So, i have builded THE zmr250 kit, with THE fpv suggested, so my questions is now, how Can i Make something, that warns Me when THE Battery is lowV so it wount just go Down. I Got THE lipo buzzer from THE kit, but THE balancer os used for THE fpv, i have grad something about osd, but IM total noob
Hi
You can still use the LED/Buzzer unit that plugs into the balance plug, just parallel up with the FPV equipment you alreadyhave on there.
BTW. how much current are you pulling of individual cells? It is not a good method as the battery will become unbalanced and will need balance charging after each usage. Better to buy a cheap BEC for the FPV gear.
OR
You could fit an OSD (on-screen display) this will tell you flight battery voltage and a whole lot of other really useful stuff. I don’t fly without OSD (but that’s because I’m a poor pilot 
)
OR depending on your radio kit you could get the battery voltage sent back to your TX. For a client I used the cheap FlySky FSi6 radio set with the FS-CVT01 telemetry module (only £4.49) which puts the voltage on the TX screen.
Hope this helps
Steve 
What do you mean by pulling? I dont even know on What voltage THE Battery dies, it just goes To THE Ground, some times hard, sometimes soft😅
The simplest thing is to add a voltage monitor alarm to your zmr250, as sit will beep when the voltage is low.