GWguy
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Things are starting to coalesce. I received my solar charger. Looks like it will do the job, but for a few minutes wasn't sure if I had undersized it. I got a 30 amp unit, thinking I wouldn't exceed that with 2 panels. That is, until I found some panels that could very easily overpower the unit.
After a lot of reading and YouTube videos, I've written off the flexible panels. The two major issues are real estate and failure rate. It takes much more square footage to equal the output of a hard panel, and and very very easy to break or develop hot spots making them useless. Warranty is typically less than half the life of a hard panel. Price is also much higher per watt. These fill a need for some and have a place, just not in my system. I found a panel that I think fits my needs. Renogy makes a 270 watt @ 24VDC poly panel for about $1 a watt. I could do better cost-wise, down to 70 cents a watt for 100 watt panels, but I'd have to get more panels to make up the difference and occupy more space. Since space is at a premium, I'm willing to spend a little more to get a lot more. They also make a 300 watt mono panel, but the poly has a higher open circuit voltage with less sun.
So, I'm going to get one 270 watt panel and test it out. (2) 270 watt panels at 24 volts is 22.5 Amps / 540 watts when wired in parallel. This is where wire sizing comes in. If you think of your home wiring, if you have a 20 amp circuit, you wire with 12 gauge wire. I'm exceeding that already. 10 gauge at a minimum, and if you wire any distance, an even heavy wire is needed to prevent loss and overheating. I could wire the panels in series, which doubles the voltage (48VDC) but halves the amps (11.25A). Smaller wire size could be used, but you run into an issue: If one panel goes into the shade or fails, the entire PV array stops working. A parallel system will continue to produce power for whatever panel is still working. In reality, I happen to have a significant length of 4-wire 12-gauge stranded rubber jacketed wire. I can use one pair of wires in the bundle for each panel (11.25A) and then combine them at the solar charger unit with a very short piece of 8 gauge. Well within wire loads using lighter wire.
Battery storage is still an unknown.
As far as the fridge goes...... ok, maybe I was being overly ambitious to get a solar fridge. Still on my radar, but not for the initial prototype. I'm going to go with the nested cooler setup. I have a few of the cheap styrofoam containers from Omaha Steaks. Going to get a larger cooler to fit two of these. When I ordered knishes from NY, it came in an insulated bag which just happens to fit perfectly inside the styrofoam cooler. Filling 1/2 gallon milk containers with water and freezing them. Perfect size for the coolers and no melted ice water everywhere. This should be good to keep stuff cold a long while.
After a lot of reading and YouTube videos, I've written off the flexible panels. The two major issues are real estate and failure rate. It takes much more square footage to equal the output of a hard panel, and and very very easy to break or develop hot spots making them useless. Warranty is typically less than half the life of a hard panel. Price is also much higher per watt. These fill a need for some and have a place, just not in my system. I found a panel that I think fits my needs. Renogy makes a 270 watt @ 24VDC poly panel for about $1 a watt. I could do better cost-wise, down to 70 cents a watt for 100 watt panels, but I'd have to get more panels to make up the difference and occupy more space. Since space is at a premium, I'm willing to spend a little more to get a lot more. They also make a 300 watt mono panel, but the poly has a higher open circuit voltage with less sun.
So, I'm going to get one 270 watt panel and test it out. (2) 270 watt panels at 24 volts is 22.5 Amps / 540 watts when wired in parallel. This is where wire sizing comes in. If you think of your home wiring, if you have a 20 amp circuit, you wire with 12 gauge wire. I'm exceeding that already. 10 gauge at a minimum, and if you wire any distance, an even heavy wire is needed to prevent loss and overheating. I could wire the panels in series, which doubles the voltage (48VDC) but halves the amps (11.25A). Smaller wire size could be used, but you run into an issue: If one panel goes into the shade or fails, the entire PV array stops working. A parallel system will continue to produce power for whatever panel is still working. In reality, I happen to have a significant length of 4-wire 12-gauge stranded rubber jacketed wire. I can use one pair of wires in the bundle for each panel (11.25A) and then combine them at the solar charger unit with a very short piece of 8 gauge. Well within wire loads using lighter wire.
Battery storage is still an unknown.
As far as the fridge goes...... ok, maybe I was being overly ambitious to get a solar fridge. Still on my radar, but not for the initial prototype. I'm going to go with the nested cooler setup. I have a few of the cheap styrofoam containers from Omaha Steaks. Going to get a larger cooler to fit two of these. When I ordered knishes from NY, it came in an insulated bag which just happens to fit perfectly inside the styrofoam cooler. Filling 1/2 gallon milk containers with water and freezing them. Perfect size for the coolers and no melted ice water everywhere. This should be good to keep stuff cold a long while.
