Dan,
Did you end up adding additional house batteries? We just took delivery of our '17 34J in February and I also have had Camping World look into adding more. They said that based on the space in the compartment that there was only room to add one battery (for three total). Looking at the space it looks like you may be able to slip one behind the existing two battery tray and then add a 4th between the tray and the hydraulic pump.
I am curious what you (or anyone else with a 34J) have been able to do with respect to adding more house batteries.
Charlie
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