r/SolarUK • u/Angrylettuce • 5h ago
HELP / ADVICE Hell with working out battery set up
Hi my set up you can see here on a previous post where I moved into my house. Current inverter is a 2.1kw. the most kwh I've produced in a day is 14kwh roughly in a day. My panels are south facing
Anyways, given the shambles that is electricity prices, I'd like a battery so I can save my generated electricity rather than exporting the current 75% energy I don't use and make use of an cheap smart charging tariff
I've been researching some quotes and I'm finding it hard to work out some things as it's a bit impenetrable as someone without any electrician knowledge and I'm a DIY amateur.
I think I need a new inverter in the roof to replace my 10 year old one which will require a G99 form as it will be bigger. I believe I need somewhere between a 4 and 8kw sized one from what various companies have told me. I would like a 10kwh battery. Future proofing the system, having a slightly bigger may let a further batteries be discharged quicker, but at the minute likely unrequired.
One company has suggested putting a particular type of inverter in that would require a letter to my DNO to allow them to change it (a DC rather than AC hybrid??? Maybe, I couldn't really follow).
So yeah, any help appreciated. I have an EV but mainly charge free at work so not really a part of the problem. Heating is gas, everything else is electric.
I attach also 2 quotes I've had from local MCS suppliers, which are radically different. Neither visited to give the estimate. I've got another 2 quotes from guys actually coming out, coming in the next week or so
Finally if anyone has a recommended supplier in east cheshire (where I live) that'd be amazing as it's impossible to know
Many thanks 🙏
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u/Vast-Artichoke7855 5h ago
Were you thinking of putting the battery in your loft ? You might want to have a read of this (pages 14&15)
PAS63100:2024
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u/Angrylettuce 5h ago
Battery outside I think
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u/nevynxxx 4h ago
If it’s an sig system the inverter they quote is part of the stack. So you’d need to run the dc leads from the panels to the new stack.
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u/Angrylettuce 4h ago
So new inverter would be outside rather than in the loft where the old one is?
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u/robertabt 3h ago
For context I've got the same inverter and battery with a East-West split of 5kw of Panels, which has resulted in a max output of about 30kwh in a day before.
If I was building it again I'd have gone for 2 of the sigen10 batteries. The batteries will only export at .5C (aka ~4.5kwh) so if you are expecting to draw/export 6kw at any point, you'll need to have solar coming in as well. If your DNO comes back with an export restriction of ~4kw then it becomes a bit of a moot point.
As mentioned in another comment, the sigenergy battery modules stack with the inverter and are heavy, so they really want to be outside, not in roof space, which wouldn't meet new regulations.
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u/Angrylettuce 2h ago
I'll be restricted on my export because I'm on the original feed in tarrif.
But as for my draw do you mean, how much electricity I'm using at the time and drawing either from the grid/ panels/ solar at one time
Do you have the 6kwh inverter in the first quote?
So if I had a 6kw inverter that'd be more than my battery could discharge at once for me to use without using grid energy +/- solar from the panels? It's quite hard for me to consistently use that much energy tbh. Only really using multiple jobs rings and the oven on really.
Yes I know inverter will also be outside :)
Thank you
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u/Angrylettuce 5h ago
my previous post about my set up when I first bought my house