I need a small solar/battery system to run a load 24/7. The load will draw about 26 AH/day @ 12V. I need at least 3 days of battery back up, 6-7 would be better. The site does get shade after about noon or 1pm but has decent morning sun. There might be some intermittent shading in the morning. I do not need an inverter. Lowest winter temp is around 0 F, highest summer temp is around 95 F. Normal winter lows are 20's and 30's, normal summer highs are 70's and 80's. We can get snow but it will usually melt off in 2-3 days, and except for when there is snow present I have access to the site. The site is at Lat 35 near Asheville NC.
My thoughts:
3 100 W panels in parallel in case one or two panels are in shade.
Victron 100/20 MPPT charge controller - supposed to have excellent response for quickly changing shade/sun conditions + has bluetooth app.
2 100-110 AH AGM deep cycle SLA batteries (should give 6+ days of back up)
Questions:
1) would a single 300+ watt panel be better than 3 separate panels, considering the possible shade?
2) would the panels in series or parallel be better considering the possible shade.
3) is there a solar panel manufacturer that would be better - the sweet spot in the solar industry is > 300 Watt panels so harder to find the lower wattage panels.
4) might it be better to use 4 80 W panels in 2S2P configuration?
5) What batteries are good for this? I was going to use Universal Power Group UB121000 or UB121100. I don't want to use LiFePo - too costly.
6) where do I need circuit breakers and what size? I'd think 20 A between the PV and CC, 20A between CC and batteries and 2-3 A between the CC to the load.
7) Lightning protection and where does it go?
8) do I need a combiner box for the panels?
9) 12v or 24V system - the load can take 12-28VDC
10) is there an issue with equalization of the batteries, since the load is small compared to the available AH's? The Midnite Classic Controllers have an option to charge batteries every other or 3rd day.
11) what am I missing?
Thanks.
My thoughts:
3 100 W panels in parallel in case one or two panels are in shade.
Victron 100/20 MPPT charge controller - supposed to have excellent response for quickly changing shade/sun conditions + has bluetooth app.
2 100-110 AH AGM deep cycle SLA batteries (should give 6+ days of back up)
Questions:
1) would a single 300+ watt panel be better than 3 separate panels, considering the possible shade?
2) would the panels in series or parallel be better considering the possible shade.
3) is there a solar panel manufacturer that would be better - the sweet spot in the solar industry is > 300 Watt panels so harder to find the lower wattage panels.
4) might it be better to use 4 80 W panels in 2S2P configuration?
5) What batteries are good for this? I was going to use Universal Power Group UB121000 or UB121100. I don't want to use LiFePo - too costly.
6) where do I need circuit breakers and what size? I'd think 20 A between the PV and CC, 20A between CC and batteries and 2-3 A between the CC to the load.
7) Lightning protection and where does it go?
8) do I need a combiner box for the panels?
9) 12v or 24V system - the load can take 12-28VDC
10) is there an issue with equalization of the batteries, since the load is small compared to the available AH's? The Midnite Classic Controllers have an option to charge batteries every other or 3rd day.
11) what am I missing?
Thanks.
Comment