Upgrade a Grid-Tied Solar PV System with battery. Solis RAI

[Bignose2]

Hi,

Had Solis inverter & panels installed last summer. Without battery as shortage & wondered if ROI OK without.

I would quite like to add battery now, partially for the UPS ability but also better use of the solar power.

Asked the guys who did the install, who were v.good then, three times now & never get to quoting, guess they are two busy!

They did advise Solis 3.0kW 5G RAI Energy Storage AC Coupled & Pylontech us5000.

So I am wondering if I can do 95% of the install & just leave a normal sparky to connect to the grid.

What I cannot work out, partially for if I do eventually get quote for the whole install, or what a Sparky might have to do/charge.

Already have a meter for the grid tied solis inverter
Do you need another meter (one comes with the RAI it seems) & do you need a spare separate MCB/RCD in the consumer unit.
I don't have one spare in the CU so could dramatically increase the cost is guess.

https://www.ginlong.com/global/document ... 6e3b0.html
shows only 1 meter & same connection into the grid but a very basic diagram.

This would make we think perhaps do not even need another cable & spare MCB slot in the CU.

Expect to pay a fair amount for their experience etc. but equally don't want to be charged a fortune if a relatively simple add on.

Thanks
I/A

[marshman]

First question. What Solis inverter do you currently have?

Second question. What meter is it, Is it just measuring generation or is it for export control?

Personally as it is a recent install and you have no worries about the old FiT payments, I would simply replace your existing inverter with a "hybrid" inverter of the same power (if your one isn't a hybrid anyway - hence first question) and then plug the batteries in to it. You can probably sell the old inverter to recoup some money.

That way no need to get involved with applications/notifications to the DNO or complications with C.U. etc. Just swap inverters and connect the batteries.

[Bignose2]

Hi,

Thank you for your reply,

Not sure of exact model but is JUST a grid tied inverter, not hybrid.
I was fairly adamant I would not want a battery ROI etc. so decided against on initial install, more fool me, think even a shortage of the hybrid inverters then so big delay on install (during those lovely sunny summer months) as well as no chance of a battery for some considerable time.

I know when I did think about it I seem to remember reading that actually adding AC coupled later, whilst end up more expensive was a slightly better option, not sure why now.
I think I was under the impression you could not easily have a battery backup (UPS) with the hybrid.
I know it is small separate circuit & not the house but actually would be a deal breaker for me if not possible Hybrid.

Am I right in thinking you can have a similar UPS circuit off a hybrid inverter (guess OEM dependant)

Has made me think again, certainly for my house as if need another CU MCB, sure I don't have a space & that's bound to cost more replacing than loss of inverter.

I have the same in my business & that would be much easier for the AC coupled option & plenty of CU space.

Thanks again

[Bignose2]

Follow up,

So you need the DNO with the RAI Ac coupled solution even when under 3.6Kw. I guess the extra inverter is direct to the grid.
So an ordinary sparky cannot do then.

I only query as the original guys have come back & approx £4600 for the hybrid install.
I think the parts are just under £3k inc VAT (4.8 pylontech & RAI 3.5 hybrid) so seems a lot for what I would have thought was half a day.
They did the full install in 2 days & the majority was the panels.

Assuming they get more of a trade price little disappointed they are onto over 2k for a days work.
I know you have to pay for their experience & paperwork but does seem a lot.

Anyway, even with the high electricity prices ROI really debatable at that.

[Thebeeman]

I would look for additional quotes.
We've had 3.87 Kw of panels since 2011 (yes a VERY good FIT) which cost £16,000 including a £1000 new inverter at 9 years
When we had 10.5 Kw of pylontech and inverter installed in August we were £6000 in profit from the panels just on the FIT, not allowing for the "free" electricity used.
We've just got onto an E7 tariff so our bills should be minimal most of the year, zero during the summer except daily rate.
Electricity is not going to be as "cheap" as it was and will only go up inline with inflation if we are lucky.
I'm happy to play the long game.

Have you tried Home Energy Group? I used them and they seemed to want the work and what they said on the tin.
I've just had a search and the Name has changed but they are still quoting £3850 for a 5Kw pylontech battery + inverter installed.
As said else thread you could 'upgrade' your inverter and resell your 'old' one and probably get a good price for it.
"Just my thoughts".

[openspaceman]

I know when I did think about it I seem to remember reading that actually adding AC coupled later, whilst end up more expensive was a slightly better option, not sure why now.

I think the only advantage is that the ac coupled battery and inverter complements the power of the PV inverter, so at sunny times more power can be drawn without grid import.

