# [EVDL] creeping resistance at the cable/lug interface



## EVDL List (Jul 27, 2007)

G'day all,

This problem is still haunting me. I make up a nice new
beautiful 2/0 battery cable with Magna automotive post lugs,
Quickcable ratchety bench-mounted cable crimper, and a healthy
hit of Noalox in the lug barrel, and finish off with shrink
tubing. I even label the cable ends with a typed label under
transparent shrink tubing. In short, I do all the steps as I
understand them. On goes the cable on the battery pack. Nice
low voltage drop across the cable from post-to-post and
lug-to-lug. Stays nice and cool after climbing hills. 150-degF
CelsiDots on the posts do not turn. All is well and good with
the world 

Come a year or two later, maybe three, I emit an :-( emoticon.
Some of the CelsiDots have turned when I check them during my
monthly battery maintenance. If I check the voltage drop across
the cable with 15 or 75 (or whatever amps) flowing, lug-to-lug
has increased considerably, while post-to-post is almost exactly
the same ==> post-to-lug resistance stays near zero and the
problem is not there. Something is going on inside the lug
barrel next to the post that flips the CelsiDot.

Any suggestions? I had thought maybe the copper would be pulling
away from the inside of the barrel, since copper is ductile and
will tend to flow. But I hacksawed one of these hot lugs apart,
and the copper was wall to wall, basically solid. My next guess
would the Noalox is drying out and causing increased resistance.
Off the top of my head, I'm not certain if I've tried filling the
lug (halfway up the barrel, as with noalox) with vaseline.
Noalox is supposedly not a conductor. I doubt vaseline is a
great conductor either. Some of this cable I've bought has some
color, ie. oxidized strands, but I still get a nice low starting
resistance.

My next escalation may be to follow a suggestion to bunch-tin the
exposed copper strands before inserting into the barrel and
crimping. No antioxidant in the barrel. The local Bay Area
person that suggested that to me some years ago is no longer with
us. My ?s mainly have to do with how to heat up the flux. I
assume you make a little pool of liquid flux in a metal cup of
some sort. I don't think a soldering iron will do the trick, and
I can't do this on the stove in the apt. Has to be done out on
the deck, probably with my small camping propane stove. Or is
there another way? Will the crimper still squeeze the lug down
around these bunch-tinned copper wires without damaging the dies?

Next step up will be to take a flight out to Corrupticut and get
a lug soldering lesson from the Soldering God - Bob Rice. :-o

I wonder if recrimping or trying to send some solder down the
inside edge of the barrel will salvage a hot end. Will lose the
shrink tubing to do that. I may try that during vacation coming
up in a week or so.

Seems that when I used the Mike Brown approach to interconnecting
the batteries in this VoltsRabbit, I had no hot post problems.
Copper straps and flag terminals. I moved to automotive posts
because I had the impression cable offered more conductor area
and the posts could be more easily covered. But it has proven to
be more of a hassle, and the voltage drops I incur with this
problem probably negate the lesser drop through the cable.

Chuck

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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
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----------



## EVDL List (Jul 27, 2007)

Hello Chuck,

One time, I had to replace a battery link where the copper strands was 
fracture by tinning it first before it was put in the lug. Tinning these 
1056 copper strands cables make these wires very brittle and harden up.

So I made up a new link with a Noalox compound in the barrel and crimp it 
with a ratchet Thomas and Betts crimpier. When I started up the EV, it felt 
like I lost a lot of power because of just that one link.

Using Noalox compound in any wire terminal that we normally use for exterior 
electrical work, it has to subject to a very high pressure using a high 
pressure hydraulic tools.

I also notice that using a high pressure crimpier on these barrels on this 
very fine welding wire, it also fractures some of the wires. So looking in 
my wire book, I found a 2/0 cable that has 273 copper strands that I use to 
replace all the links and battery terminals.

I crimp this cable to the barrels with no contact compound in a heavy duty 
barrel that has no hole on the other end, which is normally use for a solder 
type barrel.

This time the wires did not fracture and made a solid copper mass inside the 
barrel. Also bending the wire back and forth at the barrel end did not 
brake like the fine wires did.

I also use a very heavy duty heat shrink with sealant in it which will seal 
out any moisture or air. These links are now use for the last 16 years with 
no problem.

