New Solar and Battery installation

osgiliath

Hi all,

I was hoping the collective minds on the forum could assist me in optimising the solar and powerwall system we have installed for the tempoary situation we are in.

We have installed a 19 panel system and PW3 plus an extension pack giving 27kW of battery storage in the property we have purchased. We haven't moved into it as yet (due late August). We have been given a 5kW export limit by the DNO. We were given our export MPAN last week, so we now paid to export.

We are on Octopus intelligent GO for import and Octopus Outgoing for export.

As we aren't able to use the power generated and stored in the batteries so they are full very early on in a day. The PW accordingly clips generation to 5kW. When the battery is less than 100% generation is upto 9kW in the good weather we've been having.

What i am trying to do on a tempoary basis is to get the full battery to export to the grid early in the day when solar generation is less than the 5kW export limit so that the batteries are as close to the reserve as possible. This would the allow the panels to generate to thier maximum by exporting 5kW to the grid and charge the empty batteries with the surplus solar. The setup i have seems to charge the battery from the grid overnight which is fine if it can be dumped back to the grid between 5.30am to 9.30am.

I have the PW set for savings and have the correct tarrifs inputted. I have tried to add a peak export price of 99p to force it export but to no avail. Could anyone offer any advice on if what i want to achieve is possible and how to set up the PW?

As we aren't living there having a day reserve is not required for the moment. When we move in we will have the heat pump on and using the batteries as well as our normal appliance usage so the batteries will be more used then.

I hope you can offer some suggestions.

Thanks in advance

QrizB

I don't know the specifics of the PW3 but yes, you should definitely be able to force a 5kW discharge from 0530-2330 subject to having the energy available.

I do something similar (on a much smaller scale) with my Ecoflow Stream system, which has 1.8kWp of panels, 1.9kWh of battery and an 800w export limit.

NedS

In Settings, you will need to set the PW3 to Savings mode (previously called Time Based Control) and allow export from Solar + Battery (Everything).

When you look in Settings > Powerwall, do you see a section for Energy Exports that has the option to select Solar or Everything?

Here's an image I borrowed from the internet:

Sometimes this option is missing, meaning that only solar can be exported. If it is missing, you will need to phone Tesla support (or your installer) and ask them to enable export from battery. It's a two minute job that they can do remotely. You should then see the above option and be able to select Everything which allows export from both solar and battery. Installers commonly forget to enable this option when commissioning the installation. If it was missing, once Tesla (or your installer) have enabled it, the above option should show up in the App.

The PW3 will then export to the grid based on the TOU tariff details you have entered. It is best to set this up manually to encourage the PW3 to do what you would like.

For example, set the export rate very high during the periods you would like the PW3 to export, and set it to zero during the periods when you would prefer solar to be stored in the battery. By manipulating the import (buy) and export (sell) rates like this, you can encourage the PW3 to do as you desire. It takes a bit of tweaking, but you should be able to get the desired results.

osgiliath

https://forums.moneysavingexpert.com/discussion/comment/82075079#Comment_82075079

Thank you for your reply and taking the time to reply, greatly appreciated. When i searched it did say that i should have that available, however the option is missing in my app. I've asked the installer to enable the 'export from battery ' option. Hopefully they should reply soon and get it switched on.

I will let you know how i get on and see if i can increase the daily export and thus the daily generation whilst the suns is shining so well.

osgiliath

The installer remotely enabled the Export from battery function so i now have the solar/everything toggle.

I'll have a play with the settings to get the battery to export.

Alnat1

My "nasty cheap Chinese" Pylontech batteries have a very simple toggle called "charge last". When this mode is enabled my batteries only fill when export/load is maxed out. Simply put, they only fill with what would usually be capped. This gives us plenty to get through from sunset until dawn on an average summer's day and is very easy to activate or deactivate.

Sometimes you don't get what you pay for…

NedS

https://forums.moneysavingexpert.com/discussion/comment/82075258#Comment_82075258

Great that they enabled that option quickly for you.

You should now be able to set your export rates high to force export in the mornings.

Also setting the export price to 0p during the afternoon tends to encourage the system to export earlier in the day to keep space in the battery to store solar later when exporting it is seen as having no value. This can be useful to manage clipping in the middle of the day.

osgiliath

https://forums.moneysavingexpert.com/discussion/comment/82075336#Comment_82075336

I've set a high export rate from 5.30am to 9.30am and another one at 18.30-22.30 to get the battery to export during times that the solar reduced. Hope this will allow the battery to top up the export to the 5kW during these times. If i can get the battery to export in the 4 hour morning window then gateway will manage charging the battery during the day with excess.

The evening session is to allow a further discharge so that the battery will charge overnight from the grid and rinse and repeat. I'll adjust as i go on and when we move in look at it again.

So far the system has been great and the function was only switched off until the DNO was confirmed.

Thank you once again

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82075160#Comment_82075160

From an ethical standpoint, forcing full discharge of the battery during 4-7pm peak (and the odd grid demand event) really does help balance the grid. Just something to ponder over as you familiarize yourself with your new system.

Oh, and consider adding on Charge Pack to your export tariff to pay you more for this!

osgiliath

To be fair the PW3 system does this automatically. The issue was the batteries being full by 9am so the gateway clipping solar generation. With the function to export from the batteries enabled this shouldn't be an issue going forward.

It good to know that other systems have similar functionality too.