Solar panels and battery - any real world reccomendations?

Journey · 24 Mar 2022 at 14:11

Kearney_1988 said:
30kwh is impressive, what size system is that on.

Ideally I'm thinking if I had a system that produces 2kwh average (so working on a 4kwh system accounting for losses/not south facing) I'd end up with 1kwh to use and 1 to store so probably would need 10kwh or more of storage to get me through a night

It's just over 6.2kW, and is primarily east/west but every day that passes means the sun is getting higher and I'm getting more from the non-optimal panels. The 3 hours that are 11am to 2pm are heavily weighted, with almost half the days output over a 3 hour window.

Take my advice, just get as many panels as you can fit on your roof, both sides, you'll appreciate it in the winter and the extra cost is a tiny fraction of the total install. 370w panels are only £120+ VAT at retail, or should that be £120 as no VAT now. So look at your roof layout and just cram as many in as possible.

94JDH · 24 Mar 2022 at 14:17

Kearney_1988 said:
Mind letting me know too....you'll be earning commission at this rate

Can't seem to pm you?

94JDH · 24 Mar 2022 at 14:20

squerble said:
Thanks. Aware of GivEnergy and Tesla Powerwall tying to Octopus Agile which does sound very tempting. I've estimated our day usage (excluding EV) at about 2500kWh so 6.85kWh/day average.

Is that an average over the year? Is it more biased to higher amounts in the winter?
If that was usage is probably be looking at one battery with a minimum of 5/6kW up to about one of mine at 9.5kW ( to offset any of that bias).

squerble · 24 Mar 2022 at 14:28

94JDH said:
Is that an average over the year? Is it more biased to higher amounts in the winter?
If that was usage is probably be looking at one battery with a minimum of 5/6kW up to about one of mine at 9.5kW ( to offset any of that bias).

Yea it's averaged as we only have a yearly figure to go on from our last house. But usage at the new house will be the same or slightly lower as it's still gas hob, DWH and CH, all low-energy lighting throughout the house etc., I was full-time WFH then, plus I'm thinking of jibbing off my gaming rig for a Mac Mini with a max 30W power draw as I medically need to stop sitting at a computer so much.

94JDH · 24 Mar 2022 at 14:49

squerble said:
Yea it's averaged as we only have a yearly figure to go on from our last house. But usage at the new house will be the same or slightly lower as it's still gas hob, DWH and CH, all low-energy lighting throughout the house etc., I was full-time WFH then, plus I'm thinking of jibbing off my gaming rig for a Mac Mini with a max 30W power draw as I medically need to stop sitting at a computer so much.

It all depends if you are going to have solar plus battery or just battery only. ( Size wise)

squerble · 24 Mar 2022 at 14:52

94JDH said:
It all depends if you are going to have solar plus battery or just battery only. ( Size wise)

Initial will be battery-only probably. Haven't got the capital for both right now.

Journey · 24 Mar 2022 at 14:53

squerble said:
Initial will be battery-only probably. Haven't got the capital for both right now.

If you are doing that then make sure you buy a hybrid inverter to ensure you can connect panels up to it later on.

94JDH · 24 Mar 2022 at 14:59

Journey said:
If you are doing that then make sure you buy a hybrid inverter to ensure you can connect panels up to it later on.

Excellent advice, on that basis I would go for the bigger battery- also check whether the 0% VAT will be applicable as announced on renewable energies yesterday. As a battery only install that would save you 20%.

squerble · 24 Mar 2022 at 15:06

Journey said:
If you are doing that then make sure you buy a hybrid inverter to ensure you can connect panels up to it later on.

94JDH said:
Excellent advice, on that basis I would go for the bigger battery- also check whether the 0% VAT will be applicable as announced on renewable energies yesterday. As a battery only install that would save you 20%.

Yep, already twigged that one. A couple of websites offering the GivEnergy 8.2kWh + inverter were just the AC coupled inverter, so as far as I can tell I'd have to make sure it was the hybrid one ready for solar. I don't think batteries will count under the new rules, so it'd be full 20% VAT hit, but the solar would be 0% as long as I did it before 31st March 2027. I appreciate that's a hit but it'd be nice to get the ball rolling, as we'll likely need a couple of years to replenish our capital ready for solar.

Journey · 24 Mar 2022 at 16:15

squerble said:
I don't think batteries will count under the new rules, so it'd be full 20% VAT hit, but the solar would be 0% as long as I did it before 31st March 2027. I appreciate that's a hit but it'd be nice to get the ball rolling, as we'll likely need a couple of years to replenish our capital ready for solar.

