Testing the current drawn by a number of different powerbanks
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Good morning all…
Youtuber, shed dweller, solar charge controller aficionado
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Literally powered up like some super villains bad ass laser. Well, almost.
My Xiaomi Mi 3 phone appears to ramp up current slowly (according to the apps i installed, i haven't measured on the cable) and stops at roughly 600mA. It does this on ravpower "ismart" chargers, htc and samsung chargers and the 200mA rated charger that came with it which gets quite warm at 600mA. I think they have set the charge current in software as people's phones were getting too hot. a full charge takes 5 hours now. The only thing I found different was a 5V 2A power supply I got from RS with the micro USB connector. It isn't specifically for phones and that's much slower.
Man I really need one of those current meters
You should rip apart some anker products, I'd like to see the insides of them.
looking for a power bank like your tes3 marked one, any chance you have a link to where you can purchase one?
That's interesting. It does look like some of them are stepping the current up in increments and checking for a sudden voltage drop to see what the maximum they can draw from the source is. I wonder if they nudge one step back if the source voltage does start to droop.
My powergen branded pack from Amazon ramps up like that. I assume it's looking for the point where the voltage of the power supply starts dropping off to try and figure out how much current it's good for. Could work well with solar panels I suppose.
After seeing your review of the 4-cell power bank (the one with the TES3 mark) and I can confirm it does that. I discovered that "feauture" by accident as I connected it to a source with bad regulation and heard the coil whining at different frequencies (that's a characteristic of a current increase on that particular source) and then stabilising. So what I did was to take the multimeter and I can confirm it ramps gently until it senses a voltage drop. It seems to max out at about 2A (on a proper strong 5.25V source from a LM257x with short and thick cables) but on a 0.5A charger it maxes out at about 0.45A as expected.
I think this could be tested out, if you gave it 5V and when it draws 1A lower the voltage to see what will happen.
Try it with some longer cables and USB extension cables to get a bit of voltage drop and see what happens!
I really liked this video.
This is why I bought the new black yzxstudio 2.0 USB monitor. I will use it to monitor my 14 watt Sunjack folding solar panels and my Anker Powercore + and Anker 2nd generation Astro E3 power banks.
I have learned to verify what these electronics do and not blindly accept the claims made by the manufacturers. 'Buyer Beware'
Thank you Julian ILett. 🙂
The last one. Is that soft start?
They are treating the waters, see what they can get away with just like kids!
I'd be inclined to try the same test on your oscilloscope. You can't be sure whether it's a characteristic of the power bank or the measuring device, whereas a more accurate device will tell you.
a good way of protecting USB when someone plugs a power pack into a computer for charging. Shame they don't all do this.