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Should DC Charge stop at Limit set in Car ?

Posted: Fri Jul 29, 2022 6:44 pm
by SilverCupra
Hi All,

My car has been back to dealer today for a small snag fix..

When I collected the car, the dealer had it plugged into some kind of rapid CCS DC charger, and it was charged to 100%.
However, the car is set to charge to 80% as per the recommendation of the very same dealer, but it clearly didn't stop charging at 80%.
I am interested if the CSS DC Rapid and the more conventional 7KW charger I have at home have different charger settings within the car ?

As it was at 100%, and I only live 2 miles from the dealer, there was me on way home from the dealer going long way round and round in circles, trying to use up battery..
I do not need the car until Monday and I hear it is bad to leave at 100% for more than a few hours..
I got it down to 88% before I gave up and went home, so hoping this is OK to stand until Monday, even though it is currently charged to greater than 80% ?

In the month that I have owned the car, this is my first experience of Rapid charging, so me thinks I still have plenty to learn :-(

Re: Should DC Charge stop at Limit set in Car ?

Posted: Fri Jul 29, 2022 8:02 pm
by Daveion
I'm not a frequent user of public chargers but can't see why there would be any difference in set up tbh. My Born and ID3 before it never exceeded the setting in the car. Out of interest what is the setting in your app?

Re: Should DC Charge stop at Limit set in Car ?

Posted: Fri Jul 29, 2022 8:11 pm
by SilverCupra
My car is set to 80%

Re: Should DC Charge stop at Limit set in Car ?

Posted: Fri Jul 29, 2022 8:47 pm
by monkeyhanger
If it were home charging, i'd expect it to be a clash with both the car and app setting maximum charge to 80%. Never had a bother with our ID3s or our Borns by letting the car set maximum % charge and letting the charger app set when it charges. The DC charger should respect the ceiling set on the car for charging, I personally wouldn't worry about the car being at less than 97% charge and sat for a while. I have seen my car's charge level move up 1% as the weather warms up during the day, you don't want it more than 100% full with a bit of warm up, but other than that, staying under 80% unless you're on a long journey is more about balancing the charge/discharge cycles between cells evenly to maximise the life of the battery.

Re: Should DC Charge stop at Limit set in Car ?

Posted: Sat Jul 30, 2022 12:29 pm
by SilverCupra
monkeyhanger wrote:
Fri Jul 29, 2022 8:47 pm
The DC charger should respect the ceiling set on the car for charging

Exactly what I would have thought..

Doing some research on the difference between AC and DC charging, it would seem that for home charging, AC is supplied to the car and the charger is actually onboard the car, which is what all the schedules and settings are for in the infotainment.,

It also looks like that for DC charging, the charger is actually external to the car in the box of tricks the CSS cable is tethered too..

If this is correct, I can maybe see why CSS Rapid DC chargers bypass the settings set at the car, as these are for use by the cars internal AC charger !!

Not sure if this theory is correct, does anyone know for sure ?

Could this be why my dealer was able to charge my car to 100% when the settings in the car and app were set to 80% ??