When installing these links, I do a shunt test while the battery pack is 
being charge at about 10 amps. I connect a milliamp meter in parallel with 
the battery link, connected the test leads at the lead post.

I then finish torque the last 5 inch pounds with a inch pound torque wrench. 
Some battery clamps may have to be torque more than the others, where I get 
same reading of about 0.001 amp at each connection.

Caution, to do test I use all insulated Kline electrical tools and rubber 
blankets that drape over the all the batteries terminals except the one I am 
tightening and testing.

Even after all do this, you may have to re-torque the battery connections 
again, because you could loss about 5 inch pounds in the first 5 miles.

Roland


----- Original Message ----- 
From: "Chuck Hursch" <[email protected]>
To: "EVDL post" <[email protected]>
Sent: Sunday, June 07, 2009 12:25 PM
Subject: [EVDL] creeping resistance at the cable/lug interface


> G'day all,
>
> This problem is still haunting me. I make up a nice new
> beautiful 2/0 battery cable with Magna automotive post lugs,
> Quickcable ratchety bench-mounted cable crimper, and a healthy
> hit of Noalox in the lug barrel, and finish off with shrink
> tubing. I even label the cable ends with a typed label under
> transparent shrink tubing. In short, I do all the steps as I
> understand them. On goes the cable on the battery pack. Nice
> low voltage drop across the cable from post-to-post and
> lug-to-lug. Stays nice and cool after climbing hills. 150-degF
> CelsiDots on the posts do not turn. All is well and good with
> the world 
>
> Come a year or two later, maybe three, I emit an :-( emoticon.
> Some of the CelsiDots have turned when I check them during my
> monthly battery maintenance. If I check the voltage drop across
> the cable with 15 or 75 (or whatever amps) flowing, lug-to-lug
> has increased considerably, while post-to-post is almost exactly
> the same ==> post-to-lug resistance stays near zero and the
> problem is not there. Something is going on inside the lug
> barrel next to the post that flips the CelsiDot.
>
> Any suggestions? I had thought maybe the copper would be pulling
> away from the inside of the barrel, since copper is ductile and
> will tend to flow. But I hacksawed one of these hot lugs apart,
> and the copper was wall to wall, basically solid. My next guess
> would the Noalox is drying out and causing increased resistance.
> Off the top of my head, I'm not certain if I've tried filling the
> lug (halfway up the barrel, as with noalox) with vaseline.
> Noalox is supposedly not a conductor. I doubt vaseline is a
> great conductor either. Some of this cable I've bought has some
> color, ie. oxidized strands, but I still get a nice low starting
> resistance.
>
> My next escalation may be to follow a suggestion to bunch-tin the
> exposed copper strands before inserting into the barrel and
> crimping. No antioxidant in the barrel. The local Bay Area
> person that suggested that to me some years ago is no longer with
> us. My ?s mainly have to do with how to heat up the flux. I
> assume you make a little pool of liquid flux in a metal cup of
> some sort. I don't think a soldering iron will do the trick, and
> I can't do this on the stove in the apt. Has to be done out on
> the deck, probably with my small camping propane stove. Or is
> there another way? Will the crimper still squeeze the lug down
> around these bunch-tinned copper wires without damaging the dies?
>
> Next step up will be to take a flight out to Corrupticut and get
> a lug soldering lesson from the Soldering God - Bob Rice. :-o
>
> I wonder if recrimping or trying to send some solder down the
> inside edge of the barrel will salvage a hot end. Will lose the
> shrink tubing to do that. I may try that during vacation coming
> up in a week or so.
>
> Seems that when I used the Mike Brown approach to interconnecting
> the batteries in this VoltsRabbit, I had no hot post problems.
> Copper straps and flag terminals. I moved to automotive posts
> because I had the impression cable offered more conductor area
> and the posts could be more easily covered. But it has proven to
> be more of a hassle, and the voltage drops I incur with this
> problem probably negate the lesser drop through the cable.
>
> Chuck
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 

_______________________________________________
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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

I would have to agree with Roland here - do not solder, and don't use DeOx 
or Noalox, and do use the dual-wall heat-shrink. This give the best results 
on a high-pressure crimp joint.

