So far I have connected four panels in series which has produced 130 volts. My charge controller can only take 115 volts though and I didn’t realize that when I wired them four in series. Soon I will switch to two strings of two in series for 60 volts and see how much more power I get. As a nod to “Pure Living for Life” I bought a toaster yesterday and I actually made toast FOUR times today! That proves that you can make toast on solar power.
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Its worse than that woody. When you calculate strings use the open circuit voltage rating and the controller makers suggest you multiply that by 1.25 to give you your safe working string voltage for the controller. You should be fine with strings of 2. What voltage is your bank at? I remember having a good inverter for the first time. having the pump go off while the toaster was working and nothing shutting down… Freedom… 
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David thank you for your comments. If quality control tests each panel and derates the weaker ones, then that makes sense to me. I have the official spec sheet and they are grouped in a chart with 230, 235, 240, and 245 watt panels. They all have the exact same construction. I don’t see a concern there. The difference between 245 and 230 is 6%.
These are polycrystalline panels. I figured that the 60 cell monocrystalline panels would be rated at 300 watts max and that since these are poly panels that they are less efficient. That is industry standard, and again, that is not an issue for me. Maybe these particular panels were shipped and stored for several years before being offered on the market at a discount. They are in their original crates and so again that is not a concern for me. They charge my batteries and they are unused and that’s good enough for me. If Trina Solar honors the warranty in 16 years for two or three underperforming panels that would be great. I am happy either way.
My controller is rated at 145 volts max, 115 volts for the MPPT, so I thought I would be good to shoot for 120 volts. I got 650 watts or so at 120 to 130 volts with four panels in series. With strings of two at 60 volts, how much closer to 940 volts will I get? My controller is a 60 amp unit, so I cannot expect more than 720 watts.
I mean, the controller charges at 14.2 volts, times 60 amps is 852 watts. I am happy with 650 watts anyway.
What controller is it? Usually you can overdrive with excess watts as long as the voltage stays low. That’s on the magnum/outback/midnite Charge controllers. The big difference in panels is what they are calling PERC panels which is an extra coating on the back and is giving us another 15 percent from the same sized polycrystalline panel. I’m sure the panels will be fine. Im just naturally nit picky… I should go to bed!
Cheers, David
My controller is a Taiwanese Maximum Solar branded MPP controller. 60 amp rated and cost less than half of the big name brands. I like it.
Thank you for making my ignorance smaller, David.
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If it works that’s all that matters.
Cheers
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For my own use, I’ll be going ground mount for sure. Space is not an issue. Ideal placement will be way easier and I can get solar going long before the big house is built.
I’m getting 3 crates of these panels, 17.5 KW which is more capacity than I really need or can match with batteries. But it will be good for those overcast winter days, as well as plenty of capacity for direct use, ie A/C in hot sunny weather.
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Chris that is about the same size system I am planning for the farm. I am targeting 15kW. That should allow me to run a geothermal heating and cooling system here. I am still doing research on the geothermal.
Hey, some of the panels are in Louisville! I won’t have to go too far to look at them.
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Hi Chris and Dan,
If you want to run AC off of solar, talk to Randy at hotspotenergy.com 757-410-8640 #3. He has been real nice to me and I’m using one of his heat exchangers on one of our AC units to help lower our electric bill while heating the pool. I wanted to buy one of his mini-split AC units that run on pure DC, but they’re only sized for 12k btu mono and I need a 18k double. He has other units for A/C-D/C combo to run without batteries. He also has multiple other options to help you make hot water, titanium heat exchangers (I’m using), and hot water storage/recovery. Probably something he does that you could use.
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The jury rigged solution Chris is using a charge controller relay to activate an ac relay to activate the off the shelf air conditioner run through a beefy inverter system. The problem with all the dc direct ac is its all low volume new stuff and expensive. Same with the heat pump dc gear. It might drop before you build who knows. With that much solar capacity you could afford some losses. We are having to come up with all sorts of new dump methods due to crashing panel prices. It’s a good problem to have! I’ll certainly check out the links above.
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Jason thanks for the link I will definitely be looking into that. I am still digging into what the options are on the heating side.
I have plenty of solar and battery capacity so I let my air conditioner chooch all day and night long. The fan only uses 65 watts so I just leave it on. Simpler that way. If you really wanted to kill the fan when the compressor is off, then why not just use a separate thermostat to cut power off and on to the unit directly? Why the relays operating off the charge controller? Why not just manually shut the unit off like I do usually when you leave for the day?
I have 3.5 inches of polyisocyanurate foam insulation in my travel trailer walls and roof and it stays 20 degrees cooler all day in the shade. I think if you use smart modern insulation methods like radiation, air, AND thermal barriers, that you will have equally good success running air conditioning on solar. Shine, baby, shine.
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did anyone ever look at those panels or buy any? Find out anything?
Yes I bought one crate. I connected four panels to my travel trailer. They put out some good power: the most I have seen is 780 watts between the four. I have a system with a 60 amp charge controller, a 1000 watt inverter and a 900 amp hour 12 volt battery. It powers my air conditioner 24 hours if I want, my mini fridge 24 hours 7 days, and my 750 watt toaster. It makes about 4200 watts on a sunny day and I use around 3000 watts per day. Less when it’s cloudy. I leave my air on all day when it’s sunny because duh. Use it or lose it. I left the air on all weekend when I was gone to Argos IN and I came home to a fully charged battery. No worries.
My tiny house had a metal roof on an OSB deck that was new in 2015. I decided to lift the metal roof up onto 1.5 inches of strapping and install a modified bitumen membrane on the deck and a radiation barrier on the membrane. I will seal the attic and instead vent above the deck and under the metal. Then I will mount 18 panels on the metal. Most of my panels are leaning against the wall waiting to be installed.
I had occasion to roll my truck down a hill into my house and jar it enough to knock the stack of panels over. One got the corner of the next one pressed into it’s glass and shattered the glass. It still produces 32 volts of power though. Pretty tough stuff.
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I was looking into fixing broken glass on panels a while back I thought i had a supply of then for free but that didn’t work out. Anyway from the research I was able to do I think this would be the best product to use
It is actually used to seal the cells by some solar manufactures. You want to get that panel sealed up before too much moisture gets in there or it will destroy the panel.
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