Instructables

Why is my portable charger doing this.

Okay so everything is solderded correctly with the right amount of voltage on the data lines. When i check the voltage it says 6.54 but when i plug my usb up to my phone it drops to 2.89 why is this? I used this http://www.instructables.com/id/Make-a-USB-iPhone-iPod-Charger-On-The-Cheep

iceng1 year ago
You have a mistake on your 7805 regulator pins.
The unconnected output voltage MUST read 5 VDC
even before connecting up the iPhone...

5lVDC_REG.PNG
tramont (author)  iceng1 year ago
the outuput is reading 5v but its like when a load is put on it thats when the voltage drops to 2v my other charger was built successful
iceng tramont1 year ago
Insufficient Battery
Like Steve said Dec 12
tramont (author)  iceng1 year ago
yea ima try a duracell or energizer battery instead of these cheap dollar store ones
Once again, a 9V rectangular battery is going to really struggle to drive anything LIKE charging current for a USB charger.
+1

9v batteries are garbage except for very low drain 'higher' voltage applications - like smoke detectors. Everywhere else they are a waste.