If you want to use Noalox or something similar for flooded cells, use it 
between the lug and the post, not in the crimp joint.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]



----- Original Message ----- 
From: "Roland Wiench" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, June 07, 2009 1:46 PM
Subject: Re: [EVDL] creeping resistance at the cable/lug interface


> Hello Chuck,
>
> One time, I had to replace a battery link where the copper strands was 
> fracture by tinning it first before it was put in the lug. Tinning these 
> 1056 copper strands cables make these wires very brittle and harden up.
>
> So I made up a new link with a Noalox compound in the barrel and crimp it 
> with a ratchet Thomas and Betts crimpier. When I started up the EV, it 
> felt like I lost a lot of power because of just that one link.
>
> Using Noalox compound in any wire terminal that we normally use for 
> exterior electrical work, it has to subject to a very high pressure using 
> a high pressure hydraulic tools.
>
> I also notice that using a high pressure crimpier on these barrels on this 
> very fine welding wire, it also fractures some of the wires. So looking in 
> my wire book, I found a 2/0 cable that has 273 copper strands that I use 
> to replace all the links and battery terminals.
>
> I crimp this cable to the barrels with no contact compound in a heavy duty 
> barrel that has no hole on the other end, which is normally use for a 
> solder type barrel.
>
> This time the wires did not fracture and made a solid copper mass inside 
> the barrel. Also bending the wire back and forth at the barrel end did 
> not brake like the fine wires did.
>
> I also use a very heavy duty heat shrink with sealant in it which will 
> seal out any moisture or air. These links are now use for the last 16 
> years with no problem.
>
> When installing these links, I do a shunt test while the battery pack is 
> being charge at about 10 amps. I connect a milliamp meter in parallel 
> with the battery link, connected the test leads at the lead post.
>
> I then finish torque the last 5 inch pounds with a inch pound torque 
> wrench. Some battery clamps may have to be torque more than the others, 
> where I get same reading of about 0.001 amp at each connection.
>
> Caution, to do test I use all insulated Kline electrical tools and rubber 
> blankets that drape over the all the batteries terminals except the one I 
> am tightening and testing.
>
> Even after all do this, you may have to re-torque the battery connections 
> again, because you could loss about 5 inch pounds in the first 5 miles.
>
> Roland
>
>
> ----- Original Message ----- 
> From: "Chuck Hursch" <[email protected]>
> To: "EVDL post" <[email protected]>
> Sent: Sunday, June 07, 2009 12:25 PM
> Subject: [EVDL] creeping resistance at the cable/lug interface
>
>
>> G'day all,
>>
>> This problem is still haunting me. I make up a nice new
>> beautiful 2/0 battery cable with Magna automotive post lugs,
>> Quickcable ratchety bench-mounted cable crimper, and a healthy
>> hit of Noalox in the lug barrel, and finish off with shrink
>> tubing. I even label the cable ends with a typed label under
>> transparent shrink tubing. In short, I do all the steps as I
>> understand them. On goes the cable on the battery pack. Nice
>> low voltage drop across the cable from post-to-post and
>> lug-to-lug. Stays nice and cool after climbing hills. 150-degF
>> CelsiDots on the posts do not turn. All is well and good with
>> the world 
>>
>> Come a year or two later, maybe three, I emit an :-( emoticon.
>> Some of the CelsiDots have turned when I check them during my
>> monthly battery maintenance. If I check the voltage drop across
>> the cable with 15 or 75 (or whatever amps) flowing, lug-to-lug
>> has increased considerably, while post-to-post is almost exactly
>> the same ==> post-to-lug resistance stays near zero and the
>> problem is not there. Something is going on inside the lug
>> barrel next to the post that flips the CelsiDot.
>>
>> Any suggestions? I had thought maybe the copper would be pulling
>> away from the inside of the barrel, since copper is ductile and
>> will tend to flow. But I hacksawed one of these hot lugs apart,
>> and the copper was wall to wall, basically solid. My next guess
>> would the Noalox is drying out and causing increased resistance.
>> Off the top of my head, I'm not certain if I've tried filling the
>> lug (halfway up the barrel, as with noalox) with vaseline.
>> Noalox is supposedly not a conductor. I doubt vaseline is a
>> great conductor either. Some of this cable I've bought has some
>> color, ie. oxidized strands, but I still get a nice low starting
>> resistance.
>>
>> My next escalation may be to follow a suggestion to bunch-tin the
>> exposed copper strands before inserting into the barrel and
>> crimping. No antioxidant in the barrel. The local Bay Area
>> person that suggested that to me some years ago is no longer with
>> us. My ?s mainly have to do with how to heat up the flux. I
>> assume you make a little pool of liquid flux in a metal cup of
>> some sort. I don't think a soldering iron will do the trick, and
>> I can't do this on the stove in the apt. Has to be done out on
>> the deck, probably with my small camping propane stove. Or is
>> there another way? Will the crimper still squeeze the lug down
>> around these bunch-tinned copper wires without damaging the dies?
>>
>> Next step up will be to take a flight out to Corrupticut and get
>> a lug soldering lesson from the Soldering God - Bob Rice. :-o
>>
>> I wonder if recrimping or trying to send some solder down the
>> inside edge of the barrel will salvage a hot end. Will lose the
>> shrink tubing to do that. I may try that during vacation coming
>> up in a week or so.
>>
>> Seems that when I used the Mike Brown approach to interconnecting
>> the batteries in this VoltsRabbit, I had no hot post problems.
>> Copper straps and flag terminals. I moved to automotive posts
>> because I had the impression cable offered more conductor area
>> and the posts could be more easily covered. But it has proven to
>> be more of a hassle, and the voltage drops I incur with this
>> problem probably negate the lesser drop through the cable.
>>
>> Chuck
>>
>> _______________________________________________
>> General EVDL support: http://evdl.org/help/
>> Usage guidelines: http://evdl.org/help/index.html#conv
>> Archives: http://evdl.org/archive/
>> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>>
>>
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>


