Jenny, Doug, Harry and all,
First, Harry, it sounds as if you have a great set-up on your chair.
The headlight and tail lights are brilliant, no pun intended.

Some battery information: internal battery life for the vents should be
reserved for emergency (power failure) use. It's risky to use it at
other times. The PLV-100 can be powered for 'up to an hour' according
to the manufacturer. your settings (rate, volume) determine the amount
of time it will power your vent. (Alarms warn you when it is getting
low.)

Deep-cycle marine batteries are best: power the vent the longest. Gel
cell batteries may be smaller and are required in order to travel by
air. (FAA regulations which don't allow standard lead-acid batteries
onboard because of the battery acid in case they leak.)

Gel cell batteries cannot be recharged as many times as deep cycle
marine batteries.

We all worry about a power failure. If one occurs and lasts for a long
time, (more than 24 hours), a car or truck battery can become an
emergency ventilator power source. Some people choose to have two 12
volt batteries charged-up at all times, for this reason. If recharging
is necessary during a lengthy power outage, remember that all fire
departments (in the US) have a back up power generator at the fire
station. They are always willing to recharge your battery there, at the
fire station, if you have no power at home. (Yes, this means that
someone needs to take the battery to the fire station! but at least
it's a reliable way to get a charge!)

'Hope this helps. Good luck, Doug.

Bob Edwards, RRT, RCP
El Sobrante, CA