solar pop quiz: achieving Absorption voltage

Given the following information: mppt controller panels rated Vmp = 36v (parallel) measured panel voltage (Vpanel) every 4 minutes at what time (roughly) did the system reach Absorption voltage (Vabs)? Time Vpanel 0912 36.37v 0916 35.21v 0920 36.16v 0924 36.57v 0928 36.82v 0932 36.30v 0936 35.67v 0940 35.97v 0944 37.14v 0948 37.89v 0952 38.09v extra

watered batteries after three weeks of Eternal Absorption

I normally water every couple of couple of months, but thought it would be smart to check early this time just in case I was boiling off a ton of water. The water use was in line with what I normally see.  I got a couple bloops out of each cell, with the exception of one

storm rolling in; mac and cheese; DIY pinning mat

It dropped a few degrees, got darker outside, then the thunder started rolling: I am in a relatively bare spot on this hilltop but there are plenty of trees taller than me in the area. mac and cheese I don’t carry milk with me because

Mythtesting: higher voltage for additional yield in the mornings

I am a fan of higher-voltage panels, serial panel configs,etc for several reasons.   But I think there are some hyperbolic claims about their ability to collect extra power in the dawn/dusk shoulders. The theory (and actuality), illustrated with 2x 100w 12v panels is that  solar panel voltage stabilizes above ~20% insolation;  below that it falls

Amazon prime download size accuracy

Chromebooks can do android apps, which is how I run Amazon Prime video.  It allows several different quality settings: 130MB/hr is pretty danged good, and reported download sizes matched that estimate.  A couple of weeks ago the reported download sizes ballooned:

MiniDLNA + MythTV

You may remember I capture OTA TV signals with a MythTV install on Raspberry Pi ( Raspian). Traditionally if one wants to stream MythTV files across the network one sets up MythWeb.  The Pi is quite limited and the MythTV setup there is finicky, so I wanted to do it with a lighter service. MiniDLNA

MSR Dragonfly fuel line replacement

I took the Dragonfly apart the other day to see what the fuel line was like inside that braid. Today I picked up some replacement Gates fuel line.  This particular example is a rubber line with internal nylon braid, rated for 50psi with fuel.  I looked for the specs on the pressure the MSR hand pump can

Pb charging: absorption finishing amps and state of health

tracking  endAmps The Absorption stage of lead-chemistry battery charging is characterized by constant voltage (Vabs) and decreasing current.  The battery takes less and less current as it approaches full charge, and finally plateaus at a low rate.  Current is the red line in this graphic: That leveled off terminal rate in the right third is called endAmps,

a modest proposal, Covid-19 edition

inspired by reddit post The Case for Scaling Down the Economic Shutdown of Texas we have not even come close to hitting our ICU bed cap that we increased in preparation and our overflow facilities are still very under utilized Shower thought from a layman: since hospitalization is a lagging indicator, maybe communiities could tie public covid policy

rainwater/freshwater bucket upgrade

Today’s goal:  add spigot to bucket find where I stored the spigots – half day drill 1″ hole – 5 mins install spigot – 60 seconds     I’d picked up the spigots off Amazon last month.  They are typically used for bottling homebrew – the [primary] fermented beer is racked into the priming bucket, priming sugars