Overall they are more expensive and slightly lossy plus nothing works when the grid is down.

[Bignose2]

Hi,

Thanks for your reply & all the info, I will look into Home Energy Group.

Pleased you get good FiT, I think was much better back in the day

Another rant .. Sort of a warning to others
Part of the reason to add batteries now & was not so desperate then was assumed would get at least a small feed in rate, whatever its called now, I know only a few p but thought better than nothing.
Asked my supplier, Scottish Power & DNA about how I would apply etc. so ready to get asap after install, gave all my address, even all the meter info as was not sure mine was proper "Smart" , I queried this. They said no problem just apply once completed.
Day after install, contacted them, sorry not available in your area & not sure when, months or years !!
I emailed to explain not too pleased to have not been advise that this was a possibility, "very sorry, will prioritize when available" signed up for notification.
No notification (I get all other SP emails), went online to get bill. "Apply for a smart meter now", "Sorry no slots available"
Been the same for many months. No reply from SE about where is my priororaty install?
Last year they must have had a huge amount of Kwh from me during those summer months, they no doubt charged someone 30p for my supply
Almost certainly would have added batteries if I knew this.
Really just a warning that not everyone can get a smart meter & I did think mine was, all digital, not that old. So you waste all that excess but of course do wonder if the electric companies are not in any rush to stop getting your free solar.

I think probably more likely not to be a problem going forward but might influence earlier adoption of batter than not.

[Stinsy]

Hi,

Thanks for your reply & all the info, I will look into Home Energy Group.

Pleased you get good FiT, I think was much better back in the day

Another rant .. Sort of a warning to others
Part of the reason to add batteries now & was not so desperate then was assumed would get at least a small feed in rate, whatever its called now, I know only a few p but thought better than nothing.
Asked my supplier, Scottish Power & DNA about how I would apply etc. so ready to get asap after install, gave all my address, even all the meter info as was not sure mine was proper "Smart" , I queried this. They said no problem just apply once completed.
Day after install, contacted them, sorry not available in your area & not sure when, months or years !!
I emailed to explain not too pleased to have not been advise that this was a possibility, "very sorry, will prioritize when available" signed up for notification.
No notification (I get all other SP emails), went online to get bill. "Apply for a smart meter now", "Sorry no slots available"
Been the same for many months. No reply from SE about where is my priororaty install?
Last year they must have had a huge amount of Kwh from me during those summer months, they no doubt charged someone 30p for my supply
Almost certainly would have added batteries if I knew this.
Really just a warning that not everyone can get a smart meter & I did think mine was, all digital, not that old. So you waste all that excess but of course do wonder if the electric companies are not in any rush to stop getting your free solar.

I think probably more likely not to be a problem going forward but might influence earlier adoption of batter than not.

Sure FiTs were generous. But they needed to be in order to overcome super-high panel prices and to make installing profitable enough to encourage people to setup businesses providing this service.

Nowadays panels are super-cheap. They’ve come down 90% in a few years. But without FiTs you need to be using the power you generate and batteries are the best way to achieve that.

[Thebeeman]

If you can't get a Smart Meter just get a standard E7 meter. Then when your batteries are installed you ideally don't export anything and top up the batteries on "cheap" leccy overnight to use if the sun don't shine during the day. After much grief It's working for me as I type.

Afterthought. If you are only fitting 5Kw of storage you could wind up using expensive day rate power, depending on daily consumption.
Maybe just fit the battery and stop/use the exports for now and then see which way the wind blows.
At present you are exporting power for peanuts and then buying it back when you need it.

[sharpener]

I would look for additional quotes.

Have you tried Home Energy Group? I used them and they seemed to want the work and what they said on the tin.
I've just had a search and the Name has changed but they are still quoting £3850 for a 5Kw pylontech battery + inverter installed.
As said else thread you could 'upgrade' your inverter and resell your 'old' one and probably get a good price for it.
"Just my thoughts".

Last year I had a great deal of difficulty finding anyone who would add more panels to an existing installation, they were all concerned about warranty and liabilities, that may be the underlying issue here.

OTOH it might be different if you just want a standalone battery/inverter setup connected to the CU. GivEnergy spring to mind as a cheap and cheerful offering with (limited) UPS capability but I have no personal experience. Much or all of the work could be DIY if you have basic electrical skills.

I would also venture that you may find the Pylontech US 5000 too small. We started in May last year with 7.1 kWh of Pylons but by November it was obvious that even with a modest life style they were too small and I added a third module as in the sig. Now there is enough capacity to survive most winter days, and two whole days without sun if we are away.