Battery Pv Battery Storage Retro Fit

[marc8]

Hi All

got call out to a domestic fault on consumer unit totally separate from the job & client mentions to me that they had Battery storage fitted to the PV.

anyway they mention that at present they are trying to contact company that installed it as their electric bills have gone up & they don't think it is working correctly & asked me to have a look.

have a look whilst at the property & found that the original system was a 4kw split on two roofs.

PV 3.68kw SMA inverter with two strings
retro fitted Growatt SP2000

now system is one string into original inverter, second string removed & through the SP2000 & back into the SMA.
not working through the MPPT, first inverter now I don't think is operating at any sort of capacity & think most of time is just sitting looking pretty.

so now we have 8 panels trying to charge 5KW battery storage with any spare electric.

anyway speaking with client I have not touched the system & have passed on the RECC & MCS information for complaints.
the other best bit was that they were cold called & two days later & guy was out shiny suit & all, sign up today & we can install in two days.
bang & job done & any guesses to how much ............?

also customer says they installed on my android device the App & set it up & before they left they removed the system from the android device.
labour looks like about 2 hours as all in loft on the wall all to hand. (nothing wrong with that install a bit messy)

customer has had PV for some time as on top tariff, monitored electric bills for some time around £55.00 per month over the last year or so, now at £75.00 per month.
also has heat pump & solar thermal hot water. all electric but no storage heaters. only 2 at home one working.
asked if they thought Battery storage was for them & I said yes if it was installed correctly yes they would be saving a little. showed them 4 kw system with battery storage on my device only few miles away & we were making savings that day.

won't touch the system until she has gone through complaints & am going back later next week to finish of works on domestic system.
will take pictures at that time & post up.

even today we are generating battery power even with a sh.t start to the day now at 34% & climbing

 

[TedM]

SP2000 cannot handle multiple strings with dual MPPT - hence the way this one is fitted.

Need to check that the sensor is fitted the right way round and that the PV output V matches the SP2000 input V and the output V of the SP2000 matches the input V of the inverter.

Check all polarities.

 

[marc8]

Hi TedM

seeing it I knew it was not going to work due to MPPT, at present I have advised them to contact installer which they had done before I arrived 3 times with no reply.
they had also gone to citizens advice before I had been & had a look & where advised to write 3 times before further action, since then I have given information for RECC & MCS so they can contact them also.

 

[Worcester]

Go on then, the price was .... £6500

 

[marc8]

Hi Worcester £7K

 

[Deleted member 26818]

Didn't the DNO do any checks when the batteries were installed?

 

[Worcester]

Forgot the salesman's £500 commission

 

[Worcester]

I think as we all pointed out earlier (a few months ago) that we are going to see a plethora / rash of problems like this over the next 6 - 9 months, which could well result in a BBC Watchdog / Rogue Traders slot.

 

[marc8]

hi spinlondon

think you just have to inform DNO of the battery storage being installed so they are aware that if they work on the system say during the hours of darkness there could still be power being discharged into the grid.

 

[Worcester]

As per thread elsewhere (in the Green Lounge), ALL battery storage systems are considered generators and require DNO notification / approval - see also marc8's recent other thread http://www.electriciansforums.co.uk...nels-forum/108879-pv-battery-storage-mcs.html

My guess is that seeing as these system do not require MCS certification that the sales led organisations are completely ignoring all advice and guidelines from BRE / IET / RECC / MCS et al


BRE Free Consumer Guide: http://www.bre.co.uk/filelibrary/ns...66-BRE_Solar-Consumer-Guide-A4-12pp-JAN16.pdf
IET Code of Practice: Code of Practice for Grid Connected Solar Photovoltaic Systems - The IET

 

[marc8]

sP2000 system has an inverter which has now been added to the system & therefore altering the system ? am i correct ? if so this would come under MCS

 

[Worcester]

sP2000 system has an inverter which has now been added to the system & therefore altering the system ? am i correct ? if so this would come under MCS

In a retrofit environment not necessarily. It would be covered by any DNO requirements - ENA / IET Guidelines, Regulations or Codes of Practice, BS7671 and FiT scheme regulations

