Model 3 charging is draining the powerwall

[sliyk]

Hi guys,
New owner of 4kw solar panels and a powerwall 2.had the model 3 for almost a year with a pod point.

When charging via octopus go off peak time the powerwall is dumping into the car (well home cause it doesn't detect the car funnily)
Is there a way of preserving the powerwall battery from discharging to charge the car during these hours?

I don't have a zappi and the installation of one is £940

 

[Wol747]

Unplug it?

 

[AndrewGR]

Can’t you set the powerwall up so it charges during the cheap Go tariff period? Guess that might mean it doesn’t have spare capacity to mop up your surplus solar, but since the car has a much bigger battery than the powerwall that’s a more useful store for surplus solar anyway - if it is at home!

 

[Mrklaw]

Can’t you schedule what the power wall does things or is it all ‘smart’? I guess if it’s full of solar then using that is better than even cheap electric. But if not full - eg with a smaller array or a house with high usage, then you should be able to tell it to only discharge during high unit cost periods (and even charge during low cost times)

 

[Dilly]

I know nowt about pod point chargers but have good experience with solar and PW’s.
you can set the PW to charge from the grid off-peak but, if it’s benefitted from reasonable solar in the preceding days it may decide not to charge. It should, but won’t necessarily, allow the car to charge from the grid. In the depths of winter, the car and PW will charge off peak happily as solar influence is minimal.
i Have Zappi’s. In winter, I set nothing in the cars and off peak timers in the Zappi’s. In summer, because my array is quite big, l just charge everything off solar

 

[gangzoom]

Just go to the 'customise' option on the PowerWall and you can select when the PowerWall will discharge versus using the grid via the schedule times.

 

[Country Boy]

I have a solar & Powerwall setup.

As the previous post states, you can set the advanced setting to either cost saving or balanced. The power wall just does its own thing, and you have very little control over what it does or does not do. There is a "Tesla knows best" and my experiences below may well not be true for everyone all the time...

Self power mode, use battery until it is dead, then use grid...

In balanced mode, the power wall tends not to charge from the grid, but does use grid during the off peak period.

In Cost saving, the power wall will charge during the off peak period (if it feels like it) and discharge the reset of the time.

All this is variable. I have had the power wall charge from the grid for short periods when set to self power, and not take any power from the grid in cost saving mode. The AI bit just appears to look at the previous days solar and assume tomorrow is going to be the same. As usage and solar production can vary wildly from day to day, the power wall does not end up doing what you want it to do... I do find in balanced, but especially cost saving, the power wall charges from the grid at the same time you have large drain like charging the car...

So after all this waffle, what to do.. In your situation, I would try using the balanced setting with no shoulder time, just peak and off peak. Hopefully this will power the house from the power wall and solar during the peak times, and grid from the off peak...

I hope this helps,

as ever, YMMV

 

[sliyk]

Thanks for the replies guys
My powerwall is relatively new so maybe it is just doing its own crazy things. Like today on off peak it did nothing lol and let the grid power the home. I set it to self powered so then it started supplying the house

I'm seriously contemplating getting the zappi as I have heard the zappi is able to differentiate the battery and not extract juice from it.

 

[gangzoom]

@sliyk You don't need any extra hardware, when you go into the 'option' bit of the App do you see the 'customise' / 'advanced' bit?

If not wait for a few days as after the initial install the PowerWall does some calibration before giving you those options.

 

[sliyk]

@sliyk You don't need any extra hardware, when you go into the 'option' bit of the App do you see the 'customise' / 'advanced' bit?

If not wait for a few days as after the initial install the PowerWall does some calibration before giving you those options.

It has given me that option after about 48 hours. But even in the off peak time when i connected the model 3 it drained all its power into the car and then the car used the grid, the PW didnt then charge itself up. New powerwall behaviour? Today it was just letting the grid supply the house during the off peak hour despite being about 70 percent full. weird.

 

[Llama.]

Thanks for the replies guys
My powerwall is relatively new so maybe it is just doing its own crazy things. Like today on off peak it did nothing lol and let the grid power the home. I set it to self powered so then it started supplying the house

I'm seriously contemplating getting the zappi as I have heard the zappi is able to differentiate the battery and not extract juice from it.

I have a Zappi with a solar battery storage setup. (4.5 kw solar, 7.5 kWh battery).

The Zappi itself (and the Harvi with battery CT clamps ) mine is fitted with does not differentiate in the way you are after.

It will only start a charge on Eco+ mode when the battery is full and sending excess solar to the grid. There may be some settings in your inverter that can help with this but the Zappi needs to see excess Solar going to the grid before it will start a charge automatically in this mode.

