I have a number of USB cables and I notice that different combinations of cables and adapters/power banks result in different charge rates.
For instance, a short cable (eg. 0.5m) usually can output a high current (eg. 1.74A) when charging a device (eg. Galaxy S5) , whether the cable was connected to the wall outlet (charger) or power bank.
But a longer cable (1.0m) can output a high current (eg. 1.74A) when connected with a wall outlet charger, but will decrease somewhat (eg. 1.15-1.55A) when using a power bank.
While an even longer cable [good quality 2m cable] can sometimes output a high current (eg. 1.65A, sometimes even 1.74A, but not consistently) with a wall outlet charger, but sometimes it outputs a bit lower current (eg. 1.0-1.2A). And typically will not be able to output a high current when used with a power bank.
(I'm using the J7-4T OLED USB Display Tester for measuring mostly, but will also test again with the EBD-USB+ load tester/meter I recently got. In the above example, charging a Samsung Galaxy S5, whose top charging rate seems to be capped at 1.74A -- I've noted this measurement both with the J7-4T and the EBD-USB+; using different cables and wall outlets )
I'm not that well-versed in electronics, although I do have a basic budget model digital multimeter (only shows 3 digits), and I've also lately gotten some USB power meters (which I bought based on the reviews here) -- the J7-4T OLED USB Display Tester and also ZKE EBD-USB+ which seem to be pretty good (actually I also have a Keweisi KWS-V20 and KWS-V21 but these do not seem to be precise after I've used them a few months).
Is there a way of measuring USB cable resistance to check its quality? (I've read here about some Qoopow cable quality tester, but it seems to be quite expensive). Perhaps with the above-mentioned instruments (J7-4T and EBD-USB+ and a basic DMM), there's a way of testing USB cables (basically micro-USB ones). My basic DMM has only 3 digits so the J7-4T and EBD-USB+ actually shows more digits/resolution than it.
I notice there's a resistance (Ohms) for the J7-4T OLED USB Display Tester -- can that be used as cable resistance measurement, if possible? (I'll be comparing among my own cables only, since I currently don't have a way to calibrate the J7-4T to more accurate levels).