Solar Shed - Page 1
Forum section: electronics / general

author: tomgruber
author_rank: Newbie
timestamp: December 14, 2021, 03:16:32 pm
content: Hi all,I am hoping to power my shed but I want to avoid using the mains grid, so I would assume my other option is solar?From what I've researched so far, it all looks pretty complicated to me.I know I should look to hire a specialist and installer but with money being as it is, I would rather avoid doing that if I can.I would also really appreciate being able to purchase what I need on something like Klarna or on credit.So, my first question... is this going to be feasible for someone with limited experience?I do have time on my hands to throw myself into it, but it would be helpful to know roughly how much time investment will be needed before I start. I don't want to waste 6 months trying to do it myself, just to hire a specialist anyway.I want to power some lighting, maybe a small fridge and my laptop.Can anyone suggest where I should start and what I would need?Many thanks!

author: fourtytwo42
author_rank: Super Contributor
timestamp: December 14, 2021, 03:37:48 pm
content: Before I got to laptop & fridge I thought "this is going to be easy"...........So the first thing you need to do is work out how many Kwh you need a day and how to minimise it......I have a 1Kwp array on my roof and at this time of year it generates between 0.1 to 0.3 Kwh/day when its cloudy that is most days.You could of course run your laptop on its batteries whilst in the shed and bring it into the house at night to charge it.Do you really need a fridge, they are power hungry, perhaps a coolbox in summer to keep your beer in would be more practicable, do you need cold beer in winter ??There you go, a few ideas, don't buy anything till you have figured out way more

author: richard.cs
author_rank: Super Contributor
timestamp: December 14, 2021, 03:38:07 pm
content: Start by working out how much energy you need per day. Lighting is quite low power, fridge and laptop less so. For each item you want to power multiply rated wattage by running hours and add it all together. That will then guide battery size, panel area etc.Do you have a budget in mind? A low-power solution for occasional lighting is cheap and easy, running a fridge 24/7 starts to get quite serious.

author: Gyro
author_rank: Super Contributor
timestamp: December 14, 2021, 03:46:11 pm
content: I guess the first question has to be how big is the shed, and will the roof support the panels? Below a certain (fairly large?) size, the amount of stuff you need inside the shed is going to outweigh the amount of practical free space that you have inside.Of the items you mention, the fridge is the killer as it requires constant power while the sunshine isn't. Are you going to want to run mains tools? What I'm wondering is whether you can get away with, say, a 12V battery and panel, or are you thinking full blown mains supply inverter. You can get 12V caravan fridges but they are very thirsty (and as I mentioned, a continuous load!).A panel, a 12V leisure battery, and some sort of small charge controller would get you power for intermittent use - 12V LED lights are commonly available and don't take much power, you can probably get 12V laptop charging adaptors for car use too.Trying to get sensible mains power in there would be an issue - you can get cheap mains inverters (even Lidl have them occasionally) but they pull a lot of current at 12V for anything more than occasional use.

author: tomgruber
author_rank: Newbie
timestamp: December 14, 2021, 03:48:04 pm
content: Ok so it looks like I've got some maths to do then!Thanks for the advice so far guys.The point of the shed upgrade is that it's going to serve as my new office. I've managed to get it nice and insulated but the laptop and lighting is a must.I did think the fridge might be a bit too ambitious though.I won't be buying anything until I've done some more research!

author: richard.cs
author_rank: Super Contributor
timestamp: December 14, 2021, 03:52:08 pm
content: For an office where you'd expect to be working for a length of time, you presumably will want lighting and laptop for many hours, and perhaps also heating (though that could be gas). Unless this shed is hundreds of metres from the nearest mains supply you'll probably find it more cost effective to install mains than use any kind of solar setup.

author: Gyro
author_rank: Super Contributor
timestamp: December 14, 2021, 03:57:47 pm
content: Agreed, home office stuff is a rather more involved proposition than a bit of tinkering in the shed.

author: Bud
author_rank: Super Contributor
timestamp: December 14, 2021, 04:22:19 pm
content: You can google for solar kits for RV to get a sence of costs and installation complexity. RVs typically would have a fridge. But i do not know if solar installations on RVs leverage the vehicle's battery.

author: sandalcandal
author_rank: Unknown
timestamp: December 15, 2021, 12:47:40 am
content: Quote from: Bud on December 14, 2021, 04:22:19 pmLooking at RV stuff is a good idea. Lots of good info online and products available around that application. RVs normally have a separate battery system for appliances but are often connected to the motor alternator/battery via a regulator for some level of charging but can also be completely disconnected and powered only by battery/solar. Really cheap systems are only really equipped to keep a fridge running temporarily and depend on being plugged in at a parking/camping site for more general/extended use of appliances.I would also however echo that getting your office shed hooked up to mains is likely the most reliable and cost effective solution however (unless this shed is 100s of meters away from the nearest power point).It's a bit iffy but you can just run anoutdoorrated extension lead from your house to our shed if you want something really cheap that'll just work.Edit: If solar itself is the goal of the project (for learning or otherwise) then that's a different story of course.

