A Geek Goes Flying

June 11, 2026:  Solar generates more energy in US than coal for first time . “Data released on Wednesday by the global energy thinktank Ember, along with a report by the Solar Energy Industries Association (Seia) and analytics firm Wood Mackenzie, show the continued growth of solar and decline of coal in the United States despite federal policy. In May, for the first time, solar supplied more of the nation’s electricity than coal, or 12.8%, Ember said. Coal supplied 12.2%, its fourth-lowest monthly share ever.” I’d buy that for a dollar. Green energy collage Of course, other countries are ahead of us. Germany has, on occasion, supplied all of its electrical demand using renewables, at least as far back as May 17, 2016 (“If only for a brief while, the country was almost entirely powered by solar and wind–and the grid didn’t collapse”). Meanwhile, I’d still love to have something like the GoSun EV Solar Charger for truly off-grid capability. With everything I tote these days being ...

Over at the Santa Monica Municipal Airport , they have free municipal EV charging. It’s not particularly fast (I think it’s reported as being something like 4.2 kW, shared, but in practice I see 3.77 kW when charging alone, or 1.86 kW when split - which is basically L1 charging), but it’s free, and the system is kinda kick ass. Solterra connected to a Santa Monica supplied EV ARC solar charger It’s up to 4 hours free per day, with a $1.00/minute “overstay charge” if you go beyond that. It’s administered by ChargePoint. And the EV ARC (Autonomous Renewable Charger) hardware is courtesy Envision Solar , who claims to be using a “patented sun tracker” (presumably this patent ?). (Apparently Envision is now Beam Global .) A large sign reads: EV ARC™  A truly zero emissions solution  The EV ARC™ is the world’s only transportable, solar powered electric vehicle charging product. The system is completely grid independent. The patented EnvisionTrak™ sun tracking technology enables th...

So, I picked up a Storm 2 battery pack , for the capacity, the screen showing charging / discharge details, and because it can be charged via a DC port. I figured it would be a good companion for the Renogy E.Flex 50 solar panel. The panel puts out 21.6V and 3.04A to an open circuit, and has a nominal output of 18V at 2.77A (49.86W). In reality , of course, I usually see the panel top out in the low 30W range, almost always around 17V with the available current dictating the watts transmitted: 17.23V 1.76A 30.3W (12/15 9:25 a.m. direct sun) 13.96V 0.03A 00.4W (12/14 12:13 p.m. shade) 17.12V 1.00A 17.1W (12/14 10:11 a.m. direct sun) 12.12V 1.02A 17.4W (12/17 10:45 a.m. thin cirrus cloud cover) 17.06V 0.62A 10.5W (12/17 10:01 a.m. thin cirrus cloud cover) Into a full battery pack, I was seeing higher voltages but minimal current, with correspondingly reduced wattage, e.g.: 1 9.51V 0.04A 00.7W (12/20 9:52 a.m. direct sun). This should work with the Storm 2 pack, which purportedly...

A week into my wildly unscientific solar power experiment, I’ve come to mistrust all capability / capacity specifications.     Solar panels. I was told to expect about 1/2 the rated power from even the highest quality solar panels. I’m getting a bit better than that (I’m seeing the 50W Renogy top out around 32W in direct, morning, SoCal winter sunshine). Battery pack: Capacity. Just like with “normal” portable battery packs, the capacities are overstated vis-a-vis what you can actually expect them to provide in the real world. One reviewer, with instrumentation far in excess of what I have access to, observes 92% of advertised capacity is par for the course. ( https://www.californiaskys.com/blog/ebl-voyager-1000-review ) Battery pack: Efficiency.  Renogy states in its manual for the battery pack “The charging conversion rate of this power bank is around 80%-90% (the 10%-20% conversion loss is due to the heat generation when power is transferred in batteries and charging ...

Renogy power bank connected to MacBook Air It looks like the Renology R50EF E.FLEX 50 portable solar panel, and maybe also the RPB-72000PD 72,000 mAh / 266 Wh portable power bank, might be discontinued, so I grabbed ‘em while I could. The power bank comes with a Lyangel LY005SPS-200200U 40W (20V 2A) wall wort (5.5x2.1mm DC, positive pin negative shield). I used that to charge the bank to full (it arrived with a ~50% charge). So far I’ve tested wireless charging with an iPhone 12 Pro (works) and now through the Klein meter I have USB-C PD (1) connected to a MacBook Air and it’s supplying 19.73V 1.89A (36.7W). (The Mac sees it as a 60W charger.) The power bank is a beast, about the size and heft of a dense hardback book. It comes with that AC adapter, a ~19" DC to DC cord (5.5x2.1mm (“DC5521”) male connectors on both ends, about 10mm long), a set of (8) adapter tips (5.5x2.1mm female, and 8 various male ends), a soft case with a pouch for accessories, and a manual . It charges via t...

Zendure SuperTank Pro Zendure SuperTank Pro I’m still enamored with the Zendure X5, but I went looking for a solution with at least 2 USB-C PD outputs, that could power both a MacBook Air and a 15.6" UPERFECT portable monitor (that I expect will become part of a flexible sit-stand setup ). The Zendure SuperTank Pro 100W PD 26800mAh power bank seems to have glowing reviews and the specs are there (and I like the OLED screen that shows what each port is delivering, how many watt hours of charge are remaining, etc), and Amazon had it as a lightning sale item marked down from $229 to $169, so I decided to take the plunge. Update: The SuperTank arrived today. To my surprise, it came with a carrying case, a USB-C to USB-C cable, and a USB-C to USB-A adapter. I hooked it up to the UGREEN 100W charger through the Klein and observed it charging (it came with about a 36% charge, and Zendure recommends fully charging it before use). Using the red 60W-rated cable showed 56.0W on the SuperT...