--------------------------------------------------------------------------------



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Checked by AVG - www.avg.com
Version: 8.5.339 / Virus Database: 270.12.55/2160 - Release Date: 06/07/09 
05:53:00

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
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----------



## EVDL List (Jul 27, 2007)

Ok, Joe, I can drop the noalox and make cable-making life simpler
(cleaner and less gooey). Probably more important then to use
the meltable inner liner shrink tubing (is that what you mean by
the dual-wall heat shrink?).

I did use noalox on the motor cables back in 1994, and those
cables see more amps than the battery pack cables. I used a
hammer crimper back then as part of the VoltsRabbit instructions.
Those motor cables are still in use today, and I haven't detected
any heat stress in those.

Thanks (also to Roland),
Chuck

----- Original Message ----- 
From: "joe" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, June 07, 2009 4:25 PM
Subject: Re: [EVDL] creeping resistance at the cable/lug
interface


> I would have to agree with Roland here - do not solder, and
don't use DeOx
> or Noalox, and do use the dual-wall heat-shrink. This give the
best results
> on a high-pressure crimp joint.
>
> If you want to use Noalox or something similar for flooded
cells, use it
> between the lug and the post, not in the crimp joint.
>
> Joseph H. Strubhar
>
> Web: www.gremcoinc.com
>
> E-mail: [email protected]
>
>
>
> ----- Original Message ----- 
> From: "Roland Wiench" <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Sunday, June 07, 2009 1:46 PM
> Subject: Re: [EVDL] creeping resistance at the cable/lug
interface
>
>
> > Hello Chuck,
> >
> > One time, I had to replace a battery link where the copper
strands was
> > fracture by tinning it first before it was put in the lug.
Tinning these
> > 1056 copper strands cables make these wires very brittle and
harden up.
> >
> > So I made up a new link with a Noalox compound in the barrel
and crimp it
> > with a ratchet Thomas and Betts crimpier. When I started up
the EV, it
> > felt like I lost a lot of power because of just that one
link.
> >
> > Using Noalox compound in any wire terminal that we normally
use for
> > exterior electrical work, it has to subject to a very high
pressure using
> > a high pressure hydraulic tools.
> >
> > I also notice that using a high pressure crimpier on these
barrels on this
> > very fine welding wire, it also fractures some of the wires.
So looking in
> > my wire book, I found a 2/0 cable that has 273 copper strands
that I use
> > to replace all the links and battery terminals.
> >
> > I crimp this cable to the barrels with no contact compound in
a heavy duty
> > barrel that has no hole on the other end, which is normally
use for a
> > solder type barrel.
> >
> > This time the wires did not fracture and made a solid copper
mass inside
> > the barrel. Also bending the wire back and forth at the
barrel end did
> > not brake like the fine wires did.
> >
> > I also use a very heavy duty heat shrink with sealant in it
which will
> > seal out any moisture or air. These links are now use for
the last 16
> > years with no problem.
> >
> > When installing these links, I do a shunt test while the
battery pack is
> > being charge at about 10 amps. I connect a milliamp meter in
parallel
> > with the battery link, connected the test leads at the lead
post.
> >
> > I then finish torque the last 5 inch pounds with a inch pound
torque
> > wrench. Some battery clamps may have to be torque more than
the others,
> > where I get same reading of about 0.001 amp at each
connection.
> >
> > Caution, to do test I use all insulated Kline electrical
tools and rubber
> > blankets that drape over the all the batteries terminals
except the one I
> > am tightening and testing.
> >
> > Even after all do this, you may have to re-torque the battery
connections
> > again, because you could loss about 5 inch pounds in the
first 5 miles.
> >
> > Roland
> >
> >
> > ----- Original Message ----- 
> > From: "Chuck Hursch" <[email protected]>
> > To: "EVDL post" <[email protected]>
> > Sent: Sunday, June 07, 2009 12:25 PM
> > Subject: [EVDL] creeping resistance at the cable/lug interfac
e
> >
> >
> >> G'day all,
> >>
> >> This problem is still haunting me. I make up a nice new
> >> beautiful 2/0 battery cable with Magna automotive post lugs,
