Hello folks!
I'm retrotecchie, (a.k.a. Mike). I live in Surrey, just outside Guildford and I'm a grub-growing, solar-powered, compost-making electronics engineer :).
I'm 41 years old and live with my other half Mrs retrotecchie (a.k.a. Panda) and her two sons in commuter land, in a 1950's vintage ex-council house that still has 100 feet of garden and an outhouse - yay!!. It's not that easy being green slap-bang between the A31 and A3 but one tries one's best!
Wind, rain, sun, soil, bumble-bees and worms…I love the finer things in life!! I also enjoy real ale (occasionally!) and reading sci-fi.
Solar PV is my thing, and especially designing control systems for renewable energy.
11-Aug-2008
Bum! The measly 15 Wp (2x 2.4W and 1x 10W) I have available, panelwise, just isn't doing it in this grim and overcast weather. I'm only geting an hour or so from the solar…time for another 20Wp of panels :o)
I am getting charge current - just not enuf, innit?! And, for some odd reason, it would appear that the last few days, it's been clearing up and getting sunny again when the sun is almost ready to set. I think I may just put one of the new 10W panels on the other side of the shed roof, to maximise those late evening rays :)
13 Aug 2008
Still waiting on the two new 10W PV panels but I only need a topcoat of paint on my solar collector brackets now. The pump arrived and the collector itself is finished! I built the box out of timber to house my 50cm x 55cm radiator that I sprayed black. All it needed was a sheet of 3mm glass 60cm x 60cm to finish it off, but the only glass shop near me isn't open at the weekend and is shut by the time I get home from work!!
So….while I scratch my head and worry about the lack of glass, I decide to hack apart the front of my shed to make the existing window bigger. Well, I want to propagate some seedlings and work in the shed with a bit more natural light. My 8'x10' shed is nice and roomy, but is bloomin' dingy with only a 2'x2' window! Off to the DIY shop for some wood, a bag of nails and some frame sealer…and a sheet of acrylic. Two hours later, a few coats of timber treatment and the new frame is ready to accept the acrylic. Job's a good'un…
Mrs retrotecchie, bless her, comes down the end of the garden with a mug of coffee for me. "Wot you gonna do wiv that bit o' glass, then?" (because her first comment naturally isn't praise for the grand new shed modification but a comment on the crap I leave littered about the place!). Hmmm….
Hang on a mo….tape measure out….2ft in 'new money is er….about 60cm!!
Funny how some things in life work out 'just right'!!!!
1 Sep 2008
Yay! The other two 10W panels have arrived and they are now mounted on the shed roof! In half decent sunshine today I measured 1.4A going into the batteries…that's double the rate with just the one 10W panel. "Hang on!", I hear you cry, "Three panels instead of one, and only double the current?" Yep…one facing the other way so it maximises the late evening sun :o)
I could have all the panels pointing the same way and get a huge boost around 11am, then it would trickle off again mid-afty, but I'd rather have slightly less 'peak current' and just optimise my charging over the whole day.
I also finished both my solar water heating panels over the last few days and have got those plumbed in now in front of the other shed. I have the two old 2.4W panels charging an old car battery and that drives a little 150W inverter to power the circulator pump for testing. I measured the temperature in my 'test tank' after it had been running for two hours by the simple expedient of dunking my hand in the water….ouch! Well hot!! Almost hot enough to brew a pot of tea by my reckoning…but not with the harvested rainwater I'm using for testing, which is looking a little green and murky.
I now need to investigate a cylinder or some other form of heat exchanger as I definitely need an indirect system. Pumping old rainwater with a drop of anti-freeze in it isn't conducive to clean hot water now, is it?!! Trouble is…smallest cylinder I can find is about 63 litres and they aren't so common. Most tend to start around the 92 litre mark, and most 'off the peg' jobs are 18" x 36" or 117 litres. I'm not talking domestic sized 'family of four' and filling the bath…I just want a few litres of warm water for handwashing in the shed and about two or three gallons to hot-fill the washing machine. Calorifiers for making hot water on boats from the waste engine heat are looking promising….but put the word 'marine' in front of anything and the price rockets out of all proportion. I may just have to knock something up myself - but then that's what experimenting and playing in the shed is all about.
So….today's state of play:
30W of panels on one shed, charging the 48Ah battery pack and running the 500W inverter to provide light in the shed and off-grid lighting feed to the house. Working well and getting much improved charging in variable weather. Using my funky little light sensitive controller to cut the inverter in as it starts to get dark, and out again at dawn.
4.8W of panels in front of the second shed providing a 150W max 'auxilliary mains' from an old car battery and my spare inverter. This is always to hand (thanks to the croc-clips!) for daytime testing and piddling around. I used it to charge my cordless drill yesterday which worked fine - suprising as the Ni-Cd fast charger really was NOT happy running from the other inverter - must be a better quality modified sine wave from the smaller one?!
