Naze32 voltage monitoring

[shazzy]

Just wanted clarification before I fry my board.

My understanding is that live and ground wires from the power loom/pdb are wired straight into the voltage monitoring pins on the naze32?

And in CLI it';s turned on by "features vbat"  or something. 

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[Hands0n]

It is a blooming scary thing to do ::)  But a bit of a Google, the information is sparse, I found this which may help give you some confidence...

[4] Battery Voltage Monitor Optionally connect + and - from battery pack here to be able to use in-flight battery voltage monitoring and alarm.

Battery cell count is automatically detected, and cell warning voltage can be configured. Buzzer will activate when voltage falls below configured per cell threshold.

Source: http://thehqbooks.com/b/2003114

[shazzy]

Cheers HandsOn! Information is indeed sparse with only the naze32 manual having a single line dedicated to battery monitoring.  Didn';t want to fry my board with just that to go on!

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[barneyg]

Should be good for anything up to 6S if the manual is to be believed

[Soul]

My brother-in-law has his power board wired directly up to the Naze for battery monitoring and it';s fine. The KK was the same.

[teslahed]

Just make doubly sure you get the polarity the right way around. There is no reverse polarity protection. Get that wrong and you';ll instantly fry your board.

[DebianDave]

Bit of a thread necro but along the same lines. How are we all connecting our alarms/voltage monitor? I could solder it right in, but having some flexibility would be nice. Is there a tried and tested connector which plays well with 2.54mm header pins under flight conditions?

[tupoar]

I';m currently migrating to telemetry based voltage monitoring, which includes plugging straight into the Naze from the PDB. I';ve ended up using a JST connector on one and 2-pin servo on the other, however both my Naze';s have cases which make most connections quite snug.

[quadfather]

Bit of a thread necro but along the same lines. How are we all connecting our alarms/voltage monitor? I could solder it right in, but having some flexibility would be nice. Is there a tried and tested connector which plays well with 2.54mm header pins under flight conditions?

I soldered 2x3 header pins to be used for telemetry, buzzer and vbat.

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[annikk.exe]

Should be good for anything up to 6S if the manual is to be believed

Apologies for the thread necromancy...
I didn';t see anything about 6S in the manual...  and I';ve heard that the naze uses a 4:1 voltage divider to bring the voltage down below 3.3v, and 3.3v is the maximum it ever expects to see.

Going the other direction, 3.3v * 4 = 13.2volts
So for a 3S battery like I';m using, which should max out at 12.6 volts, it';s fine.
However for a 4S battery, wouldn';t that blow it?

Is anyone successfully using 4S or higher with naze';s vbat input?

[quadfather]

Apologies for the thread necromancy...
I didn';t see anything about 6S in the manual...  and I';ve heard that the naze uses a 4:1 voltage divider to bring the voltage down below 3.3v, and 3.3v is the maximum it ever expects to see.

Going the other direction, 3.3v * 4 = 13.2volts
So for a 3S battery like I';m using, which should max out at 12.6 volts, it';s fine.
However for a 4S battery, wouldn';t that blow it?

Is anyone successfully using 4S or higher with naze';s vbat input?

Not sure where you heard that.  It uses a 1:11 divider (10k & 1k to ground).  The specs say it';s good up to 25V (6S) but offers no polarity protection.

[Revs]

You don';t need to connect a negative wire, just a positive wire. One less wire going to the FC can only be a good thing, vibration wise.

[dirtyharry]

Just make doubly sure you get the polarity the right way around. There is no reverse polarity protection. Get that wrong and you';ll instantly fry your board.

Should not really matter what voltage you put into a voltage divider circuit as long as its less than 25v . The board will probably read 0-3.3v or something like that but the divider circuit will make sure it never sees full battery voltage , so no chance of smoke unless your feeding it a massive voltage or completely reverse your whole circuit , in which case the voltage divider will be the least of your worries.

Mind u i';m using a flip 32 and I think there';s only one pin , so others ma be different

I use a D4r and feed my battery voltage to a wee divider circuit directly into the receiver , I don';t see the point in going through the board if your using a taranis/th9x

http://www.multi-rotor.co.uk/index.php?topic=6513.msg53826#msg53826

[annikk.exe]

You don';t need to connect a negative wire, just a positive wire. One less wire going to the FC can only be a good thing, vibration wise.

:O  Really?
Is there a downside to not connecting the negative?

[annikk.exe]

There must be a downside... otherwise it would be a no-brainer to NOT connect it, in which case why does the Naze bother having a negative pin in the first place?

[Revs]

From what I understand there is no down side. I suppose if for some reason you were running a two battery setup and you had one battery powering the Naze through a BEC and another powering the ESCs/motors and you wanted to monitor the motor battery then you';d need it. But otherwise apparently not.

