John,

Thanks for the yearly update on how your batteries are ageing. It's nice to see what they do under constant test conditions. (I did get a 404 not found on your 2019 pdf file link?)

In (one of)2G's directions, the modern cockpit does have those pesky switchers. I wonder if an easy alternative load might be some 12 - 5v usb chargers with light bulb loads on the 5v side. The computer rig could watch V&I on the battery side and especially the time till the BMS says lights out.

Not all K2's are the same. I have 4 of 2 different ages. One of them seems a little more tired than the others. This prompted me to setup a more complicated rig.

Depending on that the VHF and transponder are doing, one K2 will keep my bus up for around 4 hours. I added a second in parallel with it thru a low drop diode. The hope was that this would keep the batteries from circulating current, and make it about 2x longer before lights out, and let me see the switchover as the bus drops 0.4v, and work with the SH battery in parallel wiring. So far, so good. It's lasted longer than I have without needing to switch to the third, get home battery.

One of these days, I need to get around to trying them with your test plan.

Thanks again,
Stu