EV "losing" 2-3% charge overnight

[sunbeam alpine]

We have a Volvo C40 EV. Got it in May and it has transformed my view on EV's. It mostly gets used for short local runs and only needs charging a couple of times a month.

Since the weather has got colder I've noticed that it appears to be "losing" 2-3% battery charge overnight. It didn't do this before. I know you can set the car to pre-warm, but as far as I'm aware there's nothing like that set (unless it does it automatically) but the car itself is cold when you get in.

The car should be on standard factory settings - I know you can install an app on a smartphone to check and configure, but I don't have it (the garage couldn't install it on my phone when we collected the car) and Mrs SA has a work phone and isn't allowed to install unapproved apps. I can look at the configuration on the screen in the middle, and it all seems standard.

Anyone experiencing anything similar?

[PistonTim]

Get the app installed, absolutely no reason to be without it especially since May.

If stuck ask on a model specific group for advice.

And no its not normal to be losing charge overnight like that.

[kambites]

It sounds like it has a system to keep the battery above a certain minimum temperature in order to protect it and/or make sure it's usable when you want to drive it. Not something I've come across but seems plausible?

[stef1808]

This drain could be anything from cars keeping their cellular connection open for the app to connect, battery conditioning or less range just due to the cold compared to when last driven etc. seems normal to me

[pills]

Thread here - https://www.xc40forum.com/threads/power-drain-with... (although USA based with colder temps).

Haven't had this with my XC40, however have had a couple of "low temp range / power limits" warnings.

Might be worth having a chat with dealer / Volvo UK?

[tr3a]

Does it have a dashcam?

[Caddyshack]

Batteries drop voltage as they cool - i.e. if you take it off the charger the batts are warm from the charge, this then settles if left overnight.

Often the traction battery tops up the 12v or aux battery so if that battery is ageing the traction will need to top it up over night.

[Basil Brush]

I've got a Polestar 2, so same platform, and parked up at home for the last week while we were away it's dropped only a couple of percent.

[OutInTheShed]

2 or 3% error in estimating state of charge in varying temperatures is no big deal.

If you leave it for 10 nights and it loses 30%, something real is happening.

[Actual]

Is the battery "losing" 2-3% battery charge overnight" cumulative so that after 3 nights it is 6-9% down.

It could just be predicting poor performance due to ambient temperature.

[C.A.R.]

Could it be that every time you are opening the vehicle to check the battery status you are 'waking' the systems? I know that's how it is in a Tesla.

My company car (Model 3) has lost 1% over the last 4 days without turning a wheel; but that's likely from me opening doors to retrieve things and "waking up" the climate control etc. in the process. If it's losing more than that and it's just sitting completely idle (ie. undisturbed) then there could be an issue.

[Paul Drawmer]

Is the car reducing the displayed state of charge from 100 down to 97.
Or, is the range mileage reducing overnight?

If it's the range reducing, it's the effect of the battery cooling overnight.

[sunbeam alpine]

Actual said:

Is the battery "losing" 2-3% battery charge overnight" cumulative so that after 3 nights it is 6-9% down.

This is what is happening.

[sunbeam alpine]

C.A.R. said:

Could it be that every time you are opening the vehicle to check the battery status you are 'waking' the systems?

I don't open the car just to check, when I open the car it's to pop to the village (a couple of km away). I mentally note the charge level when I park the car, the next day it's 2-3% lower.

[sunbeam alpine]

OutInTheShed said:

2 or 3% error in estimating state of charge in varying temperatures is no big deal.

If you leave it for 10 nights and it loses 30%, something real is happening.

It gets used every day for short runs, which is why I noticed the smaller drops. We'll be away for 7 days at the end of the month so I'll be able to test that then.

As a couple of members have suggested, I suspect it is temperature-related as it hasn't done this before.

Edited by sunbeam alpine on Tuesday 9th January 10:12

[Rob P]

sunbeam alpine said:

Actual said:

Is the battery "losing" 2-3% battery charge overnight" cumulative so that after 3 nights it is 6-9% down.

This is what is happening.

Exactly this. Mine does this too, and the opposite happens too, range increases as temp rises on the guessometer.

[plfrench]

If it's losing 2-3% every night I'd say that's concerning. Our Born was parked up over Christmas for 10 or 11 days and only dropped 1% total.

[MM]

My VW ID3 would loose that level of percentage preheating the cabin in the morning. I wonder if its heading the battery up each morning if the cabin is cold.

[sunbeam alpine]

To update - once the freezing temperatures passed, this stopped. Last weekend we had a cold snap and it did it again.

What is disappointing is just how quickly the range falls in freezing weather - less than 50% of the summer range. Tested this on a longer run (approx 200 km) last Saturday and got home with about 7% charge left. Did the last half hour without heating because we didn't want to stop so close to home (plus there aren't many chargers in our area).

It's a shame really, because based on the summer performance we were both very happy with the car.

Haven't contacted the garage yet (and it's probably dependent on many variables) but is that sort of range drop normal? Bearing in mind that we had perfectly acceptable range (400-450km) in the summer with aircon on and I know that saps power and increases consumption on ICE cars?

[LHRFlightman]

Your winter range is 50% of your summer range?

Something is wrong.

My Model 3 was about 18% down in the recent cold snap.