Solar collectors in place and now plumbed in with copper instead of garden hose and jubilee clips. Still have hose connections to my test tank until I work out the cylinder situation.
Just some electronics for differential temperature control of the pump to design and build and, of course, the cylinder to magic up.
10 Sep 2008
Hmmm…miserable wet weather! Not getting too many herbs from the solar right now. My little LED garden light with the 2" square panel and a couple of 600mAh AA batteries kicks in at about 8pm and is dead by 10pm!!
Well, I'm still working on the cylinder problem. I obtained an old 5 litre electric water heater from work which has a lovely insulated 5l stainless steel tank, but uses a 1.25" diameter immersion heater and I'm having trouble finding a brass blanking plug I can use to fabricate a solar coil. I did try winding a spiral of 10mm microbore copper around the outside but the diameter is too small and it's very hard to get a clean coil with good thermal contact.
My next thought is to use a 20 litre stainless steel electric urn (Burco boiler, sort of thing) and make a tank out of that using my helical coil. Let's see what happens on ebay!
I'm rethinking my PV panels right now. Perhaps I would be better off mounting all three as south-facing as possible and just getting maximum charge at mid day. I'm working on the calculations of lower peak current for a longer period versus higher peak current for a shorter period. Technically, my AS panels produce in 'daylight' rather than just direct sun but at fairly low currents. Right now I'm wondering….3 hours each at 200-400mA from the individual panels or 2-3 hours of 600-1200mA maybe…hmm….
06 Dec 2008
Bit of a gap since my last update. We had a sneak thief slip in through the back door - in the middle of the day, no less - and nick the bloomin' laptop. Nipper had let himself in, gone upstairs and cranked up his music rather loud. Some pikey who had been hanging round with his crowd followed him home and decided to whip the Dell away….I suppose if he'd been intercepted he would have just said he followed the boy home and wanted to see if he was up to anything…you know how it is with teenagers. Anyway, laptop well and truly had it away on its toes. The upsetting thing wasn't the laptop itself…just a creaky old dog razzed from work…BUT ALL MY DATA, solar designs, experiment write-ups, notes and meter readings plus all my energy savings spreadsheets were on it….bugger!!! So, although not quite starting from scratch again I'm having to start again on all my energy monitoring and notes. Lucky all my photos were still on the camera :o)
Not looking good at the moment….I calculate I'm getting a couple of watt-hours at best from the solar PV. The sun is so low in the sky right now that even at the right time of day to get the best light, the panels are just shadowed by next door's roof-line….aaaargggg!!! I can hardly ask Don to knock a bit off the roof, can I?!! I COULD relocate the panels….but it's a bit damp and parky out to be piddling around on the shed roof. I may move ONE of them to catch the late day sun - that may get me an extra watt or three but is it worth it I ask? Between February and September, they are spot-on!! So the house lights are running mostly off grid power now (thank God for CF lighting!!) and just the shed lights are running on solar as and when I need them. Good enough for the winter months, I feel!
On the up-side, the two 2.4 watt charger panels on the front of the other shed seem to be keeping my old car battery topped up nicely. That one just runs a 30w pump from an inverter for a few minutes every day just to circulate the water in the solar heaters…and that has even managed to raise my water tank by a degree or several when the sun has been out….even in winter, so I'm rather pleased with that!! I say tank, but I'm still using an open plastic bucket as I haven't got a Burco boiler yet to fabricate my proper tank. Ebay hasn't been working for me on that score!!
On a personal note, I've finally had an operation on my knee to relieve it of a nasty lump I've had for ages…it never bothered me much until it became infected earlier this year after a nasty bang it took, and the GP decided I ought to go under the knife. At least when it's time to get out and dig the veg patch again and resume my experimental tinkering, I should be dancing my way down the garden and back!!!
14 April 2009
I'm back! Well….it was a slow winter with nothing much doing, wasn't it?!
The clocks have gone forward and everything in the garden is rosy. The panels are now earning their keep again, and I hope to do much better than last year.
The two 2.4W panels on the potting shed are keeping the old car battery in reasonable shape and I have just added a bulhead light fitting and 11W spiral CFL to the outside wall to provide some illumination for the whirly-drier and the veggie patch. That light and the 11W lamp inside the shed are fed from a small 150W inverter so that shed is now independant from my main solar system. During the day when the sun is shining and the battery is charged, I use the inverter to charge the battery drill or boost the laptop and the mobile phone.
