lol.
I have a RoadPro Food heater that draws 15A and an Igloo 26Qt mobile fridge that draws 6A.
I'm using a custom power panel I'm installing just to be certain it never overloads.
So I ran a 12GA power cable directly to the battery (and installed a 20A fuse right AT the battery). Of course, there is no need to run a Negative cable to the battery, I just ground it nearby the panel inside the vehicle.

If only I had a quarter for every time I made the most beautiful solder joint....THEN realized I left the shrink out <double FP>
Somehow the solder joint AFTERWARDS was never as purdy

In your other thread where this began you mentioned: You were going to use an automotive cigarette lighter socket so now you plan to use a custom power panel. So since Sunday all of this has changed I assume:

I'm going to install a new USB / Power outlet in my vehicle.

It consists of two USB A sockets rated at 2.2Amps each AND one standard size "Cigarette Lighter" socket (amp rating unknown)

To power this, I intend to run positive and negative wires directly from the vehicle battery (fused of course) to this new USB panel.
The total distance is approximately 7 feet.

What I'm wondering is what is the MINIMUM gauge of stranded copper primary wire I can safely use for this?

I have 16ga primary wire on hand but I'm concerned this may not be sufficient. Surely 14ga would be adequate?

Thanks

Ron

 

There definitely is a better way. What I've done for years, and has never failed me, is first tin both wires, and then solder them together completely in parallel. Just make sure that solder has uniformly joined them through their length... this method is far easier to perform and maximizes electrical contact between both wires. I've also never seen it mechanically fail.

And yes, shrink wrap around the joint is always a must ... never ever use electrical tape...

I always use this method too. If you pull on the wire until it fails, the wire will break but the joint will still be intact.

 

In your other thread where this began you mentioned: You were going to use an automotive cigarette lighter socket so now you plan to use a custom power panel. So since Sunday all of this has changed I assume:
Ron

Not really. Maybe I just worded it differently. I think I drank decaf that morning

The different threads are about completely separate, unique things.
One was about wire gauges and the flow of current. Nothing to do with soldering at all.
The other all about soldering techniques And not about the gauge of the wire

It was my feeling they were worthy of their own thread.
If you see otherwise you can merge them if you feel it necessary.

Sorry if this caused you stress.

 

I always use this method too. If you pull on the wire until it fails, the wire will break but the joint will still be intact.

I'm no expert by any means, but I always thought that the more copper to copper contact the better.
Intertwining the strands from the end of one wire with those of the end of the other wire would seem to accomplish greater direct contact and therefore better conductance / less resistance?

In the method described by laying the wires together parallel, if you looked at the actual contact area between the two wires, there would be minimal contact surface area between the wire so the solder would then be the main conductor.

Whether or not this is of any significance, I'm not sure.

But it also begs the question....which is more important....conductance or joint strength?

 

But it also begs the question....which is more important....conductance or joint strength?

I'd say conductance is more important, since a joint is not supposed to be subjected to movement, flexing, or stress of any kind in the first place.