On-grid domestic battery storage

EVandPV

joefizz wrote: »

Just out of sheer noseyness, what would you want to remote control? grid charging capability?

Yes, exactly.
I'd be looking to charge the battery from the grid during off-peak periods when there isn't enough surplus pv through the day and depending on the weather forecast for the following day.
Not so much of an issue in the winter as it would be mostly grid charging anyway so set a timer and forget about it.
Haven't really thought the whole thing through but I'm guessing that's sort of how it would work.

1961Nick

joefizz wrote: »

Just out of sheer noseyness, what would you want to remote control? grid charging capability?

If you're grid charging, being able to remotely change the target SOC would be very useful tool to have.

EVandPV

1961Nick wrote: »

If you're grid charging, being able to remotely change the target SOC would be very useful tool to have.

Indeed.
Charge the battery from the grid at night just enough to cover your useage until the pv kicks in.

joefizz

OK, gotcha...
I installed the latest firmware version last week but dont have any documentation on it so cant give a real answer...
...there are two more operating modes though (passive and peak shaving) but only one extra in the latest documentation (passive, contact sofar to find out).



No 2 way communication option unfortunately. I cant even see a way to rig something else up to it to trigger/override it.



Nick, might be worth emailing them to see if its something they could possibly do in the future, probably not, but worth an email.

EVandPV

joefizz wrote: »

OK, gotcha...
I installed the latest firmware version last week but dont have any documentation on it so cant give a real answer...
...there are two more operating modes though (passive and peak shaving) but only one extra in the latest documentation (passive, contact sofar to find out).

Ah, so you have an ME3000 with Pylon batteries ?

joefizz

EVandPV wrote: »

Ah, so you have an ME3000 with Pylon batteries ?

Yep, started off with 2x2.4 batteries and bumped it up to a total of 4x2.4 batteries.
I dont charge it from the grid at all, just to take excess solar and keep electricity costs other than the winter quarter to a minimum.
This year have used it to power cheap ashp and immersion to stop using oil April-September to cut down on that.


Also use it as a UPS and have used it a couple of times this year already.


Im probably done now with the system, its been a learning curve and each improvment but I think the 9.6 is probably enough for me as im not going to improve on winter at all, short of a small wind turbine (which is probably useless).

EVandPV

joefizz wrote: »

Yep, started off with 2x2.4 batteries and bumped it up to a total of 4x2.4 batteries.
I dont charge it from the grid at all, just to take excess solar and keep electricity costs other than the winter quarter to a minimum.
This year have used it to power cheap ashp and immersion to stop using oil April-September to cut down on that.


Also use it as a UPS and have used it a couple of times this year already.


Im probably done now with the system, its been a learning curve and each improvment but I think the 9.6 is probably enough for me as im not going to improve on winter at all, short of a small wind turbine (which is probably useless).

Cheers.
So how do you find the performance of the batteries with the Sofar ?
One thing I just noticed is the Sofar only has one ct input. How does it know how much pv is being generated ?

joefizz

EVandPV wrote: »

Cheers.
So how do you find the performance of the batteries with the Sofar ?
One thing I just noticed is the Sofar only has one ct input. How does it know how much pv is being generated ?

Latest manual
http://www.sofarsolar.com/ueditor/net/upload/file/20170628/ME3000SP%20user%20manual170512.pdf



It has 2 ct inputs CTa, CTpv but the latest firmware also gives monitoring on screen for another CT input (not required).


There is an app for monitoring it all and I prefer it to the solaredge one at times but its not 100% accurate but close enough. The web browser desktop portal is slightly better but I like a better screen for the graphs!



I had older firmware that would only go to 20% but latest Ive changed to 15% and latest firmware does seem to be better with managing the batteries.


I started off thinking 4.8 was enough as that was more than enough for my normal overnight usages even this time of the year if it could fully charge but then realised that I could do much more and have increased my electricity usage overall but for less import and less expense. It sounds counterintuitive but over here we have metered export so if you forgo the 4p you can do much more.



Overall Im pleased with them and whilst when I bought them at first it didnt look as if they would pay back in their lifetime, electricity prices here have gone up over 20%, had a few power outs, and prices havent dropped that much in 2 years.

It wasnt as straight as that for me either (detailed in earlier thread if you can be bothered wading through the ping pong) in that it allowed a change of behaviour so in summer multiple charges/discharges per day doing other things (batch cooking/baking and freezing, dehydrating stuff, making home brew beer ;-), moving back to electric lawnmower etc etc). Installed a cheap ashp for spring/summer/autumn heating, used immersion for hot water for the same time.
It becomes not just as simple as one charge/discharge a day if you are flexible.


Thats not to say it would ever pay for itself financially but then again if electric goes up another 20% every 2-3 years weighed against low savings cost etc and what else it allows you to do.... but your mileage may vary as they say.


edit: ps one of the big advantages going from 4.8kw to 9.6 batteries was that at 7.2 you get full discharge but at 4.8 if you ran a 3kw load it wouldnt supply it all and you would still import some.

EVandPV

Actually, my mistake. I was looking at the Solis manual which only shows it with one ct input. :doh:

Do you find the Sofar ok without any remote controlling option ?
I guess it would only be a problem if your inverter was installed somewhere where access was inconvenient such as a loft.
Am I right in saying the Pylons max output is 1.2kw each ?

joefizz

EVandPV wrote: »

Actually, my mistake. I was looking at the Solis manual which only shows it with one ct input. :doh:

Do you find the Sofar ok without any remote controlling option ?
I guess it would only be a problem if your inverter was installed somewhere where access was inconvenient such as a loft.

I dont really go near it much, although its installed at head height in my spare room so if Im in there I use the screen rather than the app on my phone. Tend to work at the desktop a lot (like now) so use the web interface more than the app.
I have it handy as I have the ups mode manually switched rather than automatic (needs switched on at the wall beneath the sofar), as I wanted it that way. That and the losses from the sofar can be used to heat the room ;-)
I dont do the charging from the grid so I have rare occasion to go near it other than just sheer noseyness. Probably only really needed to go near it about 5 times in two years (power outs and software upgrade) and the power outs were just to manually flip a switch near it. The screen does give live readings though so it is a bit addictive rather than refreshing web or waiting for app to update.

EVandPV wrote: »

Am I right in saying the Pylons max output is 1.2kw each ?

Thats what the spec says and the sofar draw for up to 2 batteries matches.

Max discharge rate is set to 25a per battery for the first two batteries then 60A total after that, so the more batteries potentially the less discharge on full draw but battery management might vary that depending on inverter.
So 25a x 48v would be 1.2kw if thats what you mean. so 2.4 kw max from 2 batteries but 60a max according to the manual above but I have mine set to 65A for the full 13a. Whether it delivers it or not is a different matter and then you have losses but its all close enough.
I did notice a fair difference in load delivery going from 2 to 4 pylontech and am happy with that now, so can run kettle and toaster, etc when the sun is shining without importing.
The battery managment does seem to be quite active and vary with the sofar so on full charge low load it puts some batteries dormant and only takes from one and they do seem to rotate but Ive not watched it closely enough to give you a definitive answer on that.