Looks like you have some Sun-50s there (they all look a like), I have seen those as cheap as $100 each. What kind of charge controller do you have? only a MPPT type will harvest near all the juice that panel will give out, the 50 watts is based on 19 volts so a 12 volt charge controller will only be able to take 35 watts of it until 13.5 volts or full battery charge.johnElarue said:Ok here goes,
Got the 3- 50watt panels installed on the roof. Just waiting on the battery. Then will wire'm up and start making power. I like to think of them as my " solid state generator" , no moving parts. No fuel needed.
Firstly they'll be used for outdoor lighting, then will run some wires into the house. This setup should hopefully provide enough power to light the house in an emergency.
We have "candlenight" once a month for fun, soon we'll add "solarnight"(s)? I'll probably spring for the warm yellow LED's, maybe 5 for the house.
They're 50 watt Chinese, (yeah I know, I know) seem to be of good quality. 2$/watt , but with shipping 4$/watt.xpc said:Looks like you have some Sun-50s there (they all look a like), I have seen those as cheap as $100 each. What kind of charge controller do you have? only a MPPT type will harvest near all the juice that panel will give out, the 50 watts is based on 19 volts so a 12 volt charge controller will only be able to take 35 watts of it until 13.5 volts or full battery charge.
Actually funny to hear that, didn't plan on harvesting 100% of course, only 50%. Worse yet, we only get 5hrs of sun, when it is shining!xpcl said:Having your system de-rated from 150 watts to 100 watts without ever turning it on sucks, but every PV cell made will be the same and on average be de-rated by 30%. even those new 315 watt cells will most likely only make 220 watts by the time all the efficiencies are accounted for. Remember they rate these things in a laboratory under ideal conditions that will never be seen outside..
I had it calculated at 375watts/day based on 50% of optimum performance in full sun, so again glad to hear I'm on track.xpc said:A 12 volt battery with a 100 amp@20 hour rating would give you 60 watts total per hour, to keep the DOD (depth of discharge) at 25% or less only use that amount for 5 hours or 300 watts max. You can draw down twice as much with a total of 600 watts but will cut the battery life in half. I always use an insolation of 4 hours so your array will on average produce 400 watts a day based on 12 months year around usage..
I'd rather not go with the expense of DC fixtures, things like that here are very expensive. I also made a 30 watt wind turbine that wouldn't charge a battery, it lasted maybe 3 months.xpc said:Using 12 volt light bulbs would be best, as the cheap car inverters can have an efficiency of only 80%, costing you 2 watts for every 10 watts used. They also tend to have an automatic cutoff set too high and will not allow the full use of the battery. My experiments with a 30 watt pv cell, 15 amp charge controller, 700 watt inverter and a marine battery worked ok for a while but never got the battery up to full charge and it died beyond recharging inside of 6 months...
I originally thought using 13watt CFL's, but then figured the new 3watt LED's would be no problem with the 100watt inverter, inefficiencies and all considered. Being able to run those about 10hrs \day if necc.xpc said:As emergency lighting you should be able to run four 13 watt CFL bulbs for 5 hours on an inverter, so it should do as you plan if you don't count cloudy days.