UM25C & LD25 USB + Cable tester review by Texas_Ace - I figured out why my LII-402 was not working!

Hmm.

I would recommend you Ugreen and Blitzwolf cables if you want some low resistance ones.

Also, its mOhms, not Ohms. Otherwise, you would be seeing 4,5V at 1A, but more like 0,5V.

Dodge Reviews (member dodge_911 here) has been doing lots of micro-USB cable reviews using USB testers in his Youtube video channel. May also be worth making some cable comparisons…

That was very good troubleshooting there . I ordered an LD35 from them and will put it to good use now.

lol, once you get in the groove it moves fairly quickly. I actually found a box with about twice as many cables as the picture and sorted through them all.

I think I ended up with about 30% that were basically unusable (backed up by many of those giving me issues in the past), 30% were passable for basic small things and the rest were split between good cables and better cables.

Yep, I have some Ugreen cables and they tested very well. I will be spending the extra for good cables from now on.

You are also correct on the ohms, not sure why I didn’t catch that.

Yuu can check the quality of USB cables yourself with this devices too:
QooPow™ qualMeter (Basic)

https://www.amazon.com/Cable-Charger-Quality-Tester-Dummies/dp/B01LZIXGYW

https://www.kickstarter.com/projects/1187836018/qoometer-finally-a-smart-usb-cable-charger-tester

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QooPow qualMeter XT

https://www.kickstarter.com/projects/1187836018/qualmeter-xt-greater-experience-on-cable-charger-t

Interesting, a lot more expensive but nice to know and it is built for the task.

Say, speaking about UGreen.

I just found out they carry 20AWG and 18AWG USB-C cables.

Probably the THICKEST USB cables on the planet.

You should probably buy one of them, just to make sure you get the absolute lowest resistance.

Here is the 18AWG USB-A to USB-C:

https://www.aliexpress.com/store/product/Ugreen-5A-Nylon-Type-C-Cable-Fast-Charger-USB-Type-C-Cable-for-Huawei-P10-P10/301635_32857628201.html?spm=2114.12010612.8148356.20.60fe310aVOvIAP

20AWG USB-C to USB-C:

https://www.aliexpress.com/store/product/Ugreen-3A-USB-C-to-Type-C-Cable-for-Samsung-Galaxy-S9-USB-2-0-Nylon/301635_32888616771.html?spm=2114.12010612.8148356.30.48a1310aQAiEiV

A bit expensive for a cable, but it is worth it.

Interesting and that price is actually not that bad at all, I expected much higher.

I would get one if I had any USB-C devices that needed a cable.

I still use a galaxy S5 myself and most of my other hardware is equally aged or worse lol.

Yeah.

The highest AWG cable I could find that is in the micro-USB category was by Anker with 20AWG power wires.

Still, 18AWG on a USB cable is mind boggling to say the least. Would be extremely good to test USB powerbanks and see if the manufacturer is padding the numbers, and not having to worry about a cable losing a ton of energy to heat.

portapow also offers 20AWG USB cables.
http://portablepowersupplies.co.uk/home/micro-usb-data-blocker-usb-cable

And there are 18AWG cables too:
https://www.ebay.com/itm/50cm-1-5FT-18AWG-Micro-B-USB-Fast-Quick-Charge-Cable-2-1A-Android-Smart-Phone/112544042504

I was speaking of USB-C.

Doing 18AWG, while quite hard on micro-USB, it is doable.

Using the same diameter wire is harder with USB-C since it has extra pins for reversibility and more pins.

Here’s a video about how to check cable quality on the UM25©:

UM25© Measure Type-C and Micro cable resistance same with UM24© and UM34©)

Thanks for posting this! I just got a new phone and been researching USB type C. Studying up on chargers and cables is a must. If you go cheap or buy the wrong cable or charger you could easily brick you phone.

USB type C can pump some serious wattage!

I’ve been testing a lot of my USB cables last night… most of them came from the factory with various USB devices that I bought.
Just about all of them seem to have fairly high resistance, aside from a Blitzwolf USB C cable I paid good money for and a 6-inch Cable Creations one - that one has low IR primarily because it’s so short.

I try to order shorter USB cables these days, to help keep IR low. I just ordered a micro USB 1.5 ft UGreen one plus another 1.5 ft one from Monoprice - I’ve seen some positive comments about them. Let’s see.

I also ordered a Ugreen cable recently and it tested good as well, although I have not actually put it into use yet, waiting for my current cable to wear out first lol.

Which one did you get?

I ordered this one: Amazon.com

I don’t remember, it was a few months back, about when I did this review. It was on sale at amazon so I picked it up.

I think that ugreen generally has pretty good quality though.

@Pete7874, you are using the Drok USB load+meter combo, right? I forgot to tell you something about the method I told you about yesterday.

The method I showed you earlier does not take into account the power supply voltage dropping under load.

That means to compare cables, it is very accurate of course, and reliable within that data set.

HOWEVER, to actually measure the resistance of a singular cable, it is not reliable at all, since the power supply drops voltage under load.

You need a USB meter like the UM25C to calculate a single cable’s resistance.

The power supply I’m using has a voltage display, and I can see it dropping slightly under load. For example, at idle it’s at 5.26V. At 1A it’s at 5.24V. So, could I use this information in conjuction with voltage data from the DROK load tester to more accurately calculate cable resistance?

I ordered one.