> >> Quickcable ratchety bench-mounted cable crimper, and a
healthy
> >> hit of Noalox in the lug barrel, and finish off with shrink
> >> tubing. I even label the cable ends with a typed label
under
> >> transparent shrink tubing. In short, I do all the steps as
I
> >> understand them. On goes the cable on the battery pack.
Nice
> >> low voltage drop across the cable from post-to-post and
> >> lug-to-lug. Stays nice and cool after climbing hills.
150-degF
> >> CelsiDots on the posts do not turn. All is well and good
with
> >> the world 
> >>
> >> Come a year or two later, maybe three, I emit an :-(
emoticon.
> >> Some of the CelsiDots have turned when I check them during
my
> >> monthly battery maintenance. If I check the voltage drop
across
> >> the cable with 15 or 75 (or whatever amps) flowing,
lug-to-lug
> >> has increased considerably, while post-to-post is almost
exactly
> >> the same ==> post-to-lug resistance stays near zero and the
> >> problem is not there. Something is going on inside the lug
> >> barrel next to the post that flips the CelsiDot.
> >>
> >> Any suggestions? I had thought maybe the copper would be
pulling
> >> away from the inside of the barrel, since copper is ductile
and
> >> will tend to flow. But I hacksawed one of these hot lugs
apart,
> >> and the copper was wall to wall, basically solid. My next
guess
> >> would the Noalox is drying out and causing increased
resistance.
> >> Off the top of my head, I'm not certain if I've tried
filling the
> >> lug (halfway up the barrel, as with noalox) with vaseline.
> >> Noalox is supposedly not a conductor. I doubt vaseline is a
> >> great conductor either. Some of this cable I've bought has
some
> >> color, ie. oxidized strands, but I still get a nice low
starting
> >> resistance.
> >>
> >> My next escalation may be to follow a suggestion to
bunch-tin the
> >> exposed copper strands before inserting into the barrel and
> >> crimping. No antioxidant in the barrel. The local Bay Area
> >> person that suggested that to me some years ago is no longer
with
> >> us. My ?s mainly have to do with how to heat up the flux.
I
> >> assume you make a little pool of liquid flux in a metal cup
of
> >> some sort. I don't think a soldering iron will do the
trick, and
> >> I can't do this on the stove in the apt. Has to be done out
on
> >> the deck, probably with my small camping propane stove. Or
is
> >> there another way? Will the crimper still squeeze the lug
down
> >> around these bunch-tinned copper wires without damaging the
dies?
> >>
> >> Next step up will be to take a flight out to Corrupticut and
get
> >> a lug soldering lesson from the Soldering God - Bob Rice.
:-o
> >>
> >> I wonder if recrimping or trying to send some solder down
the
> >> inside edge of the barrel will salvage a hot end. Will lose
the
> >> shrink tubing to do that. I may try that during vacation
coming
> >> up in a week or so.
> >>
> >> Seems that when I used the Mike Brown approach to
interconnecting
> >> the batteries in this VoltsRabbit, I had no hot post
problems.
> >> Copper straps and flag terminals. I moved to automotive
posts
> >> because I had the impression cable offered more conductor
area
> >> and the posts could be more easily covered. But it has
proven to
> >> be more of a hassle, and the voltage drops I incur with this
> >> problem probably negate the lesser drop through the cable.
> >>
> >> Chuck
> >>
> >> _______________________________________________
> >> General EVDL support: http://evdl.org/help/
> >> Usage guidelines: http://evdl.org/help/index.html#conv
> >> Archives: http://evdl.org/archive/
> >> Subscription options:
http://lists.sjsu.edu/mailman/listinfo/ev
> >>
> >>
> >
> > _______________________________________________
> > General EVDL support: http://evdl.org/help/
> > Usage guidelines: http://evdl.org/help/index.html#conv
> > Archives: http://evdl.org/archive/
> > Subscription options:
http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
>
> ---------------------------------------------------------------
-----------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.339 / Virus Database: 270.12.55/2160 - Release
Date: 06/07/09
> 05:53:00
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> Chuck Hursch <[email protected]> wrote:
> > Regarding salvaging some of these cables that have incurred high
> > resistance at the cable/lug interface, I think I'm going to try
> > wicking some solder down into the lug on one of them, and see if
> ...


