G'day from Loomberah

Say g'day and tell us a little bit about yourself if you wish. If you have a wind or solar power system, big or small; flaunt its specs here!

Re: G'day from Loomberah

Postby Gordon-Loomberah » Tue Sep 29, 2009 7:45 pm

kdawson wrote:Hi Gordon,
I'm curious how you came to the figure of 40 Amps from a days charging from a 640watt system. I've got 3 x 130 watt panels (360watt total) and on a nice day like today I've used 112 Amps according to the Plasmatronics regulator.


Hi Karl, as Max pointed out I was referring to the instantaneous current flow, 40Amps. If you have that current for 2.8 hours, you will have put 112Amp Hours of energy into your system. At a nominal 12volts that will be 1.34kWh, and if it was all going into the batteries, you would be able to get pretty close to 1kWh (or 1 unit) of electricity out of them @ 80% charging efficiency. Much better if you can use the power while its being produced and not lose that 20% charging inefficiency.

Gordon
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Re: G'day from Loomberah

Postby Lyngarin » Tue Sep 29, 2009 7:56 pm

Hello Gordon and Max, I was trying to analise the graph Max posted and to me it would appear that on most days the output A/H was higher then the input A/H. Max does this mean you need to use your generator to boost charge the batteries. Otherwise they would eventually flatten right out. Regards Gary. ( lyngarin)
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Re: G'day from Loomberah

Postby Gordon-Loomberah » Tue Sep 29, 2009 8:54 pm

I dont know if any multipliers have been applied to any of the data in that graph, and clearly not all the scales are in use. I'm assuming we are looking at AH, and yes it does appear that more is being used than is being put in on many days. That cant be sustained for too long, but there are a few days with a lot of charging and much less discharge to make it up. I dont know if that is the total household usage, but it seems to be averaging not much more than 1kWh/day, which is very frugal! (assuming its a 12V system from the V scale on the left)
I struggle to keep it under 3 or 4units/day in extended cloudy periods with no wind here. Average use has been around 6 units recently, but on Sunday it was quite cold, though sunny and windy, so I went for a new high power use record ;) By using an electric oven for roast spuds at lunchtime, then leaving it on for the next 3 hours to help heat the house, running a load in the dishwasher with electric water heating, baking a loaf of bread in the breadmaker, running the fridge and chest freezer at their coldest, plus the usual lighting, tv, computers, hydronics pump and fans, microwave etc, I made it it just over 11kWh :!:

Gordon
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Re: G'day from Loomberah

Postby nicko » Tue Sep 29, 2009 10:31 pm

Gordon-Loomberah wrote:Thanks Max, yes it sure was a bit like Mars that day! ... and not too different again today with another dust storm, although it was mostly greyish dust this time, and not quite as thick, but it was enough to stop me from heading out for a 125km mountain bike ride I had planned all week :(
Here are the panels in action on a clear day :

http://astro.gunagulla.com/images/Tracking-Panels20090925.wmv

Gordon


I had a chuckle watching this clip of your solar panels rotating with the sun. It was interesting to see them in action, at the same time it got boring because it goes on for along time but I just had to watch it to the end. Then I started thinking about myself watch NASA space station footage - so similar in ways :)
Good on ya Gordon. Oh what is the wind power used for?
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Re: G'day from Loomberah

