Wire type and crimped vs solder connections

[spudbudy]

Forgive me if this has been discussed in the past my search did not return any meaningful results. I'm looking at different wires for my DC to DC converter.
I have pretty much settled on running 4 gauge wire from the starter battery to a Anderson connector then to the DC to DC charger then house batteries. In looking at different wires I have seen welding cable, Copper clad aluminum, Audio wire and others. My questions is what's what? I do not want to purchase the wrong type of cable. It's only going to be for maximum of 50 amps. and the distance 35-40 feet total. I know cheaper isn't always better. On another note is using crimped cable ends better or using soldered ends. I can't seem to find a good answer on this some say personal preference, I would like to hear what you have to say.

 

[Steve_S]

Avoid CCA (Copper Clad Aluminum) it's not much good. Fine Strand Copper is best for DC wiring for heavy things like battery banks and long term high amp usage. This is one the reasons most use Fine Welding Cable for battery wiring and also the sheathing is far more durable & flexible. 35-40 feet is a long wire run for DC Battery, basically, the longer the run, the thicker gauge of wire is needed to compensate for the loss, it's a DC thing, that is why grid power is AC. The Ampacity Charts say 4 Gauge is right on the money for <50A, if you go with Welding cable, it'll handle more so here is some of the best cable you can get below.

Crimping or soldering ? Soldering big cables has to be done with a torch and it's not easy. Most everyone crimps on Tin Plated Lugs and covers over the edges & cable partly with heat-shrink tubing (the stuff with adhesive in it is best). A really good crimp is required, a basic hammer crimper can work well if you are very cautious (do a few practice ones 1st ok that you can toss). You can buy better crimpers for more $ but check out Will's recommendations : https://www.mobile-solarpower.com/tools.html

EXCELENE 4 Gauge AWG Welding Lead Cable Copper Wire MADE IN USA | eBay

$EXCELENE 4 Gauge AWG Welding Lead Car Battery Cable Copper Wire MADE IN USA If you purchase more than one quantity your order will ship in one length 4 AWG CONSTRUCTION: This cable consists of one bare copper conductor with integral insulation and jacket. APPLICATION: Welding Cable Applications...

www.ebay.com

 

[spudbudy]

Hi Steve, Thank you that was the information I was searching for. I've been looking @ wire on Amazon and most of the cheap stuff is CCA type. I will avoid that wire in the future. Next question it looks like all 4 gauge wire is not the same size, AWG, SWG is there any good way to make sure it's AWG? I have no problem using a torch for soldering terminals on, just curious what the preferred method was. Crimp for smaller wires and solder for larger wires. Either way Thank you for the info.

Bob

 

[Hedges]

"Starter battery to DC/DC charger to house batteries"
So this is to charge an RV battery from your alternator? How much continuous current is expected, and can the alternator handle it?
I'm wondering why Steve_S says 4 awg when 8 awg can handle 50A, although with IR drop at high currents. I'd think that would be OK if most of the time current was less.

Besides crimp (generally the best way for heavy battery cables), there are also various lugs with setscrews and other clamping methods.
Obviously engine compartment by a starter battery is likely to be exposed to corrosive atmosphere, so needs to be sealed protecting wire strands.

 

[Zil]

You cannot go wrong with marine grade cables with crimped terminals. Do not use aluminum. Do not solder your stranded wires. Here is one source for quality cable and terminals. https://www.genuinedealz.com/#

 

[spudbudy]

"Starter battery to DC/DC charger to house batteries"
So this is to charge an RV battery from your alternator? How much continuous current is expected, and can the alternator handle it?
I'm wondering why Steve_S says 4 awg when 8 awg can handle 50A, although with IR drop at high currents. I'd think that would be OK if most of the time current was less.

Besides crimp (generally the best way for heavy battery cables), there are also various lugs with setscrews and other clamping methods.
Obviously engine compartment by a starter battery is likely to be exposed to corrosive atmosphere, so needs to be sealed protecting wire strands.

Hello Hedges, Yes the alternator is a 180 amp output so should have no issue with 50 amp additional draw. I checked all the wire size gauge charts and 6 gauge will work upto 50 feet, going to 4 gauge gives me plenty of overhead. This output is most likely overkill as it will be split with solar panels on the fifth wheel for a total of 50 amps. But in the event of driving in the dark the alternator would output the full 50 amps if needed. I can always set the Charger to output a lower amp output if necessary. Perhaps I'm over thinking it. I have not been too impressed with some of the hydraulic crimpers available on Amazon, Harbor Freight and such. Trying to get a good handle on everything before committing to purchasing tools and supplies. Would only like to buy the tools once

Thank you
Bob

 

[Steve_S]

50A 35-40 feet
@10% per chart for 30-50' says 4 awg. @3% 40' says 2 awg
Having buffer is good if it was me, I'd do 2 awg or even 1

SOURCE: https://www.bluesea.com/support/art...oosing_the_Correct_Wire_Size_for_a_DC_Circuit

 

[Hedges]

I succeeded in mashing some 2/0 connectors well enough with the cheap HF hydraulic crimpers, but really the die should be sized to the exact terminal being used, as wall thickness varies. There have been a number of strings and links on this forum so read up on what worked well.

So long as you know your alternator will survive the current you plan to draw. They are all hobbled by cooling. Stock alternator on my 2500 HD had positive side diodes fail, and it didn't have any extra loads during my time; maybe the winch when PG&E owned it?

Fatter wire is always better, but also stiffer and more expensive. I figure from a source to a switching regulator you can generally tolerate a lot of drop, it is just efficiency loss. In this case, depends on minimum input voltage of the DC/DC converter. Running 30A vs. 40A cuts loss almost in half.

 

[spudbudy]

I know the wire size is not 100% correct. The max output of 50 Amps and a max of 50 feet, I think it's closer to 35 to 40 feet broken up by an Anderson connector at the back of the truck, but definitely less then 50 feet overall. The DC to DC output is adjustable from 5 to 50 amps. So I can dial in what works best. This controller has a built in MPPT controller which will work along side the truck alternator side. So in an ideal situation driving in the daylight I would never see 50 amps from the truck side alone. Even in the event of nighttime driving I could easily drop the setting down or just unhook the truck side if not needed. I appreciate all the feedback and all the options available. I hope that by doing this the right way the first time, it will provide years of trouble free service.