Almost, yes
32 cm, plus once you add a bit for the wiring, and 2 or 4 tppacks LVC/HVC parallel boards the whole battery pack gets a bit bigger
For single or a pair of batteries, yes 32 , so once yo add a bit for the wiring and make up a case/holder I have been seeing about 35cm,
Looking at the pic of the white frame, I may get a pack of 4 under the cross bar, but what may end up being the problem is the width and depth of the pack. A single battery length of even 35 cm will fit, but once 4 of them get strapped together, down that low, it either becomes too wide to allow pedals to turn or th eheight of the pack is too great at the front.
I collected another Trek Frame yesterday, and can go and get the white one tomorrow and I then have two days off work Wed and THursday, so will see what I can do.