Today's Message Index:
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1. 09:02 AM - Re: Re: Melted battery terminal (Robert L. Nuckolls, III)
2. 11:27 AM - Re: Constructing an automatic RCA video camera feed splitter (Eric Page)
3. 05:23 PM - Re: Melted battery terminal (Eric M. Jones)
Message 1
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Subject: | Re: Melted battery terminal |
At 12:35 PM 7/30/2018, you wrote:
>
>It would be interesting to learn what the battery manufacturer has
>to say about
>the melted terminal. Would they put the blame on pilot error or
>battery design
>or poor connection or too small wire size or a combination of these?
I suspect they would say, why was this battery
being used to crank so large an engine? Unless
a battery's sales literature speaks to 'cold
cranking amps' or some such, it's reasonable
to believe that hte battery was designed for
more pedestrian pursuits.
Waaayyy back when, there was an endeavor mounted
by a start-up that called themselves Bolder Technologies
out of Golden. CO. They started a next generation
of the jelly-roll SVLA cell that featured
very thin electrode sheets separated by
equally compacted layers of active material.
The cell was about the same size as a c-sized
flashlight cell. It was rated at about 1.1
Ah but had an internal resistance of about
1 milliohm. Short circuit current on this product
was over 1000 amps.
Clearly, this was designed to support the extra
ordinary demands of engine cranking. We saw
some samples at B&C about 1999. There were a
few products that exploited the cell's
features. One was a 'start stick' that showed
up at OSH a year or two. Show pilots were
using them to crank up and then leave behind
for the performance. But you only got ONE
chance to get her lit up . . .
The product had some problems. To achieve
those delivery currents, they had to make
1000A capable electrical contact along the
entire edge of an electrode sheet at both
ends of the jelly roll. Not easy. I think
there were issues with service life as well.
The company went TU and was bought out by
somebody in Malaysia I think. I'm seeing some
new offerings in the 'start stick' class
of product . . . costing $killo$. sure
hope the performance issues are fixed!
Then these new kids on the block may well
be lithium based.
https://goo.gl/yCJovM
Wow, $250 for a power cord . . . a bit
rich for my blood . . .
Dug around a bit on Bolder TMF. Found
some mentions all of which are 25
years old.
https://goo.gl/G11GRS
The TMF SVLA may well have been a flash in
the fires of history . . .
In any case, when a battery is INTENDED to
perform in the low duty cycle high drain
demands for engine starting, the engineering
data sheets will speak to that capability
with high draw time limits or other qualities
like cold cranking amps.
Many UPS/RV market batteries have been used
successfully in light aircraft but will
dance up to the edge of failure in hard-
start events . . .
Bob . . .
Message 2
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Subject: | Re: Constructing an automatic RCA video camera feed |
splitter
Update on the video multiplexer project:
Alec developed and tested firmware for the multiplexer, then programmed the prototype
board that I sent him. He then returned it to me and I finished the assembly
by adding the switching IC. I then packaged it up with some ancillary
parts and mailed it to Wade, so he can give it a test when he gets to that point
in his build.
More to follow once Wade reports on how the device works with his cameras.
Once we have a solid solution, I'll forward all of the design files to Bob so that
he can host them in his archive.
Eric
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=481987#481987
Message 3
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Subject: | Re: Melted battery terminal |
Tight connection are good to a point. After that, they can induce stress in the
terminal...which was probably made of recycled crap anyway.
Stress cracking, leading to failure. Only my guess.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=481992#481992
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