DIY Battery Pack for 18650
My plan is to wire up 2 (maybe 4) 18650 batteries to power my P7 to extend the run time. My new commute to work will be about 45 minutes, and while the Medium setting is more than enough, High is killer sweet.
I need something that I can strap to the frame quickly, and remove the batteries easy once off the frame. Since most of the 18650 chargers appear to be a 2-battery setup, I'd probably stick with two.
The plan is to drill a hole in the the P7 to allow the leads in with the negative lead being a little longer so that I can unscrew the bottom if needed for any reason (as well as for access when soldering).
Where can I find a small, weather-proof enclosure, with an spot to insert a velcro strap, that will tightly hold two 18650s (stacked or side by side)?