Solar panels and battery - any real world reccomendations?
- Thread starter GinG
- Start date
Soldato
I've just picked up the first parts of my install. For what I intend to do I needed 42 meters (an over estimate) of 25mm SWA, which the cheapest I can find is about £460. A local electrical contractor recently closed, and I came across the auction on Bidspotter, just so happens there was 43 meters of said cable. Which I won for £343, also got another part I'll need for a good price along with some bits to sell.
Not sure how I'm going to thread it through the house, that's going to be a challenge.
Not sure how I'm going to thread it through the house, that's going to be a challenge.
Associate
Would be interested to see a build log of this with pics
Soldato
I'll post something up once I get started.
Weird one, but spotted the last few days that my battery will charge up to like 85-90% then just stop and then about 15 minutes later jump to 100%, any ideas whats going on there or is it just a nuance of the givenergy dashboard?
25mm SWA can handle 124 amps. 6mm SWA (53 amps) would be more typical for an outbuilding. What on earth are you powering?!
Ps. Don’t forget to run a Cat5/6 with it for the CT clamp on your incomer.
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Soldato
Mining farm.
Not even free electricity can make that profitable anymore!!
Soldato
How much are you talking for a decent solar install without battery at the moment?
And can you add a battery at a later date?
And can you add a battery at a later date?
Soldato
Will let you know when its complete. I have them on the roof now, also got the 400w panels just waiting for the spark and the inverter.
Soldato
Maybe £7k, 12-14 panels. It vastly depends on your roof space.
You can add a battery later, but as I have discovered you need a hybrid inverter for a battery.
We went solar no battery I don't really regret it.
Soldato
Yeh, was thinking 7k would probably be the ballpark figure.
Not sure how many panels would fit on our roof.
South facing which helps.
Soldato
Looks like you cold get 21 between the two sections, probably horizontally on the main roof, although it could be perspective, in 4, 4, 4,3 and vertically on the smaller roof, in 2, 2, 2 config.
Soldato
Lower roof would get shading on it from the house, I'd be tempted to go higher one only depending on install size that affords.
Soldato
The whole house
The general idea is to take the meter tails out the CU (consumer unit), put them into a 100amp switched fuse, from the switched fuse run the 25mm SWA out to the garage (approx 21 meter run). Put a Victron 8000VA inverter in there, which is capable of supplying about 6400w depending what the load & temperature is. Run another 25mm SWA back to the CU.
This means the whole house is run through the inverter (it will need a by pass switch in case its faulty or needs working on), when the house load exceeds what the inverter can supply it draws the extra from the grid, and can handle up to 100amp. My existing 4kw solar, which is connected to the CU will stay as is, and the Victron will charge the batteries with excess power from it, or export it. MPPT chargers will connect to a new 4.8kw east/west array on the garage roof and directly charge the batteries via DC, when the batteries are full the the MPPT chargers will supply power to the inverter for use or export.
In the event of a power cut the Victron inverter will isolate from the grid, and carry on producing power from the batteries/garage solar, as power is being supplied to the existing CU the original solar carry's on working as well.
I'm intending on using a 16S 304AH battery, which should give about 15.5kWh, and I could add multiple batteries.
We won't be running it at 100amp, it will likely be fused at 60 or 80amp, but its future proof, and more importantly, the longer the cable the more its affected by voltage drop, and you don't want voltage drop on solar, so the bigger the cable the less voltage drop. Also if we have to de-rate the cable, with 124 amps we've plenty of head room.
The major problem is its going to be an absolute pain to get a cable that thick (26mm) and not very flexible in to where it has to go, well actually two cables, one out, and one back in, but I'm up for a challenge. Doing it this way will also mean the CT clamp is in the garage, but I will still be running a CAT6 cable out there, with a fair bit of separation.
Soldato
Mines certainly down with the hot weather, peaked at 2700w, with 16 250w panels, so average of 168.75w per panel. Produced 23.67kWh today, with a perfect graph, go back to the highest generation day on the 2 July, it was quite a choppy graph, but generated 25.95kWh, with a peak of 3442w, or an average of 215w per panel. Looking back through quite few days, there is one day production had a very short peak up to 3.775kw.
Soldato
Yep, I was thinking this would impact the amount of sun they would get. Probably not the ideal design of house for solar panels
Might just squeeze enough panels on the main roof to be worth it though.
House is about 30ft wide in total and I think the smaller roof is about 8/9ft.
Soldato
Yep, I was thinking this would impact the amount of sun they would get. Probably not the ideal design of house for solar panels
Might just squeeze enough panels on the main roof to be worth it though.
You can chuck on optimisers or whatever to help out but it will get less sun by virtue of shading than the main ones would.