Fluctuating amps with Mintyboost

[luca662]

So I just built my mintyboost and I'm testing it with my Samsung Vibrant. It charges very slowly. I installed this app on my phone that shows me the charging rate of my charger. For my wall outlet it shows a constant 1100 mA. When I use my mintyboost, the mA bounces around. It goes from 0 mA to ~600 mA to ~200 mA then back down to zero. There doesn't seem to be pattern to it either. The numbers are always random, but its 0 at least half of the time. When I use my volt meter to check the voltage of the USB pins, it is at a solid 4.97V and does not fluctuate. I tried using rechargeable 2500maH NiMH batteries as well as brand new duracell AA's.

Pictures:
http://i.imgur.com/dXibD.jpg

http://i.imgur.com/Rh4g6.jpg

The app I used is called "CurrentWidget" for android phones.

Any help would be appreciated!

[adafruit_support_bill]

For my wall outlet it shows a constant 1100 mA. When I use my mintyboost, the mA bounces around. It goes from 0 mA to ~600 mA to ~200 mA then back down to zero.

The Mintyboost can handle up to a 500mA charge rate. It looks like the phone is trying to pull more than that and the boost converter is going into thermal shutdown.

[luca662]

the IC isn't even warm to the touch and neither are the batteries. This was after I had it plugged in for a while. Is there also a way to fix this problem?

Edit: I saw that most phone is listed as being a supported device for the minty boost.

[adafruit_support_bill]

If the IC isn't warm and the widget is reporting 600mA current draw, I would tend to doubt the widget. Better to test with a multimeter in the circuit.

Have you tried bridging D1 and D2?

[luca662]

The widget was reporting that the draw was bouncing widly between the range 0-600, but it was at 0 for almost half the time. D1 and D2 are bridged. No worries now because I fixed my problem. It was the usb cable I was using. I switched the a different cable and it works flawlessly. The widget reports a draw between ~600-850 with an average around ~750 with the different cable. It still fluctuates wildly, but stays in that range. The IC is slightly warm now and my phone has charged 5% already. Unfortunately I don't have a multimeter to accurately measure the mA.

This is the cable I was using that didn't work:
http://www.amazon.com/gp/product/B003YKX6WM/ref=oh_o00_s01_i00_details

It works fine when connected to my computer, but not on the mintyboost. Any ideas?

[adafruit_support_bill]

Cables often do make a difference. Although extra long ones are usually more prone to voltage drops. Sometimes also it is a problem with the connectors not making good contact.

[luca662]

Thank you so much for your help!