Finalization of the batteries specs depending on DNO's response?

[Bob Smith]

Hello everyone
I am seeking some help here because I struggle to understand why my installer does not want to continue discussing the specs of the batteries and he told me he has to wait to know what the DNO's response is.

My requirements so far are

1) The batteries must need to be able to handle charges of up to 8kW continuously for as long as the PV panels (new and existing) generate that much power. This is therefore not a surge power peak.
2) The batteries must be able to discharge to the house up to 8kW continuously for all long as the house needs it and there is sufficient energy stored.
3) The batteries must be able to charge at up to 8kW from the grid. This is so to maximize the use of low peak tariff. (I am starting with around 10kWh of storage but will quickly increase the storage capacity)
4) The storage capacity will be able to be extended up to a minimum of 20kWh or 40kWh depending on the space available
5) The batteries will be able to discharge to the grid at the maximum power authorized by the DNO. I believe that the limitation will be set in configuring the inverter appropriately and it is independent of the points above.
6) Ideally the battery's shape will allow to stake them up on "shelves" against the wall (Thinking of the shape of Sunsynk, Pylontech and the like but not like Tesla or GivEnergy)
7) In addition to the charge and discharge requirements above, the batteries must be among the leading brands in terms of reliability and warranties (currently min 6000 cycles, State of Charge +80% after 6000 cycles, operating temperature range -10° + 60°C etc...)

From the 7 points above, I only see #5 to depend on the DNO's response and this will be controlled by the inverter setting anyway. Therefore, I cannot see what prevent the installer to be proactive and save time by finalizing the battery choices prior to receiving the DNO's response.

Please tell me I am missing something important here and he is right and I am not. I really do not like wasting time and here I see a potential source of conflict that after DNO approval, we do things which could have done while waiting.

Thank you all for your input.

 

[Andy1733]

Simple, Change installers if your not happy

 

[Bob Smith]

Simple, Change installers if your not happy

If that was so simple...

I already paid the deposit but prior to this, I had seen about 10 of them. My installation is not a simple one (not the most complex one either but many installers simply don't understand the requirements or can't find a viable solution.

Anyway the post is about understanding the dependency between the design of the solution regarding the batteries and the DNO's response for a G99 application.

Nothing to do with me being happy with my installer or not. Actually, I am because they are the only ones (apart of another one out of 10 I contacted since last April) who understand my requirements.

 

[Andy1733]

You can't be happy with your installer as he won't answer your questions so you need to post on social platforms.
Maybe the reason he's waiting for the dno responce is he knows you can't have what your asking for but he wants them to confirm this? Maybe I don't know.
If DNO says no, you have paid your deposit. What do you do. Accept something sub STD to your requirement or loose your deposit. Win win for your installer

 

[Bob Smith]

mmmhhh, you got me thinking....

 

[johnb2713]

You can't be happy with your installer as he won't answer your questions so you need to post on social platforms.
Maybe the reason he's waiting for the dno responce is he knows you can't have what your asking for but he wants them to confirm this? Maybe I don't know.

The only thing the DNO can refuse is the export and possibly charging from off peak but the charging load is less than a lot of electric showers nowadays.

If DNO says no, you have paid your deposit. What do you do. Accept something sub STD to your requirement or loose your deposit. Win win for your installer

I would have thought the OP would still go ahead less the export and overnight charging, neither of which would make a difference to the installation cost / complexity. The installer should be able to go ahead with both features disabled until permission is gained IMHO.

 

[Bob Smith]

actually, my question is about if there is a dependency between the batteries and the DNO's response. Nothing else
That's the reason of my post. It is not about complaining about the installers. It is just a technical question.

Obviously, you are like me you do not know.

 

[Andy1733]

The only thing the DNO can refuse is the export and possibly charging from off peak but the charging load is less than a lot of electric showers nowadays.


I would have thought the OP would still go ahead less the export and overnight charging, neither of which would make a difference to the installation cost / complexity. The installer should be able to go ahead with both features disabled until permission is gained IMHO.

if the op can't charge from off peak then is this a problem to what he requested? Imo this is prob why the installer is waiting on the DNO reply.

 

[Andy1733]

actually, my question is about if there is a dependency between the batteries and the DNO's response. Nothing else
That's the reason of my post. It is not about complaining about the installers. It is just a technical question.

Obviously, you are like me you do not know.

