Higher than expected voltage when connecting panels in series
Hello, everyone. I’m new to solar and new to Reddit. So, apologies if this is a basic question that’s been asked a thousand times before. I just hooked three 100w, 18v panels up for the first time to a BLUETTI Elite 300 power station. It has a 1200w 60v 22a MPPT. When I hooked the panels up individually, the voltages were 18.0, 17.8, and 17.4. When I connected them in series, they were 65.7. I’m at a loss to figure out why the voltage spiked so high when they were all connected. I then connected two and got 36.2, so that checks out. It’s only when I connect three together that I magically gain about 12v. I used a multimeter and got the same voltage reading as I got from the MPPT, so I’ve eliminated a faulty MPPT as the cause.
So, is this what I get for buying no-name panels off eBay? Is there a fix other than returning the panels and buying new ones. If so, what are your recommendations for reputable brands? I’m sure that thread is already on here, so I‘ll do some digging, but if anyone has any recommendations, I’d appreciate them.
Thanks for your help!