Can I Use a Larger Power Bank for My LED Strip to Extend Its Battery Life?

[airstrat]

I have a 4.5v LED strip 14.5watts (unknown amp draw; maybe 3amp) 30 LED 5050 per meter that runs off 3 AA Alkaline batteries. It runs fine for several hours (with the AAs) which is great but Id like to hook it up to a small power bank. I pulled out an old old power bank of 2200mAh 5v 1A output that's been sitting for some time without a charge so I charged it up for about 3 hours and then I spliced some wires of a USB connector and connected it to the strip light which ran for about 45 minutes before the lights went out.

It worked for a little bit but my main question is that can I hook up a larger battery of 5500mAh that outputs 2.1A 5v to the strip to make it last longer; looking for several hours of power before it shuts off. The battery I used was so old maybe it lost some its 'magic" over time sitting in the drawer or because I am not getting the amps needed across the LEDs or maybe I was loosing voltage as the juice ran out. I'm not a pro at electrical stuff but I am a quick learner and any advice would be appreciated.
Thanks in advance
james

 

[NTL2009]

If the strip really is 4.5 V and 14.5 W, then you need a 3.22 A supply. I'd be concerned that 5 V would stress the LEDs. You will need 3222 mAh @ 4.5 V for each hour of use. So around 10,000 mAh for 3 hours.