There are plenty of experts on this forum, I'm not one. Just giving my opinion Maybe they don't know maybe. They are like your installer relient on the dno to give a yes or no.
Tbh I don't believe it's black or white with the dno. From threads I've read there is a few jobsworths and plenty who are willing to work with the clients.

 

[Andy1733]

Has your installer given you a spec list?
He must have said it's possible and given you a list of materials he is going to use. Maybe post those and the experts can tell you if they are capable of achieving the figures you are wanting

 

[johnb2713]

Obviously, you are like me you do not know.

Fine, not a problem, please disregard my remarks.

 

[johnb2713]

if the op can't charge from off peak then is this a problem to what he requested? Imo this is prob why the installer is waiting on the DNO reply.

Just looking at the rest of the spec it was my opinion it would not be a deal breaker and therefore they could go ahead. I merely re-iterated that it made no difference in wiring / installation costs. Not a problem however, I'll bow out of this discussion and leave to the people who really know.

 

[binky]

actually, my question is about if there is a dependency between the batteries and the DNO's response. Nothing else

Sort of, the DNO actally assess your network connection and the local gird for the extra back-feeding and potential loading. If you install a Hybrid inverter they treat it as a single system ( and they can't refuse upto 16A) , if you have a separate AC battery inverter, and solar , they treat as 2 systems o the same connection, which is when they start to get a bit 'twitchy'.

 

[Bob Smith]

Sort of, the DNO actally assess your network connection and the local gird for the extra back-feeding and potential loading. If you install a Hybrid inverter they treat it as a single system ( and they can't refuse upto 16A) , if you have a separate AC battery inverter, and solar , they treat as 2 systems o the same connection, which is when they start to get a bit 'twitchy'.

Thanks this makes more sense now. Luckily, they are planning the 8kW Sunsynk Hybrid.
https://www.sunsynk.org/8kw-hybrid-inverter
The thing , if you remember, I already have an inverter since 2016 and the plan is that the batteries are charged from the new PV system but also he existing one.

 

[binky]

Thanks this makes more sense now. Luckily, they are planning the 8kW Sunsynk Hybrid.
https://www.sunsynk.org/8kw-hybrid-inverter
The thing , if you remember, I already have an inverter since 2016 and the plan is that the batteries are charged from the new PV system but also he existing one.

So single hybrid inverter, reduces DNO issues.

 

[Bob Smith]

and lose the Fit? no thx lol

 

[Bob Smith]

Hi,
I am getting increasingly confused and puzzled by the minutes between the DNO and the installer. Hopefully, your wise guidance will help me to see more clearly.

Quick recall for those needing a catch-up

I currently have a 4kWp facing SE with FiT
I am planning to:
add 11kW of panels over 4 different locations (7.1kW NW, 1.3kW SW and 2.75kW West facing but on the gable)
Start with 10kWh batteries
Batteries to be changed from the existing 4kWp array + the new panels

A request has been made to the DNO for an 8kW hybrid inverter

Now, the DNO apparently asked to reduce the array to 17kW.

I asked where the 17kW came from and the reply was the installer is going to resubmit the application with a new inverter design and that basically, the DNO are including the battery system as part of the generator and thus judging the system size at over 17kw.

Btw the DNO is Scottish Power.

Why are they including the batteries when the export bottleneck is the inverter?
This would also mean that every time I want to add more batteries I need to ask for the DNO's approval. I never came across this.

I would really appreciate it if someone can guide me on how I should respond. To me, this is not right but I have no ground to defend my feeling.
Thanks a lot

PS: I have not seen the design from the installer. We just discussed the equipment so I do not know what he actually submitted.

 

[Andy1733]

Bob. I mentioned your installer knew it was doubtful they would except your set-up and binky mentioned they count it as 2 seperate setups so why are you surprised.

Fingers cross you have a good installer who can work the setup and get a understanding DNO worker who is willing to tweek the rules. though don't be surprised if you don't get everything you wanted.

 

[Bob Smith]

Thanks Andy for your quick response

I still do not understand why the DNO is interested in the batteries when the link between my system and the grid is the inverter. What is the point of having settings to limit the export to fulfill DNO's requirement if that does not seem to be the criteria that counts.
This is what I do not understand.
I thought you could have as much power as you want as long as you only export to the DNO's limit.

 

[Bob Smith]

So single hybrid inverter, reduces DNO issues.

can't my existing inverter be connected to the hybrid inverter and therefore there is only one "point of contact" with the grid?