It’s been a great summer here in Galera, the weather, by and large has been stunning, with temperatures up to 40c in the afternoon and really pleasant evening temperatures, ideal for BBQs. The last couple of weeks have been good – but it’s not summer – still wearing t-shirts but no-one is in a rush to go off to the lake for a swim. Yesterday it rained which was a bit of a novelty but by the look of the forecast we’re going to see sunny conditions, the odd cloud and maybe 21-22c in the afternoons for the next few days at least. Ideal for getting on with projects.
I’m currently working on a number of projects – one of which is my lighting – we’ve simplified the external lighting basically down to one colour – green. The lighting is predominantly LED-based and so I decided to go for 12v – this has the advantage that I can run the lot of a battery. I have a couple of small solar panels here, each able to give out 40w on a good day and they’re currently mounted flat on the pergola.
Well, that was fine until maybe a couple of weeks ago, every day they’d fully charge my 12v deep-discharge battery (basically an average size car battery that doesn’t mind getting heavily discharged) and so the lights would come on at dusk and go off at midnight. That, some Pergola lighting and a WIFI controller of my own design would take the battery down just below 12v in time to be fully recharged the following morning. You can see the last few days in the graph above (the system reads the battery voltage every 15 minutes). from the peak, the voltage drops with the lighting on until midnight where the lights go off, at which point the battery instantly recovers a little – but then continues to drain overnight as the controller itself takes some power – then come dawn it starts to go up again – etc. There’s a general downward slope, halted only by reducing the amount of time the lights are on but we’re only just into October here so it’s going to get worse – I’m hoping by angling the panels I can get that power back up.
Not so now, over the past weeks the hours of sunlight have dropped and this week I had to dramatically alter the timing, keeping the main lights off for an hour after dusk. I’ve been sitting here this morning looking at optimum angles for panels and of course my current flat setup is useless in winter. It turns out the optimum winter angle here is around 50 degrees – and thinking about it, the flat panel would be pretty useless if it snowed – so I need to make a little A-frame to hold the panels, easy to do when you have a B&Q around the corner, here we have a “Carpinteria” – and yesterday I tried the one in our village and the next – both closed all day!! I can see a trip to the big town coming on. It really just isn’t as simple as in the UK – on the other hand it’s probably pouring down back home by now. It’s 8am, the sun is thinking about coming up, a little damp outside but there’s not a cloud in the sky so it might well be a nice day.
All of this just just a project of course – I could just as easily power everything by the mains – but it’s a fun project and lots of knowledge is coming our of it. Between that and years of playing with garden lights I’ve a fair idea of what you can and can’t get out of solar panels.
Meanwhile, Maureen is taking an interest in local Pilates lessons and glasswork and I’m learning all about the operating system Linux – the hard way – by experimenting. Yup, it’s going to be a nice sunny day today.