Portable Battery box

I'm thinking of making myself a portable battery box so when I park the camper and take the Jeep for a run I can put the battery/box in the Jeep and have it charge up and then in the evenings put it back in the trailer for the lights etc. I'd use a quick release type plug in the Jeep and the same in the camper.
The advantages are the battery can be charged easily when camped for a while without having to idle the Jeep while hooked to the trailer or take the trailer with me. I can take the battery out of the camper and easily keep it topped up on a bench at home.
Are there any disadvantages? Moving it from Jeep to trailer is a bit of a pain but it would probably only be every 3 days or so when camped, the battery would have to be sealed so it wouldn't vent gases whilst in the back of the Jeep. Other than that I cant think of anything, anymore?
Cheers
Steve
The advantages are the battery can be charged easily when camped for a while without having to idle the Jeep while hooked to the trailer or take the trailer with me. I can take the battery out of the camper and easily keep it topped up on a bench at home.
Are there any disadvantages? Moving it from Jeep to trailer is a bit of a pain but it would probably only be every 3 days or so when camped, the battery would have to be sealed so it wouldn't vent gases whilst in the back of the Jeep. Other than that I cant think of anything, anymore?
Cheers
Steve