I would appear that 3 x 7ah batteries are a perfect fit.

I would appear that 3 x 7ah batteries are a perfect fit.
I have plans to make a battery box for field activities from this ammo box.
This is my home lab / networking playground. The cab hosts various servers, routers and radio equipment.
I have three SIMOCO radios now :-
E0 – 4m
AC – 2M
TK – 70cms