MSE guide: plug-in solar panels

Stockie

One question in general I have is that all the plug in solar guides have mention that you need modern wiring and RCD consumer units but don't really specify or give examples of what counts as 'modern' and what doesn't so joe bloggs can have a rough idea if they need a sparkie or not.

On a personal level, my flat roofed garage at the end of my garden would be ideal, however it runs off a spur which has a 30mA PowerBreaker https://www.toolstation.com/rcd-spur-white/p48767 as it leaves the house. Do the experts on this forum know if this would cause any problems or not?

prowla

https://forums.moneysavingexpert.com/discussion/comment/82107625#Comment_82107625

The current plugin legislation doesn't include using batteries, though many expect that it will be updated at some point.

However, there are current use-cases for having battery setups which do not output back onto the house mains, for example computer UPS's, fridge/freezer blackout protection, hi-fi mains regeneration, and suchlike, even just leaving rechargeable devices plugged in.

prowla

https://forums.moneysavingexpert.com/discussion/comment/82108500#Comment_82108500

800W at 240V is approx 3.5A (P=IV).

So any mains wiring should capably exceed that.

There was an assertion that many circuit breakers (the switched units in place of fuses) are uni-directional and so may not work if there is input voltage/current coming in the opposite direction. I've also seen comment contradicting that, but mine are bi-directional anyway.

It may be that case that old fuses may not be quick enough to blow if an issue occurs, so that may be where the "modern" comes in.

I guess the answer to the question really is if you don't know, then ask a sparkie.

I think the rule is to be that you can only connect one plugin unit to one ring/spur, so no buying several and plugging them into a 4-way!

There's also some common-sense things like using waterproof plugs & sockets for outdoor connections.

On the power side of things, don't get too carried away with the power-saving: generally these things alone won't supply the total power to run any heating appliances: a kettle uses 2000-2500W, a hairdryer 1500-2000W, a microwave 800-1000W, so you're not going to see your bills suddenly plummet.

FFHillbilly

https://forums.moneysavingexpert.com/discussion/comment/82107672#Comment_82107672

You'd be better off paying for scaffolding and cleaning the panels on your roof first

QrizB

You'd be better off paying for scaffolding

Or, if you can get a vehicle close enough, rent a cherry picker for the weekend. They're not especially expensive and early FITs pay quite well.

The_Bookman

This may be a very silly question, but it is a serious one; do we know how much these things are likely to weigh and whether or not they could thus be placed on an existing, sloping conservatory roof. If not, why not?

I inherited the conservatory and tbf, I wouldn't mind if it fell down. Being somewhere that could hold solar panels would be the most useful thing it's ever done.

QrizB

This may be a very silly question, but it is a serious one; do we know how much these things are likely to weigh …

A typical modern 500 watt solar panel is ~2m x ~1m and weighs about 25kg. I can handle one myself but it's easier with a friend.

That's a similar weight to a double-glazing sealed unit of the same area.

… and whether or not they could thus be placed on an existing, sloping conservatory roof.

I guess in principle they could but it's going to depend very much on the conservatory!

how much is the kit and where did you buy it from I didn't think they were on sale yet?

Kits intended for Germany etc. have been available in the UK for several years, starting from about £400 for a kit with two panels and an inverter. Judging by sales numbers on UK internet sites (eBay.co.uk, amazon.co.uk etc) there are probably mid-thousands of them already installed here.

I don't think there are any UK-IPS-approved kits available yet.

So what are we looking at for repayment period for these?

See the MSE article, or page 2 of this thread.

phil1579

the safety warning on the guide is not very accurate or clear - the issue with extension leads is that they have unreliable plugs / sockets and are not designed to be used at higher currentls for extended periods of time. its not really that they cant receive power - they are two connectors on either end of a bit of wire. if there was an issue with power going the wrong way then it would also not be designed to go back into a socket either - the power cord on these inverters is just an extension lead in disguise if you think about it. And yes most certainly dont use an extension lead, use a well designed and correctly rated long power cord. ( explaining that these can be sourced might actually stop people using extension leads )

Also the second bit about Solar panel cables needs to be seperate from the mains cable stuff - it was not clear to me on first reading that the extension was about solar cables, until I read the MC4 bit in the separate paragraph.

Netexporter

A new video from Heatable that is well worth watching:

Watch This Video Before You Buy Plug-In Solar

prowla

https://forums.moneysavingexpert.com/discussion/comment/82109771#Comment_82109771

I was just going to post that.

It's worth noting that all of the YT videos are of pre-release, converted, or diy systems.

But there is a general warning to beware of plugs outputting power; think of it as looking both ways before crossing the road, using oven gloves when you take the casserole out of the oven.

They did say that they don't use the wall socket on/off switch, but I (mostly) do; however, perhaps the imminent standard should insist that the systems must have an integral on/off switch to isolate the plug.