For a competent electrician,it should not pose a major problem from the electrical point of view, but the battery must be housed in a secure way, and it must be ventilated to the outside.
It is not permissible for safety reasons to put a battery or any electrics in the same locker as the gas bottles.
And before some contributors who are old enough tell me, I know some older caravans actually did this, but that was either because the the caravan pre-dated the regulation, or manufacturer did not know or understand about it.