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Rapid Charging Speed

fishbee

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Cambridge
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MG5
I'm interested in knowing what charging rate people have observed at service stations and the like? MG claim that the MG5 can charge at up to 80kW.

I've had my MG5 for a few months now, and when taking some long range trips that involved charging stops along the way, I've had the car charging at just under 30kW (Instavolt at Corley services on the M6, old-style Ecotricity on M1), 40kW (old-style Ecotricity on M6), and 50-60kW (at the new Rugby services on the M6). So not quite the same as what I expected before buying the car! I'm particularly disappointed by the 30kW chargers -- charging at 50kW or more means (at least for me!) that you don't really spend much more time at motorway services than with a petrol car. You drive in, plug in your car, get out, use the loo, maybe grab a snack or drink, get back to the car, and there you go, it's nearly back at 80% charge. But if the charger is only going at 28kW or so, you're there for at least an hour before you're ready to go!

Is the state of the motorway charging network simply poor at the moment? (I'm willing to believe that it's getting better -- as I said, the fastest charge I've had so far was at a brand new bank of Electric Highway chargers at Rugby services.)

Or is there a problem with my MG5? I suppose I should try it at one of the BP Chargemaster 100kW+ chargers, and see what happens there.
 
The issue for you is that the max charging speed of 80kw is only obtainable under certain conditions.
The battery needs to be (roughly) over 20% charged and less than 80% and even then the max rate will only be attainable for a short time because while it charges the power ramps up and then down again as the battery fills.
The charger you use must be putting out enough power, most 'fast' chargers around at the moment are 50kw max and you'll mostly get about 45kw of that.
If you are at a faster (100kw plus) charger you will see faster charge rates up to 80%

This is not just the MG5, all EVs have the same thing, think of 80% as a discount with the words "up to" below it, you know you're not going to get the full 80 but you can get close.
 
Yeah, that all sounds very sensible. I'm happy to only charge up to 80% when on a road trip, to save on time (and to allow other people to use the chargers too -- last time I was at at Stafford services on the M6, there were 3 cars all wanting to use the single CCS charger, which only provided a peak rate of 40kW).

I'm just puzzled that most "50kW" chargers seem to provide 40kW at most, and often less than 30kW. And charging from 20% to 80% (so about 30kWh of energy) at 28kW takes over an hour! It makes things like Zap-Map a bit useless, because they don't tell me what the "typical" charge speed is at a particular location, just what the advertised charge speed is. And I know that 100kW+ chargers do exist, but they don't seem to have appeared at any of the motorway services I've had a chance to visit in the last few months.

I guess I just have to judge by past experience (and maybe word of mouth) to know where I can stop and charge in a reasonable amount of time. Maybe I need to start my own charger review site!
 
I'm most definitely NOT an expert on this subject but I am aware that 80kW+ is a huge level of power (about half of what the battery can deliver under full load). Think 8-off power showers all running together! This charge rate (and higher ones, still) must create a lot of heat in the battery and it's probably one of the reasons that constant rapid charging is not encouraged by the manufacturers. I presume that the battery cooling system operates during charging, but as the car is not moving it's probably not as efficient at dissipating heat as it would be when the car is moving? So the faster the charge you pump in, I expect the less efficient the process is. This battery temperature factor could even be what is limiting the charge rate, especially on a hot day? I haven't used a fast charger at all yet :rolleyes: but when I do I'll probably won't be exceeding 50kW, as I just can't see it doing the battery longevity any favours whatsoever.
 
80kW is indeed a huge power draw, but there are EVs on sale now (Teslas, Porshe, Hyundai Ioniq, etc) that claim to be able to charge at 150kW, so I guess the demand for fast charging is there? Funnily enough, the fastest charging I've seen has actually been on hot days. Might be a random coincidence, or maybe it's to do with running the air con? I wonder if there is way to get the car to tell you (the driver) what the maximum rate it is willing to accept from a charger, when it does the hand-shake protocol after plugging in?

greentangerine: Ah, good to hear! I might try to find a 100kW fast charger somewhere nearby and try it, just to see what peak charging speeds my car is capable of. I've also had 60kW from a Gridserve charger, though when I came back on my return journey, it wouldn't go higher than 50kW. But it also had several cars charging at the same time then, so I guess they manage that by dropping the power delivered to each charger.
 
80kW is indeed a huge power draw, but there are EVs on sale now (Teslas, Porshe, Hyundai Ioniq, etc) that claim to be able to charge at 150kW, so I guess the demand for fast charging is there? Funnily enough, the fastest charging I've seen has actually been on hot days. Might be a random coincidence, or maybe it's to do with running the air con? I wonder if there is way to get the car to tell you (the driver) what the maximum rate it is willing to accept from a charger, when it does the hand-shake protocol after plugging in?

greentangerine: Ah, good to hear! I might try to find a 100kW fast charger somewhere nearby and try it, just to see what peak charging speeds my car is capable of.
This whole battery technology is moving on at an incredible and admirable pace (without which these vehicles would be dead in the water). It has to work for everyone's sake!!

I've never been known as an "early-adopter" and I'm happy to let others forge the way forward on my behalf :) . Can you hear the battery cooling system at work when rapid-charging?
 
