Why doesnlt my Xiaomi 16000mAH Power Bank, using its original USB, work with my Z3?

[Humprey Fetalvero]

Xiaomi 16000mAH Power Bank Needs Charge-only USB Cable to Work with Z3

Hello!

The Xiaomi 16000mAH power bank, using its original USB cable, didn't work on my Z3. Though, to my surprise, it worked on other smartphones (have tried samsung and lenovo). So I tried my friend's power bank USB cable albeit blindly (since the Xiaomi unit worked with other phones, there should be no problem with the cable right?), and strangely, it worked!

So what gives? Later on, I found out that the other cable is a "Charge-only" cable (cannot use for data transfer).

So why do you think exactly does this Xiaomi 16000mAH needs a charge-only USB cable in order to work with Z3 but not with other device? Also, do you think it safe to use it that way in the long run?

Lastly find it strange that I cannot seem to find (I mean Google) any case similar to mine (I don't think I'm the only Z3 user who purchased this power bank), but I also think it is genuine (there are many youtube and websites that gives numerous pointer to this). I've already contacted the supplier about these, I think I can still send it back, but I really had it on a good deal (from Malaysia, below $25, including everything, if converted).

What do you think?

 

[srkmagnus]

Re: Xiaomi 16000mAH Power Bank Needs Charge-only USB Cable to Work with Z3

I would suggest looking for a replacement cable that will work or sending the unit back to the retailer if it doesn't work properly with your device. As to why it would require a charge only cable? I'm not sure and couldn't really answer that question.

Let us know how it goes.

 

[Humprey Fetalvero]

Re: Xiaomi 16000mAH Power Bank Needs Charge-only USB Cable to Work with Z3

Now this gets more interesting..

I've also purchased a Sony wireless speaker SRS-BTV5, and guess what, the same happens! Using a charge+data cable won't work, but a charge-only cable would!

I guess there is a protection circuit on these Sony device that disconnects the charging (at least for this Xiaomi 16000mAH power bank), but I can't seem to imagine what would be the problem that would only be present on charge+data cable and not on a data-only cable. After all aren't power banks also do what AC charger does namely short the data pins (I just guess this since both of them is indicated "AC mode")? If this is the case, then difference between charge+data and data-only cable seem to become more non-existent!

Any help would really be appreciated. Thanks!

 

[Humprey Fetalvero]

Re: Xiaomi 16000mAH Power Bank Needs Charge-only USB Cable to Work with Z3

I'm really trying to wrap my head around this (which is hard given only the facts without relevant techincal knowledge!).

What I considered facts:

1) USB cable only have 4 wires, two for power and the other two for data (presumably the inner two pins).
2) The only difference between the charge+data and charge-only cable is that the latter had its data pins shorted presumably to signal the phone that it could do a "AC mode" charging which means it could draw greater than 500mA which is not permitted on "USB mode".
3) That's presumably is what AC adapters also do (short the inner 2 pins), and that's why we have slower charging on laptop, presumably.
4) This (shorting of 2 inner/data pins) is also how "AC mode" and "USB mode" charging is indicated/differentiated.
5) Power bank also do this data pin shorting that's why they are also indicated as "AC mode" charging

Now if the said power bank also do this (since it is indicated as "AC mode" charging), then there's shouldn't be any funtional difference between the 2 cables (but, obviously, there is)!

So we are left with the case that the said power bank do not short the data pins, (which actually makes fact 4 and/or 5 false for how are power banks indicated "AC mode"), but what functional difference then could these 2 unshorted data pins make now when we are only dealing about a power bank, meaning power supply where only the 2 power pins should be relevant?

 

[Humprey Fetalvero]

Re: Xiaomi 16000mAH Power Bank Needs Charge-only USB Cable to Work with Z3

I think I also forgot to mention one important fact, that other power bank (Pineng for instance) works without any problem with my Z3 using any of the 2 types of cable I mentioned.

So in summary other phone works on Xiaomi and other power bank works on Z3 (and speaker) on both 2 types of cable. But there's a problem between Sony devices and the Xiaomi power bank when using charge+data cable. So what could be there in either or both of them that prevents the other?!