back to test sessions

2025.05.26 Powkey 60 shade test:




I did a quick test this morning to see how the Powkey wallet performs when cells or pages are shaded. I thought
my previous experience had been that if one panel got shaded it would disable the wallet, but I wanted to test
that to see if it was really the case. (this was also my first use of my new compact power meter, I love it!)

I found the Powkey still produces fractional power if one or two pages are completely shaded, sp they appear
to be wired in parallel, with blocking diodes. Normally if a panel (or individual cell) is shaded, it will turn
into a heater, consuming power and producing heat. So if the Powkey lacked blocking diodes, I'd expect the
shaded panels to drain significant power from the sunny panels. I did see a slight reduction in Voc when one
or two pages were shade, down from about 22.5 to 21.3 volts, so there was a little impact in that regard.

The other test I performed was to shade two of the panels, leaving only one in the sun, and see how it would
perform when groups of cells were blocked. When blocking cells I saw an immediate drop in voltage, and under
load the panel cut out completely, so those cells are clearly wired in series without bypass diodes, which isn't
very surprising. Bypass diodes for individual cells would help, but it's almost unheard of. The only place I see
bypass diodes is across entire panels, or portions of panels. (Dokio's 36-cell panels include two bypass diodes,
one for each half of the string)

Interesting discovery, I watched the MPPT adjust after I shaded one page, the voltage dropped and current went
up a little, to squeak out another 200mW of power.

A. full sun	B. full loaded	C. shading one page	D one page shaded 1	D one page shaded 2	E two pages shaded
F. cells blocked	G. cells blocked

highest resolution images
last updated 05/26/2025 at 11:36:04 by make_www_index.command version 2025.05.20.B