How is CA figure so different to car?

Hi ​@Smurfarama, that is an unusual one because car charger (the bit inside the car) efficiency means the values are around the other way. The car (battery) normally reporting less energy received than what is metered due to inverter losses.

I don't have an explanation for that to be honest and I'm wondering if it's just an odd reporting error by the car. Could you track how this goes over a period of time to see if this discrepancy is consistent and then come back to us again?

Thanks

Peter 

​@Peter E Thanks for the reply.

My car (BMW i4) generally always reads higher than the CA app.

If the car has received 44kWh and OVO only credited 38.7kWh, then that’s 5.3kWh used but not discounted.

I have raised this before with OVO because it obviously adds up if every charge is like this. It was pointed out to me that in the T’s & C’s the allowable error is 10%, which this charge does not conform to (12%).

Here is my January usage for this year, pretty much exactly 10% error.

Thanks for the detail which makes it clearer. It sounds like you need to need to speak to customer service and I'm going to tag ​@Blastoise186 who is great at knowing the best contact details for technical discussions related to this issue. I'm hoping he might see this at some point but you should get a reply by early next week when the CS teams are in. I'll keep an eye on this thread to see that it gets progressed. 

I dont see a great correspondence between what you car is reporting and the OVO data.

5th OVO, BMW

6th OVO, No BMW data

13th OVO, BMW 

28th No OVO data, BMW 

30th OVO, No BMW data

Is any of that charging done away from home? I think the most concerning data is when OVO reports charging the car and your car is not showing that like the 6th and the 30th. Is there an explanation for that. I've not heard anything about BMWs not correctly reporting charge value although I'll go and have a look.

To be continued …

Peter 

Hmm… The best team for this is almost certainly the Charge Anytime team - 0330 175 9678 or ovocharge@ovo.com.

Worth noting though, you may have a better experience if you use the integration with a compatible Charger rather than the vehicle integration. Those tend to be more accurate.

​@Peter E  Thanks again.

Normally the disparity in days is because the car counts the whole charge on the day it was plugged in, whereas OVO log separate days.

This can be seen on the 5th/6th. I plugged the car in on the 5th and unplugged it on the 6th after an overnight charge. BMW log this as 48kWh all on the 5th, OVO total it over the 2 days as 45.4kWh (acceptable as it’s within 10%).

I don’t know if I may have plugged the car in around  midnight on the 29th, I’m used to seeing different days, the BMW recorded 26kWh, OVO 23.2kWh, so I’m guessing that’s the same charging session, albeit more than 10% error.

​@Blastoise186 Hi.

Ohme charger mate.

Oh. Ohme is not compatible with OVO so it will have to be the car.

I think the best couse of action is to call the number for the Charge Anytime team and give them the details. They will possibly have some experience of what has happened here and be able to assist you in a more direct way than we can do here. However, please feel free to come back on here if you get stuck or reach an impasse and we can have another look 

In general the charging efficiency of cars is the Energy reported as having gone into the battery divided by the Energy recorded by the electricity meter (Charge Anytime process). For 7kW charging it is usually around 90%. 10% being lost in connecting cables, car wiring, car inverter losses (AC to DC then DC mains voltage to DC battery voltage conversion), battery charging losses and the system power with the car awake. This means to get 9kWh into a battery you need 10kWh of energy as measured by your meter. Another point to consider. Is the car measuring the energy it receives or the energy actually stored in the battery?

Peter

When you next charge, keep an eye on the OVO Charge app vs your charger - I suspect what is happening is it’s taking a while for communication between the car and OVO to be established, so there’s a small amount of charge occurring before OVO Charge recognises the car is connected and registers it as a smart charging session.

Mine usually catches up within 15 minutes or so of being plugged in, meaning the unregistered charge isn’t particularly large each time but sometimes you notice it doesn’t catch up for quite a while and you can chew through a good few kWh without OVO CA counting it as a smart charge.

​@Peter E thanks for your help here over the weekend.

​@Smurfarama I haven’t seen this issue myself, and I can’t find anything on the Forum where anyone is reporting this same situation. I’m hoping though, as ​@Peter E suggests, that our Charge Anytime team may have seen something similar, and know how to fix it. It could be that ​@divinemadness is correct in what they’ve suggested above - our Charge Anytime team should know the answer.

We’d really appreciate it if you could let us know what they tell you, as this information might help someone else in future. If I manage to find an answer internally I’ll let you know, but I think this is definitely one of those where the team need to look at your account, which is something we don’t have access to on the Forum.

​@divinemadness Thanks for your reply.

You’re correct in that there is a delay communicating with the car. It’s something that i’ve looked at for my car by using the CA app and noting how often the ‘last update’ changes when the car is plugged in.

My BMW i4 seems to ‘talk’ to OVO every 7 minutes.

Plug the car in and lock it and normally the OVO CA app will notice this. 7 mins later will report ready to smart charge and 7 mins later will indicate charging. I have to set my car to ‘charge immediately’ for smart charging to generate the schedule. So, I stop the car charging after first plugging it in (Stops 7 mins of unregistered charging) and allow OVO to now control the smart charge.

I can see from the BMW app when the car starts charging and usually the CA app indicates ‘smart charging’ on the next ‘last updated’ 7 mins later. But for balance the CA app should then show the car charging for the last 7 mins after the car reports the charge stops and should therefore cancel out.

I have reported this to OVO before and that’s how I know that in the T’s & C’s there is a 10% tolerance. This has never been in my favour! 😉. Sometimes my reported charges are quite accurate to the car figure, sometimes not.

​@Peter E Thanks again for your replies mate.

I don’t know how the car measures the input, percentage or actual kWh, but because I have  an incompatible Ohme charger (Was a dream when that worked!!!), I have OVO CA integrated to my car.

My understanding is that OVO CA has remote access to the BMW app on my phone, and if thats the case I dont see why the figures aren’t pretty much identical. OVO cannot see how much electricity is going through my Ohme charger, just what my car is reporting.

cheers

I'm not sure exactly how it does it (Kaluza talks to BMW’s servers and then to your car) but it can command the car to charge and see how fast the battery percentage rises. (The app just receives data from the servers). That way, it can work out how long it will take to get a percentage increase irrespective of what charge point you are using from 2kW to 7kW. Depending upon the car I think it can even ask the car to charge at different rates within the limits of the charge point.

OVO can only bill you on what the smart meter sees. There is no other lawful way (Ofgem's rules) of calculating what you've used. It can't use BMWs data or even estimates.

But we need to understand what is going on so that you (and other customers) can have confidence that you are being charged correctly. If it was me I would want to know that. 

Peter