Wednesday, 6 July 2016

10:20 – More bottle filling today, after which it’ll be time to start building subassemblies–regulated and non-regulated chemical bags, small parts bags, and so on–for biology, chemistry, and forensics kits. We’re still in decent shape in terms of finished kits, but we need to get stuff piled up in preparation for building more finished kits as quickly as possible. We shipped five kits yesterday, and we’re getting to the point in the next two or three weeks where we’re going to have a lot of days where we ship 5, 10, or more kits.

Veronica Mars is as good as we remembered. Good cast and excellent writing. Veronica looks and sounds like Buffy, and I’m sure that’s no coincidence. I remember Joss Whedon commenting in an interview that Rob Thomas was a genius and “scary good”. I remarked to Barbara last night that the series still seems fresh to us, but I suspect that the music and pop culture references would date it badly for today’s teenagers.

Jen read the comments yesterday, where one reader commented that three of his four Grape Solar panels had died after only a year in service, dropping from 18VDC nominal output and about 20VDC actual to about 10VDC. Apparently, it’s the panels themselves that are the problem, rather than the charge controller. That scares me as much as it scares Jen.

Jen says they bought two 100W panels individually and two more that were each bundled with a cheap PWM charge controller, on the theory that the good MPPT charge controller they bought separately would be their primary, and the two PWM’s would be spares. But if the panels themselves can suddenly drop dead with no obvious explanation, what are the implications for depending on solar electricity?

A quick Google search for solar panel failures turns up several very interesting links, including more than a few scholarly papers. I had been proceeding on the assumption that a PV panel, once assembled and tested, would work essentially forever other than the gradual degradation that anything sitting out all day long in the sun will experience. Apparently, that might be a bad assumption.