Bosch in frame 400 vs 500 Weight?

[Wiltshire Warrior]

Has anyone opened the 400 to find out why its 200g Lighter than the 500?

in frame 500 = 2.6KG
in frame 400 = 2.4KG

is it just missing 100w worth of cells?

 

[Doomanic]

It uses less energy dense cells. Same number, just lower capacity.