The mains (inverter) powered bulkhead light doesn't half light up that end of the garden nicely…much better than the small 6W 12v garden lights that I used to run directly from the battery. Great for low-level spot illumination in a decorative sort of way, but so NOT practical. Even taking into account the efficiency of the inverter, 11W of mains powered light is far better than 18W of low-voltage tungsten and provides a much better conversion of solar energy.
I'm a bit gutted actually…I know you aren't supposed to use car batteries for solar, but so long as you don't discharge them much below 11v, they are handy if you can't afford a proper deep-cycle unit. I had the old Peugeot 309 (chip-fat burner) towed away the other day but not before I'd turned it over and started it just for a laugh. Unfortunately, I was away at the time it was towed, and I'd forgotten to take out the almost brand new battery I'd started it with and all I was left with was the old flat one! Never mind….it charged up ok and is maintaining a decent charge.
The car itself? Donated to the local fire station so they could practice with cutting equipment and putting out vehicle fires. Pehaps not the most environmentally friendly method of disposal but it's not in a dump leaking fluids everywhere and it has helped train the emergency services :o)
To be fair, the old battery that came with the car recovered well after a long slow charge from the panels, so probably has a lot of useful life left before I need to replace it.
Last year, I didn't get the full benefit from the two new 10W panels as it had just turned autumn and the clocks were about to go back. This year I hope to have six months of data to play with. I only turned the inverter on for the first time last weekend, and have been running the house lights this week after sun-down. The power meter is already reading 400Wh after just six days so I'm quite happy so far! I've started logging my consumption again on the new laptop so hopefully this summer should be a success. Easter Monday afternoon was nice and sunny after three days of cloud and rain. I measured a good .95A charge current at about 5pm when the sun had moved a good 40 degrees 'off axis'. If the sun is out around midday with the panels due south, I would expect around 2.5A or more.
The onion sets are in now, the beans are sprouting in pots in the shed and Mrs Retrotecchie's Dad dropped some lettuce seedlings round at the weekend so the veg patch is also under starters orders. Roll on summer….
26 April 2009
Oh bummer! A fried inverter….just when I was doing so well,too! Just over 2kW of solar power this spring so far….three weeks of running the house lights.
I opened up the shed this morning and the smoke fairy had been let loose! A burned out inverter and a fried 15A in-line fuse.
Ah well…..new inverter on order :o(
30 April 2009
One very happy retrotecchie today! I'm back on-line (or 'off-grid', if you prefer) and things are looking good.
I got a new inverter from Maplin which arrived on Tuesday. Somewhat more expensive than the old one but oh so worth the extra cost. 300W of pure sine power, better protection and a generally far superior item to the old 500W MSW. If you do a little research, 300W of pure sine is probably as effective as 500W of modified square wave as most devices will actually consume a little less power and run more efficiently!
I also have a new meter as the old one was well and truly destroyed by the inverter going belly up. This one is another Siemens single-phase digital meter, but can resolve down to 0.01kWh (10Wh) rather than the .1kWh (100Wh) of the old model. Now I can be far more exact in my measurements.
The CF lights in the house also run brighter and happier and there is way less hash and electrical noise generated by the sine inverter so everything is improved. The fan on the new unit only runs when it needs to so is much quieter. In fact, I ran it last night for six hours with 120W of continuous load and the fan didn't even kick in once!
I know we can all be working on a limited budget and often have to 'make do', but I will say this…spend a little more on a good inverter and it will pay dividends!
26 May 2009
Another wet and murky bank holiday Monday, but it was preceeded by a lovely Saturday and Sunday. Oodles of 'currant bun' and plenty of herbs in the batteries…talking of which, I have just upgraded my 4x 12Ah Powersonic VRLA batteries to a pair of Exrider 88Ah leisure batteries (www.batterymegastore.co.uk).
I now have 4 12W panels…would have been 5 but one got damaged in shipping :(
Anyway, replacement on the way so I'm looking forward to my home-brew installation being finished by the weekend.
Plenty of power now the batteries aren't the limiting factor and I'm using between 150 and 300 watt-hours per day, depending on what lights I need on in the house.
In the garden, progress is slow but steady. I cleared the rubbish at the bottom end of the veggie patch (overflow grass cuttings, old pots and scrap wood) and have added another 300 litre composter. All looking much nicer now and I managed to get a few tomato plants in (thanks to my next-door neighbour, Don, who had some spare plants) and start propagating my next batch of lettuces. The beans are snaking their way up the bamboo canes and the carrots have poked their green fluffy tops out of the soil. The first crop of lettuce is just about ready to harvest so I'm eagerly anticipating the 'first pick' of the season.
The lupins are in bloom and they are attracting loads of big furry bumble-bees into the garden. I bought Mrs Retrotecchie a rose-bush for her recent birthday and that has now popped out two lovely red blooms. Even the wisteria has flowered this year (the bonus spring flowering too…hoping for another burst in autumn) and most things seem to be thriving nicely after the last few mediocre summers.
