LFP charging like a boss

[fnegroni]

Stopped at a GRIDSERVE last night, arriving after 1 hour drive with 7% SoC, leaving 37 minutes later with 80% SoC.

Started charging at 7:53pm and ambient temp of 18°C

At 7:58pm it had reached 19% SoC, with the battery temperature between 27°C and 31°C and still charging at 82kW.

By 8:12pm it had reached 51% SoC charging at 67kW - battery temperature of 39°C.

In 20 minutes since beginning of the charging session it had added 82 miles of range.

by 8:23pm it had reached 70% SoC charging now at 40kW but maintaining a battery temperature of 39°C.
I could hear the battery cooling system circulating the coolant.

80% SoC was reached at 8:30pm.

The charger delivered a total of 38.62 kWh in 37 minutes, at an average of just over 60kW.

I also figured out how to charge at GRIDSERVE using the app reliably.

1. Reverse park into an available charger
2. Look for the charger number which is located high up on the post, above the screen
3. Open the app and select the charger by number
4. Plug the charger into the car and wait for the charger to connect to the car
5. When the charger's screen asks for payment, open the app and select your payment method on the app
6. Once payment has been taken on the app, the charger screen will show the payment is approved and the charging session will begin.

 

[haloweenhamster]

When I used a gridserve in December it went from 9% to 97% in 31mins, didn't keep track of kWh or temp though

 

[fnegroni]

When I used a gridserve in December it went from 9% to 97% in 31mins, didn't keep track of kWh or temp though

are you sure? Like sure sure?
97%?

 

[siteguru]

9% to 87% in 31 minutes I can just about believe ... to 97% not a chance.

 

[haloweenhamster]

Definitely 97, charged at 143kW near the start then I went for a drink, I'll have a look for an email receipt
Edit
Unless mines not LFP, can't remember which is which, I have a 64kWh
Didn't notice that bit initially

 

[Lord Randall]

NMC

 

[siteguru]

Even NMC won't do 9% to 97% in 31 minutes ... the charging curve drops off a cliff after 90% SoC, and those last 5+% take almost as long as it takes to do 20% - 80%.

 

[tsedge]

Even NMC won't do 9% to 97% in 31 minutes ... the charging curve drops off a cliff after 90% SoC, and those last 5+% take almost as long as it takes to do 20% - 80%.

I agree and I have certainly have never seen high charge rates above 90% on mine (also 64kWh NMC).

Yes it can reach 90% charging as high as 30kW but it rapidly drops off between 90% and 92% and by the mid 90% is only charging at 7kW or so and then if I stay connected until it disconnects at 97% I will be getting as little as 4kW by the end. The last few percent takes ages.

 

[haloweenhamster]

Can't find the one from Dec but these are some I did in Nov, couldn't tell you start percentage but 62.4kWh in 34min

 

[tsedge]

I don't doubt you but mine doesn't do that. No chance you have the 77kWh version (ER)?

The usable capacity of the 64kWh battery is only 61kWh, so I don't see how that figure could be possible. Maybe there is a miscalculation/ miscalibration on that charger??

 

[haloweenhamster]

You have losses in the charging system so what the battery actually takes will be less

 

[tsedge]

You have losses in the charging system so what the battery actually takes will be less

Ok, but it still makes no sense to me for a 64kWh battery, the losses are not massive for DC to DC.

Again, I am not doubting you, but I am puzzled. It would take my car well over an hour to accept that much charge and mine charges similarly to what most people have reported.

 

[siteguru]

9% to 97% in the LR is 0.88 x 61.7 = 54.296kWh into the car for your December charge. Assuming 95% efficiency (and I think that's an underestimate for a DC rapid) that would give 57.15kWh delivered by the charger.

Sticking with 95% for your 62.43kWh that would be 59.3kWh into the car, or an SoC change of 96%. (Unless the battery heating/cooling system was active to maintain a decent battery temperature - that would eat into some of the delivered charge).

 

[haloweenhamster]

The one I had in mind was a different session, the one pictured was November, I may have started at a lower percentage, every time I've use one I've gone to 97% but even this one only took 34 mins
Main reason I posted was due to the doubt of charging in approx 30mins

 

[Coulomb]

It was December in the northern hemisphere, so some heating (cabin and/or battery) could have been a factor.

I would think that chargers would be regulated to be quite accurate in their energy measurement, almost as accurate as household electricity meters, and for the same reason: that's what you are paying for.

 

[Rolfe]

Definitely 97, charged at 143kW near the start then I went for a drink, I'll have a look for an email receipt
Edit
Unless mines not LFP, can't remember which is which, I have a 64kWh
Didn't notice that bit initially

The thread is specifically about the LFP battery, so could we take discussion about the NMC batteries to a different thread? The only LFP battery in the MG4 range (at the moment) is the 51 kwh one in the SE SR (called other things in other markets).

 

[haloweenhamster]

Happy to delete my comments, I didn't notice the LFP to start with & couldn't remember what battery was in what model after I did.

 

[Rolfe]

It's OK, I just think it would be better it that line of discussion wasn't continued.

The LFP charges significantly slower than the NMC packs, so a thread about how well an owner is pleased by the LFP charging speed is likely to be overwhelmed by NMC owners declaring that their car charges a lot faster than that!

 

[Rolfe]

Any further posts about NMC batteries will be deleted as off topic.