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Re: (ET) Battery Cables



What I have found through making up my own cables for my off grid system, where the cables are rated for 175 amps, is that it is all in the preparation of the cables. Here's how I did my cables:

The cables are THHN, 00 copper wire, not the highly flexible cable used for car batteries that have some vibration associated with the connections although with the size of cables used in ET's I think I will try to use standard THHN.

1. I used commercial connectors that you can buy on the net and made a punch to mechanically connect the wire to the lugs which is very important. You don't want the connection to be solely from solder. Here's how I made the punch block. I drilled a hole the same diameter of the cable lugs in a piece of scrap 3/8 to 1/2 inch stock. Then I cut the scrap metal in half directly through the diameter of the hole so I wound up with two equal halves. 2. I prepared the end of the cable by cutting off the insulation about 1/16" longer than the inside lug length. (also use lugs with the sealed ends not lugs opened at both ends of the lug.) 3. I cut a piece of heat shrink tubing (the kind with the water proof seal in it) twice as long as the lug and slipped it on the wire. I dipped the end of the wire into flux, pushed it into the lug placed into the half round hole in the scrap metal (locked in a vice) and used a punch to crimp the wire into the lug. I then used a propane torch and very carefully heated the lug to melt solder into the connection. 4. I let everything cool and then slipped the heat shrink tubing over the connection and used a hair drying to shrink it and seal the end. What you want is a connection that is mechanically tight and also sealed from oxygen.

My battery cables have been working for several years without any corrosion or problems.

Rob

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Today's Topics:

  1. Re:  battery cables (Robert Troll)
  2. Re:  battery cables (Charlie)
  3. Re:  battery cables (David Roden)
  4.  Fully restored EGT-150 for sale (Jeff Antonucci)
  5. Re:  battery cables (William Martin)


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Message: 1
Date: Fri, 9 Aug 2013 17:18:55 +0000
From: Robert Troll <roberttroll hotmail com>
To: "elec-trak cosmos phy tufts edu" <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) battery cables
Message-ID: <BLU179-W5184BE58DEDD0787D54448BA580 phx gbl>
Content-Type: text/plain; charset="iso-8859-1"

Use tinned marine cable of the same gauge as stock. Marine cable has far greater corrosion resistance, and is cheaper to boot. I buy mine on ebay for a $1 or so a foot. And because the strands are fine you can twist it into almost any shape easily.

You can put in a larger cable, but unless you plan on putting in a larger motor that will be pulling more amps, it is not necessary. If it were GE would have put in larger cables. IMHO The place to concentrate your efforts and cash is in making sure you have good solid connections. This is where the largest source of resistance will be.

It is generally not recommended in the marine world to solder high current connections. Something to do with creating more resistance and localized heating of the connector.



I need to replace a couple of the shorter battery cables. The current (ha ha) cables are 4 gauge and may not be original?

I have a vague idea that I've read that heavier cables would be better. If so, what size, and where's the best/least expensive place to get them? I do not want to make my own, as I understand they really need to be crimped with the appropriate tooling.

My batteries have golf cart studs. Were the original E-T cables/batteries car type posts?

For some reason the E-T index is not allowing searches?

Thanks.

Thon




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Message: 2
Date: Fri, 9 Aug 2013 15:05:19 -0400
From: Charlie <medievalist gmail com>
Cc: "elec-trak cosmos phy tufts edu" <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) battery cables
Message-ID:
<CAJb3uA7KnVVQLOCdvSgusJzA1BTyEmguXMejjvEDqEcgBPiXeQ mail gmail com>
Content-Type: text/plain; charset=ISO-8859-1

I thought people didn't solder heavy current cables because the solder
will melt out and run into other stuff if the connection overheats?

If I have my home foundry up and running by the time I need a new set
of cables, I'll see if I can lost-wax cast solid copper ends onto 4
gauge, and sidestep the whole solder vs crimp issue altogether.

--Charlie

On Fri, Aug 9, 2013 at 1:18 PM, Robert Troll <roberttroll hotmail com> wrote:
Use tinned marine cable of the same gauge as stock. Marine cable has far
greater corrosion resistance, and is cheaper to boot. I buy mine on ebay for
a $1 or so a foot. And because the strands are fine you can twist it into
almost any shape easily.

You can put in a larger cable, but unless you plan on putting in a larger
motor that will be pulling more amps, it is not necessary. If it were GE
would have put in larger cables. IMHO The place to concentrate your efforts
and cash is in making sure you have good solid connections. This is where
the largest source of resistance will be.

It is generally not recommended in the marine world to solder high current
connections. Something to do with creating more resistance and localized
heating of the connector.



I need to replace a couple of the shorter battery cables. The current (ha
ha) cables are 4 gauge and may not be original?

I have a vague idea that I've read that heavier cables would be better. If so, what size, and where's the best/least expensive place to get them? I do not want to make my own, as I understand they really need to be crimped with
the appropriate tooling.

My batteries have golf cart studs. Were the original E-T cables/batteries
car type posts?

For some reason the E-T index is not allowing searches?

Thanks.

Thon




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

Message: 3
Date: Fri, 09 Aug 2013 16:09:26 -0400
From: "David Roden" <etpost drmm net>
To: elec-trak cosmos phy tufts edu
Subject: Re: (ET) battery cables
Message-ID: <52051436 21446 104166BE etpost drmm net>
Content-Type: text/plain; charset=US-ASCII

One road EV converter I know of - can't think of the name right now, but
they converted Ford Escorts - used to lead-weld the battery interconnects
onto the terminals.  The connections were solid, that's for sure, but it
made battery replacement a wee bit challenging.

On the ET, the currents involved are far more reasonable, and certainly
don't require such drastic measures.  Welding or marine cable from a
trustworthy supplier in the #1 or #2 range, a good quality copper lug, and 
a
hammer crimper will do fine.  Bellville washers are gorgeous if you can 
find
them easily, but I've used a combination of flat and split washers with no
problem.

If you want pre-made cables, you might check truck repair and supply shops.
Watch out for low-qualty lugs and undersized wire in cheap discount-store
imported cables, though.

You'll find the same Chinese junk wire sold as welding cable on Ebay, at 
low
prices.  Some of it has undersized conductors - often a size or two under
the advertised gauge - and thick, flammable plastic insulation to make up
the size difference.  Caveat emptor.


David Roden - Akron, Ohio, USA

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