Hi Rick,3 years now. I was thinking why should the battery and the necessary equipment for caravanning be in the caravan. There is good space in the spare well, just plug into the caravan like the 240v at a caravan park.
I managed to squeeze a Renogy 100 amp lifepo and an enerdrive dcdc charger under the spare, the battery is fairly compact and the charger is quite large but they do fit inside the upturned spare when its in there. When towing the van I put a full size spare on the roof and leave the spacesaver at home. If you never have to put the spare in there you will have miles of space for all the gear you may need.