Can someone help me understand this USB problem?

Hello,
I have several USB Power Banks.

They seem to work fine with most devices. However, they do not work with my Samsun Galaxy cellphone for reasons unknown UNLESS I use a particular USB power output adapter. I must use THIS one for it to charge my cellphone…When this blue one is plugged into the power bank and then the charging cable is plugged into the blue power meter, it works partially ok. But even with this blue adapter, the current output seems to fluctuate all over the place showing for example .27mA one second then .003 the next, then .004, .16, etc and it keeps bobbling around like this. But at least for the most part it charges the phone with this one.

When I plug the cellphone into an AC powered USB charger it charges just fine.

When I use the Power Banks on other devices, they work great showing up to and sometimes over 1amp of current flow to the device being charged.

But no matter what, I can’t get the Samsung cell phone to charge when plugged directly into the Power Banks unless I first plug in the blue USB port tool above. It doesn’t make sense since the output of the USB power bank is 5v + just like the AC powered device.

.
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I also have this USB voltage / current tool (shown below) but I can’t get my Samsung phone to charge when it is plugged in no matter what.
I have several of these and they all are like that. They work fine on other devices but not with my Samsung cel phone.

I don’t understand why I have to use the blue USB tool just to get my PowerBanks to charge my phone?

Thanks

http://lygte-info.dk/info/USBinfo%20UK.html
Mike

Thanks. Read most of it already. Seems this usb cable thing is more complex than I thought

Have a Samsung Galaxy S3. I have 3 different USB testers, none work with that phone. Lots of Power banks don’t work, even top notch ones. It’s EXTREMELY fussy about cables, with monoprice being almost the only reliable one. A lot of the ones that come with cheap devices have poor throughput, but work. They almost never work with the Samsung.

Fly, that’s exactly what I have…the S3

A Monoprice USB cable or USB powerbank?

I’m able to charge my S3 with a DIY powerbank I assembled but I have to use that blue USB power thingy I posted in the first post.

Monoprice USB cable.
I like the colored ones, easier to find. The [Select Series] also seem to work.

I have several different powerbanks. Only ENB+loose cells will charge it reliably WITH the monoprice cable. (I’ve thrown away all my single cell cheapies and all my crappy cables. The ones I have left work well on everything (Window phone, Motorola phone, Kindle) BUT the S3

I have 3 different USB power meters, including the blue one, which doesn’t necessarily mean it’s the same as yours. Could be different components inside. Anyway, ALL of them screw up and won’t charge the S3. They sometimes start, then screw up. Doesn’t take very long to go bad.

The S3 is just peculiar. I got it for free from someone frustrated that they couldn’t charge it. Took me a couple weeks to figure it out. Had to use an external charger for awhile. Been fine every since I found the ‘magic’ cable.

I used to have an S3. Wondered why it took for ever to charge it if I was using any cable other than the Samsung cable. I found out about this while searching Amazon for a 10ft cable, that you wanted a cable specifically for charging. Portapow makes the ones I bought.

I have an S6 now, and it works with everything including Qualcom fast charging and wireless charging.

Thanks for the link.
It seems they only have PINK right now. When they get white or green back in I’ll try a few.

Long ago I decided not to chase the dogs tail with these new phones because they come out every year with the new “latest and greatest”.
The S3 actually does everything I need a phone to do but it does have flaws and is slow so I’m looking at an LG now.
The biggest problem I have with the S3 is the charging issue like flydiver is having.

My wife has an LG and I really like it.

Don’t know if I’m helping but wanted to say that usb cables are just weird.

Also the charger doctor you use gives different readings also, for example.

I bought 10 fast charging cables that I tested with a BlitzWolf® BW-S2 4.8A 24W and the same charger doctor you got tells me that 0.45 amps goes in the cable but the Ampere app I use on my Idol 4 tells me only 300mAh reaches it.
Now this could be normal due to mAh loss in the cable which is arround 20cm but I tried the same with 10 shorter usb cables that were not sold as fast charging cables and the Charged doctor tells me 0.25 amps go in the cable the app tells me 1200mAh reaches the phone!
When I use the cable that came with the phone it says 0.25 amps goes in the cable and the app tells me 900mAh goes into the phone?
I did check by cutting 2 usb cables and both are 26 or 28 AWG as far as I could measure.

Just my 2 cents.

Edit: also try if THIS helps with a spare usb cable you have laying arround.
I did try and it worked with a Lumia windows phone that could only “fast charge” with it’s own usb cable, after I lost that cable.

I hear ya there. I had the S3 for a long time, and going on two years with the S6. Really the only reason I upgraded, was the camera. With two kids, the S6 camera blew the S3 and S5 or any of the iphones out of the water. Looks like apple finally caught up with their iPhone 7 though. The S7 camera is really the same except for the dual pixel thing (low light). If the S8 camera isn’t much better, I won’t be upgrading to that either.

The new LG’s are nice for sure. For me, it’s all about the camera.

Ah, yes the camera. I can see why you upgraded. The S3 camera is more than enough for my photography needs which are pretty basic actually.

Great info. Thanks for taking the time to post it : - )