Liveaboard fire

[DandyDon]

Do you have any recommendations for a battery operated Smoke/CO2 alarm for travel?

Choices vary in the marketplace from month to month. I take a simple battery-powered First Alert Smoke & Carbon Monoxide combo unit, one of the alarms I keep active at home. Just shop around and find any available and remember to test it after each trip each way and carry spare batteries just in case.

I'm heading to Raja Ampat in a month and want to use one for ANY travel from now on.

Yep, I take mine anywhere I am going to spend the night.

Do they all have to be placed on the ceiling/ High up on wall??

Smoke alarms work best high but will work okay lower, and carbon monoxide alarms will work at any height as CO mixes well with air, so for a combo unit I place mine around five feet above the floor.