inexpensive panels
Hi all, I know nothing about this firm--but the prices appear to be low: https://www.santansolar.com/?fbclid=IwAR17Xx_DhkB3h13BFmTjqejxTlf92ZO7UsVEAiNjNmcyNzrOkJx9XgYN26c
Forum Discussion
Thanks all for the MPPT vs PWM explanations...I understand now. These ~37v panels will need the MPPT controller to be properly utilized.
Well...I found myself in Arizona within 10 miles of SanTan Solar so I couldn't resist going over to check them out. I had anticipated purchasing 2 of their 250w solar kits each which come with a 20a MPPT controller. Each kit cost $165. Seemed like a "reasonable" way to add solar onto my 2nd RV. I've already got a 200w WindyNation PWM kit (~$280) that I am putting onto my other RV (I have two) once I get some free time. (I planned on buying an "extra" 250w solar kit because I'm expecting to add a third RV in a couple of months.)
I want to (eventually) run a test to compare the output of the 200w PMW WindyNation system to the 250w MPPT SanTan Solar system. I'll let you know once I do that and post the results here (might not be for a while).
Well, as luck would have it, just the other day they lowered the price on the 250w panels from $50 to $35....they are practically giving them away...lol. So I could have bought their complete 250w solar system for $150 total each. They have a nice showroom and were very helpful. Because the panels were so cheap, I asked them what would be the easiest way to upgrade the system to be able to handle 2 panels (500w). Well, for just $10 more, they had a 30a MPPT controller. Might not be completely large enough to handle all 500w, but for just a few dollars more I could go with 500w of panels. Total cost for each "500w" solar system was just $225. Considerably less than the 200w WindyNation system I recently bought. This system will likely be a total overkill for my needs, but because it was so cheap I couldn't resist. :)
I was able to test each freestanding 250w panel. They were producing at 37V and 9.1amps as measured on a volt/amp meter. Seemed very healthy. They have a VMP of 30.3v and a max current rating of 8.27amps. If I understand correctly, the MPPT controller will covert that down to (for example) 14v with a current of 17.9amps (per panel). (30.3/14.0 x 8.27). Does this sound about right (under an ideal scenario)? Assuming this is correct, then in real life application the 30amp MPPT controller should work okay (during peak sunlight, the panels might be outputting slightly more than 30amps so there would be some inefficiency, but I can live with that because everything was so inexpensive).
The reality is that I probably only need 200-250w of solar power. I have currently just ~200AH battery bank in each of my RVs (could pretty easily expand up to 400AH if I felt the need). I kinda just bought the extra panels because a)They were only $35 each, and b)I was in my RV so I could easily transport them back to NorCal for future use. Not sure yet if I'll put up 250w or 500w. When I do and have some results I'll let you know.
-Chris
Well...I found myself in Arizona within 10 miles of SanTan Solar so I couldn't resist going over to check them out. I had anticipated purchasing 2 of their 250w solar kits each which come with a 20a MPPT controller. Each kit cost $165. Seemed like a "reasonable" way to add solar onto my 2nd RV. I've already got a 200w WindyNation PWM kit (~$280) that I am putting onto my other RV (I have two) once I get some free time. (I planned on buying an "extra" 250w solar kit because I'm expecting to add a third RV in a couple of months.)
I want to (eventually) run a test to compare the output of the 200w PMW WindyNation system to the 250w MPPT SanTan Solar system. I'll let you know once I do that and post the results here (might not be for a while).
Well, as luck would have it, just the other day they lowered the price on the 250w panels from $50 to $35....they are practically giving them away...lol. So I could have bought their complete 250w solar system for $150 total each. They have a nice showroom and were very helpful. Because the panels were so cheap, I asked them what would be the easiest way to upgrade the system to be able to handle 2 panels (500w). Well, for just $10 more, they had a 30a MPPT controller. Might not be completely large enough to handle all 500w, but for just a few dollars more I could go with 500w of panels. Total cost for each "500w" solar system was just $225. Considerably less than the 200w WindyNation system I recently bought. This system will likely be a total overkill for my needs, but because it was so cheap I couldn't resist. :)
I was able to test each freestanding 250w panel. They were producing at 37V and 9.1amps as measured on a volt/amp meter. Seemed very healthy. They have a VMP of 30.3v and a max current rating of 8.27amps. If I understand correctly, the MPPT controller will covert that down to (for example) 14v with a current of 17.9amps (per panel). (30.3/14.0 x 8.27). Does this sound about right (under an ideal scenario)? Assuming this is correct, then in real life application the 30amp MPPT controller should work okay (during peak sunlight, the panels might be outputting slightly more than 30amps so there would be some inefficiency, but I can live with that because everything was so inexpensive).
The reality is that I probably only need 200-250w of solar power. I have currently just ~200AH battery bank in each of my RVs (could pretty easily expand up to 400AH if I felt the need). I kinda just bought the extra panels because a)They were only $35 each, and b)I was in my RV so I could easily transport them back to NorCal for future use. Not sure yet if I'll put up 250w or 500w. When I do and have some results I'll let you know.
-Chris
