These are my "Mark 1" combiners, made in a rush the night before a Field Day. The panel combiners have all
exposed contacts and wiring, making them hazardous to handle, since Voc can get over 90 volts DC. And since
they have no enclosure, rain is a major concern. Despite looking terrible and delicate, they proved to work
very well and haven't gotten damaged. I did have to place them in 1 gallon zip-loc bags though in case we got
rain. (and on a few occasions, we have gotten light rain) The volt meters were kind of an afterthought, but
I've found them to be useful in verifying panels are working correctly. I also made up some "bypass plugs" in
case I didn't want to connect all four panels in a string. So far though I've always uses the full four panels
on the combiners, so I'll probably not bother with plugs when I re-design the panel combiners. The panel
combiners connect up to four panels in series, increasing voltage without changing current.
The string combiner was made to only support two strings since at the time I only had two strings, although
that'll be a problem if I get additional strings of panels that need to be combined. I was under a lot of time
pressure when I made it, and each of those powerpole plugs take considerable time to carve out and install.
two panel strings can be connected into this string combiner, which places the two strings in paralel. This
doubles the current without changing the voltage.
Two strings of four "100 watt" panels will combine to produce a maximum of 90 volts at no load, or 60 volts /
10 amps at the full 600 watt load. (assuming Iowa sun)
