Charging with Intelligent Octopus Go - 5% Short

[Chris H]

I use intelligent Octopus Go for my charging, with a Zappi charger.
The way it works is that you tell Octopus what charger you have and what car you have when setting it up.
To charge, you can plug in any time of day and you say you want it to add X% charge by a certain time, and Octopus schedule the charging and whatever time of day they schedule the charging to take place (usually overnight, but not always) they charge 7p/kWh. All great.
I had an MG ZS SR and the charging was spot-on every time. If the battery had 40% left I could set Octopus to add, say, 50% by 8:30 am and I'd get in the car in the morning and it would be at exactly 90% charge. Great.
I now have an MGS5 LR and reconfigured IOG for the new car and it charges every time, but is always around 5% short. So if it's at 40% I might set IOG to add 50% and when it has finished it will be 85%, not 90%. If I set it to add 20% it will add about 15% etc. All a bit strange because the configuration looks right, it's set up for a 64Kwh battery.
It's not a big problem, I can always add an extra 5% to the amount to add but I'm interested to find out anyone else had this, or if anyone can speculate as to what might cause it.

 

[Guinea Pig]

That's odd, mine does the exact opposite!

 

[Chris H]

So yesterday the car was at 49%, so I set it to add 45% to be ready by 08:30.
While it was still charging I checked the charging rates. Zappi was saying the power was 7.2kW, yet the MG was saying 6.6kW (see screenshots). When it had finished Zappi says it had added 31.05kWh (which is 50% of the 62kWh usable capacity), yet the MG says it is now at 90%, ie it has added 41%, which is around 25.5kWh.
What is going on? Where has that extra 5.5kWh gone (31-25.5), which I'm being charged for? I'm only getting 82% of he energy I'm charged for into the car.
(I'm not setting any battery heating or pre-warming the car.)

 

[Everest]

What is going on? Where has that extra 5.5kWh gone (31-25.5), which I'm being charged for? I'm only getting 82% of he energy I'm charged for into the car.

Inevitable losses. Most will be lost in the conversion from AC to DC within the charger. Some will be used to heat the batteries to a suitable temperature during charging. Some will be lost powering the vehicle's electronics. Some, hopefully a smaller amount, will be lost as heat in the cables between the Zappi and the EV.

 

[tsedge]

These are normal conversion losses. Just add 5-10% to the amount of charge you request and it will reach your target.

 

[Kenp1]

.

 

[tsedge]

Have you got battery heating set to on?

They've already said no.

 

[Jto]

I use intelligent Octopus Go for my charging, with a Zappi charger.
The way it works is that you tell Octopus what charger you have and what car you have when setting it up.
To charge, you can plug in any time of day and you say you want it to add X% charge by a certain time, and Octopus schedule the charging and whatever time of day they schedule the charging to take place (usually overnight, but not always) they charge 7p/kWh. All great.
I had an MG ZS SR and the charging was spot-on every time. If the battery had 40% left I could set Octopus to add, say, 50% by 8:30 am and I'd get in the car in the morning and it would be at exactly 90% charge. Great.
I now have an MGS5 LR and reconfigured IOG for the new car and it charges every time, but is always around 5% short. So if it's at 40% I might set IOG to add 50% and when it has finished it will be 85%, not 90%. If I set it to add 20% it will add about 15% etc. All a bit strange because the configuration looks right, it's set up for a 64Kwh battery.
It's not a big problem, I can always add an extra 5% to the amount to add but I'm interested to find out anyone else had this, or if anyone can speculate as to what might cause it.

With LR on the battery you can scroll the amount of max charge as should be set at 80% unless you are going to do a long journey the next day. This could set at 85% so the car stops the charge not the wall box.

 

[smurfblue]

I use intelligent Octopus Go for my charging, with a Zappi charger.
The way it works is that you tell Octopus what charger you have and what car you have when setting it up.
To charge, you can plug in any time of day and you say you want it to add X% charge by a certain time, and Octopus schedule the charging and whatever time of day they schedule the charging to take place (usually overnight, but not always) they charge 7p/kWh. All great.
I had an MG ZS SR and the charging was spot-on every time. If the battery had 40% left I could set Octopus to add, say, 50% by 8:30 am and I'd get in the car in the morning and it would be at exactly 90% charge. Great.
I now have an MGS5 LR and reconfigured IOG for the new car and it charges every time, but is always around 5% short. So if it's at 40% I might set IOG to add 50% and when it has finished it will be 85%, not 90%. If I set it to add 20% it will add about 15% etc. All a bit strange because the configuration looks right, it's set up for a 64Kwh battery.
It's not a big problem, I can always add an extra 5% to the amount to add but I'm interested to find out anyone else had this, or if anyone can speculate as to what might cause it.

Mine was like that at first but seemed to get it right after a few charges.

 

[Jaygee]

Mine is off by2-3% using my ohme pro. Just conversion and other losses which could change day by day depending on so many variables it would be hard to account for all of them. Some of these chargers can directly talk to the car via the API but MG have never opened theirs up to others (they are not the only brand who haven’t done that though) so we are a bit stuck.
I just guesstimate at each charge.

 

[emmrecs]

Some of these chargers can directly talk to the car via the API but MG have never opened theirs up to others

That may not be wholly true!!

I've commented elsewhere that the ev.energy app, which communicates with and controls my Rolec charger, also shows the battery percentage of my MG S5, so some degree of communication car>charger or app is certainly happening for me.

 

[Jaygee]

That may not be wholly true!!

I've commented elsewhere that the ev.energy app, which communicates with and controls my Rolec charger, also shows the battery percentage of my MG S5, so some degree of communication car>charger or app is certainly happening for me.

I am no expert in this but that would be interesting as mg uk (and I have asked them) has not opened the api to 3rd party as far as I know. Might be something new. You don’t happen to have some kind of a obd device attached ?
Just checked the EV energy app and they log in to your mg uk account to access soc. this is different than 3rd party api support which is what I was on about.