Which Voltage 12v or 5v

[aburn09]

Just a quick one.....I';ve built quite a few quads now using naze32 boards on cleanflight but I';m now trying a SP racing F3 EVO flight controller using betaflight...... I';m now connecting the flight controller to the pdb but i can';t remember does the v bat on the flight controller go to a 12v or 5v on the pdb ?

[Digit]

Neither, Vbat is to directly connected the battery for voltage monitoring. For powering the FC I';ve always used 5v.

[Cheredanine]

As per digit, vbat is for monitoring BATtery Voltage, hence the ohrase, the evo should be powered from a 5v source. Most decent flight controllers have a built in 5v reg so can take a single connection to the battery voltage and use it to both measure the voltage and power the board but the evo ain';t one of them

[aburn09]

Must be getting my wires crossed......i know the board is powered by a 5v source which I will take from the 5v supply from the pdb to the header pins........But on the SP EVO board I want my buzzer to sound when the voltage drops to a certain point which you set through cleanflight or betaflight as I';m now trying so I have to connect somewhere a positive and negative lead from the pdb to the sp evo board to monitor the battery voltage as I have done on the naze32 boards so I thought the connection was made where it says battery +/- on the board itself which it';s also showing as v bat?

[Cheredanine]

Here is the manual for the evo, the vbat voltage pads are on the west of the board

http://seriouslypro.com/files/SPRacingF3EVO-Manual-latest.pdf

[aburn09]

I already have the manual downloaded and the v bat terminals were what I was going to use but from there to the pdb board is the problem do i connect the vbat to a 12v or 5v supply on the pdb as the manual doesn';t say specifically?

[Cheredanine]

As above, you power the board from a 5v reg connected to one of the 5v pads.

The bat terminals labelled - v + do not power the board, they just monitor the battery voltage, they should not be fed from a reg as they would then monitor the reg voltage, not the battery voltage

[aburn09]

Yes I appreciate the v bat terminals don';t power the board but do they need a 12v or 5v supply I';m thinking as per my naze which I connected straight to the 12v supply ?
The manual does state only power with a 5v supply.....but I as you say the v bat terminals don';t power the board but they i assume have to have a 12v supply to be able to monitor the 11.1v Lipo battery but I just wanted to check as I didn';t want to connect up the v bat to 12v then blow the board

[Dave1701]

As I understand the vbat terminal   should be connected to 12v which is how I have connected mine, speed racing f3 clone. Check out painless 360 on YouTube he does a series on spr f3 not sure if it';s the evo

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[Cheredanine]

As I understand the vbat terminal   should be connected to 12v which is how I have connected mine, speed racing f3 clone. Check out painless 360 on YouTube he does a series on spr f3 not sure if it';s the evo

Sent from my SM-G900F using Tapatalk

absolutley not, sorry don';t mean to stamp on you but that is wrong, nothing on the fc should be connected to a 12v reg.
The board runs from 5v power, vbat pads are to monitor battery voltage, they should be connected directly to the battery voltage

[aburn09]

Lol this is going on longer than i thought........Cheredanine if the v bat terminals have to be connected to the battery voltage then the battery voltage would be 11.1v which I would take from the pdb board ie any terminal which doesn';t state 5v............So technically the SP F3 EVO board would have 11.1v going to it via the vbat terminals via a feed from my pdb which again technically won';t be 12v as the pdb board will only be getting 11.1v from the Lipo battery connected to it which is what Dave1701 was on about ?  ....... ........Think I';m answering my own question here 

[atomiclama]

Think you just did  ::)

When people talk about 12V and 5V they are generally referring to regulated 12V or 5V supplies not the raw voltage from the battery. Think that is where the confusion is coming from.

[Cheredanine]

From the manual mate:
For connecting a 2-6S LiPo battery (25V MAX). Used for voltage monitoring ONLY. Will NOT power the board or accessories.

That is the battery pin entry. It is only used for monitoring the voltage, it does not power the board.  If you do not connect those pins, it will not monitor the voltage but has no bearing on how he board is powered or flys.
(The one thing that is a little ambiguous is the evo does not have pads called vbat. There is no such entry in the manual or lettering on the silk screen, however the pads that are called vbat on other boards are the battery pads on the evo

To actually power the board, again from the manual:
Connect only one 5.0v SOURCE of power to the VIN pins / Do not connect more than one SOURCE of
power to two or more of the VIN pins

And
Do not connect SOURCES of power to the pins marked with 5v. They are OUTPUTS for supplying power
to other devices.
Do not connect a LiPo to the 5.0v VIN pins.

Edit:

Think you just did  ::)

When people talk about 12V and 5V they are generally referring to regulated 12V or 5V supplies not the raw voltage from the battery. Think that is where the confusion is coming from.

That';s a good point, when we are talking 12v we are talking a reg, a 3cell lipo will start at 12.6v and will tail off during flight to 10.5v or less (hence the need for voltage monitoring)

[Dave1701]

No worries. On the f3 boards there is a vbat connector that as I understood from painless 360 video is the only place that the fc should be connected to 12 v. I have connected these to 12v without smoke and connected a buzzer to monitor voltage.  In the video he makes a point of stressing to check and double check that you don';t mix the wires at this connection.

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[Cheredanine]

The vbat connector is the only place the board can tollerate 12v, it can tollerate more though, the point of vbat pads is to monitor the battery voltage, on 4s builds that means 16.8v, that is also the only purpose of the pads, (to let the fc know the battery voltage), connecting to a 12v reg is pointless. Connecting it to battery voltage is only of any interest if you are doing something with it (providing to an osd, providing as telemetry back to the radio or running vbat compensation on the pid loop)

[aburn09]

Ok I think I can see where the confusion is on the SP F3 manual it does show a v bat connection on the diagram however on my SPF3 EVO (picture supplied looking from underneath there is no v bat terminals top or bottom....... there is a battery 2-6s on the right side bottom corner which is where I think I need to connect the battery voltage monitor wires from there to my pdb which will be 11.1v ......my buzzer obviously goes on the left side bottom corner hopefully this will be correct ? The board will be powered from 5v from one of the header pins  ;D

[Dave1701]

Apologies I didn';t realise you were talking reg voltages. I connected directly to the battery.
Just when you think you are beginning to understands something you realise youve just scratched the surface! Love it.

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[atomiclama]

Just when you think you are beginning to understands something you realise youve just scratched the surface! Love it.

Spot on that man.

I take the opinion that I know Fcuk all about anything and I';m happy to be corrected.

[aburn09]

I';m getting more and more confused now myself  this was suppose to be one or two replies and the topic would end 
So can someone just clarify what I ';think '; is right actually is before I burn my board out   
Through betaflight as I';m already doing on cleanflight you can set the battery voltage monitor to sound the buzzer when the battery voltage reaches a set point.........So here we go again  I need to put the full battery voltage ie 11.1v to the SP F3 EVO board so it knows when the voltage drops and it will activate the buzzer bottom left on the picture (hopefully everyone is with me so far ?) The only place I can see where this can happen on my board is the battery +/- bottom right of my picture..........The board itself to clarify any confusion will be powered by 5v taken from my pdb to the pin headers.......Phew hopefully everyone understands and just says yes ? 

[Cheredanine]

Look at the manual, see the pins marked vin ? They need to connect to 5v and gnd. That powers the board and is what you need to fly.


If, for some reason you want the fc to know the voltage use the bat pins and connect + to battery voltage and gnd to ground. The is not necessary to fly but is used to either tell something like a minim osd the battery voltage or send it back to a taranis

[aburn09]

Here';s the answer I was right 😊

https://youtu.be/aG8jNFKzkNA