----------



## EVDL List (Jul 27, 2007)

> On 17 Jun 2009 at 13:16, Chuck Hursch wrote:
> 
> > I think I'm going to try wicking some solder down into the lug on one
> > of them, and see if I can return it to service.
> ...


----------



## EVDL List (Jul 27, 2007)

Saturday I bought a propane torch kit at Orchard Supply Hardware
to get set up for doing a little solder flowing on a test cable.
Also bought a 4-ft stick of 1"-dia. meltable-inner-liner heat
shrink tubing at the local electronics store for $20 (yeeooww!,
that hurts - now I remembered why I didn't have any of the
meltable stuff on hand, only the plain-jane stuff for what, $4?;
I wonder if there is a cheaper place to buy meltable stuff?).
$20 is more than the propane torch kit with its bottle of propane
at $17, and implies $0.62 per each cable end (1.5" of tubing /
end).

Then, Sat. evening, I read Lee's post (my comments interspersed):


> > Chuck Hursch <[email protected]> wrote:
> > > Regarding salvaging some of these cables that have incurred
> high
> > > resistance at the cable/lug interface, I think I'm going to
> ...


----------



## EVDL List (Jul 27, 2007)

EVDL Administrator (David Roden) wrote:
> On 17 Jun 2009 at 13:16, Chuck Hursch wrote:
>
> > I think I'm going to try wicking some solder down into the
lug on one
> > of them, and see if I can return it to service.
>
> Have you considered hacksawing or cable-shearing the lugs off,
and crimping
> on new lugs? Or would that make the cables too short?

On the pack itself, there are four lengths of cable, if one is
not too picky. Roughly: 10", 7" (most of them are this length),
4", 2" (a real shorty at the end of the VoltsRabbit L that was
tough to make). So a 10" could be made into a 7", but whacking a
7" means it can't be used anymore in one of those positions.
Whacking is probably going to take off a good inch to an
inch-and-a-half, minimum.

Note that my EV's pack cabling was changed from stock VoltsRabbit
when I got my second pack in 2001. I went from the copper strap
and L (flag) posts approach to automotive posts and cables. The
reasons for this:

- The uncovered posts always bothered me. Sure, it's easy to
take voltmeter readings, but it's also easy to drop a tool on
those posts. And if you're at a show, you never know who might
come along and make a point of it. Second, if you're plugged in
with your non-isolated charger, as I was in those days many a
time with the hood open at a show, and somebody comes along and
touches your uncovered post while on damp ground... Well, there
were some bothersome thoughts, even with a high-voltage sign,
that I didn't like.

