Off-Grid Solar Project
Harbor Freight – Part# 90599
Maximum current, 3000 mA.
15 watts max per panel.
Peak voltage: 23.57 volts open current.
Panel dimensions: 12.40'' x 36.42'' x 0.75''; Weight: 9.7 lbs.
Kit includes a
• regulator with battery connections for charging and maintaining a battery(1+)
• regulator has 3, 6, 9, 12 VDC outputs
I am building an Off-Grid remote site. After considering the cost of commercial utilities for power, water, I decided the same, and even lesser cost, of going off-grid would be a wiser investment (and GREENER ). I need to design and build from the top down, as it were.
I am finding the average cost for the panels them selves seem to be in the range of $6+/watt. I also found that the panels had a lifespan (? ? ?) of maybe 20 years (is that correct???)
Then I stumbled on this 45watt kit from Harbor Freight –
Retail sale price is $250. It occasionally goes on sale for under $200. I am considering negotiating with them to get a bulk discount – maybe go straight to the manufacturer. I just want the panels. . . If I can get them for say $50/each or $150/kit (or LESS…), then a ‘24VDC’ array, with about 2200Watts would equal 100 12volt kits???. . . (about $3-$4/Watt. . .)
I figure the panels can be connected in series/parallel to produce whatever array configuration I desire. I am reasoning that the higher the voltage (48-56 VDC vs. 12-14VDC) will be more efficient to ‘Invert’ to 110/220VAC. Any specific advice would be greatly appreciated on this initial theory . . . .
My power needs would be:
• Computer/network power – 7X24
• Refrigeration – a residential refer and chest deepfreeze – (on demand with high IPP – compressors. . . cant get around it. . .)
• LP gas water heater – electronic ignition (pilot less)
• High efficiency front-load washer/LP gas dryer – electronic ignition (pilot less)
• Lighting – Florescent, LED.
• LP gas range - electronic ignition (pilot less)
• Microwave oven
• Cistern Water storage – electric paddle to circulate water in a 1500 gallon storage tank (something about keeping it from stagnating)
• Air compressor – for shop tools
I would also have a 5500Watt gas/diesel GenSet. Wood/coal/pellet/junk mail stove for primary heat.
So what I need to confirm is:
• Wire size – AWG to run to the panels – 8AWG?. . . 6AWG? To run from the PV array back to the Charge Controller – 100’ for discussion.
• Wire type – Copper? Aluminum? Each has a calculable voltage drop/loss back to the Charge Controller (MPPT) – overhead/ buriable NEC spec.
• Charge Controller – MPPT vs. PWM – MPPT makes more sense – they seem to be available in specific input/output configurations. . . (12, 24, 48VDC)
• Battery configuration – that I think I have – 12, 24, 48 – each manufacturer has specifications on the float voltage. I figure I can use Deep Cycle batteries from Wal-Mart (12V 115 ampere hour) – cost around $60/ea. May be able to negotiate that down for a bulk order. . .
• Inverter – I am hoping to find something that has a 220VAC output that would match what commercially connects to the residential main panel – 2 110’s 180* out of phase, with a neutral return. Would like something which only draws from the DC side when there is an AC demand – doesn’t idle?. . . If 110 is more cost efficient, I can simply bridge the breaker panel.
What am I forgetting. . .?. . .
Any and all comments, suggestions, recommendation are greatly appreciated.
Thank you.
