Topics

#v5 #power issue #v5 #power

Tim Helming
 

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

Dale Parfitt
 

Hi Tim,

It is a simple procedure to measure the output of the regulator and see whether it is nominal  or not. A 7805CV is rated as max input (from memory) of around 25V.  Let us know what you find.

 

Dale W4OP

 

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

Jerry Gaffke
 

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

Tim Helming
 

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

Jerry Gaffke
 

Could indeed be a defect in both the Biennio BMS and in the uBitx, as you suspect.

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.

Good luck!

Jerry, KE7ER


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. 
 
Tim

 

My boards have worked continuously on 15V with no issues. The power output
increases, you only need to put a heat sink on Raduino 5V regulator as it gets
uncomfortably hot. It may then drop voltage.

If the board has 2822 audio amp then put a 9 or 10 78L09 or 10 in series with
chip supply. This mod is documented.

Trace power on the board and find what is happening.

Raj


At 25/06/2020, you wrote:
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.

Tim Helming
 

Update:

There is voodoo in this uBitx. I did nothing more than start measuring the voltages at the output of the regulator, and the radio started working on a power supply on which it did not previously work. A similar thing happened when troubleshooting a microphone a few weeks back--mic didn't work, started checking some voltages etc, did not actually change anything, then mic started working. 

So, cool, but I don't feel like I can trust that it's going to keep working reliably.

But I did put a homebrew heat sink on the regulator (just a strip of copper a few inches long). On this board, the regulator is very close to one of the toroids and in fact touched the toroid until I gently bent the regulator away from it a bit. But there's no way I could get the same kind of heat sink on it that the final transistors have unless I put some kind of riser between the main board and the Raduino to create space. 

I've had the radio running for several hours so far, and it hasn't blinked. Checked in to a 75m net in British Columbia last night (I'm in Seattle), too. 

It's not going to be my main Field Day rig but it seems I have a working radio for now so I'm happy :)

Thanks for the assist, as always.

Tim

Jerry Gaffke
 

Sounds like a bad solder joint, making an incomplete connection at times.
I'd get it working on receive, then try pushing stuff around with a finger to see if I could get it to fail.  
Perhaps around that regulator, make sure power and ground wires from main board to Raduino are well connected.
Maybe have one voltmeter on the 12v rail of the main board, another voltmeter on the 5v raduino rail
while pushing stuff around with your finger so you can get another clue.

Could also be a short somewhere.

That 7805 regulator can work fine when it's really hot, has very good
thermal conductivity from silicon die to the TO220 metal heatsink tab.
So long as a wet finger doesn't sizzle, it's probably ok.

The IRF510's, not so much.
They have poor thermal conductivity from silicon die to TO220 tab.
If they ever get too hot to hold your finger on them comfortably, that's approaching too hot.


On Thu, Jun 25, 2020 at 10:41 AM, Tim Helming wrote:
There is voodoo in this uBitx.

Don - KM4UDX
 

If you look closely, you can notice where I cut back some of the heat sink's soft aluminum right over the toroid.  Easypeasy.