- I disliked, to some degree, the cross-over cables on the front
pack that went over the step. I noted that Anna Cornell's (as
designed by her husband, Scott) bunny had a much cleaner-looking
engine bay, and part of that was the cabling arrangement, with no
step-over cables. I changed to that cabling arrangement.

- I was reading that the automotive post was the most robust
post, and that if one does the calculation for resistance between
the copper straps on the standard VoltsRabbit, it is like running
1-ga cable, as opposed to 2/0 cable.

So I made the decision to change, for better or worse. I kept
the battery arrangement, but the electrons flow through a
different, (hopefully) lower resistance, path. It would be
interesting to do the analysis to see whether I actually gained
anything, considering the connector problems I've had. I think
the VoltsRabbit kit uses the copper straps to avoid some of the
complications, especially for people trying to get their first EV
going, as I was in 1994. Also, the copper straps cost less than
those automotive cable lugs.

Chuck

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## EVDL List (Jul 27, 2007)

Good work, Chuck! It looks like re-crimping helped a lot. However, I 
wonder if they weren't crimped properly in the first place (were high 
resistance from day one), or were initially low but then went up (some 
kind of creepback as you surmised).

A tight crimp is essentially a cold weld (pressure weld). It shouldn't 
loosen up over time. With a loose crimp, it is possible that moisture or 
battery acid got inside there, and corroded things. Re-crimping it may 
have "broke through" the layer of corrosion to improve the connection. 
But if moisture continues to get in there, it could corrode again.

This is why I suggested dip soldering them in a solder pot.

-- 
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > Good work, Chuck! It looks like re-crimping helped a lot.
> However, I
> > wonder if they weren't crimped properly in the first place
> ...


----------



## EVDL List (Jul 27, 2007)

<snip>
> As I've mentioned before, when I cut a lug open, it looked
> like a
> solid mass
> of lug and copper, but maybe a visual inspection doesn't
> tell
> all.
</snip>

Back when I was just out of high school, I got a job at the Fracture and De=
formation lab at the National Bureau of Standards. When they would cut a s=
pecimen in half to look at it's crystal structure, or to look at a crack, i=
t was quite an involved process. Usually cut with a diamond saw, and then =
it goes through several steps of sanding and polishing. To see the crystal=
structure they would quite often etch the sample, sometimes with hydrofluo=
ric acid (nastiest stuff I've ever seen). And these are with steel samples=
. I can only imagine cutting soft copper won't really show how "cold welde=
d" the copper is. I bet the process of cutting it smears all the copper st=
ands together. It's good that you actually checked; not many people go thr=
ough as much trouble as you did, and I appreciate you sharing your results.


<snip>
> However, if I gotta do this every
> couple of
> years,
> using that expensive meltable inner-liner shrink tubing is
> maybe
> not a good idea? Or maybe one re-crimp is all it will
> take? I
> guess time will tell...
</snip>

When I couldn't find the heat shrink with glue in it locally (and didn't pl=
an ahead enough to mail order some), I used a lot of hot melt glue. I firs=
t put a ring around the gap between the ring and the exposed copper on the =
cable end. I then put a ring on the lug around where I expected the heat s=
hrink to end. I reused a bunch of cables from an old 150kVA UPS, which use=
d AGM batteries, not the floodies I was using. So some of the lugs had ope=
n ends (so you can see the individual stands sticking through the lug). I =
filled that up with hot melt glue. When I shrunk the shrink, I did it long=
enough to re-melt the hot melt glue. This seems to have helped a lot. Oh=
, I forgot to mention. I didn't do all this at first when I just replaced =
a few bad cables, and they corroded pretty bad over time. Before all this,=
I cleaned the corroded ones up with a wire wheel and dunked them in some l=
iquid solder flux (used for PCBs in wave soldering machines) and
then in a solder pot, to tin them. I doubt much solder wicked up into the=
connector; that wasn't my goal, but I did make sure it got hot enough to p=
roperly attach to the lug. Those lugs are still very clean.

Thanks for taking detailed notes and sharing your results!

Steven Ciciora


=


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## EVDL List (Jul 27, 2007)

>> This is why I suggested dip soldering them in a solder pot.



