Got Solar Panels - now what?

[PinkBobble]

So, we got our solar panels installed just before Christmas and we have been watching the generation meter ticking round on light days! Now, thinking ahead to the better (hopefully!) weather, I'm wondering if there is any way to easily tell how much of what we're producing we are using... ie if the washing machine is running should I wait until it's finished to run something else... or is it just working out the maths!

[buymeabook]

You can get things fancy monitoring software which will tell you. Or there is a gadget that is green when there is spare power.

But generally speaking, you're not in a position to time everything exactly. We just try and stick stuff like the washing machine on during the day if we can if it's sunny. And we'd tend to run big equipment separately (but if it is really nice you'd probably be generating enough to run two things from it).

[PinkBobble]

I thought there might be a gadget! I think we'll see how we go when the weather improves... I have been running one big thing after another on sunny days so far!

[buymeabook]

Thing is if you work out how much electricity you need to use to make the gadget worth it, it's such a long payback period that we didn't think it was worth it. Unless you really like gadgets of course!

We got ours installed just before christmas last year. It does get much better and is fun seeing how much more you generate as the days get longer. We beat our forecast for the year but the last few months have been complete cack!

[PinkBobble]

That's true, although my DH does love a gadget! We can log on to the inverter so I've been setting the washing machine and dishwasher to start one after the other during the peak times, but there's only been a few decent days so far as we are close to where it's flooded!

[PigletJohn]

Get an Owl (or two)

Unless your inverter has facilities for wifi link or data download, or a remote sensor, you can get an Owl (model 160 with USB connector). You put a sensor on one of the wires into your electricity meter, and it will tell you what current is going to the grid. It sends it wirelessly to a small display which you can carry around or plug into your PC. It has a memory which holds (I think) about a month of data if it is unplugged from your PC and unable to upload it. Your PC can display data from each Owl by the year, month, day or minute. If your inverter can be networked, do that.

If you have a second such Owl, you can put its sensor on one of the wires from your inverter (if it is wired in singles). If you keep an eye on them you will soon learn by looking out of the window what "generating 3kW" looks like, and you will learn the points in your dishwasher and washer cycles when they are heating the water, and drawing 2kW or so. Your tumble drier probably uses 2kW all the time it is heating.

Sadly an Owl on the meter can't tell whether the current is coming in or going out, but you will learn to recognise the patterns. There are devices that can, but I have not yet seen them cheap and widespread.

If you can schedule your washing and drying for sunny periods, you will notice the saving. A drier uses about 30p of electricity per hour. An oven night cost about 12p an hour on average (it is more expensive while warming up from cold).

You can get used Owls for a few pounds on ebay. The other models do not have USB connectors.
www.ebay.co.uk/sch/i.html?_from=R40%7CR40&_udlo&LH_PrefLoc=1&_sop=10&_sacat=0&_mPrRngCbx=1&_udhi=12&_nkw=owl+usb+monitor+-connect&_trksid=m194&ssPageName=STRK:MEFSRCHX:SRCH

You can also get devices such as Immersun which divert excess generated current to a heating device such as a convector heater or an immersion heater; but I have calculated that the payback on these is very poor, so don't buy one. They can't be used with e.g. a washer or drier because they cut the voltage back when the sun goes in.

[CointreauVersial]

We have a bluetooth thingy which tracks exactly what we're generating at any moment, and produces a graph for each day/month.

But we struggled to measure what we're actually using, because of the way our meter is wired - there's nowhere to attach a sensor to measure how much we are actually taking from the grid.

So we just use our judgement, really - run whatever we can when the sun is shining.

[PigletJohn]

can you attach a photo of your meter, consumer unit, and the wires around and between them?

[CointreauVersial]

Sorry, I didn't phrase that right. We wanted to install a meter which measured what we were actually using (i.e. consumption), not what we were taking from the grid (which is what the electricity meter shows). So we could compare it to what we were generating and make adjustments in consumption accordingly (i.e set off the washing machine, or shout at DCs for leaving lights/TV on....). But it wasn't possible - our spark had a look and confirmed it. The necessary wire is somewhere inside the consumer unit. We ended up having to return the smart meter.

[PigletJohn]

photo photo

[CointreauVersial]

Gah! Need a stepladder; will do tomorrow (risk assessment says something about not climbing ladders after consumption of wine )