The only number you really need to care about is watts. Most USB devices these days use digital switching power supplies that can adjust for low voltages… but no device can compensate for low wattage. So the second screen that showed volts, amp & watts is the most useful. The iPadPro comes with a 12W charger but can be used with a 30W charger for fast charging. There’s debate that fast charging will decrease the battery life but given the short lifetime of these products it don’t know that it’s relevant. Oh, and upvote! ;-)
when you turn both resistors it makes the equivalent resistance to 1.5 ohms (shown in blue on the screen). Since Current = Voltage / Resistance, in order to supply 5.2v across 1.5 ohms you will draw about 3.47A of current. Since Power = Current * Voltage, in order to draw 3.47A at 5.2v you would need about of about 18W of power. Since the charger you are using has a rated maximum output of 12W (2.4A @ 5.2v) you are overloading the adapter by pulling more current than it can across the 1.5 ohms. Since Voltage = Power / Current, if the adapter's max power output is 12W and it is drawing 3.47A that would give us a voltage of about 3.45 which explains the low voltage reading.
True enough, the silk screening of Ohms law on the board reminds you :) Just interesting to see how some supplies fall off immediately after passing their limits, and some struggle on for quite a bit further.
@@CKHaun ya, i found your video when searching for clearer calibration instructions for the j7-c. I accidentally cleared the 5v and 2A calibration values. I ended up ordering a XY-UMPD to use with my LD25. I should be good.
Glad you found it. By the way, you might want to check out Voltagestandard.com . He provides high stability voltage sources that I use to calibrate or check my meters and 'scopes.
Thanks C.K. I enjoyed watching that video. I am thinking about getting one of these things as I just recently purchased a 1260 Wh EcoFlow Delta power bank (and I already had two NOCO Boost car jump starter/power brick devices) so it would be nice to see if my cables and charging devices are doing what I think (or hope) they are doing. Is this still what you would recommend for a USB testing newbie such as my self, and also in that $20-$40 range?
Thanks! And yes, I still find this unit is great utility for the price. Some of the functionality is almost hidden by various button presses, but spend 15-20 minutes exploring it and you'll find everything you want.
Well... some days ago I burned it off... There is a newer version that can handle 6.7A although might not have helped but the old is 5.1A - sadly no 10 Amp version of it or more, would have been nice.
@darkijah-andersjehovahsn7893 Thanks for the info, I may grab the new one and give it a spin. Hmm, power at 10 amps through USB might burn the wires :)
To the best of my knowledge and my use of this device, no there is not a way to capture the data externally. I’ll do a little research to see if I can find one that does, and if I can find one I’ll do a video on it.
They really have VERY high quality ones. If you want to see an expert on power supplies, go over to the @DiodeGoneWild channel, he's disassembled and analyzed more than 100 USB power supplies, from the best to absolute junk.
@@CKHaun Awesome, thanks for the lead. I have to laugh about USB adapters that come with new units. Most places if you have a problem with the device say "try replacing the USB adapter" and usually don't offer to send you another one. I'm curious to see how Anker fares - that was my choice after much frustrating research. Thanks again.
@@NoferTrunions I've had a lot of good luck with Anker devices. USB 3 to Ethernet adapter with three extra USB 3 ports, iPad chargers (because kids destroy theirs). I know I've bought other stuff from them, just blanking at the moment.
Great video!
I just got this tester to test inverters and power source on my channel and now i can't wait to try it.
It's a good little unit, though I will admit to squinting at the tiny text ;).
The only number you really need to care about is watts. Most USB devices these days use digital switching power supplies that can adjust for low voltages… but no device can compensate for low wattage. So the second screen that showed volts, amp & watts is the most useful. The iPadPro comes with a 12W charger but can be used with a 30W charger for fast charging. There’s debate that fast charging will decrease the battery life but given the short lifetime of these products it don’t know that it’s relevant. Oh, and upvote! ;-)
Watts is Watts, as they say. Good pointer on the wattage screen, and thanks for watching!
Thank you for the video of this test.
You're welcome! Another coming soon, a higher amperage one.
when you turn both resistors it makes the equivalent resistance to 1.5 ohms (shown in blue on the screen). Since Current = Voltage / Resistance, in order to supply 5.2v across 1.5 ohms you will draw about 3.47A of current. Since Power = Current * Voltage, in order to draw 3.47A at 5.2v you would need about of about 18W of power. Since the charger you are using has a rated maximum output of 12W (2.4A @ 5.2v) you are overloading the adapter by pulling more current than it can across the 1.5 ohms. Since Voltage = Power / Current, if the adapter's max power output is 12W and it is drawing 3.47A that would give us a voltage of about 3.45 which explains the low voltage reading.
True enough, the silk screening of Ohms law on the board reminds you :) Just interesting to see how some supplies fall off immediately after passing their limits, and some struggle on for quite a bit further.
@@CKHaun ya, i found your video when searching for clearer calibration instructions for the j7-c. I accidentally cleared the 5v and 2A calibration values. I ended up ordering a XY-UMPD to use with my LD25. I should be good.
Glad you found it. By the way, you might want to check out Voltagestandard.com . He provides high stability voltage sources that I use to calibrate or check my meters and 'scopes.
Thanks C.K. I enjoyed watching that video. I am thinking about getting one of these things as I just recently purchased a 1260 Wh EcoFlow Delta power bank (and I already had two NOCO Boost car jump starter/power brick devices) so it would be nice to see if my cables and charging devices are doing what I think (or hope) they are doing. Is this still what you would recommend for a USB testing newbie such as my self, and also in that $20-$40 range?
Thanks! And yes, I still find this unit is great utility for the price. Some of the functionality is almost hidden by various button presses, but spend 15-20 minutes exploring it and you'll find everything you want.
Well... some days ago I burned it off... There is a newer version that can handle 6.7A although might not have helped but the old is 5.1A - sadly no 10 Amp version of it or more, would have been nice.
@darkijah-andersjehovahsn7893 Thanks for the info, I may grab the new one and give it a spin. Hmm, power at 10 amps through USB might burn the wires :)
May I suggest wearing your readers next time you make a video? You misread the outputs numerous times, which causes confusion.
A reasonable request, sure.
I purchased one but came with no manual, does anyone know a link where I could get it? Thanks
Here's a link to the instruction PDF from the Amazon page; m.media-amazon.com/images/I/91Xq8hRhscL.pdf
Question? Is there a way that you can store the data streaming from the USB digital tester into your laptop?
To the best of my knowledge and my use of this device, no there is not a way to capture the data externally. I’ll do a little research to see if I can find one that does, and if I can find one I’ll do a video on it.
Maybe Apple is the highest quality USB power supply?
They really have VERY high quality ones. If you want to see an expert on power supplies, go over to the @DiodeGoneWild channel, he's disassembled and analyzed more than 100 USB power supplies, from the best to absolute junk.
@@CKHaun Awesome, thanks for the lead. I have to laugh about USB adapters that come with new units. Most places if you have a problem with the device say "try replacing the USB adapter" and usually don't offer to send you another one. I'm curious to see how Anker fares - that was my choice after much frustrating research. Thanks again.
@@NoferTrunions I've had a lot of good luck with Anker devices. USB 3 to Ethernet adapter with three extra USB 3 ports, iPad chargers (because kids destroy theirs). I know I've bought other stuff from them, just blanking at the moment.
That second USB adapter gizmo might be a data blocker.
Maybe, when I get another tester I'll take a look again.
Why do a review with music playing, so distracting, gave up watching, will look for other reviews.
I appreciate your feedback.
I agree, the music distracts from what you are saying.