Solar panel advice, too many options to choose from

teamwillis

teamwillis

teamwillis

Associate
Joined
12 Mar 2022
Posts
5
Location
Bournemouth
We are budgeting around 10k for a solar system. We have had varying quotes and found a company I am happy with (local company, their own installers no subcontractors) but need to decide on a system before I negotiate on the price.


Our property is south facing and has space for up to 20 solar panels ( 8 on the front pitch, 8 on the back pitch and 4 on the garage roof) no shading or obstructions on the south coast, Bournemouth.


Our typical usage is around 4,000kwh/annum but looking to increase running a pool filter and in the next 5 years we will be getting 1 maybe 2 EVs.


So my questions are:


I’ve been quoted for 12 (8 and 4) JA 365 panels which would give us about 5,000 kWh coverage.


I’ve also been quoted 20 of the same panels which would give 7,000+KWH


There is also an option to go with sun power 400w maxeon 3, which is more investment but better warranty and performance for longer.


I’ve not thought about a battery for the moment as they only supply the solar edge 10kwh or Tesla power wall 2, however would it be better to use less panels and get a decent sized battery?



Our daily usage is about 10-11kwh at the moment but that’s not running the hot tub and pool yet.


What would be your advice on steps forward? Is it best to invest more into more premium solar panels because adding more is expensive or just budget for 5 ish KWh and that would be ok when we add EVs?


I’m on a fixed rate 17.8p tariff until December so don’t want to lose that for the moment. Also I don’t want to be spending forever tweaking tariffs to get the best return on charging in off peak. A set and forget would be ideal.


There is an immersion tank as well so will get a solar edge hot water thing or an eddi.

I’ve been through lots of the threads here and it’s all been invaluable getting to this point. Very much appreciated
 
I'm no solar panel expert but I would go for whatever option includes a good size battery so you can utilise the power generated during the evening/night. Feed-in rates aren't anywhere as good as what they used to be, so you might as well make as much use of your own power generated.
 
norm said:
I'm no solar panel expert but I would go for whatever option includes a good size battery so you can utilise the power generated during the evening/night. Feed-in rates aren't anywhere as good as what they used to be, so you might as well make as much use of your own power generated.
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Just to add if you're not using the electricity and mostly exporting then the utility companies are making a killing on the power your producing ie 4-5 per Kwh is what your paid while they sell it to us for 17-20p per kWh at the minute and that's before your fix ends.

Also don't worry about the EV's. I've read you'd need 20kw or something that size to charge your EV's well. I suppose if you think about it a fast charger at home feeds 7kw per hour so if you were really looking at charging it would need to be 10-12kw i guess.

I think a 10kw battery might be about the size for your needs although going up to 12kw wouldn't be bad.
 
sja360 said:
Also don't worry about the EV's. I've read you'd need 20kw or something that size to charge your EV's well. I suppose if you think about it a fast charger at home feeds 7kw per hour so if you were really looking at charging it would need to be 10-12kw i guess.
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This is really hard to understand with the mixed units, I can't make sense of it. I don't mean to offend but discussions on here are usually a bit of a wreck in terms of clear units.

Power supply and needs in watts and kilowatts W/kW

Total energy production/consumption in watt-hours and kilowatt-hours Wh/kWh

teamwillis said:
Our daily usage is about 10-11kwh at the moment but that’s not running the hot tub and pool yet.
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IMO it's time to start having storage if you're producing energy. Batteries will help you maximize value, if money is your reason for doing this. If you just care about the environment, max out on panels and be done. If you want to focus on economical outcomes...

Work out what time of day your energy usage is. 10-11kWh mostly at night heating your water and home? Or 10-11kWh during the day because you run the washing machine/drier/home gym heater/home office?

If you're getting solar but you use most energy at night in winter then, batteries needed. If you will charge your car during the day and do your power-hungry chores too, maybe not needed.
 
Thanks. We’ve been out for the past 36 hours and the house idled on 9kwh over the whole time. During the day we are working from home and can run the washing machine etc. in the evenings it’s just lights and tvs mostly.
Would a 3.68kwh inverter have issues with the 10kwh battery? Would it be better to have a 5kwh and get the DNO completed? I’m thinking of the 12 panels and the battery with the smaller investor then I don’t need the paperwork?

thanks again
 
teamwillis said:
Thanks. We’ve been out for the past 36 hours and the house idled on 9kwh over the whole time. During the day we are working from home and can run the washing machine etc. in the evenings it’s just lights and tvs mostly.
Would a 3.68kwh inverter have issues with the 10kwh battery? Would it be better to have a 5kwh and get the DNO completed? I’m thinking of the 12 panels and the battery with the smaller investor then I don’t need the paperwork?

thanks again
Click to expand...

This all depends on you max load at anyone time - if you use more then 3.6kWh at anyone time it will pull the difference from the grid, 5kWh will give you a higher threshold that's my understanding as I'm looking to install panels and batteries as well. It also depends on the battery discharge rate as well when you are running just off the battery.
 
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