Wouxun 805G Battery Drain

[OldRadioGuy]

I just discovered that my 805G's drain the batteries dead while sitting on the shelf.  (They were not sitting in the charger bases or connected to anything.)   They drain the batteries right down to 6.2V which is where the battery safety circuits shut them off.  This is not good for the batteries.  It's rather disappointing to find a flaw like this in an otherwise good radio.

So.... if you have these radios remove the batteries when you store them for more than a day or two.  My Cobra radios do not have this problem and that's good because the batteries are not easily removed.  At least the Wouxun batts come off very easily.

It looks like you could easily insert a strip of sandwich bag or paper between the battery and the radio.  So you could have the battery installed but not bleeding to death while stored.  Just yank the plastic strip when you are ready to use the radio.  I think I'll try that.

When I was working as an engineer we had engineers who just put the processor to sleep when you "turn off" a device.  It's not truly turned OFF.   It was mostly so they wouldn't have to do a reboot every time you power up.  But storage would kill the batteries dead.  I always made my stuff shut off below 5uA which is like a wrist watch.

Most tablets and cell phones are pretty good.  A short press puts it in standby but a longer press powers it OFF for storage.  So you can have it both ways.

Vince

[mbrun]

Good day Vince.

I put a microamp meter (Fluke 87-V) in circuit between a power supply and one of the 805G that I have. I measure zero current flow when radios is off, but ample current when the radio is on.
I am wondering if perhaps you have some bad product or if there has been some form of design change that might be a contributor.

LiPo batteries with their internal circuits can draw a battery down as they sit idle. Some can do so far more more rapidly then others. I am wondering how the same pack fairs after a full charge and being left disconnected from the radio compared to being left in the radio in a powered off state for the same period of time.

I did check battery voltage on the two units I have. Both were stored will a fully charged state about 2-3 weeks ago. However both batteries where in a completely different state of charge when I just checked them. So you may have stumbled onto something. At least on my end this would suggest battery self-discharge.

Just goes to show you can’t rely on rechargeable batteries being ready for use after a long period of storage.

Regards,


Michael
WRHS965
KE8PLM

[mbrun]

OK, I stand corrected. Cockpit error on my part. Double checked my work and discovered a parasitic drain of 1.04mA. So indeed both of my radios are discharging the batteries at exactly that same rate.

Good catch on your part!


Michael
WRHS965
KE8PLM

[wayoverthere]

Discovered mine dead as well. It's gotten a little use since last charge but mostly sitting on the shelf. The 2nd battery that was full charged prior to a trip in August and stored in the box shows 8.0v on the radio, where 8.2 or 8.3 seems to be normal "full charge" voltage. So..little bit of drop for the battery alone, but more when on the the radio.

[MichaelLAX]

16 minutes ago, mbrun said:

OK, I stand corrected. Cockpit error on my part. 

Just curious: What was the error: not directly connecting the meter to the internal battery connections?

[mbrun]

Just curious: What was the error: not directly connecting the meter to the internal battery connections?

Failed to switch amp meter setting from AC to DC.


Michael
WRHS965
KE8PLM

[axorlov]

That's not unheard of. My ham Yaesu gear drains battery when turned off. I now remove battery from FT1XD, and I'm in the process of fabricating high(er) capacity LiPo battery for FT-817 that will include a mechanical switch to disconnect battery. My Kenwoods do not drain batteries, though.

[OldRadioGuy]

I should add that my two spare batteries were still fully charged after sitting the same length of time- but not on a radio.  Both of my radios were stone dead. 

Having worked in this stuff, some designers just don't worry about such things.  They put the processor in sleep mode and figure that's good enough.  They don't want to bother with circuits that wait for the switcher to reach voltage and reboot the processor whenever the power is turned on.  It certainly can be done but they just don't bother.  They probably imagined that people would store the radios in the charger base when not in use.  But not everyone does.

At my last job it took about 2 full days of arguing to get a lazy project engineer to change the design so the batteries were not drained while being stored.  And they were not removable batteries!!!  And it was a product that is often stored for long periods between use.  The fix cost like 20 cents.  But this is how some engineers think.

I have inserted paper tabs in my 805G radios so I can leave the packs attached but not connected.  This way I don't have to carry the batts separately.  When I want to use the radio I'll just release the pack and remove the paper.  Seems to work well.

Vince

 

[WyoJoe]

I have a couple of Wouxon KG-UV9 radios, and both slowly drain the batteries when stored. They were stored after being charged a couple of weeks ago, and they're currently reading 7.4V on the display when turned on. The battery indicator shows about "half full." My other radios seem to maintain a charge for a much longer period of time, but it's hard to tell since they don't have the same quality of battery indicator as the Wouxons.