[quadfather]

Your entire system should have common ground.  If you do a continuity or resistance test between any two ground pads anywhere on your quad you should see continuity or 0 resistance.

The exception would be the use of true opto ESCs where you use a separate battery to power the Naze and RX.

[annikk.exe]

So is negative the same thing as ground?  I think that';s the thing that';s confusing me the most..

I';m running KISS 12amp ESCs, they have no BEC so I';m using a seperate UBEC.  That seems to have a positive and a negative wire connecting to the Naze board on the 5th set of ESC pins.  Do I therefore have a ground from that?  And, should I then disconnect the negative vbat monitoring wire to avoid a ground loop?  (Ground loops are apparently bad, I have heard about them but don';t fully understand them..)

[quadfather]

So is negative the same thing as ground?  I think that';s the thing that';s confusing me the most..

I';m running KISS 12amp ESCs, they have no BEC so I';m using a seperate UBEC.  That seems to have a positive and a negative wire connecting to the Naze board on the 5th set of ESC pins.  Do I therefore have a ground from that?  And, should I then disconnect the negative vbat monitoring wire to avoid a ground loop?  (Ground loops are apparently bad, I have heard about them but don';t fully understand them..)

This is a very boiled down answer.  Voltage is the electric potential energy relative to a reference point, usually ground.  Certain power supplies can offer positive and negative voltages, but a conventional battery only has a positive voltage.

The reason why people say positive and negative in relation to batteries is because you have a cathode (+) and an anode (-).  So when someone says negative they mean the battery contact with the - symbol, not that it has a negative voltage.  Since you connect the negative pole of the battery to ground you could say it';s the same thing, but it';s technically not correct.  They do however have the same potential, i.e. 0V.

I only know ground loops from AC circuits, where two devices with different power sources connected to each other are generating noise, e.g. guitar amps.  I don';t think it';s an issue on quads.

[annikk.exe]

Thanks for the explanation. :>
I saw the reference to Ground Loops here: http://www.hobbyrc.co.uk/frsky-battery-voltage-sensor-frsky-telemetry-system


The "Note" near the bottom:

Note: If you are using only one battery in your model without a separate receiver battery i.e. you are using the ESC BEC, you should NOT connect the black (GND) wire of the voltage sensor because GND is already supplied to the receiver from the ESC. Connecting another ground is likely to cause a ground loop that could result in premature failure of attached electronic components.

I use a UBEC which has the negative (presumably ground) wire attached, and I also want to measure voltage with the vbat pins on the naze board.  Should I only connect the positive, and get rid of the negative wire altogether?  The funny thing is, the negative wire is actually what came loose and fried my naze board last week, so it would be kinda ironic if it turns out it';s actually a 5th wheel.

[quadfather]

Thanks for the explanation. :>
I saw the reference to Ground Loops here: http://www.hobbyrc.co.uk/frsky-battery-voltage-sensor-frsky-telemetry-system


The "Note" near the bottom:

I use a UBEC which has the negative (presumably ground) wire attached, and I also want to measure voltage with the vbat pins on the naze board.  Should I only connect the positive, and get rid of the negative wire altogether?  The funny thing is, the negative wire is actually what came loose and fried my naze board last week, so it would be kinda ironic if it turns out it';s actually a 5th wheel.

The note refers to a voltage sensor module, not the Naze, so that may be slightly different.  At any rate, there';s no need to connect the ground wire to the voltage sensor on the Naze since all ground is interconnected, but there';s no harm if you did.  If someone knows otherwise I';d love to hear their explanation for it.

I';m running the same configuration as you.  My ESCs have their power wires disconnected, the Naze is powered by a dedicated BEC, and I have the voltage sensor connected with ground.  On another quad I have gone one step further and also removed the ground wires from the ESCs to the FC leaving only the signal wires, and that works equally well.  The key is having a solid ground connection for all components, which is achieved through the PDB.  NB, this is different when you';re using true opto-isolated ESCs, but this is not the case here.

[Friskle]

All you need remember is, an ESC only needs the signal wire connected, after all, thats the only wire that tells the esc when to work basically, the other two are merely for providing a step down of power for the RX or FC, the ESC`s main power to run, obviously comes from the Main battery, If you are requiring an ESC to power the RX, then all you need is one ESC providing power to the RX or FC, unless of course if using a seperate BEC, then No ESC is required to output power, and only need "telling" what to do, so you only need the Signal wire connected.

the negative wire has come loose and obviously created a short for it to do that.

Your main Ground is via the PDB.

[annikk.exe]

Okay, thanks guys. :>  Guess I';ll leave the negative wire connected for the moment.