However, sometimes I see in OCD far beyond 5A and 6A. ... Shouldn't they burn down?
This is the difference between a rating for continuous, burst, and instantaneous current flow:
- Continuous: maximum constant current load over a long period, e.g. >15s
- Burst: maximum temporary current load over a short period, e.g. <15s
- Instantaneous: maximum spike of current load over an ultra-small period, e.g. <0.5s
In the case of the Tiny Whoop FC you link to, the rating for continuous current load is 5A and the burst current limit is 6A. This does not mean, however, that the electronics aren't capable of momentarily supplying more for a very short period of time. This is likely what you're seeing.
more C is better in LiPo
I'm not sure if I would say it's necessarily better. All it means that the battery can supply more current to the motors.
What ??? !!! ESC that can handle 1, 800 A !
No. First of all, you cited specs for the battery's maximum discharge limits, not those of the ESCs. The weakest link in the battery-ESC-motor chain will be the first to fail, so an over-speced battery can cause the ESCs to die if you try to push too much current through it.
Second of all, I think you made an arithmetic mistake. The conversion factor between C's, battery capacity in Ah and a current in A is $\text{Ah}\cdot\text{C's} = A$. Therefore:
- Max continuous discharge rate: $150C \to 1.2 \cdot 150 = 180A$
- Max burst discharge rate: $260C \to 1.2 \cdot 260 = 312A$
It should be noted that the C-ratings marketed by consumer battery brands are often overstated, so it's likely that measured discharge limits in the real world will likely be substantially lower than this.