If you really want everything inline it's gonna end up pretty looooong! Depending upon selected battery, figure 2-3" for batt+ends, 1+" for cart, 1 to 1-1/2" for atty with connector, and the bottle height (figure 2 to 2-1/2"). So all told, it'd be 6" to 8" long! And that's assuming you only want to run 1 battery and that any switches don't add length.
This is where I am getting stumped, but give me time to think about it. I might not come up with a solution to the length, but who knows... my Beta PV is 6" long with the 901 atty, I would not want to have anything much longer. I would probably have to make it with the 16340 3.7 batteries to keep the length down.
IMHO, this is why you normally don't see inline designs. It
can be done, but who'd want to use it?
I doubt I would make these for sale, unless I could find a way to mass produce them, with quality. Too much competition out there already. I do want to give it a go for my own entertainment though
Thus, I'd at least consider a 2-stack configuration. Where the battery is offset (and possibly switch(es)) so that your total height is more manageable.
This is my second choice in design, which may be my first mod to try.
It's you PV so you can build it however you want, just thought I'd point out why it's not normally done inline.
Whatever you decide, post pics so others can see and be inspired!
