Low Speed charging rate variable

[JonE]

I have a 7kW wall charger. Sometimes when I plug in my MG4 LR it charges at 6.8kW but other times it chooses 3.3kW. It seems quite random. Once it has decided on the lower rate no amount of plugging in / out / restarting the charger etc. will change its decision. On the dash it is set to "maximum" charge rate. Has anyone else seen this?

 

[Martinonline]

Are you sure it is random? What limit has been set for the battery level? Does the 3.3Kw occur when nearing the charge limit?

Note, Posters have reported the charge level changing, usually upwards, but other events may occur.

 

[Jomarkh]

Do you have an EVSE with load monitoring which is see extra load coming from the house?

 

[JonE]

Are you sure it is random? What limit has been set for the battery level? Does the 3.3Kw occur when nearing the charge limit?

Note, Posters have reported the charge level changing, usually upwards, but other events may occur.

Yesterday when this happened the car was at about 70% when I started so I don't think so.

Do you have an EVSE with load monitoring which is see extra load coming from the house?

Well I was taking advantage of Octopus Energy "power up" which gives free electricity for 2 hours so the consumption on my house would be high as I was also charging my solar battery etc. But I can't see how the EV charger would have known this? As far as I know it doesn not monitor overall consumption of the house.

 

[Surfdog]

If you are on an Octopus tariff then I presume you are using an Ohme charger. Then power fluctuations are quite normal during smart charging. The amount of power supplied through the charger will vary depending on amount of electricity available on the grid. For past 2 months all my charging session have all been at 7.4kwh from the moment I ask for a charge, even during peak times. Prior to this, Octopus would calculate a variable smart charge schedule, mostly during off peak hours with varying rates if charge.

 

[JonE]

I wish I had an Ohme but I have a brain-dead BP Chargemaster unit which was installed a few years ago before I switched to Octopus and before I had the MG4.

 

[JonE]

I have found that the car charges consistently at 7kW during the night and 3kW during the day. If I look at the grid voltage through my PV system data I see that the grid voltage is 240-245 at night and 230 - 235 during the day. So I assume this is why the rate is being limited. My question is: "Does the charger determine the rate or does the car?" I assume this is agreed during the intial negotiation between the two. If it is the charger I will buy a new charger but I don't want to spend that money and find it makes no difference. Does anyone know?

 

[DrAndyPerry]

I've just caught mine doing this (MG4 XPower). It's really annoying, cheap electric and we're trying to charge up both of our cars. Mine is holding out at 4kW... grrrrr

 

[JonE]

Yes, it is very annoying - we have Octopus "powerups" which provide 2-3 hours of free electricity during the day from time to time. I want to charge the car at max. In the end I replaced my charger with an Ohme one which improved things a bit but I still never get 7kW during the day. Usually around 5kW but last week it was only 4kW. I always get 7kW at night. My assumption is that either the charger or the car is assessing the supply (by voltage or frequency or both) to determine if it thinks the supply is in danger of being overloaded. If so it reduces its demand. Just a theory.

 

[Martinonline]

Does Octopus have access to your EVSE? (eg, via its sim.) And if so could Octopus be controlling the power.