Refer to page 232 of the owner manual for jump starting instructions.
As for charging, use any one of several available adapter cables to connect whatever charger your heart desires.
One reason to place the battery in a low position, which you might not have thought of, might have something to do with the center of gravity, not silly design.
Yup and the conventional routes:
1. Like the old Monster, under the tank: always created a compromised small airbox and the 4v makes more bang and needs more airbox volume than the aircooled motors did in the first place. The new Monster also has a lot more wires and electronics to hide under there anyways.
2. Like UJMs, in the rear subframe: Had a look at the Monster's subframe? Thin and delicate to create that svelte stinger rear which would be bollocked up with a battery. Also tiny packaging problem with the rear shock.
3. Like the superbikes, strapped to the side of the frame: yeah, no.
Not that I'm a fan of the arrangement, makes living with the bike a little more tedious and since I do miles, I worry about having to screw with it on the road but (fingers crossed) how often to you really have to mess with it? But I do realize engineering is a compromise. The vexing part isn't so much about the location of the battery as it is they piled a bunch of stuff on top of it making it hard to get to the poles.
For the adventurous, I got to fiddling around with putting the warmnsafe heated gear lead on the battery since the shop left my battery tender one off (note I didn't change it for any particular reason other than it suits my gear setup better, could've just put the SAE ended harness back on) and by grounding the harness at the ground point on the motor, I didn't have to access the one on the battery and therefore didn't have to drop the battery. DO KEEP IN MIND that big chunky metal screw thing on the positive of the battery will be hot and take GREAT care when tightening it down not to ground your wrench or ratchet on something metal. Otherwise you might have an enlightening moment. Not that I encountered that. Nope. Not at all.