the new guy Posted March 12, 2011 Report Share Posted March 12, 2011 I have been thinking about setting up a 180w solar panel on our roof to charge a battery bank so it can power our fishtanks that only requires about 120w of power. i am also trying to think of some other alternative so i can curb the monthly power bill! It would also help a lot if we had a power outage so it could keep running. there is a auto transfer switch i have been looking at too just in case. yes i know it has an initial setup cost but its clean and its green! it could also help power things like cellphones and laptops. im still looking at a few different solar and wind options(because there seems to be quite abit of wind out here. anyway i would love peoples opinions on yet another one of my project ideas! lol Quote Link to comment Share on other sites More sharing options...
Stephanie Posted March 12, 2011 Report Share Posted March 12, 2011 Solar power is like my dream! Sure the setup costs are huge but once it's paid for it's all good. I've been reading a lot about it in lifestyle and farming magazines lately. I need to buy a house, until then i'll keep dreaming. :roll: Quote Link to comment Share on other sites More sharing options...
kiwiplymouth Posted March 12, 2011 Report Share Posted March 12, 2011 This is my back up for the fishroom Quote Link to comment Share on other sites More sharing options...
the new guy Posted March 12, 2011 Author Report Share Posted March 12, 2011 i have been looking at generators but they cost fuel lol. but as i found out in a disaster a couple of weeks ago fuel is hard to come by..... and if you store it it does go off over time. :tears: Quote Link to comment Share on other sites More sharing options...
spoon Posted March 12, 2011 Report Share Posted March 12, 2011 solar panels are a huge cost i wouldnt bother with them unless your wanting to go massive and try and run your whole house with them it would likely take decades before you recovered your power costs anyway i think your time and money is better spent trying to make what you already have more effiecent eg more effiecent pumps , perhaps led lights, insulation on tanks etc Quote Link to comment Share on other sites More sharing options...
the new guy Posted March 12, 2011 Author Report Share Posted March 12, 2011 yup thats another option. i have decided on a set of LED lights from the website you gave me they only take 9.8W of power! the biggest drinker is the heater which is 100W. Quote Link to comment Share on other sites More sharing options...
spoon Posted March 12, 2011 Report Share Posted March 12, 2011 have a think about the heater though its on a thermostat so its only going to be on sometimes the better you insulate the tank or heat the room the tank is in the less it needs to be on so less power it uses Quote Link to comment Share on other sites More sharing options...
Warren Posted March 20, 2011 Report Share Posted March 20, 2011 I have been thinking about setting up a 180w solar panel on our roof to charge a battery bank so it can power our fishtanks that only requires about 120w of power. i am also trying to think of some other alternative so i can curb the monthly power bill! It would also help a lot if we had a power outage so it could keep running. there is a auto transfer switch i have been looking at too just in case. yes i know it has an initial setup cost but its clean and its green! it could also help power things like cellphones and laptops. im still looking at a few different solar and wind options(because there seems to be quite abit of wind out here. anyway i would love peoples opinions on yet another one of my project ideas! lol If your tank uses 120W of power you will need approx 1800W of solar panels to 100% supply the tank with power. This is because it's only light for half the day maximum. Also, in the morning and evening the sun is at an angle to the panels so efficiency is very low (less than 10%). As the sun moves throughout the day the efficiency improves to a maximum when it's perpendicular to the panel. The panel's rating of 120W is only for midday sun at the equator. Since we are a long way from the equator and the sunlight must pass through more atmosphere it loses some of its energy. In winter it can be quite cloudy, reducing the efficiency down to only 10%. Then you will need a battery that can store 120W of energy for about 18 hours (120J/s * 60 seconds * 60 Minutes *18 hours = 7.776M Joules) which at 80% charge / discharge efficiency works out to about a 180AH battery (for 100% discharge). Since only 50% max cyclic discharge is recommended to make the battery last a long time you will actually need 360AH. Then you will need an inverter to convert the 12VDC into 230VAC. Costs: Solar panels - 1800W @ $7.00/W = $12,600.00 Batteries - 4 x 100AH @ $400ec = $1,600.00 Inverter - 300W Sinewave = $700.00 This setup will take approximately 20 years to pay back compared to just buying power (assuming no maintenance will be required). Since the batteries need to be changed every 7-8 years and the inverter at least once the payback time can extend to well beyond 30 years... In other words, solar power is still just too expensive unless you are setting up a really big solar farm occupying several square km's. Wind power can be a good alternative but only if you can make the windmill yourself and only if you get a grid connected inverter so you can push extra power back into the grid. This also only works if you have an old style meter that will run backwards if you are generating. Most modern digital meters won't count down on negative power flow. Your power supplier will also have to allow you to generate as not many do yet in NZ. We are way backwards with our thinking - NZ is supposed to be a 'green' country but we're not very green in our attitude to home power generation yet. Even Australia is way ahead of use there and we certainly can't have that... Quote Link to comment Share on other sites More sharing options...
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