Newbie - would appreciate thoughts on equipment

[up_north]

EDITED BECAUSE SINCE I FIRST POSTED THIS ANOTHER INSTALLER HAS GOT BACK TO ME

First, thanks to all the experts who contribute to these discussions; I only found this site recently but already have learned loads. I'm considering solar and battery storage.

We use on average about 9kw/h of electricity per day of which 4 is used from about 6pm onwards. This excludes car charging. We're on Octopus Go Faster so have reduced rate electricity from 8.30pm till 1.30am.

We're just north of Newcastle, the house faces a few degrees east of south. It's a small roof but sufficient for 10 panels. The only issue is that until about 9.30am four of the panels would be in full shade from a neighbouring, taller house but completely clear after that.

The way I'm hoping it will work is that during solar generation hours, solar would power the house and divert any excess to the battery. Then outside of those hours the battery would power the house as much as possible but I don't think I'd want it to discharge during our cheap electricity hours, I'd want it to charge at these times.

I've spoken to a number of installers, some say they'll send a quote but never do, others stop communicating when I ask them questions and of course others are just so busy they can't quote and this is fair enough.

So I'm left with a few options from a couple of installers.

INSTALLER ONE
JA Solar Percium 385w panels
Solis S6GR1 3.6kw inverter
A choice of batteries including Alpha, Puredrive, Plylontech in capacities from 5-9kw/h
Total price for SOLAR ONLY (so excluding battery) including installation, bird protection is £6250
He has suggested that the array is wired as two strings to mitigate the shading issue.
My concern with this is the inverter is quite basic, although I appreciate that's not always a bad thing and it only has one MPPT.

The same installer has also given me a quote for an alternative:
Same Panels as above
Solar Edge inverter and optimisers
Givenergy 9.5kw/h battery and inverter
He has quoted an additional £1,100 for the solar only part for the SolarEdge upgrade.

INSTALLER TWO
Eurener 410w panels
Solis RHI 36K-48ES-5G inverter
Puredrive 5kw battery
Overall quote INCLUDING battery, installation and bird protection is £10360

This installer doesn't offer Solar Edge but can offer an Enphase solution for £2300 more.

INSTALLER 3
Hyundai 410w panel
Growatt 6.5kw/h battery
Growatt 3.6kw hybrid inverter
Tigo optimisers
Total cost - 9900 including installation and bird protection

I appreciate that's a lot to read. Would really appreciate any thoughts on the choices offered. I can't compare price wise as mentioned above the first installer has given me choices with regards to battery.

Thank you.

 

[binky]

If you have shading, I would go with Solaredge, I certainly wouldn't accept a single MPPT inverter.

 

[up_north]

Thanks binky. The single MPPT concerns me also. But not sure if Solar Edge might be overkill considering the shading is only till 9.30am. I thought the sweet spot might be a 2 MPPT inverter with the shaded panels on one MPPT and the others on another and also going for higher output panels.

 

[stuboy]

shading massive issue, if you have it then minimum 2 mppt or micro inverters. No shading the one mppt will be ok as long as the 2 strings are identical, ie position and panels.
Cheers

 

[michael8554]

Massive issue ? Please explain, how much generation would there be before 0930am ?

 

[stuboy]

Just had a look at my logger and I started generating at 5.30 am this morning have already produced several KW of electricity.
If you can isolate the 4 shaded panels on one MPPT and have all the others on the other then that would be the best option, or maybe you have to add a couple of non shady panels to meet the input spec of the inverter. That is the beauty of having a 2 MPPT system, load one up to the max and let the other deal with the shading.
Hope that helps
Stu

 

[michael8554]

Wow, several kWh generated before 0930 - what would you expect without shading ?

 

[binky]

Wow, several kWh generated before 0930 - what would you expect without shading ?

long days, it's light around 5am currently.

 

[Bob Smith]

EDITED BECAUSE SINCE I FIRST POSTED THIS ANOTHER INSTALLER HAS GOT BACK TO ME

First, thanks to all the experts who contribute to these discussions; I only found this site recently but already have learned loads. I'm considering solar and battery storage.

