I noticed these Renogy panels are on sale:
Was thinking about getting 4 (2 parallel sets) to input into the AC300. Anyone have experience with these? Right now we have ground mounted basic panels that only take in about 1200W (should be bringing in closer to 1600W, but they’ve been having issues lately). I’ve never used bifacial panels, but they sound pretty neat, and like they’d be more efficient.
Thanks!
What data do the panels have (volts, amps)?
Open Circuit Voltage: 49.95V
Short Circuit Current: 14.05A
Optimum Operating Voltage: 41.97V
Optimum Operating Current: 13.11A
Maximum System Voltage: 1500VDC
Maximum Series Fuse Rating: 30A
Module Efficiency: 21.3%
We’re planning to do 2 parallel sets of 2 panels each, so well below the ac300 VOC limit.
It works well but it is not optimal.
You should get as close to 150V as possible in series.
The specified power of the panels is only a theoretical value.
The voltage is always available.
The current can be higher than 12A per input.
Then you have reserves if the sun does not shine
enough.
I would get 3 of these Renogy 550W panels and connect them in series to give you just under 150V. That should be enough to stay under the voltage limit and still produce slightly more current during the sunniest conditions that you AC300 can use.
They come in pairs so I had to buy 2 pairs to get three of them wired in series, and the 4th one is plugged directly into one of my B300s batteries.
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Here’s a catch. They can gather sunlight from either side, but they need to be mounted where both sides can get light. If mounted against a surface, say on a rooftop, you won’t get as much power output. I came up with making a giant seesaw using a scaffold from Home Depot. I started with an aluminum pole across the top of the scaffold, then attached 2 10’ superstrut bars to the pole using U clamps. From there I mounted 2 panels end to end. So the panels seesaw east to west and back. I did the same with the other two panels on another scaffold, so everyday I rotate them from facing east to west (then back to east for the next morning. I hit up to +1400 Watts with 3 of them in series; They start producing about 80W as early as 7am, then 1300-1400W during the day, then about 80W as late as 7pm. Sometimes I’ll follow the sun morning, noon, and evening if the batteries are not charging fast enough.
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The one left over panel gives me mostly 460W to one of my batteries (it also is part of the seesaw).
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With this arrangement, the panels are facing flat towards the sunrise and sunset, and at noon if I aim them up, The pivot point is some 6’ off the ground so they are catching light reflected from the concrete below. As you can imagine, they stick up pretty high and every now and then I hear a distant voice, “What the heck is that?” when I’m rotating them. 
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I should add that I made “outriggers” for the scaffolds because the are top heavy and on wheels. I attached 16’ 2x4s at the bottom just above the wheels, then used cinderblocks on each end of the 2x4s. We get high winds here all the time and the scaffolds are stable. I do have to strap down the panels from seesawing when I don’t want them to.
The additional profit from the back pages is insignificant and just marketing.
I’ve heard that you have to be careful with the voltage spiking in extreme temps though - our current panels are VOC 44.6V, and 3 of them threw a voltage error last winter, presumably because we got really cold temps.
bummer, i was hoping for some extra boost.
That sounds like a really cool panel setup - got any pics to share? Not sure I’m visualizing it right. Are you able to move them yourselves? cuz the panels are quite big right?
btw, I’m curious why you don’t run the 4th panel in parallel, since the AC300 can take two inputs, 150V each? Is there a reason why you preferred to run it straight into a B300 instead of the parallel setup?