The Zappi is clever in the way you can set the proportion of solar / grid usage though. And I like the Eco mode that draws a steady 1.7 kw and tops up from the grid. So the Zappi is still useful but not the magic device I was hoping for in terms of solar battery integration.

For example my Zappi can see rate of charge and discharge from my battery but not state of charge (ie % full).

As others have suggested, if I set my storage battery to charge off peak with cheap .05p electricity during the night, it tends to be full enough by 10AM for the car to charge on excess solar.

But this is only helpful if you are certain that you would have consumed this off peak juice anyway at some point in the day. During summer months when I can go days in a row without any grid usage this seems pointless.

In practical terms though I tend to be home when my car is at home so can just start a charge when excess solar is available and manually bypass this battery storage issue.

Sorry for the long post. Hope that helps.

 

[Gatsojon]

I have a Zappi with a solar battery storage setup. (4.5 kw solar, 7.5 kWh battery).

The Zappi itself (and the Harvi with battery CT clamps ) mine is fitted with does not differentiate in the way you are after.

It will only start a charge on Eco+ mode when the battery is full and sending excess solar to the grid. There may be some settings in your inverter that can help with this but the Zappi needs to see excess Solar going to the grid before it will start a charge automatically in this mode.

The Zappi is clever in the way you can set the proportion of solar / grid usage though. And I like the Eco mode that draws a steady 1.7 kw and tops up from the grid. So the Zappi is still useful but not the magic device I was hoping for in terms of solar battery integration.

For example my Zappi can see rate of charge and discharge from my battery but not state of charge (ie % full).

As others have suggested, if I set my storage battery to charge off peak with cheap .05p electricity during the night, it tends to be full enough by 10AM for the car to charge on excess solar.

But this is only helpful if you are certain that you would have consumed this off peak juice anyway at some point in the day. During summer months when I can go days in a row without any grid usage this seems pointless.

In practical terms though I tend to be home when my car is at home so can just start a charge when excess solar is available and manually bypass this battery storage issue.

Sorry for the long post. Hope that helps.

I have a similar situation to you and use my Zappi in a similar way too. I have purchased a CT clamp for the battery but not fitted this yet as I need to turn everything off first before playing with that and there never seems to be a good time.
Anyway, I’m hoping that when the Zappi sees the battery as a separate source, it will work as the OP intends. Currently, on Eco+, once the battery is full the Zappi charges from the solar plus draws 3.7 kW from the battery as it can’t distinguish the difference between the battery and solar. That’s working ok provided I manually stop the charging at some point I decide will leave enough in the PW to last until solar kicks back in.

 

[Llama.]

I have a similar situation to you and use my Zappi in a similar way too. I have purchased a CT clamp for the battery but not fitted this yet as I need to turn everything off first before playing with that and there never seems to be a good time.
Anyway, I’m hoping that when the Zappi sees the battery as a separate source, it will work as the OP intends. Currently, on Eco+, once the battery is full the Zappi charges from the solar plus draws 3.7 kW from the battery as it can’t distinguish the difference between the battery and solar. That’s working ok provided I manually stop the charging at some point I decide will leave enough in the PW to last until solar kicks back in.

Yup this is my situation. Zappi will still pull from full battery and solar when Eco+ charge starts.

I’ve committed hours to resolving this issue and have chocked it up as a first world problem I can live with.

So long as I can put 40 miles of range in my Tesla every day from solar and still have a full battery at sunset charged by solar then I’m done trying to solve the battery integration thing.

 

[sliyk]

I have a Zappi with a solar battery storage setup. (4.5 kw solar, 7.5 kWh battery).

The Zappi itself (and the Harvi with battery CT clamps ) mine is fitted with does not differentiate in the way you are after.

It will only start a charge on Eco+ mode when the battery is full and sending excess solar to the grid. There may be some settings in your inverter that can help with this but the Zappi needs to see excess Solar going to the grid before it will start a charge automatically in this mode.

The Zappi is clever in the way you can set the proportion of solar / grid usage though. And I like the Eco mode that draws a steady 1.7 kw and tops up from the grid. So the Zappi is still useful but not the magic device I was hoping for in terms of solar battery integration.

For example my Zappi can see rate of charge and discharge from my battery but not state of charge (ie % full).

As others have suggested, if I set my storage battery to charge off peak with cheap .05p electricity during the night, it tends to be full enough by 10AM for the car to charge on excess solar.

But this is only helpful if you are certain that you would have consumed this off peak juice anyway at some point in the day. During summer months when I can go days in a row without any grid usage this seems pointless.

In practical terms though I tend to be home when my car is at home so can just start a charge when excess solar is available and manually bypass this battery storage issue.

Sorry for the long post. Hope that helps.

thanks for the detailed post. So in essence Zappi does still draw from the battery... but as @Gatsojon has stated, a clamp on the battery will give it that SOC and possibly input output activity of the battery as well?

