Could indeed be a defect in both the Biennio BMS and in the uBitx, as you suspect.
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Very weird that the uBitx works (for awhile) with the Biennio, but not with a bench 12v supply.
You could be right that something in the uBitx needs an the extra volt or two
that the fully charged Biennio offers, but not the bench supply.
That would explain why the BIennio only works for awhile, until the cell voltage drops some.
The Raduino regulator is the first place I'd look.
On Wed, Jun 24, 2020 at 01:47 PM, Tim Helming wrote:
Hi Jerry et al
The other sources I’ve tried are plenty beefy—the 30A supply I use for my home station (incl Kenwood TS-590s) and some 30Ah AGMs with full charges. Current draw isn’t our culprit.
I’ll try measuring the voltage directly at the regulator—not sure why I hadn’t already thought of that. I doubt it is thermal protection cutout because I’ve tried to power on the rig from dead cold from the 30A supply. Also, when the LiFePo cuts out and I “reset” it, the radio comes right back to life.
Not sure about the BMS. I can’t imagine that I did anything to hurt it, and it did work ok for a while. Never charged it with anything but the charger it came with. I suspect it had a lurking factory defect—a component that was almost dead and then did die once it was put into service.
I’ll reply again when I’ve taken some measurements off the voltage regulator.