Charging issue with Zappi and Powerwall

[Taycan4sUK]

Dear All,

I am having issues charging car between 1-6AM to utilize 8p EDF tariff
I have Powerwall and zappi charger but no solar panels (as yet)
I am using location dependent profile for charging up to 85 % with Preferred charging time of 1-6AM
If I set up Zappi to use as Fast charging mod then Powerwall starts charging my car as soon as its connected to charger. It doesn’t wait for 1-6 AM time
If I restrict charging in Zappi to 1-6AM it only adds 2-3 KW and then stops charging.

Can somebody shed some light re how I can just get the car to charge from grid only between 1-6 AM?

Thanks in advance

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[bn8959]

I dont yet have a Zappi, but I have an Eddi and a Powerwall (with PV).

I also see some quirks and have been trying to work out the best way to fix it.

I am on ECO7 tariff and my Powerwall is set to Time based use. Its been doing pretty well at charging to the right level overnight etc.

I believe the CT (current transformer) placement is critical. I also dont beleive there is a correct answer - so Im working on a cunning plan.

Ideally you dont want the Powerwall to see the Zappi (or Eddi) use as 'house' use. That means thhe Zappi and Eddi need to be wired to a seperate distribution board, and the CT for the Powerwall needs to be on the 'house' side, and the Zappi CT needs to be on the 'grid' side.

This would ensure the powerwall would never discharge to the Zappi.

The only downside to this is that if you want preconditioning of the Taycan to come from the battery (for example if it happens in peak electricity period) then the Powerwall CT would need to be on the grid side of the Zappi connection.

I am planning to put the breaker for the Zappi in the small distribution board inside the Powerwall Gateway, and fit an extra CT with a switch on it, so I can select if the Powerwall does or dosent see the Eddi/Zappi use.

I hope that makes sense! I did draw a diagram, but it was terrible, need to redo it, but ill post it if I do.

 

[bn8959]

I'd suggest also using the timer on the Zappi, and not the Taycan (will be more important when you get PV and want to charge from them)

 

[Taycan4sUK]

Thanks for replies
I just can't understand why the car won't stick to charging within 1-6AM if I keep the Zappi in normal mode

If I use timer in Zappi, which profile should I use in Car if I want it to be charged to just 85%?

 

[bn8959]

Don’t have a Taycan yet, so may not be best person to answer, but from what I understand you don’t want any profiles set on the car, other than the ‘minimum’ charge 85%. The car should take a charge at any time. Again, don’t yet have a Zappi, but you should be able to set a boost schedule (or whatever the terminology is’ to charge at full speed during your night hours.
I believe the car shows a charging error outside of the Zappi schedule (as it’s connected but can’t take power), but will start charging when the Zappi allows it.
when PV is online, Zappi will allow the car to consume the excess generation in a similar way (just charging rate is automatically limited to match your solar excess).

 

[bn8959]

And if the Zappi schedule matches the off peak rate on your Powerwall, then it shouldn’t supply power for charging (but it would also not be powering your house at that time either).
preheating outside of your offpeak will drain the battery, unless you can position your CT clamps as I eluded to earlier.

 

[coop]

In the location based profile, set your minimum value to 25% (the smallest allowed value). That value is really the minimum setting, so any time you plug in, it will charge to that value and stop.

You also want to add a timer with a departure time of 6:00am and set the value to 85% there.

I know it's not very intuitive, but this works so you get your charging done during the window you want.

Profile, 25% and set the hours you want to charge.
Timer, 85% and the departure time = end of the hours you want to charge.

 

[Midlifecrisis]

I have a battery system which is on the DC side of the circuit rather than AC like the powerwall. I get the impression that none of these systems do quite what is intended and the battery confuses the system. You have to use a workaround to get it to do exactly what you want and be prepared to tweak the system settings to make it behave as you intend.

 

[bn8959]

I have a battery system which is on the DC side of the circuit rather than AC like the powerwall. I get the impression that none of these systems do quite what is intended and the battery confuses the system. You have to use a workaround to get it to do exactly what you want and be prepared to tweak the system settings to make it behave as you intend.

Yep, my thoughts too. Which is why I want to have the breaker for the EVSE (Zappi) between the grid and the battery grid CT. That way it won’t ‘see’ any use by the ESVE and won’t try to discharge to supply it.

 

[Midlifecrisis]

Yep, my thoughts too. Which is why I want to have the breaker for the EVSE (Zappi) between the grid and the battery grid CT. That way it won’t ‘see’ any use by the ESVE and won’t try to discharge to supply it.

Is it not possible with the Zappi to use a Harvi device on the battery discharge wire so the Zappi can sense what is coming from the battery? I don’t have a Zappi and am not an expert, but I thought this was a possible configuration so that you can set it not to use the battery up. Having said that, we have come to the conclusion that it doesn’t matter if our stored energy goes into a car or the house. Although we are trying to keep our grid energy use to the cheaper hours.

 

[bn8959]

Yes that is possible via the ‘avoid discharge’ setting, but is only really relavent when it comes to PV, as the Zappi can see the amount of PV and can see the amount going to grid and will therefore want to ‘soak’ up that excess, but monitoring the battery will allow that to charge first from PV.
Not really relavent without PV.

there is another really odd Powerwall behaviour I’ve seen, and it’s a classic case of the systems fighting. The Powerwall is very intelligent and learns you use and knows your import and export costs. I found there were certain times where it would think to itself ‘I know I now have enough charge to power the house until the 1am off peak time, so I’m going to power the house now and let 100% of PV go to grid’.
However the Eddi/Zappi then see - ooh lots of excess here and I see 2kw of PV generation, therefore I’m going to consume that 2kw. But, due to the wiring the battery then sees the house as using an extra 2kw - so the net result is that you end up export to grid what you are generating plus then discharging the battery by the same amount you are generating in to the Eddi/Zappi!
MyEnergi have confirm this is a quirk of their logic and will cause battery drain, even if set to not drain battery (as Zappi thinks it’s just using the PV).
Only way I can think round that is to move CT clamps so battery is totally unaware of Zappi use - that way it will never try and power it.

 

[Gwaihir]

I just use the Zappi2 on fast mode - no zappi timer - and use the Tycan to set the charging time. You will need to set a timer and profile.

 

[Midlifecrisis]

The bottom line here is that without some sort of over riding energy manager with permission to control every connected device it is going to do strange unpredictable things. I don’t know if the Porsche home energy manager could coordinate it all. Probably not given their track record with coding

 

[Gwaihir]

My Zappi will use the solar to charge the car but if it drops below 1.5kW going to the Taycan it will trip out. So I just charge on the night rate.

 

[Taycan4sUK]

In the location based profile, set your minimum value to 25% (the smallest allowed value). That value is really the minimum setting, so any time you plug in, it will charge to that value and stop.

You also want to add a timer with a departure time of 6:00am and set the value to 85% there.

I know it's not very intuitive, but this works so you get your charging done during the window you want.

Profile, 25% and set the hours you want to charge.
Timer, 85% and the departure time = end of the hours you want to charge.

Thanks
This has worked!!!

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