You are right, it is very much a first world problem but my ocd is going haywire. The powerwall is new so maybe still adjusting to life in the real world. I have been told to not put it into backup mode often as that messes the up the algorithm (dunno really).

at this point in time I have been using the tesla 3 pin charger to charge at a steady 2kw when my 4kw solar is producing excess that I can monitor on the tesla app. It would help if the charger did it by itself.

Ideal world situation (wishful thinking?);
-car charges off excess solar in the morning, powerwall also charges up.
-car charges off octopus go off peak night time rate, battery stays as is to provide power to the house

is that too much to ask? (lol)

 

[gangzoom]

-car charges off excess solar in the morning, powerwall also charges up.
-car charges off octopus go off peak night time rate, battery stays as is to provide power to the house

is that too much to ask? (lol)

Give it a few days for the PowerWall to learn your usage, set up your 'high cost' times, and leave it alone!! - DONT FIDDLE with the software as does what it wants, so every time you fiddle it has to 'relearn' your usage.

That's exactly what/why our PowerWall works, except for the charge up with solar. I don't have enough solar PV to charge the car and PW at the same time.

You can set the car to charge by the app, but you will need to drop the charge rate on the car to match the solar ouput, to be honest you save so little money that way its not worth the effort. If you have a water heater linked to your solar PV, using excess solar to heat the water work better.

 

[sliyk]

Give it a few days for the PowerWall to learn your usage, set up your 'high cost' times, and leave it alone!! - DONT FIDDLE with the software as does what it wants, so every time you fiddle it has to 'relearn' your usage.

That's exactly what/why our PowerWall works, except for the charge up with solar. I don't have enough solar PV to charge the car and PW at the same time.

You can set the car to charge by the app, but you will need to drop the charge rate on the car to match the solar ouput, to be honest you save so little money that way its not worth the effort. If you have a water heater linked to your solar PV, using excess solar to heat the water work better.

Thanks for the advice, I wonder how 'intelligent' the powerwall is as I am not charging my car every night as currently working from home. In any case I will leave it be and allow it to 'learn' my behaviour.
I do have an immersion heater and I am attaching a shelly addon to the plug that will allow me to set the water heater to turn on at specific times of the day thereby not needing the boiler to heat the water.

was keen on getting a zappi charger but feeling that the £940 is a bit much to ask for for this little issue?

 

[sliyk]

My schedule

 

[Burley]

We've got a Zappi & Powerwall and even with the 'Do Not Drain' option on, it still seems to draw some power from the PW when charging on Eco+. In fact, I see power going from PW to the grid, whilst the Zappi gives everything coming off the roof to the car. It pretty confusing, but it seems like the PW & Zappi fight with each other. All the settings are as they should be, AC battery, CT clamp on the battery and Do Not Drain, but what we see is the PW discharge to the point it wants to refill a bit from the solar, which leads to the charge pausing. The charge resumes after the battery goes back onto standby, but after a few cycles like this, it goes to charge delayed and the M3 decides there's an error with the charger..

 

[gangzoom]

We've got a Zappi & Powerwall and even with the 'Do Not Drain' option on, it still seems to draw some power from the PW when charging on Eco+.

Odd, this is what our PW does at night on 'cost saving' mode. During E7 rates times it never discharges from the PW, any charging, including the PW is done via the gird using cheap electricity.

When charging using solar, as long as the cars pull rate is less than the solar PV generation rate it will not pull from the PW. But I don't have big enough solar array to support sustained day time charging via solar.

 

[Llama.]

Hi Sliyk

Yes, even with a CT clamp on the battery the Zappi will still drain the battery when charging. It was explained to me that the Zappi sees live solar and battery storage as ‘green’ energy and will just take them both together.

Also even with this CT clamp my Zappi (and Harvi) only sees rate of charge to the battery. It has no idea how full it is. So no state of charge (ie 86% full) is displayed on the Zappi or app. Enclosed is a screen shot of Zappi live data.

The Zappi doesn’t have a function that allows you to change which is prioritised for charging: car or battery. So most likely your inverter will default to filling your battery first as mine does which is why charging your battery at night on cheap juice might be preferable. You are sort of committing the grid expenditure into your battery but then it does allow the Zappi to begin a charge automatically, albeit with a drain on battery too.

However.......there may be a way to change your inverter settings so that it only accepts a given level of amps of solar generation letting some very small amount (100w) of solar production to briefly slip past as ‘export’. When your Zappi sees this as ‘excess solar’ it will begin a charge. In this way you may be able to share solar production between the Zappi and the battery.

I decided this wasn’t a rabbit hole I was prepared to go down and just charge my battery first and then the car with available solar.