Tapping Vcc before current sensor for BEC's

Today I made the decision to tap Vcc before the current sensor to power the BEC’s on a 650 class copter. The BEC’s will power the Cube (MAUCH BEC), a HereLink, a FPV camera, and a mapping camera. I suspect the total load will be less than an 1 AMP.

I made this decision for convivence of wiring.

This copter will user either a 8000mAh or 12000mAh battery.

Other than setting the “reserve” mAh on the battery failsafe to consider the load of the electronics, are there any other parameters or operational considerations I should consider with this configuration?

I can change the configuration if necessary - but if there is little or no down side, I’d prefer to keep it as it is.

I’m wondering - there might even be some benefits to this configuration - as the current sensor (Mauch) will only see the motors load.

I’d appreciate any advice or comments as appropriate. Thank you!

Usually we position the current sensor to measure all load including accessories. I can’t immediately think of a benefit to excluding the accessories.

Vcc usually means the regulated supply voltage, like 5.0vdc

Probably Vbat or B+ might OK to use for the unregulated battery voltage. Just so everyone is on the same page.

Thanks @xfacta -

Interesting - on the PDB’s I’ve used to date, the pads with battery voltage are labeled Vcc.

Yes - this arrangement isn’t ideal. The issue is the difficulty connecting a tap from the battery lines on such short runs. I did it on my 450-class copter, and it wasn’t much fun.

I’m just trying to be on the lookout for “gotchas.”

You can definitely do what you are proposing, you just have to be aware the consumed current/capacity measured by Ardupilot will be just slightly off

So the current sensor won’t include the BEC’s. If you leave the battery connected but don’t start motors, the current sensor indication would indicate almost 0, but after C/1A (as you suspect) the battery will be empty.

True. But I can’t think of any instance where I might do this.