We use on average about 9kw/h of electricity per day of which 4 is used from about 6pm onwards. This excludes car charging. We're on Octopus Go Faster so have reduced rate electricity from 8.30pm till 1.30am.

We're just north of Newcastle, the house faces a few degrees east of south. It's a small roof but sufficient for 10 panels. The only issue is that until about 9.30am four of the panels would be in full shade from a neighbouring, taller house but completely clear after that.

The way I'm hoping it will work is that during solar generation hours, solar would power the house and divert any excess to the battery. Then outside of those hours the battery would power the house as much as possible but I don't think I'd want it to discharge during our cheap electricity hours, I'd want it to charge at these times.

I've spoken to a number of installers, some say they'll send a quote but never do, others stop communicating when I ask them questions and of course others are just so busy they can't quote and this is fair enough.

So I'm left with a few options from a couple of installers.

INSTALLER ONE
JA Solar Percium 385w panels
Solis S6GR1 3.6kw inverter
A choice of batteries including Alpha, Puredrive, Plylontech in capacities from 5-9kw/h
Total price for SOLAR ONLY (so excluding battery) including installation, bird protection is £6250
He has suggested that the array is wired as two strings to mitigate the shading issue.
My concern with this is the inverter is quite basic, although I appreciate that's not always a bad thing and it only has one MPPT.

The same installer has also given me a quote for an alternative:
Same Panels as above
Solar Edge inverter and optimisers
Givenergy 9.5kw/h battery and inverter
He has quoted an additional £1,100 for the solar only part for the SolarEdge upgrade.

INSTALLER TWO
Eurener 410w panels
Solis RHI 36K-48ES-5G inverter
Puredrive 5kw battery
Overall quote INCLUDING battery, installation and bird protection is £10360

This installer doesn't offer Solar Edge but can offer an Enphase solution for £2300 more.

INSTALLER 3
Hyundai 410w panel
Growatt 6.5kw/h battery
Growatt 3.6kw hybrid inverter
Tigo optimisers
Total cost - 9900 including installation and bird protection

I appreciate that's a lot to read. Would really appreciate any thoughts on the choices offered. I can't compare price wise as mentioned above the first installer has given me choices with regards to battery.

Thank you.

Hello Up_North

How are you getting on with your project? Di you go with the puredrive battery? I have just discovered this manufacturer (Hurray. they are British!!) (probably still made in China lol). and I am trying to find out more about them.
Thanks

 

[johnb2713]

I may be wrong in my thinking here but what I have found through experience is that a bigger inverter is worthwhile. with 3KW inverter every time the load exceeds 3kW then grid power will be used. Switch on the kettle, oven, hob, washing machine, coffee machine etc. This seems madness when battery capacity is available to provide the energy. My system has a Growatt 6kW invert with battery and PV feeding it, the reult is our daily use of peak rate energy is usually around 1.5 kWh. I am constructing an AC coupled battery to increase the inverter capacity on my system to 12kW along with storage to 23kWh.
I would suggest you get another quote with at least a 6kW inverter.

 

[up_north]

Sorry it’s taken so long to get back on this guys. New job and other stuff got in the way. Still not placed an order. The installer who provided the first quote has op increased prices significantly. I asked them to quote for the new GivEnergy 3.6 hybrid inverter and the new 9.5kw/h battery. Total cost including 10 Jinko 380w panels is £12k. Looking at wholesale prices of the equipment suggests they are charging £5k for labour which seems excessive?

I‘ve done some detailed analysis of our usage and I think I can get away with a lower capacity battery. So, from a different installer, I have a quote of £8.5k for 10 Trina Vertex 390w panels, Solis RHI 3.6kw inverter and 5kw/h Puredrive battery along with a few Tigo optimisers for the panels that will have early morning shade.

 

[Bob Smith]

Welcome back and thanks for keeping us updated.

