Battery Cable Crimp Question

[mrekim]

The ring connectors that connect to my battery are the type where you can see the cable strands on the ring side of the connector. If I wiggle the cable, the strands on the ring side move.

My understanding of a good crimp is that the the cable and crimp ring get cold welded together. I would think that a good crimp would not transfer movement through that cold weld, so a slight wiggle on the cable side should not transfer to the ring side.

Is this something I need to pursue further - or am I looking at this wrong?

[kneal44]

i have had several new lugs crimped for less than $3 at my local auto parts stores. they have the tools to do a great crimp.

i just spend the better part of the morning cleaning the battery tops and each crimp. then recoating with corrosion resistant spray.

should be good for another season.

[JaxDad]

I use those lugs, but don't crimp them. Instead I put a little soldering past in the hole, then the wire and with a propane torch then sweat solder down into it.

It makes a pretty solid connection and never works loose.

[brulaz]

Chris Bryant wrote:

brulaz wrote:

Maybe I should just get one of the hammer crimpers and a bunch of closed-end lugs and do/redo all those connections.

EDIT: or those Fusion solder lugs.

The hammer crimp doesn't impress me at all- a picture of one with clear overheating problems-


Name brand labeled lug crimped with an approved crimper. *Not* heat shrinked, though, just taped.

That's 4/0 cable.

The hammer crimper seems to work better with 6ga cable. The head of the crimper I got is about as wide as the lug itself, so you don't get that deep indentation in the centre that you see with the 4/0.

[SCVJeff]

It really doesn't matter the load, drop is the drop. Just because it doesn't make heat and burn like Chris's did doesn't mean it's OK. I recently found a jumper across the 6V batteries that I didn't make and THOUGHT was good until I happened to see a voltage drop across this 6" jumper. It was only 1 or 2/100v, but that's a big deal when trying to balance out a series/ parallel battery bank.

[brulaz]

Chris Bryant wrote:
I found this by finding a voltage drop in the cable under load- I forget the specifics, but under a heavy load (probably ~300 amps) I had a significant loss, exacerbated by the fact that this system uses 2 volt batteries, so a fraction of a volt per connection adds up.

I'm estimating my max MPPT charging amps as 25A, and it's possible my my 110V battery charger could get up to 60A if the batteries are severely depleted, but I'm sure it will be a lot less normally. I'm fusing it at 60A anyway.

As for loads, well they are a lot, lot less, and I'm not even wiring for those. That wiring came with the trailer and I wasn't planning on changing that.

[Chris_Bryant]

I found this by finding a voltage drop in the cable under load- I forget the specifics, but under a heavy load (probably ~300 amps) I had a significant loss, exacerbated by the fact that this system uses 2 volt batteries, so a fraction of a volt per connection adds up.

[brulaz]

BoonHauler wrote:

...
I agree with Jeff, the vise idea is a bad one!

well, it's in the mail so I'm using it. And I'll probably never do this again so am definitely not spending the $$$ on a hydraulic crimper.

Found some info via google that should help with making a reasonable crimp. It doesn't have to be perfect.

[BoonHauler]

SCVJeff wrote:

brulaz wrote:

Chris Bryant wrote:

...
The hammer crimp doesn't impress me at all- a picture of one with clear overheating problems-
...

hmmm, are you sure it was the crimp and not just the load? But yes, too deep a crimp.

I'll be using a vice, not a hammer, so more control. Does somebody have instructions/advice for using these things? Should you do a partial crimp and then rotate?

The load is the cause of the heat, but only because the crimp is defective. It should carry the same load as the cable. There are different kinds of 'crimps'. One chould argue that this 'crimp' stretches the metal, not compresses it. A good hex crimp literally compresses and re-shapes the metal itself (think Superman and coal= diamond). If you start making multiple compressions on a vise, I think you stand an excellent chance of fatiguing the metal and splitting it.

I agree with Jeff, the vise idea is a bad one!

[SCVJeff]

brulaz wrote:

Chris Bryant wrote:

...
The hammer crimp doesn't impress me at all- a picture of one with clear overheating problems-
...

hmmm, are you sure it was the crimp and not just the load? But yes, too deep a crimp.

I'll be using a vice, not a hammer, so more control. Does somebody have instructions/advice for using these things? Should you do a partial crimp and then rotate?

The load is the cause of the heat, but only because the crimp is defective. It should carry the same load as the cable. There are different kinds of 'crimps'. One chould argue that this 'crimp' stretches the metal, not compresses it. A good hex crimp literally compresses and re-shapes the metal itself (think Superman and coal= diamond). If you start making multiple compressions on a vise, I think you stand an excellent chance of fatiguing the metal and splitting it.

[SCVJeff]

silicone can take a tremendous amount of heat

[time2roll]

I don't see the heat issue. If the copper is discolored from heat where is the melted insulation?

TWECO T-120 lug seems to compatible with a wide range from #1 to 2/0.

[brulaz]

Chris Bryant wrote:

...
The hammer crimp doesn't impress me at all- a picture of one with clear overheating problems-
...

hmmm, are you sure it was the crimp and not just the load? But yes, too deep a crimp.

I'll be using a vice, not a hammer, so more control. Does somebody have instructions/advice for using these things? Should you do a partial crimp and then rotate?

[SCVJeff]

The depth of that crimp looks like trouble to start

[Chris_Bryant]

brulaz wrote:

Maybe I should just get one of the hammer crimpers and a bunch of closed-end lugs and do/redo all those connections.

EDIT: or those Fusion solder lugs.

The hammer crimp doesn't impress me at all- a picture of one with clear overheating problems-


Name brand labeled lug crimped with an approved crimper. *Not* heat shrinked, though, just taped.

That's 4/0 cable.