author: Gyro
author_rank: Super Contributor
timestamp: December 15, 2021, 07:45:34 pm
content: Quote from: sandalcandal on December 15, 2021, 12:47:40 amAgreed, it's a bit iffy but doable to use a tough outdoor extension lead. At the same time, it wouldn't cost you much (certainly against a solar installation!) to run a proper armoured cable from the house to the shed.You still haven't said how far the shed is from the house, but if you look at Screwfix and Toolstation, 2.5mm2Armoured 3 core cable really isn't that expensive. You could either run it in a narrow trench, or clip it securely along the bottom of the fence, depending on circumstances. With 2.5mm2, you could run a 20A feed to the shed if you take the cable all the way back to the consumer unit.If you have an RCD protected downstairs sockets ring circuit, you could take a feed for the cable from that, using a 13A fused spur (or an RCD one if the existing house circuits aren't protected). That should still be be more than adequate for what you have described. At the shed end, the armoured cable would terminate into a little cheap (again look at Toolstation and Screwfix prices) 2 way consumer unit with lighting and socket circuits.If you're prepared to do the legwork of laying the cable yourself, then I'm sure a friendly electrician wouldn't charge much to terminate the ends for you to make a proper permanent job of it... and you get your fridge!

author: M0HZH
author_rank: Regular Contributor
timestamp: December 15, 2021, 08:07:29 pm
content: I'm running a 250W panel and 400Wh of battery storage in the shed. It's enough to run a RaspberryPi (monitoring, weather station, etc) and shed lights but not much else in the winter. For laptop and other stuff it's much more convenient to run mains (armoured cable, outdoor grade sockets, dedicated fuse & RCD) than to rely on solar, the sun is just not enough here in the UK.

author: themadhippy
author_rank: Super Contributor
timestamp: December 15, 2021, 08:26:18 pm
content: QuoteOr 2 core if the sums work out,and if the incoming supply is TNC-S then its only job maybe for cable protection anyway.

author: Gyro
author_rank: Super Contributor
timestamp: December 15, 2021, 08:58:54 pm
content: I'm pretty sure it's normal for it to be 3 core, with a dedicated CPC conductor. The armour is earth bonded too as extra mechanical piercing protection.It's probably a moot point anyway as nobody seems to sell 2 core armoured.

author: richard.cs
author_rank: Super Contributor
timestamp: December 15, 2021, 09:30:24 pm
content: In the UK, 2 core with armour as earth is common, and 2 core swa cable is widely stocked, though maybe in real electrical wholesalers rather than DIY places. 2 core with armour as earthed mechanical protection but the far end TT earthed with a rod (no connection to source earth) is also common. Not that there is anything wrong with using a 3rd core for earth (and in some situations it is needed), just realise that doesn't mean you can get away without earthing the armour too.

author: zeke.
author_rank: Contributor
timestamp: December 16, 2021, 12:52:16 am
content: I'm assuming you will need a permit to install it on the shed.Idk the laws in the UK, but you could install the panels in your yard and power the shed like that.I don't think you would need a permit for that.

author: themadhippy
author_rank: Super Contributor
timestamp: December 16, 2021, 11:49:22 am
content: QuoteMaybe.although its known as notifiable work here,if you come of a fused spur you might be fine, put in a new feed from the fuse board and then its notifiableQuoteOnly because the wet behind the ears,fresh out of collage sparkys cant find an R2 value in there shiny regs book.Using the armour as the cpc is pretty common,especially in industrial installs.Next they'll be telling me i cant use metal conduit as the cpc.Quoteevery decent electrical wholesaler will have the common sizes in stock,for examplehttps://www.tlc-direct.co.uk/Products/SW2dot5slash2.htmlhttps://www.cef.co.uk/catalogue/products/2326451-2-5mm-2-core-pvc-swa-xlpe-armoured-cable-cut-length-sold-by-the-mtr

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 16, 2021, 12:04:26 pm
content: Agree with the above - unless it's really hard to get a cable there, running a mains feed will be the cheapest and easiest option.If you plug the house end into a 13A socket then you can legally DIY it all. But if you know what you're doing, nobody's going to find out if you do it all yourself. (And after 1 year they can't presecute anyway)Failing that maybe look at a portable powerbank, e.g.https://www.hampshiregenerators.co.uk/product/generators/portable-power-stations/jackery-explorer-1000-portable-power-station/?gclid=Cj0KCQiA5OuNBhCRARIsACgaiqW3Ucs4gvc0ge-9pP9XMhkIcuJXbKdBj_wH5xC6tfH_zcBgdFyI9LkaAiSOEALw_wcBWhich can double as a backup power source for power cuts, camping etc.

author: Gyro
author_rank: Super Contributor
timestamp: December 16, 2021, 04:40:35 pm
content: Ok, use 2 core then (I hadn't bothered to check CEF and TLC). I notice that TLC page also has 'Electrical cable below' tape which is very useful precaution if burying the cable (put it a few inches inches shallower) and Piranha Nuts, which are apparently work very well for earthing the cable glands.Quote from: mikeselectricstuff on December 16, 2021, 12:04:26 pmWas that meant to be prosecute or persecute (or both!)?

author: themadhippy
author_rank: Super Contributor
timestamp: December 16, 2021, 05:35:41 pm
content: QuoteBack in the dark distant days of my apprenticeship we were taught to back fill the trench with 6 inches of sand ,then warning tape,and finally 12 inches of soil, the sand hopefully gives a warning if you miss the tape.Quotequicker and easier yea,better connection than a properly assembled banjo and bolt? debatable. One plus is they do maintain the enclosures IP rating