Huge voltage drop in QUAD

Hi there !

I’m using Pixhawk based custom built QUAD X configuration. 3S brand new GEN ACE 5000 mah battery, 1045 prop, EMAX 980kv motors, Simonk 30A ESCs

The problem is with the Voltage during the flight.
The voltage drops by >1.5V (as seen onthe power module reading and through the flight observation).

I’m using 12AWG wire through out, a pixhawk 90A power module, an a PDB between ESC and the battery.

The battery is all perfect, i assume 12 AWG is also sufficient (peak current will be <60A), Power module is also 90A.

Could there be a PDB issue ?

I’m using the following PDB, with the webstores rating it 60A continuous.


The battery voltage will drop under load. Have you checked all the solder points on the
PDB, etc?

There could be no issue. Insufficient information to know. How much battery was consumed (mah) when it dropped 1.5V?

Yes. All solders are good

Around 40A.
But the battery itself is 60C 5000mah

is the PDB getting hot? if it was high enough resistance to cause that kind of voltage drop you would feel the board getting hot quickly.

also 12.6v 3s battery is going to sag with heavy load on it. 11.1v under load isnt unreasonable.

What was the consumption in mah when the battery had dropped 1.5V? That’s 3.7V/cell which is in the normal range of operation.

~40,000 mah. (Each motor taking around 12A which satisfies the datasheet mentioning)

Yep. But the drop to 11.1 at the beginning goes down to 10. something as the battery drains linearly.
Doesn’t match my quad lift requirement thereafter.

Normal voltage sag for a 5000 3s under a 40 amp draw, nothing strange.