[Public-List] Bizzare electrical problem

Wed Apr 10 04:46:17 PDT 2013

Glenn,
The hose clamps dressing the cable to the antenna are the most
likely candidates to some sort of high-energy (lightning strike) event. I
suggest that you look closely at those connecting points for evidence of
burning or discoloration.

Randy  MOIRAEIII #283

On Tue, Apr 9, 2013 at 11:55 PM, Glennb <brooks.glenn at comcast.net> wrote:

> As followup to my weird electrical problem, today I inspected the
> batteries and starter system. Interestingly both batteries were wet on the
> outside of their cases, and they were sitting In some small pool of water
> in their battery cases.   Assume this is due to condensation somehow
> working its way up from the bilge, although the rest of the FG'd areas in
> the battery compartment were not wet with condensation.  (I built new
> battery boxes under the cockpit floor two years ago when I rebuilt the
> cockpit.  There is no way rain water could have dripped in through the
> cockpit floor or hatch above.)
>
> Q: So, thinking about last weeks earlier comments on the list,  can wet
> batteries sitting  in smallish pools of water (>1/4 cup) somehow cause
> sufficient impedance in the electrical system to semi melt coax cable
> attached to the backof a VHF radio, when the engine is started ???  This
> seems beyond bizarre!
>
> As FYI, my battery ground and positive cables and connections are in good
> visual shape, some slight corrosion on the engine ground, (such as one
> would expect from one year of service); look  like new on the battery
> terminals.  The batteries are new AGM deep cycle I installed last spring.
>
> The  battery ground, on the engine, had two or three years normal
> corrosion on the grounding bolt, not bad looking.
>
>  I started the engine once with each battery with no ill effect on any
> wiring in the general area of the engine, including the radio antenna, so
> again could not duplicate the overheated wire condition.
>
> Verified that The pushpit is not shorted or grounded to any electrical
> circuit, but is grounded to the emergency VHF antenna via clamps that
> attach the antenna to the structure.  I am going to find some insulated
> clamps to,replace the hose clamps I presently use to attach the antenna to
> the stanchion.
>
> I guess my next step will be to remove batteries and starter and go have
> them bench checked.  Also will remove the engine ground, clean and
> reinstall.
>
> A lot of trouble to do this as the starter is mounted on the lower back
> (port) side of the engine, behind the alternator.  doable, but a major pain
>  unless performed under nice 80 degree sunny weather conditions and
> preemptively fortified with some high grade of chocolate and dorito rancho
> cheese  snacks to a-swage the usual bursts of rage and doom which broach
> forth when the alternator bolt or the one usable  wrench  slips out and
> tumbles into the bilge.
>
> Gpb
>
> Sent from my iPad
>
> On Apr 7, 2013, at 6:16 PM, n4lbl <alan.schulman at gmail.com> wrote:
>
> > I'd be really interested in the quality of the starter battery ground.
> > On Apr 7, 2013 2:09 PM, "Glennb" <brooks.glenn at comcast.net> wrote:
> >
> >> Yep, thats kind of what I though.  So far as I know, the hull was dry,
> >> except for sitting in the water at the slip.  iam going to go check for
> a
> >> short or ground to,the pushpit tomorrow. Still amazed a heavy gauge
> >> shielded coax cable would heat up three feet away from the radio as
> well as
> >> the back side of the radio, with no damage to any of the much smaller
> >> ground or positive wires leading to the  radio, or nearby parts of the
> >> wiring system...
> >>
> >> Maybe iam thinking along the wrong lines.  Perhaps the impedance ran up
> >> the radio ground wire from the negative bus to the back of the radio,
> >> thence started to cook the coax? The radio,itself still works and only
> the
> >> heat sink on the back and rear part of the frame was hot.  Maybe had
> >> nothing to do with the pushpit - which i still believe is isolated from
> the
> >> electrical system, except for the emergency antenna clamps.
> >>
> >> Still Weird!
> >>
> >> Glenn
> >> Dolce 318
> >>
> >> Sent from my iPad
> >>
> >> On Apr 7, 2013, at 12:23 PM, Gordon Laco <mainstay at csolve.net> wrote:
> >>
> >>> The glass in the hull can't carry a current, but moisture on it
> >> certainly can.
> >>>
> >>> On 2013-04-07, at 1:53 PM, Glennb <brooks.glenn at comcast.net> wrote:
> >>>
> >>>> I can see stray electrical currents, but can fiberglass hulls conduct
> >> enough electrical energy to heat coax antenna cable to the melting
> point???
> >> Never thought that was possible.
> >>>>
> >>>> Btw,  i havent looked into the battery compartment yet - under the
> >> cockpit behind the engine- but everything is new back there this past
> year.
> >> Plus I did hose off the engine last spring as part of a serious cleanup
> >> following a lot of FG and wood sanding .
> >>>>
> >>>> Gpb
> >>>>
> >>>> Sent from my iPad
> >>>>
> >>>> On Apr 7, 2013, at 8:54 AM, n4lbl <alan.schulman at gmail.com> wrote:
> >>>>
> >>>>> That was true, but,,,,
> >>>>>
> >>>>> http://www.thebatteryterminal.com/TechTalk_Batteries_on_Concrete.htm
> >>>>>
> >>>>> http://www.snopes.com/autos/techno/battery.asp
> >>>>>
> >>>>>
> >>
> http://www.cartalk.com/content/business-batteries-and-concrete-floors-needs-be
> >>>>>
> >>>>>
> >>>>> On Sun, Apr 7, 2013 at 9:19 AM, Don Campbell <
> dk.campbell at xplornet.ca
> >>> wrote:
> >>>>>
> >>>>>> That is the quickest way to drain a battery that sits without being
> >>>>>> recharged,  and if you set a battery onto concrete,  this is the way
> >> charge
> >>>>>> is lost to ground, i.e. through condensation between the battery and
> >> the
> >>>>>> concrete. By setting the battery onto a piece of wood,  that breaks
> >> the
> >>>>>> continuity of the water film and so maintains the charge in the
> >> battery.
> >>>>>>
> >>>>>> Don
> >>>>>> On 4/6/2013 2:31 PM, Gordon Laco wrote:
> >>>>>>
> >>>>>>> That's good advice.   I once had a shock (pun intended) when I
> >> casually
> >>>>>>> touched the probe of a multimeter to the inside skin of my boat
> >> while the
> >>>>>>> other probe was touching the SIDE of one of my batteries.    There
> >> was a
> >>>>>>> slight current.    I noticed everything was damp with condensation.
> >>  I
> >>>>>>> dried everything I could reach and was able to kill the stray
> >> current, at
> >>>>>>> least so far as my meter could detect.   If ever there was a good
> >> reason
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