ESC / BEC problems with Flite Test ESC

[ArcherPilot]

Hi Folks- back to the hobby after a 40 year break!
I'm having troubles with the ESC supplied with the Flite Test "power pack B" (it's labled 35A / BEC 3A 5V / LIPO 2S-4S). I've got a Tattu 1300mAh 45C 3S battery.

The issue is that when I connect the battery to the ESC, I get the full battery voltage (like 12V) on the small red connector with red and black wires which I assume is the BEC output. Before I measured it I connected my Rx and servos and everything seemed to work ok until one of the servos smoked and I started measuring voltages.

I've send a message to FT support but it's the weekend. Hoping someone can quickly confirm that the little red connector on the ESC should be outputting 5V, not 12.

Thanks!

 

[Corsair714]

Hi Folks- back to the hobby after a 40 year break!
I'm having troubles with the ESC supplied with the Flite Test "power pack B" (it's labled 35A / BEC 3A 5V / LIPO 2S-4S). I've got a Tattu 1300mAh 45C 3S battery.

The issue is that when I connect the battery to the ESC, I get the full battery voltage (like 12V) on the small red connector with red and black wires which I assume is the BEC output. Before I measured it I connected my Rx and servos and everything seemed to work ok until one of the servos smoked and I started measuring voltages.

I've send a message to FT support but it's the weekend. Hoping someone can quickly confirm that the little red connector on the ESC should be outputting 5V, not 12.

Thanks!

View attachment 195321

Someone can correct me, but I believe that red connector wire is for running led lights or something of the sort. The power from the bec will be supplied through the other lead (The one with three wires that you plug into your rx).

 

[Corsair714]

In other words your esc is fine and you just shouldn't be connecting the wires with the jst connector on them to anything unless you need 12v for something. Just plug in the other lead to your receiver and you'll be good to go.

 

[ArcherPilot]

Thanks! That's very helpful. I just tried it and everything seems OK now.

One follow-on question though... my Spektrum AR620 can telemeter the battery voltage back to the Tx, which is great, except now it reads 4.9V which is the BEC voltage. Any way to get the actual LiPo battery voltage sent back to base?

 

[Corsair714]

I'd have to look into your second question there as I don't know if you can do that or how you would do it, if you can, off the top of my head.

 

[Piotrsko]

It's reading the voltage from the red black wires(or equivalent) of the servo connection. To get battery voltage, you need a different sensor system

 

[Taildragger]

To get battery voltage you would need a spektrum SMART esc and smart battery.

 

[Merv]

Most people use a cell checker to get the battery voltage. It' not telemetry but it's cheap & gets the job done.
Something like this.

 

[sprzout]

Someone can correct me, but I believe that red connector wire is for running led lights or something of the sort. The power from the bec will be supplied through the other lead (The one with three wires that you plug into your rx).

Pretty much that exactly. Lights, and it's been suggested that one can use it for powering an FPV transmitter, although I haven't tried myself yet.

 

[ArcherPilot]

Oh, too bad. After reading the Spektrum marketing I thought that my AR620 receiver would telemeter the main battery voltage, but I see now that it's just the BEC output, which is not very useful. I am not too thrilled to go out and replace my ESC and batteries with "smart" ones. But I'm an electronics guy, so.... I just found this doc on the Spektrum website which describes how to develop sensors for their "X-bus" which I guess is the magic protocol the TM1000 speaks. Do any of you know if this is the same protocol as things like the AR620 "data" port?

https://spektrumrc.com/ProdInfo/Files/SPM_Telemetry_Developers_Specs.pdf

 

[Corsair714]

The voltage range for the receiver has a maximum of nine volts so I don't think you'll be able to plug in your 3s there. Sorry. Idk much about the ar620, but I doubt that it will do telemetry other than just the receiver voltage. The data port is for data not plugging batteries into it.

 

[Bricks]

The Spektrum receiver needs to have a T in it`s description to use telemetry, you can then buy add on sensors for anything you want . Or if your receiver excepts something like the TM 1,000 then ad sensors to it. The link for for battery voltage sensor.

Air Telemetry Flight Pack Voltage Sensor: EC3/IC3 (SPMA9556): Spektrum - The Leader in Spread Spectrum Technology (spektrumrc.com)