Rethink, all the panels could be put in series with one high voltage regulator. Simply use a relay and switch it in and out the panel array depending on the batt bank voltage. What I had in mind was to use a separate solar panel and small inexpensive regulator for each battery. This eliminates the dc/dc upconverter. This sounds expensive using 20 regulators, 20 solar panels and 20 batteries (at 12v), but the regulators are all low power and second hand 33 watt panels are cheap. Smaller batteries are easier to handle and if one fails it is not a huge loss. I have spoken to people transporting big 2v cells and the problems they have. Peter what is a "sine former (using magic sine etc)". That is the last piece of the system. Justin Quite a logical approach, Peter. You've always got the problem of getting 12V (or other solar cell voltage) to be 120V (or 240 take your pick). < > > Does it not make a lot of sense to use a high voltage DC storage battery > and a sine former (using magic sine etc) and to charge it with a dc/dc > upconverter from the solar panels and/or a wind generator and/or mains > grid and/or generator for such power levels ? Because I think that it > *significantly* reduces switching and I^2R losses at high load time. With > ~8-10 24V batteries in series and charge equalization control this could > supply significantly more than 5kW for a short time. The lower current per > battery would mean that inexpensive smaller batteries could be bought in > Peter > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body