Introduction: No-frills USB to MicroUSB Heavy-duty Cat-5e 5+ft 1'5+m Charging/data Cable


Well, thanks to its wide hose, my latest DIY 5V DCP supply showed me how my puny 4-feet 28AWG USB data cable was effectively limiting the current supplied to my smartphone. Since I had some spare supplies, I decided to build me a proper USB to microUSB power/data cable.

«Heavy-duty» performance explanation: since Cat-5e cable houses in 4 twisted wire pairs, and one must be reserved for data duties, 3 pairs can be used for power delivery, which means around 0'615mm² of wire section is available for this purpose. With just under 57'71mΩ per meter of total wire resistance, total voltage drop for this barely above 1'5 meters long cable is expected to be less than 87mV per amp of current flow. For a 2'4A current flow, that's still less than 207'75mV of drop. Now go find me a commercial USB data cable which can hold up to this kind of performance.

3xAWG24 gauge = AWG19'26

Step 1: Bill of Materials

  • 1'5+m of used standard Cat-5e cable in good condition; 4 twisted pairs of AWG24 gauge wires inside.
  • An USB type A male plug ripped from an “El cheapo” USB to miniUSB cable which came with an MP4 player. A cutting disk equipped multitool was used to achieve this.
  • An USB aerial female plug shell I had lying around. Equipped with a cutting bit, me and my multitool enlarged the shell's cable hole as for it to properly grab hold of the Cat-5e cable.
  • A B-type microUSB aerial male plug with shell.
  • Miscellaneous: hot glue + gun, eutectic solder wire + iron, various tools, skill, patience, etc.

Step 2: A-male Assembly

Cable pin arrangement:

  1. Vcc is soldered to orange, green and brown wires.
  2. -D is soldered to white/blue wire.
  3. +D is soldered to blue wire.
  4. GND is soldered to white/orange, white/green and white/brown wires.

The only requirement here is a somewhat decent skill with hot glue, just that. Since the innards of the female shell are somewhat bigger than what the male plug requires to fit in, after wire soldering on the plug, a carefully measured layer of hot glue must be spread out inside of it and, quickly afterwards, the plug is carefully landed over, taking an eye on keeping the plug at the proper heights. As I had left a slight scar on the side of the male plug (at the back innards of the plug, near the cable tabs), somewhat purportedly at about middle height, this helped me in order to make sure the plug would be perfectly centered between both shell sides. All this positioning duty was mainly achieved with my finger over the cable end at the plug entry. Once this harder part is achieved, a good layer of hot glue on the other side of the shell and... close up!

After this, I used a sharp knife to remove the leftovers of hot glue over the plug. Done!

Step 3: Micro-B Male And... Work Completed!

Cable pin arrangement for this plug:

  1. Vcc is soldered to orange, green and brown wires.
  2. -D is soldered to white/blue wire.
  3. +D is soldered to blue wire.
  4. Not connected.
  5. GND is soldered to white/orange, white/green and white/brown wires.

Notice my pliers covered with a tad of insulating tape. It must be noted that, since this kind of cable seems to be primarily designed as crimping tool fodder, I noticed that merely holding the wires tightly with the pliers in order to strip them off was enough for the cable sheathing to become damaged. Sheathing material heat resistance is also pretty poor. I had to redo the micro-B male because of short circuit issue. Bear in mind that soldering these wires must be done quickly and skillfully in order to prevent any excess heat melting that solder-wise puny sheathing. If unsatisfied with your just done solder dot, be patient and wait a good deal of seconds before redoing it; either this or face-off a melted sheathing.

Hope you like it!

Step 4: Ouch! Slippy Cable Jacket!

Just a not so important update. As time went by, somehow the cable jacket slipped out of the micro-USB shell (Damn! It was hot glued from the inside!). Of course I could have rebuilt the whole thing but instead, I've opted for some hot-glued creativity in order to prevent any chance of wire strangling. Oiled sticky tape was used to give some sort of elegant shape to the thing. (-:


Step 5: Final Update: Slippy Cable Jacket Botch Eliminated; Elegance Restored. (-:

Well, well, well!

More time went by dears and my previous hot-glue inspired slipped sheathing fix-up broke off.

I decided to redo the whole micro-USB male with an improved design to avoid the network cable sheathing to slip out of the connector.

Please bear in mind this has to do with this particular type of cables because of the intrinsically slippery nature of its sheathing. My solution was to use some sort of means to properly tie the sheathing to the pack of internal wires: twisted tie.

After finishing the soldering job, I slided the sheathing back in, close to the male connector, and made sure to firmly coil some twisted tie to the cable; applied then some hot glue and closed the thing. After a minute or two, I used a sharp knife to do away with any outside glue remainings.

I've been using the upgraded cable for a while, and feels solid. :-)

Hope you enjoy it!

Cheers ^:-)