Instead of a heavy deep cycle battery, why not a good high cApacity lithium ion battery...or 2 if needed. Those will be considerably lighter while providing ample power. As for a solar panel to keep them charged, I use a solar battery maintainer panel from Harbor Freight or Northern Tools ...(about $20 each on sale) to keep my dozers 1100 amp battery charged when itís parked in the field away from electricity. I leave it connected all winter long and it has never overcharged the battery.
I have seen some smaller Lithium-ION batteries, but never one large enough to give any real power reserve to a heavy load. They are usually for recharging cell phones and such, but with this deep cycle marine battery, I could set up campsite lights, run a computer or two for many, many hours, run a CPAP machine all night long (I haven't yielded to that
admission of old age quite yet) and even jump start my own bike or another bike, ... or that old Beetle stranded on the side of the long lonely country road driven a beautiful young nymph with a cute pouty face and body that could cause the Pope to kick in a stained glass window, sitting in the driver's seat in barely enough clothing to be legal in public because of the hot night air ...
Hey, it COULD happen!
I travel alone, but I take TWO helmets. Boy Scout Motto: Be Prepared!