Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Reduced charging speed down to temperature or other factors?

This site may earn commission on affiliate links.
I’ve noticed that I can get less charge in my car during the 4 hr Octopus Go window recently.

In late Sept, I was able to add 30.6 kWh in 3h 59min which is an average charging power of 7.7kW

More recently, I got 23.4kWh in 4h 7min which is an average charging power of 5.7kW.

Is this 26% reduction in charging rate just down to the lower temperatures of late or could there other factors at play?
 
The supply voltage can dip a bit in winter, might make a small difference to charge power, perhaps. For example, right now, in bright sunshine, our local voltage is right up near the maximum of the tolerance band, currently it's showing as being 251 VAC (maximum is 253 VAC). I suspect that, come this evening, when the temperature drops and demand rises, that will drop back to maybe 235 VAC or so, which seems to be our normal winter lowest voltage. The voltage can drop right down to 216 VAC and still be within spec, but we've always had a fairly high local voltage here, something I've been on to the DNO about a few times, as we often hit the 253 VAC upper limit in summer, which causes our solar inverter to stop exporting.

Perhaps worth looking at the voltage when the car's charging, to see if there's a voltage drop. If there is, then it might be worth checking to see the cause, just in case there's a wiring fault causing the drop.

As a guide, a 32 A charge point will charge at about 7.36 kW at the nominal mains voltage of 230 VAC, but this will drop to about 6.9 kW with the supply at the minimum limit, or rise to nearly 8.1 kW with the supply at the maximum limit.
 
  • Like
Reactions: MadScientist
I’ve noticed that I can get less charge in my car during the 4 hr Octopus Go window recently.

In late Sept, I was able to add 30.6 kWh in 3h 59min which is an average charging power of 7.7kW

More recently, I got 23.4kWh in 4h 7min which is an average charging power of 5.7kW.

Is this 26% reduction in charging rate just down to the lower temperatures of late or could there other factors at play?

I see variable charging sometimes but it doesn't seem related to temperatures. The app for the Zappi shows a graph of the charge and the variations as it progresses. Sometimes it's very consistent and at other times it can be quite a "ragged" looking graph with the rate briefly dipping and coming back ... so the overall average can sometimes be below 7kW. We are in a country area so voltage out here can fluctuate a bit. My charge point is taken off our garage supply which is a long way from the house and the meter/mains, so there's some voltage drop involved as well. I usually expect to be able to put in 28kWh over the four hours though it will often be potentially more than that. (nice wee pun there!)
 
  • Like
Reactions: MadScientist
If you have something like TeslaFi you can see the voltages, charge current and charge speed over the course of the charge. That will indicate what variables may be in play and when.

However, temperature at AC charging rates seem to have little affect once a charge is under way, although may affect how long it takes for charge to actually start being recorded as added to the battery. Also, transient SoC % changes may affect what is added if charging by set % limit.
 
Last edited:
  • Like
Reactions: MadScientist
Thanks for the replies. I think I have found the issue. My Konnect app (which I use with my Andersen charger) appears to have started reporting the incorrect kWh usage. Whilst in the past, it agreed closely to what I saw on Teslamate, it now seems to be massively under reporting the energy usage. Not sure what’s going on but could be a bug introduced in an update. On Teslamate, the data look ok.