Bought an OLED version with transparent blue plastic shell version from an EBAY seller in china (http://www.ebay.com/itm/361006461953).
I was happy it arrived so quickly, but I was disappointed to find that while it passes the data connection (under some circumstances) it doesn’t work at all (no charging, no data connection) with iOS devices with the original Apple supplied cables and a variety of power sources (Mac laptop, various USB power banks, 10W iPad power brick)
Some pix…
Maybe the data pins just need different resistance?
Perhaps, but I thought it would just pass-through.
I contacted the seller. It sounds like I may have received a dud. They are sending a replacement that they’ve tested with a range of iOS devices.
I got the one sans case which works fine with iPhone 5 using new digital apple cable and ancient ipod with old 30pin cable. I was mainly interested in checking capacity and voltage sag between my chargers and such. I have old white MB (2007) so will test it when time permits. iPhone 5 capacity showed 1360 out of rated 1400mah so I’m satisfied. Also works great on my $4 Xtar MC1 for checking charge rate and capacity on the cheap.
Thanks for the report. I’m pretty sure the one I received is a bit hinky. I borrowed an iPad Mini to test with, since the product listing shows it working with a lightning device (an iPhone 5 or 5s). Mine didn’t work with that either. I’ll probably have the new one by next week (shipping was nice and fast the first time).
I’m kind of wishing I’d gone for the case-less version. The construction with the case is a bit flimsy and it doesn’t have the button to flip the display.
The replacement oled meter in a blue plastic case came today from axeprice.
It is much better than the last, USB data pass-through works when used between iOS devices and a computer. When connected to my Tomo V8-4 powerbank the device recognizes that there is a charger attatched and draws substantial (but less than max) current, strangely, the powerbank doesn’t seem to notice and powers itself down. I think the issue, in this case, is strangeness with the powerbank itself. It shows similar behavior with a dummy load whether attached directly, or through the meter…
not sure if posted yet
This one retains the mAh count, has 0-9 position
nice price! linked to ebay a few posts up 
i bought the oled version with case… an interesting thing about it is that it is reversible, in that you can use either female/male end for power input. could be useful if you have a limited array of usb adapters lying around
I have compared the oled versions, and the one with case has a bigger display with one digit more on capacity and power. Lol unsure if anyone is better in total…
It works good and it is fun to actually see how inefficient these USB power banks are…
Sad is that if you measure a power banks capacity in total the device will shut off after power down and loose the mAh value so you need to check it from time to time to see the result, haven’t thought of that until it was too late.
The last one linked does not suffer from this.
It does indeed shut down after the powerbank is empty but it has memory function so if you hook it up to another usb source, (a new powerbank or computer usb port or wallcharger or whatevery) it will show you the mAh count. And if you don’t attach a load to it it won’t add more to the counter.
They are not that inefficient, if they deliver 65% of battery capacity they have good efficiency.
I have one well-reviewed powerbank (Coolook), and it sometimes fails to detect insertion of USB-stick LED lights. I’m guessing the power banks have a threshold for detection of the presence and some devices don’t signify.
It’s all a question of the perspective… I got around 60% ratio of the mAh in the small one I have in my edc bag. So it isn’t so bad at all if 65% is good. 
It would be cool if these things would measure Wh because I recognized on some power supply’s the voltage rises if you pull out more current…
The problem is that the rated capacity is for the battery, that battery only has an average voltage of 3.7 volt. If the boost circuit was 100% efficient the output capacity would be 74% of battery capacity (With a 3.6 volt battery it is 72%).
A Wh rating would get around that.
Thanks for the explanation, now I can understand what you meant.
I just compared the mAh I charged in my phone with the mAh I filled In the power bank to charge it up again.
I also depleted it totally but like I said above I didn’t thought about the fact that if the bank shuts off I loose the info.
I will do that again if I have time to monitor it continuously, the cell inside is a single ncrA so it shouldn’t take too long on 1A load and probably 80% efficiency 0.74*2.9*0.8=1.7Ah. ->1h43min
using the usb doctor’s readout? depending on the voltage sag the mAh would be comparable, but then you are influenced by buck+boost+charging inefficiencies?
i have been interested in using it for gauging the capacity of e-cig batteries while charging. the results can vary quite a bit depending on the capacity class and charging circuit. i wonder if there is a typical formula for estimating it.
The charge circuit in a power bank is often a linear regulator, i.e. for a 3000mAh battery you need to fill 3000mAh into the box.
that is surprising. what would be the logic for that?
on an unrelated note, does anyone know if these types of oled displays will fade if left on for long periods at a time?
It is cheap and gain from using a switching regulator is not very large.
When charging you are not supposed to be limited in power. If you are using solar cells the that is, of course, not correct.
LCD does not fade, but oled does.
FYI folks…
Inline/passthru DCP enumerator
This is a passthru single port version of what I built, well…other than using the power provided by the port of course…mine uses an external power source
Truthfully you could take a standard USB cord, open it up around 1/2 way down, short the D+ and D- cords together and the device will pull up to a max of 1A then heatshrink it closed again…a “5 watt dedicated charge cable”
