2021 Discovery LXE 40M

Chassis batteries replaced 1 year ago. When motorhome is stored for more then a week, batteries are drained and will not start motorhome. Even with the house battery assist.

When checked at RV shop, the batteries measured 795 ma with battery disconnect switch on (batteries not disconnected). When the disconnect switch is off (batteries disconnected) the draw is 285 ma.

From what I am told, the 285 ma draw is extremely high and the reason for the batteries losing charge.

I can solve this by installing a disconnect switch that completely isolates the batteries. The downside of this is not maintaining power to the engine computer. 

I'd like to isolate what is drawing the excess ma and eliminate that draw. Can anyone tell me what is still connected to the batteries even with the disconnect switch off?

Thanks,

Doug