Postby Gordon-Loomberah » Tue Sep 29, 2009 11:06 pm

Hi Gary, yes I spend many nights looking out into the solar system- for Near Earth asteroids ;)
Hmm, a tricky situation... I guess you have quite a bit invested in 12V equipment, so suggesting you swap to 24V probably isnt an option ;)
I assume that both batttery banks are the same chemistry, ie both flooded cells or gel cells? Its not a good idea to parallel different types of battery for charge or discharge. I dont think its really an ideal system. If the load you transferred from the 780AH bank to the 220AH bank was taxing the big bank, then I suspect the life of the small bank may be fairly short. Also charging of parallel banks of different capacity batteries at different states of charge is not ideal. Some will probably end up not getting enough charging, and others might suffer from too much gassing, unless you keep a close eye on the charging every day and disconnect batteries as they reach full charge. I think its safe to go under 80% charge with your main bank of batteries reasonably often, but try not to go below 50% very often.
Do you find you have plenty of power in sunny weather, as in the regulator is floating the batteries in the afternoons? Batteries aren't the only way to store your solar power. You mentioned a freezer- you could turn it up to its coldest setting and freeze multiple 1litre bottles of water during the day- put 3 or 4 in the fridge at night and turn it right down or off, the ice will keep everything cold. Next day you re-freeze the bottle of ice. If the freezer is of large enough capacity you can run a continual production line of ice for your fridge, and only rarely need to run it at all, particularly in cooler weather. Before I had enough panels I did this and it works quite well.
Also you can reduce the amount of power your fridge and freezer use by adding insulation to the outside. Just make sure you only add it where the metal is cool- not where its warm, as some modern units have the coils built into the back or side- great for keeping them compact, but hardly ideal for minimising the power they consume.

Gordon
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Re: G'day from Loomberah

Postby Gordon-Loomberah » Tue Sep 29, 2009 11:11 pm

nicko wrote: ...Oh what is the wind power used for?


Charging my batteries... if I'm not using it for something as it is being produced ;)
This is not an ideal site for wind power, but sometimes, mainly in the first half of the year when the SE winds blow, it can be heavily overcast with a strong SE wind, so it makes up for the lack of solar power.

Gordon
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Re: G'day from Loomberah

Postby Lyngarin » Wed Sep 30, 2009 10:38 am

Good Morning Gordon, Thank you for such an informative answer. You have helped me heaps. Both battery banks are lead acid type, primary unsealed so specific gravities can be taken daily. the other sealed so have to rely on voltage readings at 7.00 am and 16.30 PM. I have always tried to maintain above 80 % on my primaries by using the charger / generator if going below. The worst I have recorded is 72% this is by the read out on the Plasmtronic 40 amp reg. From your info I may be able to relax a little on the generator. Fuel cost rises has been the worst differing factor when I decided to use solar power. Another factor would be the replacing of batteries they have increased in price by about 50%. We have wood burning every thing, stove ?oven, lounge room fire, water heating by wood fire. We also have ample timber on site. We use the bread maker to mix the bread ( lauchie brand we find best) then bake it in the oven, which is always ready to go. In the summer we use the combustion stove installed on the verandah, so not to over heat the house. For these reasons we cope fairly well with 12volt system. As you said to change over would be too costly. All our lighting are 12volt 12 watt, compact flourescent globes, they are extreemly efficient using about 0.7amp when running and giving a brilliant white light.. I purchase these from an electrical wholesaler next to Blackwoods in Taminda Tamworth ( GMC or similar) for about $24. Regards Gary
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Re: G'day from Loomberah

Postby Lyngarin » Wed Sep 30, 2009 10:48 am

Gordon, just quickly, did you ever work at the obseratory at Coonabarbran ? My interest in astromony is only staring into the skies on a nice summers evening whic I do everynight, enjoying a small wine or two. The beauty of living a long way from town, I particularly enjoy the very dark moonless nights. Cheers Gary
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Re: G'day from Loomberah

Postby Gordon-Loomberah » Wed Sep 30, 2009 2:46 pm

Hi Gary, yes still working there now, only part time these days, 8 nights observing per lunar month ;)
I have nice dark skies here at home, one of the reasons I chose this area to live ;) There are a few astronomical photos on my web pages, including one showing the whole sky and horizon with a fisheye lens.
Unfortunately, I can also see the glow from Sydney, 300km away! It just goes to show how much energy is being wasted in light pollution.

Gordon
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Re: G'day from Loomberah

Postby Lyngarin » Wed Sep 30, 2009 3:22 pm

Hello Gordon, Interesting, fi you drive to work via W.Creek, Premer and Purlewaugh you by pass our place by 16 Kilometres. Had a squiz at your web site, wish you could drop another few storms over my place in the next few days, like the January one. Also loved the pics. you are obviously a very experienced photographer. Cheers Gary.
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