Octopus Go for Charging my Solar system batteries

I am hopefully moving on to Octopus Go tariff (Smart meter being installed in November by Octopus after a very long wait)
My Solax X1 hybrid has a setting to charge the Triple Power Batteries (9kWh) from the mains at a certain time, so at 00:30 until 04:00 I can buy a kWh for 5p and get my batteries up to 100% to use all through the day. I realise that this would not be much use in the summer but at this time of year I am getting so little sun I am lucky to get 50% charge.
I am not really sure if this is cost effective and wondered if anyone had similar thoughts or system in place.

I think you might want to look at a scheme where you get variable pricing. there are half hours where the price is negative and if you can charge then it’s clearly best of all.
You need to check that you don’t have a Landis & Gyr meter, or if you do that it isnt the type which overreads the daytime usage of the powerwall’s occasional tiny current draws to sync the frequency. Some owners have been grossly overcharged

I do something similar on Agile rather than Go.

Hi Thank you for the information, I will check my meter. I would love to charge my batteries when power costs are negative but on my inverter I have to program in the times I want to charge the batteries from the grid so I think I will have to stick to GO

Hi. I will investigate Agile and see if I would be better off than using GO. That link to Energy Stats Uk has so much information re charging batteries from the grid I will give it a good read. Thanks for the info

I tried Agile for a couple of month and was charging our house batteries and EV during the cheapest times.
Our average cost went from around 5.5p on Go to 8p on Agile so we switched back to Go.
Agile pricing only goes negative a handful of times throughout the year and is outweighed by the higher average prices the rest of the time.

Hi @Scobo Thank you for your reply, I am interested to get views on both Go and Agile, It seems to be a close call between the two tariffs. On paper Agile looks better with cheaper rates after 04:30 (except the peak time about 16:00-19:00) and a standing charge of 21p. I am still waiting for my smart meter, maybe I need to try both and see how it goes. I don’t have a EV but do have a 9kWh battery to charge.
Thanks again for you input

Hello @fishman
It seems as though you have a similar system to me.
Did you manage to sort out the charging of your Solax battery with Octopus Go?
Just moved over to them and so trying to get things sorted.

Hi @smithev
Yes all working very well charging my Solax batteries with Octopus GO.
IMO at this time of year you may as well set the force charge to fully charge the battery between 00:30 and 04:30. This will then just about last until 00:30 the next day (with a bit of sun shine). (2 X 4.5kWh triple) and all your power for the day will be at about 6p/kWh If its really sunny then any excess power generated by the panels heats up my hot water tank.

I also use Node Red to control my charging but that’s another story.

What is your solar site called on PVoutput ? I looked for Solax Smith but could not find you

We’re force charging our Solax battery whilst on economy 7 tariff and it works perfectly. We now use virtuallly no peak rate tariff power, just the minimal amount coming from the PV panels and whatever we’ve stored in the batteries during cheap rate. We’ll stop doing this in the summer when there is now solar available though.

Only issue we have is that the Solax inverter measures ‘yield’ as everything coming out of the inverter so that includes the power coming out of the battery as well which means we can’t actually measure the yield from the panels.

Hi @justal Yes I know exactly what you mean, I had the same problem. It seems wrong that the yield includes the power that you have put into the battery overnight. The way I get round this is to read the PV1P and PV2P output (I have 2 strings of panels) using a Raspberry Pi to get the data from the inverter. This data is then fed into a Node Red flow to convert to kWh and upload to PVoutput. You can see the results here Bens Solar Power 5.400kW
Its all a bit of a pain and not really worth the effort but if you are already extracting the data from your inverter locally its not much more work. I would be interested to see you site on PVOutput, always great to talk to a fellow Solax owner