Car not charging to full

[bc1979]

The last two nights I have put my Car on charge at around 85% to go to full during the Octopus Go window of 00:30 to 04:30 and woken up to find the Car only got to 96% with some messages about slow charging.

I am using an Ohme home charger and the scheduling worked fine for the first 5 days of ownership with the battery being topped up to 100%.

Now I know the final little bit of charging takes a while but surely it should have been able to get more than 10-12% in 4 hours?

Am I doing something wrong or is this something to do with trying to charge when the battery only needs a 15% or so top up?

 

[M1tch]

Only thing I can think of is maybe it’s due to how cold it’s been for the past few nights? Around -2c (Gloucestershire) here so maybe the battery hasn’t been at optimal temperature to take a charge?

 

[bc1979]

Yeah I figured that may be part of the reason, I am near you in Bristol. Just surprising to not charge enough in 4 hours.

It’s not normally an issue but I have a long journey every Monday and could do with knowing the car is at 100%, and also that there isn’t a fault with the Car or charger preventing it getting to 100%.

 

[M1tch]

Is the car showing that’s it’s pulling 7kw when it’s plugged in? By my terrible maths, you it should be able to take 10-12% in that time easily

 

[btc1k]

Really interesting thread as I plugged in the other night at 2030 at 40% to find the next day it had only reached 67%.

Ohme charger or the car had stopped charging, by itself at 2130 and then restarted later in the GO period, with no intervention for me.

I very much doubt it is the temperature as 7kw is slow charging even in minus temps.

Maybe it was an issue with Ohme... Or Bristol grid!

 

[bc1979]

I have just put it back on charge now to see what it would do and it’s pulled the full 7kw and gone from 96% to 100% in about 25 minutes and is now at 100% but saying there is 30 minutes remaining.

I am just going to leave it to it but I am a bit mystified, it charged up from around 70% or below up to 100% in the Octopus Go period without any issues in the first few days I had it.

 

[dcsh]

I assume that if you are repeatedly trying to charge from 85% to 100% you have a LFP battery Model 3? It could be that by not discharging the battery more that car is struggling to determine how full the battery is and that is affecting charging, ie showing 96% but the car thinks that is ”full” based on other metrics. It appears that LFP batteries have different behaviours to the others, so the Tesla recommendations are different as mention here

 

[GRiLLA]

As far as I know the error about slow charging isn't anything to do with temperature. It typically happens when there isn't a good connection between the car and cable, or sometimes a fault with your charge point.

I have just put it back on charge now to see what it would do and it’s pulled the full 7kw and gone from 96% to 100% in about 25 minutes and is now at 100% but saying there is 30 minutes remaining.

I am just going to leave it to it but I am a bit mystified, it charged up from around 70% or below up to 100% in the Octopus Go period without any issues in the first few days I had it.

That's also normal. Firstly as the battery will be cold a significant amount of power is diverted to warming the battery, and only a small amount goes to adding charge. In the final stages of charging, the battery spends time balancing the cells so they are all at the same level, my rule of thumb for my LR is that 90-100% takes twice as long as any other 10% charging. With a fully warmed battery I see it taking about a 1 KW of power while it does this (LFP batteries will have different timings but a similar cycle).