 

[marc8]

I see

think the system won't work as I think the SMA is only single MPPT same as the SP2000, i will find out when i get back there next weekend & will have more details by then

 

[Worcester]

p.s. forgot they should also comply with this : BREbookshop.com

 

[Gavin A]

now system is one string into original inverter, second string removed & through the SP2000 & back into the SMA.
not working through the MPPT, first inverter now I don't think is operating at any sort of capacity & think most of time is just sitting looking pretty.

so now we have 8 panels trying to charge 5KW battery storage with any spare electric.

does this return into the 2nd MPPT on the inverter?

If so then it's installed correctly.

Not sure why anyone is talking about DNO notification as nothing has changed, it's still only the SMA inverter connected to the grid, the growatt is connected through the inverter.

customer has had PV for some time as on top tariff, monitored electric bills for some time around £55.00 per month over the last year or so, now at £75.00 per month.
also has heat pump & solar thermal hot water. all electric but no storage heaters. only 2 at home one working.

erm, it's winter, PV does much less in winter, heat pumps will be running a lot more, solar thermal will be doing nowt, and there will be very little spare generation to charge batteries up in winter.

What makes you think that it's odd for the bills to be higher now than the average for last year?

 

[marc8]

well don't know that much about it, but my own system had 86% storage today & it was not that great.

I would expect the bills to have gone up slightly with increase in the electric wholesale price if there was an increase.

customer had been paying £55.00 per month & that was enough for their bill for the previous year.

as mentioned when i go back i will get pictures of the system & full details & how it is connected to the system, as for the DNO part please see previous #9 I think it explains why the DNO would want to know & a previous thread on battery storage with the MCS bringing in notification to the DNO.

 

[Gavin A]

hi spinlondon

think you just have to inform DNO of the battery storage being installed so they are aware that if they work on the system say during the hours of darkness there could still be power being discharged into the grid.

not true.

The DNO only needs to know if there is a new grid connected inverter, the inverter still can't output more than it previously did and would cut out in the event of grid failure (or working on the line) under the G83 protection settings, there is nothing for the DNO to be concerned with where the battery is connected on the DC side of an existing G83 inverter as in this case.

eta - please let's not make things more difficult for ourselves than we really have to.

 

[Worcester]

The DNO only needs to know if there is a new grid connected inverter, the inverter still can't output more than it previously did and would cut out in the event of grid failure (or working on the line) under the G83 protection settings, there is nothing for the DNO to be concerned with where the battery is connected on the DC side of an existing G83 inverter as in this case.

Please let's not make things more difficult for ourselves than we really have to.

Thanks Gavin forgot that

As apparently this SMA inverter only has a single MPPT, it would be interesting to know how the Growatt manages to match the other strings' characteristics, especially if it can supply the shortfall between generation and demand when charged, and also what it outputs when no generation and demand only (I've not looked at the Growatt system..)

... I suppose I shouldn't be surprised to hear about it being installed this way by the commission sales led companies.

 

[whinmoor]

As apparently this SMA inverter only has a single MPPT, it would be interesting to know how the Growatt manages to match the other strings' characteristics, especially if it can supply the shortfall between generation and demand when charged, and also what it outputs when no generation and demand only (I've not looked at the Growatt system..)

... I suppose I shouldn't be surprised to hear about it being installed this way by the commission sales led companies.

OP said the system was split over 2 roofs. Can it sensibly be a single MPPT? Do/did SMA offer a 3.68 kW single tracker?

 

[Gavin A]

Thanks Gavin forgot that

As apparently this SMA inverter only has a single MPPT, it would be interesting to know how the Growatt manages to match the other strings' characteristics, especially if it can supply the shortfall between generation and demand when charged, and also what it outputs when no generation and demand only (I've not looked at the Growatt system..)

... I suppose I shouldn't be surprised to hear about it being installed this way by the commission sales led companies.

almost certain to have been a 3600TL which is dual tracking, SMA never made a 3680W single tracker to my knowledge.