Paul wrote:
A question about bypass diodes:
....

Do most panels have the bypass diodes (to allow current flow through shaded
cells)? The specs for my Shell 100W panels do not mention them. I'm not
talking about the series reverse-current blocking diodes, but the per-cell
bypass. I am considering an MPPT controller, and if the panels have these
diodes, it should be better to connect the panels in series, rather than in
parallel. My installation has three panels, and does have issues with panel
shading. Currently I have the panels in parallel, and use a non-MPPT
controller.

I will probably do some V/I curves for the panels with varying types and
degrees of shading, which should answer the bypass diode question, but until
then any advice would be appreciated.

I may be wrong but I don't think most panels come with diodes - mine
don't. In fact, diodes aren't really the right thing to use. The
Blue Sky (and I'm guessing the Outback) comes with a relay that closes
when appropriate and opens to prevent reverse current flow. This is a
much more efficient way to do it.