I have a 12'x12' greenhouse. Its roof is the "hip style barn" type. The sides are 6mil plastic with fiberglass insulation (R13) sandwiched with another layer of 6mil plastic. The roof is only covered with one layer of 6mil plastic. So far for energy I have one (1) 45W solar panel kit from Coastal Freight which also included the charge controller and I purchased a 400W/800W inverter. (not much, I know). As far as storage I have 5 12v sealed lead acid batteries (they are quite small), 2 12v garden tractor batteries, and 1 12v deep cycle marine battery. I am working on a wind turbine to "add" to my energy needs. Any help would be considered and appreciated.

 

Your batteries would last far longer if they were all the same type. Different battery types have different charge/discharge curves and different internal resistances. I strongly suggest investing in some deep cycle marine batteries.

Do you know how many Watts you will use and for how much time you will use them? Knowing this makes it possible to determine the size of system you require.

 

Thanks thingmaker3. Right now, I will be running a 4' grow light w/ "ultra bright" tubes (2), sometimes all thru the night approx 12hrs for one month, then every other night for 2 months. During Spring to Fall I will be running a 13" oscillating fan and 2 smaller fans that use 6V DC each. Also have converted a bathroom exhaust fan to vent air out. Then, of course, in winter, I want to be able to heat it, but I think with the wattage needed, I should go with a external wood stove, plus have finally built a working solar heater for water heaters, which I could run tubing (PVC pipe) in a grid inside. I would run prop. glycol in the coils and tubing)

 

You amy add any battery that you have in series the problem with that is the power cannot output be greater then the smallest installed . you may add all the batteries that you have in parallel. The problem with that is power sharing Adding diodes in series or a very small resistor will alleviate the problem. Having said that have considered a light source like LED and venting air out I don't think it is neccessary just small holes here and there. solar for heating and charging batteries 45 watts is never going to do it. You will need a very big solar panel. Sodium or very salty water will retain the heat more then just plain water. drawback corrosion on metals.. the wood stove will work but then again stoking at interval becomes a problems don't you think?.

 

Thanks thingmaker3. Right now, I will be running a 4' grow light w/ "ultra bright" tubes (2)

Do you know how many Watts those are rated for?

I will be running a 13" oscillating fan and 2 smaller fans

Do you know how many Watts those are rated for?

Then, of course, in winter, I want to be able to heat it, but I think with the wattage needed, I should go with a external wood stove

Not electronics related, but have you considered a rocket stove and a thermal mass heater?