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Michael Qulek wrote:Rather than focusing attention on crimping right now, I'd recommend you focus more attention on overall system design, and worry about crimping later.
The grinder or sander will be your biggest loads, and I focus on supplying those first. Other stuff is trivial compared to the draws those two will need. If you focus your attention on those, the rest will be easy.
A good rule of thumb I follow is to have about 2X your largest load as for how many solar Watts you need. So with a 800W load, maybe 1600W of solar panels. The good news is that high-voltage residential panels are getting dirt-cheap right now, and you can find 30V/250W panels for 40-50$ right now. So, six of those would be close to perfect in terms of meeting your wattage needs. That's about 300$ right now in the cash and carry market. Don't order panels online! You will pay outrageous shipping fees. Shop locally on Craigslist, with cash and carry purchases.
The amperage to handle 1600W is a bit too high for a basic 12V system, so I'd recommend going with at least 24V. That's what I have in my workshop right now. In terms of a budget charge controller, take a look at Epver's new XTRA Series MPPT Solar Charge Controller. 40A of current at up to 150V, for only 120$. 40A would be good for more than 1000W of panels. In general, it's OK to exceed the recommended amps of a unit. Under no circumstances though should you ever exceed the voltage. Remember though that the voltage of panels goes up as the temperature goes down. A good safety margin is ~20-25%. So, for a 150V controller, never surpass ~120Voc. That should be good for three 30V panels in series. Their Voc at freezing is going to be ~40Voc.
I have a clamp meter with "inrush current" capability. What I've found is that the brief starting surge for motors that start under load is ~4X. So, for that grinder or sander that needs 800W to run, expect them to need up to 3200W for less than 1 second to start. So, I'd suggest shopping for at least a 3000W 24V inverter. Get Sine-Wave for anything that will be running an electric motor. Cheaper modified sine-wave models are well-known for burning out electric motors in short order.
Lastly, you'll need batteries. You might want to take a look at CostCo's 210Ah 6V golf-cart battery. At 110$ right now, you'd need four of them in series to make a 24V battery bank. That would be 440$ plus tax and core charges. Assuming you don't drain these lead-acid batteries more than 50%, you'd have 2.5kWh of available power.
If you built a rotating array frame like I have, you could reduce your panels needed to down to 1000W. My frame easily holds four large residential panels in portrait, but can hold as many as six oriented in landscape. I just sunk a 3.5" schedule 40 pipe in concrete, and slipped a 4" schedule 40 pipe on top of it. The array frame is welded to the top of the 4" pipe. This will allow you to rotate (by hand) East in the morning, South around noon, and West in the afternoon. That will basically double the number of watthours you can make in a day.
BTW, I've made excellent terminals for my solar wire with cut lengths of copper tubing. For my 000 battery wire, I belled 1/2" copper tubing, slid the wire halfway inside, then flattened the other end. Once flattened, I soldered the wire to the tubing. I then drilled 5/16" inch holes in the flattened ends to accommodate that stainless steel mounting bolts I used to attach the batteries to the inverter.
Jr Hill wrote:
I am new here and this is about the first time I've been able to comment on something worth writing. You can McGivor whatever but if you aren't available SOMEONE has to follow up behind you. Don't put this on other people. Build, as best you can, something that is manageable, by those behind you. If you love them you won't saddle them with a complex system that no one can operate in your absence.