KX3 Internal battery issue

[Anthony de Maillet]

Hi,

I have a new (last week) KX3 built by Waters and Stanton in the UK.  It has all the extras other than the 2m/4m Transverter.  I have installed a fully charged and new set of Eneloop 1900mah NiMH batteries.  If I trun the radio on the battery voltage drops from 10.9 volts to 7.9 volts over about 2 minutes then the radio switches off.  If I plug in the external power (13.6 Volts) the battery voltage inceases back up to about 10.7 volts - again over about 2 minutes.  Presumeably the batteries are recovering? The Batt Chg in the menu is OFF at this point.

Any ideas?  Radio issue, Battery issue or normal behaviour?  I’m wasn’t intending running from internal batteries except in an emergency.  Pre amp, NB, NR etc. all off.  Backlight is on though.  I’m a bit puzzled.

Tony
M0ZZA
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[Matt Zilmer-3]

You may have a bad cell in your Eneloops.  Try monitoring the current
drain while discharging the battery.  At idle, it should be200 mA or
less.  If it's much more than that, there may be a different problem
with the KX3 itself.  But I'd guess you're looking for a single bad
cells in the bunch.

After a load is removed, most types of batteries recover to a much
higher open-circuit voltage.  The internal resistance doesn't add
voltage drop without the load present.

There are instruments out there that assess battery health. Can you get
access to one?  I believe MFJ makes one...

73,

matt W6NIA


On 4/10/2017 7:00 AM, Anthony de Maillet wrote:

> Hi,
>
> I have a new (last week) KX3 built by Waters and Stanton in the UK.  It has all the extras other than the 2m/4m Transverter.  I have installed a fully charged and new set of Eneloop 1900mah NiMH batteries.  If I trun the radio on the battery voltage drops from 10.9 volts to 7.9 volts over about 2 minutes then the radio switches off.  If I plug in the external power (13.6 Volts) the battery voltage inceases back up to about 10.7 volts - again over about 2 minutes.  Presumeably the batteries are recovering? The Batt Chg in the menu is OFF at this point.
>
> Any ideas?  Radio issue, Battery issue or normal behaviour?  I’m wasn’t intending running from internal batteries except in an emergency.  Pre amp, NB, NR etc. all off.  Backlight is on though.  I’m a bit puzzled.
>
> Tony
> M0ZZA
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--
"A delay is better than a disaster."
-- unknonwn

Matt Zilmer, W6NIA
[Shiraz]

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[Elecraft mailing list]

Tony,
Your voltages are NOT normal.  Matt's suggestions are good ones.  You should also, as soon as possible, take the cells out of the holder and do two things:
1.  Inspect each cell for damage to the plastic cover that is around each cell.  Look around the positive terminal for damage that plastic cover.  That can cause a short in that cell.  Check the side of each cell for damage caused by a battery holder attach screw that is too long.  If the builder used the wrong screw when attaching the holder, it can extend beyond the surface of the battery holder and damage the plastic causing a short to ground.  Elecraft issued and alert to check the holder for the proper screw length.  I can't emphasize enough that damage to the plastic covering is unacceptable.  I don't think that this is the most likely cause since the cells return to a reasonable voltage while resting.
2.  Measure the voltage of each cell.  After charging and resting for an hour or so, they should all be within about 0.1 volt of each other.  A little more variation is OK for cells that are partially discharged.  Be careful when probing the positive terminal.  It is easy to short the cell if the plastic cover does not extend completely around the top of the cell.  That falls under item 1 above.

These are good steps to take a few times per year.  Matt's suggestion of looking at the current draw is important.  That should help isolate the source (radio vs. cells) of the problem. 

It is possible that the wrong screws were used somewhere during the radio's build and one extends too far causing a short in the supply.  Elecraft supplies all the proper screws for the job, but it is easy to put the wrong one in the wrong place.  I don't know what your situation is, but you may want to consider returning the radio to the builder for repair.

FYI, I have never seen a bad Eneloops from the factory, but it is possible.   

    On Monday, April 10, 2017 7:54 AM, Matt Zilmer <[hidden email]> wrote:
 

 You may have a bad cell in your Eneloops.  Try monitoring the current
drain while discharging the battery.  At idle, it should be200 mA or
less.  If it's much more than that, there may be a different problem
with the KX3 itself.

   
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[Elecraft mailing list]

Oops!  Pressed SEND before signing my previous e-mail.
Mark,
KE6BB
 

    On Monday, April 10, 2017 10:14 AM, Mark Petiford <[hidden email]> wrote:
 

 Tony,
Your voltages are NOT normal.  Matt's suggestions are good ones.  You should also, as soon as possible, take the cells out of the holder and do two things:


   
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[Anthony de Maillet]

Thanks Mark and Matt.  I’ll report back when I know more!

Tony

> On 10 Apr 2017, at 18:14, Mark Petiford via Elecraft <[hidden email]> wrote:
>
> Tony,
> Your voltages are NOT normal.  Matt's suggestions are good ones.  You should also, as soon as possible, take the cells out of the holder and do two things:
> 1.  Inspect each cell for damage to the plastic cover that is around each cell.  Look around the positive terminal for damage that plastic cover.  That can cause a short in that cell.  Check the side of each cell for damage caused by a battery holder attach screw that is too long.  If the builder used the wrong screw when attaching the holder, it can extend beyond the surface of the battery holder and damage the plastic causing a short to ground.  Elecraft issued and alert to check the holder for the proper screw length.  I can't emphasize enough that damage to the plastic covering is unacceptable.  I don't think that this is the most likely cause since the cells return to a reasonable voltage while resting.
> 2.  Measure the voltage of each cell.  After charging and resting for an hour or so, they should all be within about 0.1 volt of each other.  A little more variation is OK for cells that are partially discharged.  Be careful when probing the positive terminal.  It is easy to short the cell if the plastic cover does not extend completely around the top of the cell.  That falls under item 1 above.
>
> These are good steps to take a few times per year.  Matt's suggestion of looking at the current draw is important.  That should help isolate the source (radio vs. cells) of the problem.  
>
> It is possible that the wrong screws were used somewhere during the radio's build and one extends too far causing a short in the supply.  Elecraft supplies all the proper screws for the job, but it is easy to put the wrong one in the wrong place.  I don't know what your situation is, but you may want to consider returning the radio to the builder for repair.
>
> FYI, I have never seen a bad Eneloops from the factory, but it is possible.  
>
>    On Monday, April 10, 2017 7:54 AM, Matt Zilmer <[hidden email]> wrote:
>
>
> You may have a bad cell in your Eneloops.  Try monitoring the current
> drain while discharging the battery.  At idle, it should be200 mA or
> less.  If it's much more than that, there may be a different problem
> with the KX3 itself.
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
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