Current Cost Support Forum

The fan I am insterested in requires a 20 watt solar panel. The fan runs directly off this panel and as the sun increases the fan increases speed. It would be hooked up to a thermostat so that it wouldn't start running untill the greenhouse is a certain temperature. The fan is .7 amps when 12vdc is used.

A light would be like 130 watts 2.1 amps 12vdc
This is just a normal light, so I can work in the evening. It is not for the plants. I am sure I can find suitable lighting elsewhere because the greenhouse place only offers this light.

I would like the battery to store power for the lights and maybe something else like a small fan.

I understand that the solar panels are NOT cheap however I just think that buying them from a company that specializes in solar products, rather than greenhouse products, would be smarter. Then I can buy the fan and other special stuff from the greenhouse place. I really only want a simple setup and right now my main concern is ventilation so starting with the simple battery-less system is fine with me. I can always upgrade later. Ventilation is a necessity as other things, like lighting, are not right now.

I have always wanted a greenhouse however I don't want to use more power for it. I am trying to build a greenhouse so I can get rid of some of my light stands and save energy.
I think that also building the greenhouse with a smaller projection from the house would also save money (less air space to heat by the sun)
I haven't fully determined what to do for winter heating yet though. We use a pellot stove mainly and will be buying a second one this summer hopefully. Our current one doesn't have a battery backup. I think the heating situation really depends on how much it does actually cost to heat. The "greenhouse heating cost" calculators don't predict it will cost too much to heat but I really don't believe them that much.

Google is your friend!

I mean that seriosly. It depends on what part of the world you are located in as to what companies there are in your area/country to supply you with what you need.

There are often solar cells and panels of varying sizes and ratings to be found on the likes of eBay etc.

I bought a "shed light" from my local Bunnings store (hardware chain store) for $12.50. It has a 15cm square Solar Cell, 3 AA rechargeable batteries and a 10 led light. Ih has a tiny "battery charging" circuit which I suspect just shuts off the solar cells when there is not enough ligth. Runs for about 4 hours on an 8 hour charge. Enough light to work but not enough for my old eyes to read with.
Not sure what I will do with it, either replace the batteries on my weather station or build an insolation meter.
Point is I could hardly buy 3 rechargeable batteries for $12.50! The solar cell is free.

On your fan, remember it will need extra boost to cover the start up current. If you don't already have the circuit for that google "DIY solar air conditioning" you will find a bit of experience there in running fans from solar cells. The most popular fan seems to be a car 12v radiator fan. Pick one up cheap from a wreckers yard.

_________________
Seeker
"The Truth is out there!"