR range with quick re-charge is probably 20-80% or 120 miles WLTP (100 miles real world?). 60% is about 30kWh which (depending on charge speeds) could be done in about 30 minutes(?).

So.... boiling it down (if I have it right). Long journeys (>150 miles) with the SR would likely mean stopping every 100 miles for 30 minutes, e.g. 250 mile trip == 150 miles + 30 min recharge + 100 miles.

Apologies if I am making it complicated but I'm trying to get my head around what the practical life with SR would be. I think it would suit me as very rarely do a long trip and it looks like charging would be fast enough with the small battery to top-up, but I'd love to hear owner's experiences.

Thanks again.

That looks about right. So with the SR you would need to find a free charger after about 150 miles but before 180 miles. The LR will just about make it in the summer months without a stop and in the winter, will require a short stop anywhere after about 50 miles into the journey.

 

[MAJ]

tsedge
I Think you got it about right but charge speed KW/hr varies by Rapid Charger Type,
60-65 KW/hr for both battery types would be more typical.

 

[hmadsen]

Shouldn't that be kW?

Well the charger delivers 80 kilowatt per hour, so i think it is mostly correct to say KWh.

Edit Coulomb: No, it's 80 kWh/h (80 kWh of energy delivered for every hour), so we call that 80 kW of average power.

 

[Gadget Geek]

Well the charger delivers 80 kilowatt per hour, so i think it is mostly correct to say KWh.

Only if you stay there for one hour.

 

[tsedge]

That looks about right. So with the SR you would need to find a free charger after about 150 miles but before 180 miles. The LR will just about make it in the summer months without a stop and in the winter, will require a short stop anywhere after about 50 miles into the journey.

Great, thanks.

 

[Gadget Geek]

I use ev-database for range estimates, it gives real world measurements collected over seasons and city/motorway driving.

EV Database

A comprehensive overview of all electric vehicles in the UK. Search and compare by range, make, model and price.

ev-database.uk

Also, don't forget the lower end of the battery. 20% to 80% is 60% of advertised range, which effectively gives the LR 135 miles and the SR 99 miles between top ups.

My first EV was a 28kWh Ioniq with around 160 miles of range. I currently drive a 64kWh Kona with around 300 mile range. I have never had any range anxiety with either car, but find the longer range more convenient for my use case.

 

[tsedge]

tsedge
I Think you got it about right but charge speed KW/hr varies by Rapid Charger Type,
60-65 KW/hr for both battery types would be more typical.

Yes, understood. In my calculation I assumed 60kW to give a 30 min charge to add 30kWh to the SR battery.

 

[tsedge]

I use ev-database for range estimates, it gives real world measurements collected over seasons and city/motorway driving.

EV Database

A comprehensive overview of all electric vehicles in the UK. Search and compare by range, make, model and price.

ev-database.uk

Also, don't forget the lower end of the battery. 20% to 80% is 60% of advertised range, which effectively gives the LR 135 miles and the SR 99 miles between top ups.

My first EV was a 28kWh Ioniq with around 160 miles of range. I currently drive a 64kWh Kona with around 300 mile range. I have never had any range anxiety with either car, but find the longer range more convenient for my use case.

That's good to know, thanks.

 

[hmadsen]

Only if you stay there for one hour.

Yes, but you also say "Miles per hour" even if you only do a 5 minute drive

The charger has a "meter" that tell you with which "speed" you charge (80 Kwh) and a meter that tell's you how many Kilowatt you have charged the battery.

 

[tsedge]

Yes, but you also say "Miles per hour" even if you only do a 5 minute drive

The charger has a "meter" that tell you with which "speed" you charge (80 Kwh) and a meter that tell's you how many Kilowatt you have charged the battery.

I think there may be some unit confusion here.

'miles' is a distance measure, so 'miles per hour' is indeed a rate/speed measurement.

But energy is measured in Joules (J) and power in J/s, or alternately kW, which is already a rate measurement. So the 'speed' is 80kW and meter is in kWh (or should be), just like your electricity bill.

Then, converting kW to miles per hour is even more confusing, because this is 'miles added per hour' but not the same as how fast the car is going!

I'll get my coat.

 

[Gadget Geek]

Yes, but you also say "Miles per hour" even if you only do a 5 minute drive

The charger has a "meter" that tell you with which "speed" you charge (80 Kwh) and a meter that tell's you how many Kilowatt you have charged the battery.

Just think of it as filling a bucket. How fast the water is coming out of the tap is kW, and the amount of water in the bucket is kWh.

 

[hmadsen]

Just think of it as filling a bucket. How fast the water is coming out of the tap is kW, and the amount of water in the bucket is kWh.

But we do agree that when the charger says "80 kw" what this actually means is that "If connected for 1 hour, you will have added 80 KW to your battery" right ?

 

[Gadget Geek]

But we do agree that when the charger says "80 kw" what this actually means is that "If connected for 1 hour, you will have added 80 KW to your battery" right ?

No, you will have added 80 kWh. kWh is a unit of energy, not power. Just as a Watt is the product of current multiplied by the voltage, a Watt-hour is the product of power multiplied by time. 1kWh could supply 2kW for half an hour, 4kW for 15 minutes and so on. They are not the same units.