So I've built the ever popular altoids charger, except in a setup that i haven't quite found on the internet yet. I went for a 2 AA setup with a DC to USB step-up board. I have attached pics below to demonstrate the equipment used, along with the schematic.
I used the following parts:
1) 2 AA battery holder from RadioShack
2) SPDT submini slide switch from Radioshack
3) DC to USB step-up with variable output voltage
4) Various types of AA cells
Everything seems to be working except one detail: the contraption won't charge my smartphone (Samsung Galaxy Nexus if it matters). The best result I've had was a 20% charge on a fresh set of alkaline batteries. On my rechargeable NiMh batteries, I got about a 5% charge. However, after the phone fails to receive any more juice, I test the "spent" cells on an SMD flashlight, and they are actually still running well.
What am I missing? The only other thing I haven't really tried is to mess with the USB step-up settings. The item came as preset for 5V output. I'm not even sure how to adjust anything properly on it, and I'm not willing to ruin my phone to try my luck. If you look at the pic, there is a small brass knob on the blue box located on the step-up board. The brass knob appears to be adjustable for something.
Any insight as to what's causing the insufficient charge?
Note: I am using "current widget" on my phone to see what kind of voltage the charger is delivering to the phone. On both a wall charger and my DIY charger, there have been an average of 3.9V being recorded by the widget.
I used the following parts:
1) 2 AA battery holder from RadioShack
2) SPDT submini slide switch from Radioshack
3) DC to USB step-up with variable output voltage
4) Various types of AA cells
Everything seems to be working except one detail: the contraption won't charge my smartphone (Samsung Galaxy Nexus if it matters). The best result I've had was a 20% charge on a fresh set of alkaline batteries. On my rechargeable NiMh batteries, I got about a 5% charge. However, after the phone fails to receive any more juice, I test the "spent" cells on an SMD flashlight, and they are actually still running well.
What am I missing? The only other thing I haven't really tried is to mess with the USB step-up settings. The item came as preset for 5V output. I'm not even sure how to adjust anything properly on it, and I'm not willing to ruin my phone to try my luck. If you look at the pic, there is a small brass knob on the blue box located on the step-up board. The brass knob appears to be adjustable for something.
Any insight as to what's causing the insufficient charge?
Note: I am using "current widget" on my phone to see what kind of voltage the charger is delivering to the phone. On both a wall charger and my DIY charger, there have been an average of 3.9V being recorded by the widget.

