Here's a tip on buying solar panels

Check your local Craigslist. People are selling brand new panels out of their garage, half the price of a store. I’m guessing they were surplus from those rooftop solar companies. But DO NOT BUY USED PANELS. They are not worth it as all panels degrade over time. You don’t want them unless they are free, and even then the owners probably just want someone to take their junk off their hands.

Several years ago I built a small off grid system just to see if I could do. Still works great, except lead acid batteries were the only way to go back then. I picked up some HUGE rooftop panels for a few hundred dollars, all brand new. I had to buy a roof rack for my BMW to carry them home, and they were almost as long and wide as my car. Should have seen the looks I got at stoplights. “Mommy, is that a solar powered BMW?”

Bring a voltmeter with you if you find one of these sellers. Google how to check them, to see if the voltage matches the placard on the back of the panels. Learn how to safely check them, as the large panels will shock you if you’re not careful. You, of course, half to measure them in sunlight, but you might want to throw a blanket over them to make the volt/current connections, THEN remove the blanket.

You should add to confirm that the panel cables end in MC4 connectors as all Bluetti stations use this type. Else buy kits with pairs of male and female MC4 connector pins and bodies, and a good crimping tool.

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@Raymondjram Agreed. I purchased a bulk box from BougeRV and it has come in handy ALOT! Also I have found that some panels’ MC4 connectors vary from brand to brand, and my “disconnect” tool doesnt always work with them? Strange, I know… So by putting the bougerv ones on all them, I dont have to worry about the disconnect tool not working to get them apart.

All the regular glass panels I’ve seen come with MC4. Only the folding panels seem to have oddball connectors.
I wouldn’t waste my money on those folding panels when the rigid glass is much cheaper and more efficient. Of course, I don’t plan on going mobile with the ac500.
I am disappointed how panel prices have increased. I paid $.50 a watt for mine 4 years ago. Now they are over $1/watt. You would think competition would have driven prices down over the years. I’ve got 2-600 watt arrays in the back yard, and I can rotate them to catch the morning sun, then swing them westwards in the afternoon. I forget what extra % power you can get from this, as rated by some gov’t agency, but I’m ready for a major blackout.

My 400 W panels are from a South Korean manufacturer, and I get them cheaper through a fellow engineer and contractor who has a local supplier. They cost me $280 or about $0.70 a watt. Today during very bright sunlight each panel produced 450 watts, and with four panels per AC300, this is about 1.8 kW. I plan to add more in parallel so I can get the maximum of 2.4 kW.

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I know you have the AC300, but I noticed that on the AC500, even though it’s rated at 3000 watts PV input, the “catch” is that it’s actually 1500 watts per each PV input (DC1 and DC2). I don’t know the max wattage/input for yours, but it would be easy enough to split the wattage in half. Of course, in the real world we’re lucky if we get the rated wattage.

I’ve been shopping for more panels, but now that I’ve got the AC500 wired in and running, the one B300s just isn’t enough after the sun goes down. It was down to 12% at 2AM, so it would shut down before sunrise unless I plugged in the AC cord to charge it up to around 40%. We’re in a valley so it gets dark in winter around 4:30 pm, and the panels showed there wasn’t enough sun until almost 6:30 am. I’m waiting on my Bluetti Bucks to use on a 2nd battery.

I wouldn’t be too worried about used panels. Most will be fine. I have 1 kW of 10 year old panels and they are going fine. Tested them all with a Voltmeter

I have had solar on my roof for 23 years now and no more than 10% loss in output.


Well again, bring a voltmeter to check them, even for “new” panels. But hey, it’s your money.
Old used panels are likely polycrystalline. New panels are monocrystalline and push out a bit more power in hot climates, like Vegas, where I live. They also have better low light and cloudy capabilities.