Got my X-Racer F3 from fpvmodel today. Looks to be nice quality. Uses SPRACINGF3 hex. However, no vbat connection (voltage monitoring). So I added my own.. solder a voltage divider (same as i.e. for CC3D, 10k and 1k to BAT+/GND) to the pin shown.






The pin used for VBAT is PA4 according to the STM32 F3 datasheet.

Shared from Sascha Michalke on our FB Group

Thanks a lot for this! I'll be working on this later today.

Here's the pretty version using SMD resistors.

(27-Jan-2016, 04:46 PM)Arakon Wrote: Here's the pretty version using SMD resistors.

That's awesome mod thanks for sharing that!

Oscar, how did this mod work out for you? I am considering doing the same thing because voltage divider directly into X4R is giving erratic voltage readings once I start flying.

I am actually not using this mod... I am reading voltage from my MinimOSD
The soldering is a bit too challenging for me hehe

Yeah, I took a look and it's pretty tiny, alright. I have solder paste (solder and flux combined) which is really good for stuff like this. Just not sure about the soldering tip I have. Maybe I'll practice on the processor on an old burnt ESC and see how that goes. If the wire is placed on the side of the pin vertically, then if you press a flat tip parallel to the side of the processor, it should just touch that wire and melt the solder paste. It's a job you want to last about 1 second and it's done.