those of you who have been watching my mail bags for a while will know that
I've accumulated a small pile of USB cables for powering stuff like we all do
and I've also got some some connectors some of the female connectors so that we
can connect them up to a test rig of my own devising now then what I'm testing
for is not the day to capability that just works or it doesn't work what I'm
testing for is can they actually handle a charging current for instance for
charging my phone the one that you're using here to watch this devices these
days tend to charge it like over and amp I think my tablet can charge it up to 2
amps and that's just using these USB micros not even getting into USB C like
that one there because it can negotiate a higher power and a higher current
their higher voltage but what I want to check is is are these things actually
capable of being used for charging at any reasonable rate because those wires
look pretty skinny this one and this one are dollar store cables this one this
one and that one are from eBay that one came with a power bank this one is a
Samson or is it this one is a Samsung branded cable came with a phone this one
is a blackberry branded cable obviously came with a phone - so my testing
methodology is going to be I'll wear this female a jack up to my power supply
which is pretty stable voltage output and I can monitor the current on it as
well because the current is going to be the same anywhere in a circuit it's just
as easy to monitor it there and I don't care if it's a hundred percent a Q
as long as it's consistent from one cable to the next however in my previous
playing with this thing it is very close close enough anyway to minimize the
influence of my test rig in this I'm going to make up some short wires to to
reduce the losses the resistive losses and to do that I'm going to use this old
PC power supply cable which is 20 gauge wire I'm just getting your twinks of it
but 20 gauge wire is gonna be heavier than anything that's in there and the
shorter I can keep it the more realistic this test is gonna be and the same thing
at the other end I'm going to connect these guys to a power resistor because
they don't want to cook a small resistor obviously I'm going to be pulling
hopefully an amp so I don't really want to cause smokeless fire it's not
unintentionally it's all good to do that normally so I've got two resistors here
that I found out of my assortment seven and a half walked home and a 10 ohm
resistor and based on their their tolerances and whatnot I thought I'd get
very close to a decent load here so that is as close as you're going to get to 5
ohms I'm just trying to get closer on the stab onto this and get through the
crud 5.03 ohms that's pretty close so with a little bit
of poems on magic 5 volts over 5 ohms equals 1 amp so that's what this thing
is gonna draw and then I'll be able to measure with again the expensive
voltmeter that our board from work what the actual voltage is here is that
to be here you give us the voltage drop through the cable we'll subtract that
from the voltage that we we subtract ya that from the voltage going into it over
here and then I'll tell us our losses right right the first thing to do I
don't think this is too exciting you don't uh do you want to watch me cut
wire and solder maybe if I hadn't lost my wire cutters later that same evening
okay so uh I was going to measure that okay let's turn this on no measure the
voltage the back at the coming right off the power supply
it turned up until it's exactly five
okay so there we go I mean agree that that's as close to five volts as we're
going to get this happens to say 5.11 but we'll just go with that there's the
current reading okay so with this short little cable that came with the power
bank plug him in he that's reading one amp there probably should have put some
meter socket or something on here so that is four point four eight shall we
call it
so let's got about a half a volt drop across it at 1 amp load for a really
short cable that's not performance 4.51 that's pretty much the same thing ooh
4.30 4 point which we call it four point three one be generous well that's not
great four point seven zero that's the best one that we've had so far what
three point five that's horrendous four point four six that's not too bad let's
call it four point one six just to be generous
okay let me just clear the deck here a little bit and get my results set up all
right here's the rogues gallery from best over here the Samsung of cable that
came with the Samsung phone second best the blackberry brandy cable that came
with a blackberry phone and then the next one is this woman came with a power
bank although that is really disappointing for a cable that short it
shouldn't be losing that much power the next two are a couple that oh no this is
this one that I got off eBay that came with USBC adapter and then the two from
my local dollar store and finally the cheapest one I could find on eBay it's
just not worth the effort it's just that's a lot of stuff won't even run off
of that I don't even know why you'd want that anyway thanks for watching I hope
that was vaguely informative the at the very least the I hope that in the
testing method is useful to somebody obviously you're not going to be buying
these exact same cables although if you want a good charging cable stick with
the ones that came with your phone thanks for watching I will talk to you
later