Bat Bone Motor Cut Out/ Power Failure

[happyman88]

I seem to have run into a snag building a bat bone tricopter i am using all recommended parts from the plans on the store except the escs are 30 amp instead of 10 or 15 amp( just what was in stock at the time) . The issue is that on a fresh charged battery all 3 motors will start spinning i can take it off then anywhere between 2 to 6 minutes into the flight 1 or 2 motors will just slow down to the point where it crashes. I have checked the voltage in the battery after this has happened and it is not anywhere near where the low voltage cut out should activate and i believe that i have programmed them o that there is not a lvc. This issue has cost me a motor and a few props and any input would be great.
Thanks

 

[FinalGlideAus]

Can you tell us what exact brand esc's and motor's you are using? That may help with the diagnosis. Do your esc's have SimonK Firmware flashed on them? What is the voltage when the motor dies. Is it always the same motors that stop?

 

[happyman88]

The escs are multistar 30 amp and do not have simon k firmware. The voltage that the motor(s) die at is usually around 10 volts but it has been as low as 8. The motor that dies most often in the air is the tail but if it happens while im trying to take off it is completely random which motor it is. there is a low voltage alarm on the tricopter but it has never actually gone off when this happens.

 

[xuzme720]

That is low cutoff...
You are using a 3S lipo? I'm assuming 3S because of the cutout at 10v. Need to keep the voltage above 3.5 per cell on lipo's. dropping below 3v (per cell) is early death for them...

 

[happyman88]

oh ok that makes sense.

 

[happyman88]

then why doesnt the low voltage alarm go off

 

[xuzme720]

What flight controller board are you using? Most boards that have an LVA require them to be set and have a feed from the battery to a sensor point on the board.
For instance, on a KK2 board, you have to run a voltage wire to the board from the battery. Then you have to set the alarm for the value you want to be warned at. On a batbone, just hovering, set it for around 106-108. (the KK2 has no decimal in the setup so 106 is actually 10.6v. Some firmwares also set 1/10 of a volt as the setup value.)

 

[happyman88]

No it's an alarm from hobbyking that goes between the board and a servo

 

[xuzme720]

That voltage won't change...it's going to stay at 5v. You need one that plugs into the battery or that reads from the main battery voltage.