Artillery ... New Patch Effect

[Beruldsen]

With the latest patch ... is it now advisable to build artillery brigades larger than 12 guns?  Many topics ago ... I read numerous posts that building anything larger than 12 guns was counter-productive and actually resulted in a negative effect in battle.

[Wright29]

Actually all unit types lose efficiency like artillery, but not to the point where there are negative marginal returns. As an example, 750 sized skirmisher cavalry will not do twice as well as a 375 sized brigade. However, unlike arty, it will not be completely outperformed. 

When I talk about diminishing returns, I mean a 16-gun arty brigade will very likely do better than a 12-gun arty brigade. But it will be better for the player to have a 12 gun brigade and a 4 gun brigade. However, a 12-gun battery will likely do 1.5 times better than a 8-gun battery. 

The patch did give 12.5% damage increase for large arty brigades, but did not structurally change the way the artillery returns work. 
 

A side note on the diminishing returns- larger units are always better in melee, have better "morale resistance", and are more difficult to shatter. This is a lot more practical for infantry and especially cavalry. But it is definitely relevant if you are bold with your artillery placement or if the enemy counter-battery fire is heavy (which is more prevalent in the current patch). 

I guess I still haven't answered your original question- probably no given that increasing size costs you money and you're better off making additional arty brigades. 

[Bigjku]

My advice, keep your rifles cannons at 12 or right around it.  If you want to take 14-16 smoothbores or howitzers that will be right in the middle of the fight it can make sense.  They are gonna take losses.

[Col_Kelly]

I'm going for 14 canons batteries and it works just fine. Other than that, as Wright has pointed out, it's better to have many small batteries rather than a few large ones.