[NSRCA-discussion] What the heck .... starter battery charging ouch

[Richard Lewis]

The transformer in the Wall-Wart type charger generally cannot supply the amps to melt the wire.  The current that melted the wire came from the battery.  Even a well discharged battery can provide enough current into a short circuit to melt/burn the tiny wire in this type of charge cord.  The wires likely shorted together somewhere in the wire or inside the charger and the battery discharged across this short circuit path melting the wires, etc..chances are by the time you reacted to the situation, the wires had melted in two and cleared the short.

...my 2 cents...:)

Richard




________________________________
From: Michael Cohen <precisionaero at hotmail.com>
To: NSRCA <nsrca-discussion at lists.nsrca.org>
Sent: Wed, May 5, 2010 2:27:03 PM
Subject: Re: [NSRCA-discussion] What the heck .... starter battery charging ouch

 I am not an electrical guy, nor do I play one on TV, but how about this theory:
 
The battery itself has been showing signs that it might be at the end of its life.  After spending a winter in hibernation in the basement, it was having trouble spinning the YS170 and a pair of LA40s in a Pica Duelist after about 4 flights.  Normally, 4 YS starts and a few sport motor starts are not a problem at all a session or two in a row without a re-charge.  If the battery's resistance is higher due to its age, can the wall charger be forced to work harder, heating up the wiring until the plastic wire sleeve started to melt and a short occurred finishing off the charger once and for all?
 
________________________________
 Date: Wed, 5 May 2010 12:10:47 -0700
From: bob at toprudder.com
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] What the heck .... starter battery charging ouch


The "built-in" circuit breakers are typically GFCI outlets and don't offer any over-current protection, just ground fault protection. Not sure this would have helped. All outlets should be protected for over-current by a breaker in a panel somewhere. There are some newer breakers that offer arc-fault protection, that may have tripped in your case.
 
It would be interesting to diagnose the failure and determine what happened. Perhaps just a fuse in the charge jack would have prevented this.
 
I have a friend that replaced all his 3 pin charge jacks with 1/8" mini-jacks since they were easier to mount in a plane (just drill a round hole). I advised him against that, since those can short if not fully inserted. He never had a problem, though.
 
Bob R.


--- On Tue, 5/4/10, Michael Cohen <precisionaero at hotmail.com> wrote:


>From: Michael Cohen <precisionaero at hotmail.com>
>Subject: Re: [NSRCA-discussion] What the heck .... starter battery charging ouch
>To: "NSRCA" <nsrca-discussion at lists.nsrca.org>
>Date: Tuesday, May 4, 2010, 8:22 PM
>
>
> >Yeah, with LiPos and LiFe, I always stick around.  For NiMh, NiCd, and Pb, I usually plug it in, wait 30 seconds, and then I turn away.  The outlet did not have a built in circuit breaker either, so guess what I will be doing before the next charging event.....
> 
>________________________________
 >Date: Tue, 4 May 2010 17:09:25 -0700
>From: brett.terry at gmail.com
>To: nsrca-discussion at lists.nsrca.org
>Subject: Re: [NSRCA-discussion] What the heck .... starter battery charging ouch
>
>IIRC it was a similar situation that took out all of Chip Hyde's planes a few months back.  The wall wart charger for his car "jump starter" that he was using  as a field charger caught fire and destroyed the garage.  
>
>It is a good thing you were there to witness it and prevent further damage!  I can't count how many times over the years I have plugged in the charger and not looked back until the next day.
>
>i am glad to hear the only damage was the smoke in the air.
>
>Brett
>
>
>On Tue, May 4, 2010 at 3:58 PM, Michael Cohen <precisionaero at hotmail.com> wrote:
>
>I was working on my Brio out in the garage after having plugged in the wall charger for the (glow) starter battery about 10 minutes ago.  You know, us internal combustion guys need to do that once in a while.  All of the sudden, I was standing in a cloud of smoke!  I thought the Triton2EQ, that was also charging the Brio, was the culprit but somehow, the wall charger's wire's were the one's smoking!  I quickly pulled the both plugs from the outlet and got out of the garage ASAP.  Never seen that happen before!  I guess you high powered LiPo guys don't have exclusive rights to smoking batteries/charger excitement.
>> 
>>Mike C
>>
>>
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