The lawn has suffered though…plantains everywhere. I'm digging them out but it's leaving lots of 'holes' which hopefully re-seeding and patching with a mix of compost and sand will repair.
Lots to do…but keeping me busy :D
16 June 2009
Well, the good news is that my grass seed has germinated and the huge holes in the lawn are growing back nicely. A few more weeks and a couple of mowings, and the new grass should blend in with the existing a little better. Still a lot more plantains to grub out but by doing the job a few at a time, the lawn shouldn't look like the runway at Entebbe!
The first lettuce harvest was superb. Nice crispy leaves and good solid hearts on the Iceberg II. Last year I don't think I left them long enough to form hearts but the leafy salad was yummy so this year was even better. The beans are flowering and the carrot tops are up to about six inches now so I'm looking forward to some nice veggies with forthcoming Sunday lunches.
Thanks to a little 'gift' from my Dad, courtesy of a family legacy, I had a little extra money to play with last month. I now have a couple of big leisure batteries on the solar PV system and so decided to add two more panels. The broken one was replaced by the supplier, and with the two additional panels, I now have 84Wp (7 x 12W). Plenty of welly on a good sun day, but now I have added the upstairs lighting circuit to my system I have a couple of other issues I need to fix.
Technically, a 300W inverter should (allowing for losses) draw about 30A on a 12v supply. To be on the safe side, I fused my inverter feed cable with a 20A fuse. I have now blown two 20A fuses….one trying to run a 300W strimmer (!!) and one just yesterday evening. Yes, I calculated my loads correctly for lighting and ceiling fans, but forgot to add in the shower pump which is wired across the lighting circuit. The last evening or so when it's been warm, we haven't used the bathroom lights and shower and the bedroom ceiling fans simultaneously…yesterday we did. Well within the safe power capability of the inverter, but not fed via a 20A fuse (240W)! I now have a pack of 35A fuses and I will tentatively try one of those. Personally, I'd rather be safe than sorry so I'm still tempted to use 20A and limit my system to 240W, but perhaps rewire the shower back onto grid power :)
I also got chatting to another NHF forum member who said 'hello' after she spotted I was in the same town. She mentioned she had a little-used chicken house up for sale so I went for a look and have decided to go for a couple of hens. I should hopefully get the house this week and then get a couple of 'girls' from a local poultry dealer. It was nice to meet Karen and her hubby (and chooks) and I'm looking forward to keeping hens as a 'hobby'.
21st July 2009
Ok….got me chooks a month ago. Copious quantities of chicken-poo for the compost heap but not much else. Until today :)
Henrietta laid her first egg. I was well chuffed when I got in from work as I'd stopped off to get some straw on the way home and was going to clean out the house and make them up a fresh bed and then found the egg in the nest box! I know it was Henrietta rather than Brenda as she is a White Leghorn and will lay white eggs and Brenda is a RIR based hybrid and will lay brown eggs. So, the first egg - a white one - and the first entry on the Hall of Fame. The lad chose the brown hen from the poultry farm and named her Brenda, so I guess she's 'his' chicken. Henners is MY hen and she laid the first egg so it's Retrotecchie 1 - Alex 0.
I'm keeping a score-sheet in the Potting shed and it was great to make the first entry tonight…even better that it was a tally on my side!
So eggs are go, the lettuces are dwindling as I've harvested about ten out of the 16 I planted, I've pulled the first baby carrots and the tomatoes are coming on nicely. The runner beans have produced a few pods but nothing to write home about but they are having another flowering right now and fresh pods are setting. I harvested a few onions a bit early - small but very tasty, and there are some monsters still growing in the patch. All in all, not bad for this season.
2009 has proved to be a very good year in the grounds of Retrotecchie Mansions. The garden has flourished, the veggies are doing well, the Hen House has begun production of more than just compost additive and the solar power has been going great guns.
Solar so far? Started this year's readings 104 days ago and I have racked up just over 15kW. I know that doesn't sound like much, but 10kW of that has been in the last month, which puts me well on track for my average of 0.2 to 0.3kWh per day, or approximately 5% of my household needs. The averages will improve as I now have more panel wattage than I started the season with and my batteries have a far higher capacity. I also had a few interruptions caused by blown inverter and meter problems and there were a couple of weeks at the beginning of June when I was away on business so the solar wasn't used. I really must give Mrs R the crash course on how to crank up the system!
I may do a few more of the panels….I reckon I can fit at least one more on the shed, taking me to 96Wp. I'm tempted to up the capacity on the potting shed, but don't use the power I get already at anywhere near capacity, so I may just leave well alone.
