Maintain charge limit after charge session has ended

[Rizzle]

Context
We're charging a MY and have an Easee One charger on a 7kw home charger. In the Easee One app 'power at all times' is set to Yes.

Question
If I set the car to charge to 80% overnight, I find that after the charge limit has been reached, the car will no longer draw power and in the morning the battery will be at 79%, even though the car is still plugged into the wall. Is it not meant to draw power from the wall charger whilst it's plugged in so that it maintains the charge limit you've set in the app? Am I missing a setting somewhere or is it only possible to draw from the wall for preconditioning?

 

[browellm]

Context
We're charging a MY and have an Easee One charger on a 7kw home charger. In the Easee One app 'power at all times' is set to Yes.

Question
If I set the car to charge to 80% overnight, I find that after the charge limit has been reached, the car will no longer draw power and in the morning the battery will be at 79%, even though the car is still plugged into the wall. Is it not meant to draw power from the wall charger whilst it's plugged in so that it maintains the charge limit you've set in the app? Am I missing a setting somewhere or is it only possible to draw from the wall for preconditioning?

Your "usable" battery % as reported by the BMS will fluctuate, especially at this time of year in cold mornings. In reality you haven't lost any charge and it will be available once the pack warms up.

 

[Helguson17]

Context
We're charging a MY and have an Easee One charger on a 7kw home charger. In the Easee One app 'power at all times' is set to Yes.

Question
If I set the car to charge to 80% overnight, I find that after the charge limit has been reached, the car will no longer draw power and in the morning the battery will be at 79%, even though the car is still plugged into the wall. Is it not meant to draw power from the wall charger whilst it's plugged in so that it maintains the charge limit you've set in the app? Am I missing a setting somewhere or is it only possible to draw from the wall for preconditioning?

Have an almost identical scenario and "issue", save for it's an Ohme Home Pro instead of an Easee. Had picked up the helpful explanation @browellm gives above from a different thread, and unsurprisingly the experienced hive mind seems to be right - based on seeing how much drop off there is as reported by the BMS in warmer (approx 12 degrees) v cold (nearly freezing at the weekend).

However - when I precondition the car in the morning, this still seems to eat a bit of battery even when it is plugged in. Difficult to tell precisely how much of course without getting into all the data monitoring apps that I really can't be bothered with. Will just wait and see as the weather warms up.

 

[dakaix]

Have an almost identical scenario and "issue", save for it's an Ohme Home Pro instead of an Easee. Had picked up the helpful explanation @browellm gives above from a different thread, and unsurprisingly the experienced hive mind seems to be right - based on seeing how much drop off there is as reported by the BMS in warmer (approx 12 degrees) v cold (nearly freezing at the weekend).

However - when I precondition the car in the morning, this still seems to eat a bit of battery even when it is plugged in. Difficult to tell precisely how much of course without getting into all the data monitoring apps that I really can't be bothered with. Will just wait and see as the weather warms up.

The car will use 7kW to heat the battery, plus that which it needs to heat the cabin (which varies depending on your vehicle age). Since your wall box will be providing at most 7kW this can result in the battery being slightly depleted - unless you wait long enough for the battery and cabin to be fully heated.

 

[Helguson17]

The car will use 7kW to heat the battery, plus that which it needs to heat the cabin (which varies depending on your vehicle age). Since your wall box will be providing at most 7kW this can result in the battery being slightly depleted - unless you wait long enough for the battery and cabin to be fully heated.

Really helpful, thank you. Makes even more sense as currently my Wallbox is limiting itself to 4kw, thanks to a faulty CT clamp.

 

[Rizzle]

Your "usable" battery % as reported by the BMS will fluctuate, especially at this time of year in cold mornings. In reality you haven't lost any charge and it will be available once the pack warms up.

So does the car continue to draw power from the wall after charging? I’m not seeing any fluctuation(I.e up/down), it’s consistently down 1% at least the following day. Sometimes we might not unplug the car until midday and I haven’t seen the battery reading return to the charge limit set once we start driving.

 

[Louis0w]

So does the car continue to draw power from the wall after charging? I’m not seeing any fluctuation(I.e up/down), it’s consistently down 1% at least the following day. Sometimes we might not unplug the car until midday and I haven’t seen the battery reading return to the charge limit set once we start driving.

If HVAC is on and the car is plugged into the wall, then it will prioritise using energy from shore rather than the battery, However, if the car is just sleeping after charging it won't continually draw power from the wall charger. What it will do is periodically top-up the battery from the wall charger once the battery has been reduced by a few % or so. In the sleep state, this reduction in battery capacity generally only happens after a period of days,

 

[Adopado]

So does the car continue to draw power from the wall after charging? I’m not seeing any fluctuation(I.e up/down), it’s consistently down 1% at least the following day. Sometimes we might not unplug the car until midday and I haven’t seen the battery reading return to the charge limit set once we start driving.

The car doesn't keep sipping power once the charge has completed.

The return of percentage (if/when it happens) is not usually visible ... but in circumstances where you get some return it is simply that the rate of decrease when driving changes so the drop is slower than it otherwise would have been. First couple of miles always shows the quickest drop of course but once things settle down the percentages drop more slowly. Also be aware that when the car charges to, say, 80% it can only report in full percentage points ... the temperature change or whatever may mean it reports 79% ... but is that 79.9% or 79.5% or 78.9% ? Very occasionally I have seen displayed full percentage points return shortly after stopping. One day last week I drove 50 miles then parked with 53% ... walked away for 10 minutes, came back and car was showing 54%. However, despite me reinforcing your "overthinking" it's best to just put this stuff to the back of your mind!