Wiring VBAT to an SP F3 Acro 6

[Cookieman10101]

Hey all. I've been looking around the internet and can't find a clear explanation of how the wiring for VBAT works on the SP F3 Acro 6. what I've found out so far is that your supposed to wire the battery directly to the VBAT pins on the FC.
My questions are:

1. Does it matter which voltage goes into the VBAT on the FC? whether it be a 2S or 4S so on
2. Do you use the VBAT connection as the power source for the FC? Or do you also power it from a 5v connection off the PDB as well?

Thanks for the help!

 

[Craftydan]

Hey Cookieman, Welcome to the forum!

The Vbat pin on this particular control board is only a measurement point. The connected pin on the processor is only safe up to 3.4-ish volts, but it has a voltage divider circuit between it and the Vbat pin that chops the main battery voltage down to stay well under that. Not sure of the max cell count before you over-power the voltage divider, but 4S is fine.

It can't be said enough: Don't get the polarity on the Vbat connection swapped. In my builds, I don't even solder a pin on the "-" side and only connect the hot side of the battery to the "+" side of Vbat -- can't connect it backwards if it's only one pin. If your pin-header is already soldered in, you can clip the "-" pin off with a pair of dykes and you'll never try to use it again.

For this controller, you will need to provide regulated power to it (5v). It has a tiny 3.3v regulator to power the processor (which can also power 3v sat receivers or GPS) but even 2S is probably too hot to power that. You'll need an internal/external UBEC or regulator to power that. The common choice these days is to get a PDB with one built-in -- they're cheap and can clean up the wiring significantly.

 

[Cookieman10101]

Ahh I see, thanks so much! I'm waiting for all my parts to arrive for my first build and i'm getting all my ducks lined up