Last night, myself and Jake
@MG ZS EV WEST YORKSHIRE took the Chorley Group Burnley demonstrator on a journey to test the real-world rapid charging capabilities.
I picked up Jake around 7pm from Oakworth, and we headed to the Ionity chargers at Leeds Skelton Lake Services. I used the "Battery Heater" option to ensure that we had warm batteries on arrival. This appears to use around 7kW (20A@360V) at peak, although once the batteries had heated up (after 40 mins), the battery heaters automatically switched off.
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On the way there, the "Low Battery Warning, Please Charge" message came up at 24% (46 miles indicated) remaining.
Unfortunately, when we arrived there just after 8pm, there were 4 cars charging (2 Porsche Taycans, and MG5, and a DPD delivery van, with 2 other DPD drivers queuing to use them. Faced with a potential delay of over an hour (the DPD vans needed 90%+ to be able to do their deliveries the next day), we checked on Zap-Map, and found there were some 100kW+ Instavolt Rapid Chargers in Barnsley, 26 miles away.
We had 15% battery.... and it was mainly motorway, but were showing 30 miles range on the GoM, so figured we might as well go for it.
At 14% (24 miles remaining), another "Low State of Charge, Please Charge" warning came up on the dashboard.
At 7%, the GoM went to "---", and power was restricted - we were on the M1 going up a hill past Woolley Edge services, and our speed (with foot flat to the floor) wouldn't exceed 50mph. We started to get a little bit nervous. We decided to come off the M1 at the next junction, and go on the A/B roads to Barnsley, as we didn't want to be a hazard for anyone.
We finally got to the chargers (next to McDonalds) with 3% battery remaining. Thankfully, the chargers were both available and working (not ICEd).
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We started the charge, and recorded the Amps & Volts from inside the car, to calculate the charging power. The charge was started at 20:56 (nice round number... should have waited a few minutes I guess!).
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Initially, the charge started quite slowly, as the charger and car decided what power was best. At 4%, it was delivering 181A @344V (61kW). By 6%, the current had increased to 200A, where it stayed fairly consistently (did drop to 199A for a bit) until it got to 60% SoC. As the battery voltage rose, so the total kW increased, peaking at 76kW at 59/60% SoC.
From 61-71%, it continued at 179/180A, then from 72% it dropped to 151A, where it remained until 82%. At 83% (21:41 - 45 minutes after we started), it then dropped off quite quickly to 67A, stepping down to 61A by 89%. At 90% it dropped to 52A, and at 91% it was at 40A@403V (16kW). This is where we decided to disconnect the charger (it was 21:56, so exactly one hour from when we started).
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For reference, it got to 22% after 10 minutes, 41% after 20 mins, 58% after 30 mins, and 83% after 45 mins. This compares very favourably to MG's own stated charge times of 42 minutes to 80% when using a 100kW rapid charger.
Graphs showing the Volts/Amps, and then the calculated kW Power are below:
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In conclusion, the new ZS EV has a great charging curve, where it draws 70kW+ from 7% to 60%, and then maintains 60kW+ up to 80% SoC. The battery heater works well (but bear in mind that the heater will draw up to 7kW, so if you're already low on power, you're going to lose another 20-30 miles of range by using the battery heater). It decimates your efficiency - whilst it was working, I was getting 1.5-2m/kWh rather than 3m/kWh!
The battery heater switches itself off when you turn the car off, so it's not something you can accidentally leave switched on and drain all the battery - you need to actively turn it on for each journey.
I would not recommend running the car down below 10% SoC. The charging speed doesn't benefit, and the reduced power (particularly on a motorway) is not a pleasant experience. It might not be too bad around an urban environment, but hills become an issue when it's limiting you to around 25kW (33bhp!). We struggled up a hill in Barnsley town centre with foot flat to the floor, and scraping to 24mph.
We've got loads of photos etc, but I don't want to make this any more difficult to read than it already is
I've added my excel sheet with the values for Volts/Amps that we saw.
