4-6C ? are you sure?

That's only good for 7.2A continuous and 10.4A peak. (30 seconds MAX).

You will want around 10 to 12A continuous to hover a Zoom/Shogun and more to fly.

Your battery is WAY underpowered.

Even cheap chinese batteries are usually 8 - 10C - And would still be marginal for your application. And still insufficient for 3D or fast climbs etc.

If your battery really is 1800mA 4-6C, you have a serious issue. Don't fly with it.

David.