Solder or crimp

[asdex]

Hi, I have some 50mm and 70mm lugs to attach. I don't have that size crimper and was wondering if soldering just as effective?
Thanks,

[lkruper]

Hi, I have some 50mm and 70mm lugs to attach. I don't have that size crimper and was wondering if soldering just as effective?
Thanks,

I believe 70mm lugs corresponds to a 2/0 AWG cable. I have read on this forum that anything bigger than 6AWG should be done with professional (read expensive) crimpers and that there is quite a bit of skill necessary to do it right. The connectors are where all the fires start. Since you are asking these questions, I perceive that you are not experienced. It has been recommended in this forum for inexperienced people to purchase cables with connectors and not make their own. It is a safety issue.

[Mike90250]

Solder will actually melt and the wires fall out, not good to do on top of your batteries with molten solder.

Crimp with a hydraulic crimper ($50 on flea bay) or buy cables pre-made. use UL listed lugs only

[asdex]

Hi, thanks for that. Will go with crimping then.
Cheers,

[inetdog]

Solder will actually melt and the wires fall out, not good to do on top of your batteries with molten solder.

Crimp with a hydraulic crimper ($50 on flea bay) or buy cables pre-made. use UL listed lugs only

As a technicality with some possible practical application too, the typical crimp on lug comes with instructions that require a specific type of hydraulic crimper and a die set for each size which embosses the die ID into the finished terminal.
That is a lot more functionality than your $50 eBay tool will have.
As an alternative you may be able to find a golf cart shop or welding supply shop that will cut the cables to length and crimp the terminals for you for a reasonable price. They have amortized the cost of their $1000+ tool set already.

In any case, once the connectors are properly crimped soldering will not add any strength or conductivity to the connection and runs a risk of causing the wire strands to break over time because of the concentrated stress point at the end of the solder area.

[asdex]

Hi, thanks for your information.
I think I'll look at the cheap hydraulic crimpers. I see they have them on TradeMe here.
Cheers,

[Mike90250]

Hi, thanks for your information.
I think I'll look at the cheap hydraulic crimpers. I see they have them on TradeMe here.
Cheers,

Yep, we are saying beware, if you have not used proper crimping tools, and know what a good crimp looks and feels like, and how important the die size is to be right and not just look good and then slide off a day later, pre-made cables are better for you. I had 30+ years in aircraft and spacecraft dealing with wiring and crimpers. I even sacrificed a cable to do a stress test, to make sure my $50 crimper was actually doing it's job deep in the lug. A good crimp cold welds the lug to the copper strands in the cable, and needs no solder.

Here is a pretty good article about crimping

http://www.klauke.com/en/electrical/technical-reports/which-cable-lug-suits-which-application/

and a so-so instructable, that does not cover large cable crimps.

http://www.instructables.com/id/How-to-Make-A-Quality-Crimped-Joint/?ALLSTEPS

and please don't use welding cable, it's flexible, but not UL rated for power wiring and many lugs don't properly fit the hair sized strands that make it so flexible, the inner strands almost never get properly compressed.

[asdex]

Thanks, good looking article from Klauke.
I bought one of the 4-70mm 8 ton hydraulic crimpers so will see how it goes.
I expect the dies won't fit AWG sizes well but our metric lugs should be ok.
I notice I need 2/0 or our 70mm sq cable for my inverter connections so will be a good test.
Cheers,

[Mike90250]

If you don't have a match for the die/lug, you can get close, by using a die that just barely clears the bare copper leads. It's a fine line between too much crimp, and not enough. They sure won't be certifiable or "rated" crimps though.