Advice on setup

[Evian_domino]

Hi All,

This is my first post so go easy on me! I decided in early 2022 to add solar to the roof of my business. I went with a company who I wont name at the moment and its been a bit of a nightmare. Despite paying a considerable amount of money we didn't get anything done until April 2023. The original plan was for 40kw system with no battery. That then evolved into a 50kw system with battery back up. After many excuses on supply we finally had 20kw of panels installed. However I was told that inverters were an issue so a 10kw Solis 5g inverter was installed. Its all working but despite many calls we just get ignored. So legal route it is.

Thats the history but now I want to get the system up and running as it should be. I have done a lot of homework but want to check what what I think is a good set up works.

One point to make here is that I have a very experienced electrician available to do this work. He doesn't have a lot of solar experience but I am confident he can do the work required. We also worked initially with the contractors to route cable and fit the panels to that we can do again.

The system:

48 x Longi LR5-54HIH-410M panels
1 x Solis 10kw Inverter 3 phase connected to the grid

We also have the wiring in place to fit a further two inverters that were going to be hybrid.

The plan I am thinking of:

3 x S6-EH3P10K-H-EU Hybrid inverters connected to 3 x Pylonforce H2 HV batteries (size to be determined)
Enough additional panels to get to 39kw (based on 10kw x 130% x 3)

I now that at the moment this inverter doesn't seem to be available in the UK. However my business travels to Europe regularly and picking some up is not an issue.

The questions I have are:

1. Does this seem like a sensible solution?
2. Given the panels we have now do I do the same again? Or is there better value for money?
3. What is the best route to sizing the batteries for the system?
4. Does any one have any reasons why this would not be the best setup?

Thank you in advance for any comments or advice on this.

Regards,

AK.

 

[timselectric]

First, you need to know what your loads are.
Then, you should size the inverter/s to cover your highest possible momentary loads. (Also accounting instantaneous surge)
Next, you size the battery capacity to cover your loads, when the sun isn't shining.
Lastly, you size the solar production to cover the loads and recharge the battery, when the sun is shining.

 

[Evian_domino]

Hi Tim,

Thanks for that. We went through a process with the original company and have went with the sizing they settled on. So going with that being about the right numbers. 40kw system. However that was never with battery. That’s the bit that was an addition.

I had in my head right or wrong to go smaller but have capacity to increase if needed. Is that a sensible approach that can work? Also the pylon tech H2 battery’s allow me to do that.

Thoughts?

 

[timselectric]

Allowing room for future expansion is always a good idea.
I'm not a fan of Pylontech 48v batteries. But I don't know anything about the high voltage ones.

 

[MisterB1959]

as youre in the UK, check out Fogstar batteries, they work on pylontech protocols, you may also be pleasantly surprised re their cost

Fogstar Batteries | The UK’s #1 Lithium Battery Retailer

18650 Battery Retailer | 12V Leisure Batteries | 48V Solar Batteries | UK Based | 5* Reviews | Fast & Free Shipping - Same Day Despatch

www.fogstar.co.uk

also, you need to make sure whatever inverters you choose actually meet the UK approved 'list; for inverters

ENA Type Test Register

ENA Type Test Register

www.ena-eng.org

Sunsynk seem to do a very good range of inverters and have UK offices - ive always found that theyre really helpful, plus there are loads of 'training' videos on youtube

re a competent electrician as opposed to a 'qualified/MCIS' electrician ..... given the choice, i would go with a competent electrician you know and can trust all day long !!

the issue only arises in terms of setting up the inverter and batteries to communicate, most of which isnt difficult but can be time consuming.

i have no links to either fogstar or sunsynk other than being a satisfied customer

 

[Evian_domino]

Thanks you for the information. I see the Inverter on the list but it’s “awaiting assessment” not sure how long these things take.

I will have a look into the Sunsynk Inverters also. The Fogstar batteries look good.

Is there any advantage to having multiple smaller inverters linked or just go for a larger one with excess capacity? Any views on that would be appreciated.