Under-slung storage and battery-boxes.

Frame for the second box under construction.

Our reasoning & expectations behind this 

More info and Photos and full write-up to follow soon.

Other related or affected

      Flooring.
      Pipework.
      wiring.

 

In use reviews for this 
 
Our conclusions.
Pros.

Larger batteries can be used.
Battery weight is lower so lower centre of gravity.
A reasonable amount of extra storage.
Storage is suitable for heaver seldom-used items.
Additional storage or usable space where batteries where.
Additional storage is accessible from within the van.
Not obvious.
Shorter route for the power cable to the engine, (starter motor).
A small amount of weight distribution is possible.

Cons.

Quite a lot of work to install.
Whirring and pipework need rerouting.
Full-size right-hand box requires a different gear linkage system.
Batters and box vulnerably to possible damage.
Loss of some ground clearance.
Some additional weight.