> Chuck Hursch wrote:
> > Ok, I'll have to look up dip soldering, and see what that
> > entails...
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Steven Ciciora wrote:
> > Fracture and Deformation lab at the National Bureau of Standards.
> > When they would cut a specimen in half to look at it's crystal
> > structure, or to look at a crack, it was quite an involved process...
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > >> This is why I suggested dip soldering them in a solder pot.
> >
> > Chuck Hursch wrote:
> ...


----------



## EVDL List (Jul 27, 2007)

Steven Ciciora wrote (between dashed lines):
--------
Back when I was just out of high school, I got a job at the
Fracture and Deformation lab at the National Bureau of Standards.
When they would cut a specimen in half to look at it's crystal
structure, or to look at a crack, it was quite an involved
process. Usually cut with a diamond saw, and then it goes
through several steps of sanding and polishing. To see the
crystal structure they would quite often etch the sample,
sometimes with hydrofluoric acid (nastiest stuff I've ever seen).
And these are with steel samples. I can only imagine cutting
soft copper won't really show how "cold welded" the copper is. I
bet the process of cutting it smears all the copper stands
together. It's good that you actually checked; not many people
go through as much trouble as you did, and I appreciate you
sharing your results.
--------

Yeah, a hacksaw frizzes the copper strands just a bit, but it
still looked pretty solid. I'm not remembering for sure just
where I cut. It may have been right at the edge of a crimp,
between the two that are applied to these lugs.

Interesting background out of high school, there at NBS (I assume
you're speaking of the Boulder, CO campus). My father worked
there back in the early '60s, and I know Bill Dube works there.
I went by it many times when I was a student at CU and shortly
before in the late '70s to mid '80s.


--------
Thanks for taking detailed notes and sharing your results!
--------

I have three log books (am on the third) full of notes on this
car since 1994. I love taking data, something I learned to do to
some degree back at CU in college physics labs (although we
learned data error analysis back then, something I don't do
here - seems too involved). However, I don't always like taking
the time to write it down. And finding it years later can
sometimes take awhile. My monthly hydrometer readings are all in
spreadsheets on the computer (with printouts pasted into the
logbooks) as well as the occasional pack load tests I've done
(along with connector resistance readings I've done at the same
time).

One thing I haven't been so good on is keeping the circuit
diagrams for the VoltsRabbit updated as a few new circuits have
been added in. I remember Mike Brown making a point about that
in his class. It's something that some time on the computer
would take care of.

Chuck

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## EVDL List (Jul 27, 2007)

> Chuck Hursch wrote:
> > You basically immerse the lug all the way up to the gap between
> > the lug and cable insulation?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

Lee Hart wrote (June 21-ish):
> Good work, Chuck! It looks like re-crimping helped a lot. However, I 
> wonder if they weren't crimped properly in the first place (were high 
> resistance from day one), or were initially low but then went up (some 
> kind of creepback as you surmised).
> 
> A tight crimp is essentially a cold weld (pressure weld). It shouldn't 
> loosen up over time. With a loose crimp, it is possible that moisture or 
> battery acid got inside there, and corroded things. Re-crimping it may 
> have "broke through" the layer of corrosion to improve the connection. 
> But if moisture continues to get in there, it could corrode again.
> 
> This is why I suggested dip soldering them in a solder pot.
> 

Last weekend I had the occasion to do a pack mini load test (the pack 
was seeming a little down and I wanted to catch any weak batteries 
before they got hammered any further - didn't find any too out of sorts) 
with the ~15A RUSSCO heater. Ran for two hours. At any rate, I took 
the opportunity to measure the voltage drops on the cables. Basically, 
the re-crimped cables' resistance have all doubled at the copper - lug 
barrel interface in about one month's time, from ~3mV @ ~15A to roughly 
7mV (I'm measuring lug-to-lug across the length of the cable). I was 
not too happy to see that. It basically tells me that crimping alone 
won't cut it, one's going to have to solder dip. There's some 
mechanical issue going on, since I don't think one month's time is 
enough for more corrosion to build up inside a gooey heat-shrinked 
connection.

I did try to purchase an American Beauty solder pot on Ebay - there was 
one for $9.99, but got quickly outbid (the last I saw it was up near 
$26). Maybe I should buy the one for $50 that a List'r mentioned.

No more gooey expensive heatshrink till I get this problem handled.

Chuck




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