So, I have a model that has 233 verts and 239 tris. The vert/tri information is from Unity, not the modeling program. It’s my understanding that models less than 300 verts will dynamically batch together if they share the same material. There are no scripts on the objects, so I know I’m not changing anything with the renderer. Why won’t the model batch? Has the batching threshold been lowered? Does the entire batch need to be less than 300 verts (a.k.a. my model has to be <150 verts)?
Its 300 basic verts (1 UV, normal, position)
if you add a second UV coordinate, vertex color or tangent, it will correspondingly less
also if their scale isn’t 1 then they won’t batch either.
(Pixel) Lights also affect Dynamic Batching. For example one Directional Light has no effect, a second one will not batch at all!
Pointlight and maybe Spotlight lit objects don´t batch, too.
And thats out of my test project with a bunch of 2sided triagnles (6 Vert, 2 Tris, 1 UV).
May someone is interessted:
400 of these triangles where batched into 6 Batches so 400 Verts per Batch.
900 triangles where batched into 12 Batches with 450 Verts per Batch.
2500 where 34 Batches so ~440 Verts per Batch.
Well what i call Batches here where just my DrawCalls what i guess is equal.
My conclusion: Useless for most 3D Games which make use of Lighting, but very powerfull for 2D (Sprite) based applications.
So it works fine for what Dynamic Batching was made for: Mobile Devices.
If anyone knows it better please let me know 
Yeah, I have the scale to 1 and I’m using zero pixel lights, or lights of any kind. The only thing I’m doing is changing the position and rotation of the object. I’ve used batching before in other games, so I’m pretty sure the artist did something. Thanks for the info.
there are more to it actually, but search forums for that 
Also for 3.4 we fixed some bugs with batching - it should come out soon - maybe yours was fixed