SolarEdge DC Coupled battery draining when charging car with ZAPPI

[Paul Colu]

First charge on my MG4 And I have a problem. Recently had solar panels and solaredge inverter with dc coupled battery installed. At same time ZAPPI car charger was installed. I don’t seem to be able to stop my SolarEdge dc coupled battery from discharging when I charge the car from my ZAPPI charger. As recommended in the ZAPPI manual I have tried setting the export margins at various levels but none stop the solaredge battery from discharge while the car is charging. Does anyone know how to stop the solaredge battery discharging while the car is charging?

 

[Diggsy]

That’s been discussed in this thread, from page 2…

Zappi Charging Overriding the MG4 Schedule

Any help would be appreciated. I just installed a Zappi but no matter what I set it to it seems to start charging the car even if my MG4 schedule is not set to run until night. Some background: I have a battery and small solar array that are not big enough for support a car. The Zappi...

www.mgevs.com

…hopefully you’ll get a workaround of sorts in there.

 

[Paul Colu]

Spoke to myenergi and they informed me that when you are in fast charge mode the charger will take energy from wherever it can regardless of whether you have a DC or AC coupled battery. Therefore the battery gets drained. The export margin work around for a DC coupled battery only works in ECO and ECO+ modes. If this is set correctly it should stop the battery discharging when using these modes.

 

[RobQuads]

Yeah to get it to stop pulling from the battery at all would require you to connect the zappi up before the CTs for the battery so it didn't know to export.
That said I think the theory is fairly sound. If your in eco you don't want to drain the battery as your mostly interested in your excess solar but if your forcing a charge then if you have "cheap" electric best to use it, If you pull from grid your going to be still paying the same $$$ than if you drained the battery and then pulled from the grid later

 

[Paul Colu]

I am with Octopus Go so plan to charge mostly between 00.30 - 04.30 when rates are low. If I do need to charge during the day I will just have to accept that I will have to drain the battery and pull more expensive energy from the grid. Charging up at night a couple of times a week should meet my needs most of the time.

 

[rosmith52]

I've found that if I use Manual Controls on the battery and add charging times from 00:30 to 04:30 (cheap rate time) then it not only charges the house battery overnight but if i scheduled the zappi for this time it charges the car as well without draing the battery.

 

[johnb80]

First charge on my MG4 And I have a problem. Recently had solar panels and solaredge inverter with dc coupled battery installed. At same time ZAPPI car charger was installed. I don’t seem to be able to stop my SolarEdge dc coupled battery from discharging when I charge the car from my ZAPPI charger. As recommended in the ZAPPI manual I have tried setting the export margins at various levels but none stop the solaredge battery from discharge while the car is charging. Does anyone know how to stop the solaredge battery discharging while the car is charging?

The ONLY way to stop this happening is to have the feed to the ZAPPI before the solar / battery connection to the grid. It's quite easy to do but would probably mean adding a small consumer unit, typically a 2 way one circa £30 and about an hour of an electricians time. If your Zappi is already fed from a small CU only the CT needs to be moved.

 

[eejp1007]

The ONLY way to stop this happening is to have the feed to the ZAPPI before the solar / battery connection to the grid. It's quite easy to do but would probably mean adding a small consumer unit, typically a 2 way one circa £30 and about an hour of an electricians time. If your Zappi is already fed from a small CU only the CT needs to be moved.

View attachment 22857

I've got a Powerwall and had talked the company doing the install through this exact scenario and we'd agreed for a new consumer unit to go in before the Gateway so that there is no risk of discharge. When they installed it last week, the electrician said he could do it straight on the Gateway non-backup side without the need for an extra consumer unit and it would all be cleaner and neater.

Of course, as it is in the Gateway box, even on the non-backup side, it sees the consumption and pushes out 5kW into the car!
They should be here in 3 hours to put the new consumer unit in!!!

I'm also playing around with Home Assistant to get the best use of slots outside of the Intelligent Octopus Go standard times but that is for slow time once the system behaves as it should.

 

[JimD]

I have a Solax inverter for my panels and you can set that so it won't use the battery during a set time window (you can set up to two time slots). That's the only way to stop it using the battery in my set up anyway, so maybe yours has a similar feature (though at best it counts as a work-around).

 

[johnb80]

I have a Solax inverter for my panels and you can set that so it won't use the battery during a set time window (you can set up to two time slots). That's the only way to stop it using the battery in my set up anyway, so maybe yours has a similar feature (though at best it counts as a work-around).

But that means your battery wont be supplying the house either?

I've got a Powerwall and had talked the company doing the install through this exact scenario and we'd agreed for a new consumer unit to go in before the Gateway so that there is no risk of discharge. When they installed it last week, the electrician said he could do it straight on the Gateway non-backup side without the need for an extra consumer unit and it would all be cleaner and neater.

Of course, as it is in the Gateway box, even on the non-backup side, it sees the consumption and pushes out 5kW into the car!
They should be here in 3 hours to put the new consumer unit in!!!

I'm also playing around with Home Assistant to get the best use of slots outside of the Intelligent Octopus Go standard times but that is for slow time once the system behaves as it should.

If you link MyEnergi into HA, you can see the ZAPPI when it's charging, you can also pickup the additional sessions via Octopus Energy Mini integration. Armed with that info you can instruct house batteries, Immersion heater etc to all start consuming too

 

[JimD]

But that means your battery wont be supplying the house either?

Correct. I generally don't bother with it for that reason. However, in the summer I almost never need to charge the car from the mains anyway, and in winter I charge during the night, when the solar battery has usually been used up supplying the house.

 

[johnb80]

Correct. I generally don't bother with it for that reason. However, in the summer I almost never need to charge the car from the mains anyway, and in winter I charge during the night, when the solar battery has usually been used up supplying the house.

With the current energy pricing it's not worth doing anything with solar other than exporting (15p kWh with octopus), I can buy energy back to charge batteries etc at 7.5p, win - win.

 

[JimD]

With the current energy pricing it's not worth doing anything with solar other than exporting (15p kWh with octopus), I can buy energy back to charge batteries etc at 7.5p, win - win.

To be honest, I haven't bothered applying for a time of day tariff. My battery's only 5 ish kwh and I don't do many miles in the car these days. Also my heating & hot water are all on gas and it's probably too late in life for us to invest in heat pumps etc.