My MG5 saw 81kW on a Shell charger in Windsor a couple of weeks ago and 64kW on one of the new / Ecotricity replacement Gridserve chargers earlier today (Sutton Scotney services) so it is possible.

Had 80 ish on a new gridserve the day I picked up my car, unfortunately the most powerful chargers in my area are 50kw.
 
I'm most definitely NOT an expert on this subject but I am aware that 80kW+ is a huge level of power (about half of what the battery can deliver under full load). Think 8-off power showers all running together! This charge rate (and higher ones, still) must create a lot of heat in the battery and it's probably one of the reasons that constant rapid charging is not encouraged by the manufacturers. I presume that the battery cooling system operates during charging, but as the car is not moving it's probably not as efficient at dissipating heat as it would be when the car is moving? So the faster the charge you pump in, I expect the less efficient the process is. This battery temperature factor could even be what is limiting the charge rate, especially on a hot day? I haven't used a fast charger at all yet :rolleyes: but when I do I'll probably won't be exceeding 50kW, as I just can't see it doing the battery longevity any favours whatsoever.

I suspect but don't know that the HV battery disconnect fault has something to do with overheat.
This happened to me a couple of days ago when the battery got to 95% using a 50kw charger on a very hot day. Charge ended on 'error' and the car wouldn't start for about ten minutes after.
 
I suspect but don't know that the HV battery disconnect fault has something to do with overheat.
This happened to me a couple of days ago when the battery got to 95% using a 50kw charger on a very hot day. Charge ended on 'error' and the car wouldn't start for about ten minutes after.
Interesting. I'm glad to know that my habit of stopping fast charges at 80% might actually be good for the car!
 
We were charging at 65KW in the ZS at the new Electric Highway Gridserve Rugby Services in fairly high ambient temperatures of 26 degrees C recently.

The Battery Cooling kicked in during that charge, sounded like the Aircon on Speed.
 
I've only tried rapid charging once on mine, and it was a 'cool' night at 29C, without having driven far before starting the charge. It is a 40kW DC station, and from 25% all the way up to 90% it was pulling the full 40kW, about 45 minutes. 90% to 100% took another 25 minutes, as expected (we just wanted to see what it did a full charge... electronic/mechanical things here don't always operate as 'expected')

The cooling system was running, AC compressor on, and the battery pack was so damned cold at the inlet side it was condensing water! On the outlet side of the pack, it was cool to the touch, but not quite condensing.

To be noted, car has ~6000km on it, and never rapid charged before, only granny charged. Suspect that lots of rapid charging will also slowly degrade the pack's ability to pull full current?
 
I could only ever get anywhere close to 50KW (or max of 80KW) if i had travelled a considerable distance (100 mile+) and the battery pack was hot but obviously will change depending on the outside temperature. For me, my MG ZS EV and i presume the MG5 is the same but normally and even with low SOC i would see anything from 19 -> 38KW, and i wonder why they don't put this is any literature, unlike the 40 minutes from 0 -> 80%...
 
80kW is indeed a huge power draw, but there are EVs on sale now (Teslas, Porshe, Hyundai Ioniq, etc) that claim to be able to charge at 150kW, so I guess the demand for fast charging is there? .
Then there's the 350kW jobbies around. A chum of mine has colleagues working on very very high rate chargers. Whether it's the 350kW ones or something even hairier I don't know. What he did say was that to keep the charging cable a sensible size yet still able to handle the power, the ones he was using were water cooled.
 
Then there's the 350kW jobbies around. A chum of mine has colleagues working on very very high rate chargers. Whether it's the 350kW ones or something even hairier I don't know. What he did say was that to keep the charging cable a sensible size yet still able to handle the power, the ones he was using were water cooled.
That is a totally phenomenal amount of power! But I suppose it is the only way of making this technology ultimately acceptable to the masses. Not sure what it does for (fire) safety, though!
 
snip - What he did say was that to keep the charging cable a sensible size yet still able to handle the power, the ones he was using were water cooled.
Therein lies the problem. the cable for a 150kw charger is heavy and awkward even for a big lad like me, anything bigger is going to be a problem for (especially Mrs) joe public to deal with. I've never seen a 350kw charger up close so never had a chance to test the ease of use of it but I suspect we won't see anything more powerful until they can find a way to pass enough current through a thinner cable. Plus, CCS connectors already get damaged too easily but with folk dropping them attached to hefty cables I can see lots of problems.
 
Therein lies the problem. the cable for a 150kw charger is heavy and awkward even for a big lad like me, anything bigger is going to be a problem for (especially Mrs) joe public to deal with. I've never seen a 350kw charger up close so never had a chance to test the ease of use of it but I suspect we won't see anything more powerful until they can find a way to pass enough current through a thinner cable. Plus, CCS connectors already get damaged too easily but with folk dropping them attached to hefty cables I can see lots of problems.
There are ways that the cable can be supported rather than just free to move. TeslaBjorn has various videos showing 350kw chargers with supported cables.
 
I used a 150kw charger today at MFG Crow Orchard near Wigan. I wondered why the cable was so big and heavy. Luckily it was relatively simple for me to plug in. Not so for the IPace 2 bays down who had to drive in at an angle and take up 2 bays in order to connect his cable.
 
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