I am in a similar situation with the batteries. I think I will op with smaller batteries around 3kWh to start with. I will start with 3 and see how it goes for a year and decide to add later another 3kWh or more. If you go too big to start with and realize it is too big indeed, you can't really downsize without adding unnecessary cost. This is my view though.

 

[johnb2713]

Welcome back and thanks for keeping us updated.

I am in a similar situation with the batteries. I think I will op with smaller batteries around 3kWh to start with. I will start with 3 and see how it goes for a year and decide to add later another 3kWh or more. If you go too big to start with and realize it is too big indeed, you can't really downsize without adding unnecessary cost. This is my view though.

Or alternatively, better to have too much capacity than too little.

In terms of the inverter, every time you exceed the demand that your inverter can supply you start to consume peak rate power from the grid.
In terms of battery capacity, once youve charged everything and heated the hot water, excess solar is then exported bringing very little income. If you have the capacity, you can usefully store it. My 7Kw of storage is a perfect match for us during the summer but I can see from modelling it wont be anywhere near enough for winter time. 16kWh being added before winter plus another 6kW inverter to keep us away from peak energy prices. Our background consumption is around the 460w mark and obviously peaks when you boil a kettle, use the oven etc. The little excursions into peak rate power average at around 1.5kWh per day at the moment, that looks like it would rise to 14kWh per day and more as we head towards winter..

 

[Bob Smith]

Finding the sweet spot

 

[up_north]

The thing that I struggle with isn't necessarily battery capacity but the output from the battery. We can physically only get 10 panels on our roof which ties in nicely with a typical 3.6kw inverter. But that inverter also means that we can't draw more than 3kw from the battery. At the moment we use washing machine, dish washer etc during our Octopus Go Faster cheap rate from 8.30pm till 1.30am. This will probably draw more than 3kw so will be topped up from the grid. So - how about moving the high draw appliances to day time to run from solar? But they could still draw more than our solar generates so again will draw from the grid.

It hurts your head after a while. So may what-ifs?

 

[Bob Smith]

Is there not confusion between the instant power and what you'll consume over a period of time?

Also, I think it has been the same for everyone, habits have to change to make the most of your system.
I recall before 2016 (when I got my first PV system installed), we did not think twice as to when run the washing machine, or dishwasher etc....
Then after the installation of the PV; I started to check what power each device needed (toaster, standby TV, game console etc...)
and we checked what power was available and estimated how long for looking at the weather before deciding what to do next in the house and staggered the usage when possible. We have to change our habits

With battery, (I do not have them yet). I am expecting the same.

If your system limits you to a power of 3kW (not 3kWh), then you will have to see what you can run at the same time and what you can't. As you know if you run appliances and they need 5kW of power to run at the same time and your system only provide 3kW, then you'll have to pull from the grid.

Another consideration is the power peak discharge of your battery which could also be a limiting factor.

 

[up_north]

Is there not confusion between the instant power and what you'll consume over a period of time?

Also, I think it has been the same for everyone, habits have to change to make the most of your system.
I recall before 2016 (when I got my first PV system installed), we did not think twice as to when run the washing machine, or dishwasher etc....
Then after the installation of the PV; I started to check what power each device needed (toaster, standby TV, game console etc...)
and we checked what power was available and estimated how long for looking at the weather before deciding what to do next in the house and staggered the usage when possible. We have to change our habits

With battery, (I do not have them yet). I am expecting the same.

If your system limits you to a power of 3kW (not 3kWh), then you will have to see what you can run at the same time and what you can't. As you know if you run appliances and they need 5kW of power to run at the same time and your system only provide 3kW, then you'll have to pull from the grid.

Another consideration is the power peak discharge of your battery which could also be a limiting factor.

A very thorough answer - thank you. And you’re absolutely right, we need to put the work in to maximise savings. And if that means checking tomorrow‘s weather and deciding if I should charge the battery off peak tonight or wait until it’s sunny tomorrow then so be it.


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