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. 

 

Tim

On Jun 24, 2020, at 12:28, Jerry Gaffke via groups.io <jgaffke@...> wrote:

Tim,

Hmmm, radio only powers up when tied to a big battery capable of supplying several amps,
not when powered from a wimpy 1 or 2 amp 12v supply?
Check current consumption into the uBitx when receiving, should be under a half amp.
Is something getting hot when you power the rig from the big battery?
If the rig is drawing more current than the Bionenno is designed to deliver, the BMS circuit
will shut the rig down.

Maybe try powering an 1157 type incandescent tail light from the battery, see if that behaves?
That's about 0.66 amps on the tail light filament, about 3 amps on the brake light filament.

I haven't looked much at the v6, but I assume the voltage regulator you refer to 
is something like an LM7805 on the raduino.  What is the voltage going into this regulator
when it is failing?   If it's over 7 or 8 volts, it should be doing just fine.
It is possible that the regulator overheats and goes into shutdown (till it cools off)
if the battery voltage is too high or if there is an inadequate heatsink on that regulator.

That BIoenno battery probably has four LiFePO4 cells, from  
    https://www.robotshop.com/media/files/pdf/hyperion-99v-2100mah-lifepo4-transmitter-pack-datasheet.pdf
>  Each LiFePO4 cell has a NOMINAL voltage of 3.3V. A fully charged LiFePO4 cell is 3.6V, and a fully depleted LiFePO4 cell is 2.5V. 

So nominally 3.3*4=13.2volts,  fully charged 3.6*4=14.4volts,  discharged:  2.5*4=10volts

The Bionenno datasheet says the charging voltage maxes out at 14.6volts:
  https://cdn.shopify.com/s/files/1/0219/0154/files/BLF-1220A_User_Manual_rev_04_23_2019.pdf?209

Those are open circuit voltages, when drawing current the internal resistance of the battery will
bring that voltage down a bit.  You will seldom see exactly 12.0 volts out of that battery.

I am curious what symptoms were seen to verify that the BMS of the Bioenno was failing.
And curious why it failed, as that should provide pretty much full protection from abuse.
From the manual:
>    Protection: PCM/BMS Overcharge, overdischarge, overcurrent, temperature, balancing

Was the battery perhaps charged by something other than a Bioenno provided charger
prior to the BMS failure?

Jerry, KE7ER

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of wt1im@...
Sent: Wednesday, June 24, 2020 2:51 PM
To: BITX20@groups.io
Subject: [BITX20] #v5 #power issue

Another mystery!

I power my uBitx v5 with a LiFePo 3.5Ah battery from Bioenno. It's a new battery but a little while back, the radio stopped powering up. Long story short, the battery was found to have a bad BMS (battery mgt system). The only symptom that I might have needed to pay more attention to before the radio failed was that the battery put out a little more than the 13.8v that nominal 12v systems typically do. My VOM is analog but it looked to be between 14 and 15v. 

With the LiFePo out of commission, I thought, no problem, I have lots of 12v sources. 

NONE of them would power up the radio. All verified good power sources that work fine on other things, test well, etc.

Meanwhile, the fellow ham who diagnosed the BMS issue charged my LiFePo by bypassing its BMS and using an external one. 

With the LiFePo back, it, and *only* it, will power the radio. But not for long, due to the BMS issues (I'm going to get a new BMS)--it cuts the voltage to zero. I can "reset" it by momentarily connecting it to a charger. Not a viable solution, just part of the troubleshooting chain. 

I do notice that the LiFePo shows 12v now--not the higher voltage it was showing before all of this happened.

My best guess is that the voltage regulator in the uBitx is bad, and will only power the rig with a very narrow range of voltages. The LiFePo is the only DC source I have handy that delivers less than 13.8v. 

I have read that the uBitx "wants" 12v or less. But the symptoms of running it with a bit more seem to be things like distorted RX audio. I haven't seen anyone say that 13.8v actually kills the radio. 

My best guess is that the 7805cv voltage regulator is bad It's not fully dead since I can get the rig to turn on with (only) the LiFePo, but perhaps it's gravely injured. Maybe the 14-15v that the LiFePo originally delivered fried it? Is my best next step to replace the regulator and see what happens? 

And--if 13.8+v really did kill this regulator, does it make sense to swap it with another part that can accept slightly higher voltages? I really am hoping I don't have to do deeper hacking on the power supply system to drop the voltage below 13.8 since that is such a universal DC voltage. A swap-in regulator replacement would be ideal. 

Thanks in advance!

Tim

Bill -
100% with you on homebrew rigs.  I've spent the last few months building a 100% scratch built 40 meter SSB transceiver, and I have learned a ton along the way.  I've been documenting it on my blog- check out kk4das.blogspot.com if you have a few minutes.   But I will admit homebrewing batteries is outside of my area of interest.
73,
Dean
KK4DAS