Quick Test Proves High-Quality USB Cables Make a Big Difference

Charging our mobile phone is a daily activity for most of us. Like me, you've probably got your USB cable plugged into a charger. I've got plenty of USB cables lying around. I think they multiply like tribbles. Every time I buy another rechargeable gadget it comes with a full-sized USB to a micro USB cable.

I've got an 800 mA charger at my desk with a high-quality USB cable, right next to my coffee cup. The micro USB has a right angle, like the 3021080-10 USB A male to USB micro cable from Qualtek Electronics. The inner conductors are 24 AWG power and ground, and 28 AWG twisted pair for data. The diameter of the outer jacket is 4.5 millimeters (mm).

One morning I had my usual desk charger cable on another assignment. My phone was at 55% so I pulled a cable from my tangled cable stash and put it to work charging my phone. An hour later had only gone from 55% to 65%. It took all afternoon to charge my phone!

Okay, time to do some experimenting. I found an app for my Android called “Ampere” that displays the battery current draw when unplugged, and the charging current when plugged in. I took my favorite heavy-duty USB cable and repurposed it to charging my phone again. The charging current shown was a healthy 720 milliamps (mA), almost the same as the rated capacity as the AC adapter (Figure 1).

Figure 1: High-quality USB cables with a good AC adapter provide a healthy charging current. The AC adapter has a rated 800 mA capacity. (Image source: Bill Giovino)

While it’s expected that charging current may fluctuate while the phone runs mysterious tasks in the background, the charging current never went below 560 mA.

The cheapo unbranded USB cable only gave me a lousy 50 mA charging current (Figure 2). The charging current never faltered from 50 mA. I also had connection problems with this cable when trying to use it to transfer data between my phone and my laptop.

Figure 2: Low-quality USB cables with the same 800 mA AC adapter provide a sad charging current that never goes above 50 mA. (Image source: Bill Giovino)

The unbranded cable measured at about 10 AWG seen with my handy gauge meter in Figure 3, which according to specifications is a 2.588 mm outer jacket. The inferior cable is extremely flexible, while the quality cable is much more rigid. The quality USB cable clearly has thicker wires compared to thinner, less expensive cable.

Figure 3: The low-quality, unbranded USB cable measures as 10 AWG, circled in red. The high-quality cable is clearly thicker. (Image source: Bill Giovino)

Most mobile phones can sense if they are connected to a high capacity charger and adjust the charging current, from full charge down to slow trickle charge. All my high-quality USB cables charge the same, but for the lessor quality cables, no two cables charged with the same current – they are inexpensive cables with inconsistent quality.

Quality, plus innovation: USB cable is reversible!

As anyone who has used these cables can tell you, the annoying bit can be plugging them into the phone. Murphy’s Law of USB cables states that when plugging the USB cable into the side or the back of your laptop for the first time, it never seats. We’ve all done it. You plug it in, it doesn’t fit. Flip the connector over, plug it in – it still doesn’t fit. It can take 3 or 4 flips to get it right.

There’s a solution. The UR050-003-24G reversible USB A male to USB micro cable from Tripp Lite is very easy to use. The USB A Male end can be plugged into a computer in either direction, without having to flip it (what a great idea!). It’s also a heavy-duty cable. I’m getting two of them.

It’s not worth the hassle of buying the cheapest cable online when a few extra dollars spent on quality cables can make life so much easier.

About this author

Image of Bill Giovino

Bill Giovino is an Electronics Engineer with a BSEE from Syracuse University, and is one of the few people to successfully jump from design engineer, to field applications engineer, to technology marketing.

For over 25 years Bill has enjoyed promoting new technologies in front of technical and non-technical audiences alike for many companies including STMicroelectronics, Intel, and Maxim Integrated. While at STMicroelectronics, Bill helped spearhead the company’s early successes in the microcontroller industry. At Infineon Bill orchestrated the company’s first microcontroller design wins in U.S. automotive. As a marketing consultant for his company CPU Technologies, Bill has helped many companies turn underperforming products into success stories.

Bill was an early adopter of the Internet of Things, including putting the first full TCP/IP stack on a microcontroller. Bill is devoted to the message of “Sales Through Education” and the increasing importance of clear, well written communications in promoting products online. He is moderator of the popular LinkedIn Semiconductor Sales & Marketing Group and speaks B2E fluently.

More posts by Bill Giovino