Can't you just offset the saved electricity costs of solar into a short term loan to pay for the solar, and get it all at once? Work out how much you'll save over 4-5 years on electricity, since that is a bill you will most not be paying if you have both, then see how much that would get you. e.g £75 a month for 48 months is £3,600. Just a thought.

squerble · 24 Mar 2022 at 17:20

Journey said:
Can't you just offset the saved electricity costs of solar into a short term loan to pay for the solar, and get it all at once? Work out how much you'll save over 4-5 years on electricity, since that is a bill you will most not be paying if you have both, then see how much that would get you. e.g £75 a month for 48 months is £3,600. Just a thought.

Yea I've considered that. It's looking like we'd need to loan close to £5k, so we'd have our roughly £625/year saving (or £52/month) plus anything else saved via solar. Not sure it would work out once you factor in interest.

Vanilla · 24 Mar 2022 at 17:46

My current bills with 2kW of Panels and no battery. Of course rates are going up and up. Quoted £4700+VAT for the GivEnergy 3kW AC inverter and 8.2kWh battery installed. If rates were not so high i'd say leave it but with higher rates it could pay itself off in under 5 years assuming it cut my electricity bills by a further 80%, unless i'm dreaming.

Need to do the same for my dad whom I think is paying about £200pm on electricity (big house, no solar) but that's been made harder by igloo going bust (can't get bills online). Damn these paperless companies!

Tinders · 24 Mar 2022 at 19:21

If the current high energy costs are only here for ~2 years is it still worth sinking £7-10k into solar?

Im in a quandry right now, my energy costs are mad, mainly down to being in a 4 bed victorian house and having my mum with us. She has bad arthuritis, so we need to have the house warm, so gas makes up most of my bill. Solar would be great as ive got a PHEV and EV could be on the cards in the future but apart from PC gear, and using the washing machine a lot due to 3 kids, im not sure our electric load is high enough to benefit?

The quandry is that i dont see us staying in this house for 10 years, any house that im likely to buy would be massively more efficient.

If i were to consider solar, we are in a south facing house, and the roof is 15m wide, but its a 3 story house so very tall, maintenance would be a scaffold job everytime

TNA · 24 Mar 2022 at 19:32

The feeling I get is we won't be going back to the 12/13p kWh on electricity for a long time. We may get back to 20-25p in 2 years.

Really hope in a couple of years when I am ready to go for it the tech matures more and prices come down. Would be nice to have an all electric house.

Journey · 24 Mar 2022 at 19:34

Tinders said:
If the current high energy costs are only here for ~2 years is it still worth sinking £7-10k into solar?

If your only concern is cost, then flip a coin, if you want some level of independence and care about the environment for the future of your children then maybe consider it on those facts as well.

Ron-ski · 24 Mar 2022 at 19:55

squerble said:
Yea I've considered that. It's looking like we'd need to loan close to £5k, so we'd have our roughly £625/year saving (or £52/month) plus anything else saved via solar. Not sure it would work out once you factor in interest.

Interest? Isn't that what 0% credit cards are for? Done it many a time over the years, just shifted it to another prior to the 0% running out. You do have to be really on the ball with it though, and never miss a payment, so not for everyone.

squerble · 24 Mar 2022 at 20:08

Ron-ski said:
Interest? Isn't that what 0% credit cards are for? Done it many a time over the years, just shifted it to another prior to the 0% running out. You do have to be really on the ball with it though, and never miss a payment, so not for everyone.

Perhaps. Though a huge part of me is completely averse to credit right now - I became debt free a few months ago and for the first time in my life actually have savings. So aside from taking on a mortgage it's hard to stomach the idea of credit after being so bad with money for 15 years.

Journey · 24 Mar 2022 at 20:14

squerble said:
Perhaps. Though a huge part of me is completely averse to credit right now - I became debt free a few months ago and for the first time in my life actually have savings. So aside from taking on a mortgage it's hard to stomach the idea of credit after being so bad with money for 15 years.

It's a different proposition though when you aren't buying something totally pointless like a sofa, a holiday or other item that loses nearly all its value once purchased. You are buying an investment to reduce an outgoing in the long term, a debtvestment if you will.

94JDH · 24 Mar 2022 at 20:43

squerble said:
Perhaps. Though a huge part of me is completely averse to credit right now - I became debt free a few months ago and for the first time in my life actually have savings. So aside from taking on a mortgage it's hard to stomach the idea of credit after being so bad with money for 15 years.

I know what you mean- I've funded most of mine by the savings of swapping to an electric car over the last few years - it was nice having a good lump of cash sat there, but it will bring me a better return of investment this way

1pudding1 · 25 Mar 2022 at 10:37

With these battery systems, does the battery and inverter need to be very close to the incoming house supply and meter? Most installation diagrams Ive looked at seem to want a CT clamp around the incoming supply jsut before/after the meter. Our incoming supply/meter box is on the rear wall of our house, and then solar panels and battery/inverter would be in our garage, about 10m away. Is this going to be a big problem, or are the CT clamps connected to wireless transmitters that would send a signal that far, or do they need to be hard wired?