I like to take my SJ4000 camera out when I ride so that I can record things that are happening. Also more so than ever I’m kind of thinking that having one attached to me while riding is just a good idea as there are more and more times that riders are getting hit by inattentive drivers and having a recording of the incident can become very useful.
Problem is recording time.
On my SJCAM I get just over an hour in normal mode and under an hour if I have the wi-fi turned on. 
My question was how to get more time. I have 3 batteries for my camera, but who wants to pull over every hour or so to change batteries. I know for a fact that I don’t.
What to do.
Well I ended up going out and buying a small 2600mAh battery pack. I wanted something small so that I can mount it to my helmet. With a small USB cable and some velcro I was able to let my camera run off of this batter instead of the internal. 
Giving me over 4 hours of record time. AWESOME!!!
Check out the videos below. Theres a part 1 and 2 so make sure to watch them both.
Let me know if you have any questions in regards to it.