What to tweak to improve the car charging accuracy?

[ppmt]

I was wondering what parameters I should tweak.

I have 2 EV cars. One seems to overcharge by a few kWh while the other always undercharge compared to what I request.
While I am not worried about overcharging I am more concerned to make sure the second car charge at least to what I requested.

If I ask for 100% and it will stops around 95 or 96 %
If I ask for 80% and it will stop around 75%

I can see several parameters but none of them seems to be able to explain that

I guess I could "cheat" and increase the size of the battery to compensate but I am hoping there is a nicer way :)

[springfall2008]

Maybe increase car charging loss?

[ppmt]

The problem with that is that it will be affect both cars.

Doing a bit more reading it appears that the car in question a Ioniq is not very good at doing short charging slot in cold weather.

It looks like it would work better for that car to have consecutive charging slot rather the cheapest one.

But the other car doesn't seem to care about scattered charging slot :(

[ppmt]

I have been doing some test and it confirmed that this car behaves better when the charging slot are consecutive. It seems a lot of energy is wasting in "conditioning" the battery before it really charges it and that in turns seems to confuse Predbat.

I have the "Car Charging Plan Smart" set to true so that it uses the cheapest slots. I tried to turn it to False hoping it would help by choosing consecutive slot around the cheapest zone but instead it just start charging immediately even if it is the most expensive slot.

Is that the expected behavior for that switch?

and if it is then may be having a "start charging at" sensor would help us tricking the system to not charge before a specific time?

[gcoan]

I have the "Car Charging Plan Smart" set to true so that it uses the cheapest slots. I tried to turn it to False hoping it would help by choosing consecutive slot around the cheapest zone but instead it just start charging immediately even if it is the most expensive slot.

Is that the expected behavior for that switch?

per the documentation:

Turn on switch.predbat_car_charging_plan_smart if you want to use the cheapest slots only. When disabled (turned off) all low-rate slots will be used in time order

So predbat should charge the car in low rate slots, choosing sufficient slots to reach your target car SoC. The definition of 'low rate' is a bit complex though, so if you think it's not working right we'd need to see the logfile, predbat plan and debug file to see if there's something incorrect

[ppmt]

Thanks for your help.
I plugged the car around 16h45 and change the smart charging to False around 16h55.
The plan then decided to charge the car from 17h00 to 18h30 when the price was the most expensive around 35pkwh
When I turned it back to ON it correctly selected the cheapest slot again later in the night.

I will try again and will collect the file you mention. To get the debug file do I just enable the debug and the file will be created automatically?