• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Powering vTX

#1
Hi guys,
I am new to the forum and just got back into RC aircrafts after about 25 years!
I just got what i need to setup my plane as FPV. My post is related to powering FPV cameras. I searched the forum prior to posting but found a lot of mixed messages hence the reason for me posting all options that i have seen available.

My equipment:
  1. Akk A2 vTX - (3.7v-5v)
  2. I have a Power Pack A
  3. 3s batteries 850 mAH (for motor)
  4. fat Shark goggles
  5. 1S 230mAh batteries (have lying around)

My question is: What is the best way to power the camera on the airplane?

1- Splice off the BEC wires coming off the ESC that go to my RX?
2- Get power off an Aux channel off the receiver with a JR plug?
3- Power the VtX with a 1S standalone battery?
4- Use the second lead (JST) off the ESC and run it to a separate BEC circuit?
5- Powering off the balance plug off the flight battery. Would this not deplete just one cell of the lipo pack (bad)

I am trying to achieve:
  1. Ease of use
  2. Least amount of interference

I am an engineer so don't worry about getting too technical! I love it! :)

Thanks ahead of time for your help.
 
Last edited:

Merv

Well-known member
#2
My vTx runs on 12v, I power mine from my 3S flight pack, I tap the balance plug. Some slight interference but very flyable.
A separate battery or BEC will certainly work. You may be able to use the BEC from your main ECS, provided is has enough amperage.
 
#3
My vTx runs on 12v, I power mine from my 3S flight pack, I tap the balance plug. Some slight interference but very flyable.
A separate battery or BEC will certainly work. You may be able to use the BEC from your main ECS, provided is has enough amperage.
So you recon that having a separate uBec connected directly to the battery would eliminate the interference that you are getting by going straight into the balance plug?
 

Merv

Well-known member
#4
So you recon that having a separate uBec connected directly to the battery would eliminate the interference that you are getting by going straight into the balance plug?
I have no idea, I get very little interference, I’m satisfied with it as is. I have a separate onboard camera for recording video.
 
#6
I run a ubec from the balance plugs and I also run a LC Filter Module 3A 5-36V for VTX FPV and get a clean image
https://www.banggood.com/IFlight-LC...p-1458137.html?rmmds=myorder&cur_warehouse=CN
So you tap the full voltage off the balance plug (3S = 11.1v) and use the uBEC to drop it down to 5v for your video equipment? Or you tap the right leads to only take 3.7v off a single cell from your pack?

In the meantime, I will purchase a couple of the filters now just in case i run into interference problems.
thanks!
 
#8
Tapping one cell will work. If yo do, be sure to balance the pack.
That was my concern about tapping only 1 cell. I think I will use the balance plug to get all 3 cell voltage and run everything through a uBEC to the vTX to ensure a constant 5v. If I get interference, I will do what Aireal described and get a filter in between the ubec and the vTX.
Thanks for your help everyone!
 

Aireal Anarchist

Well-known member
#9
I tie diredtly to the balance plug to get balanced 12volts then step it down so I dont drain one or two cells....you can buy both male and female connectors on ebay

otherwise the more powerful your TX the easier it is to hurt a cell, of a 5.5 min runtime of my flyzone beaver it gets cut down 1 min flight time from the FPV gear they drain that much power ....so one could hurt a cell continuously draining one or 2 cells harder then the rest
 
Last edited:
#10
I tie diredtly to the balance plug to get balanced 12volts then step it down so I dont drain one or two cells....you can buy both male and female connectors on ebay

otherwise the more powerful your TX the easier it is to hurt a cell, of a 5.5 min runtime of my flyzone beaver it gets cut down 1 min flight time from the FPV gear ....so one could hurt a cell continuously draining one or 2 cells harder then the rest
Yup. I definitely do not like the idea of draining just 1 cell. I have the balance plugs ordered already and will tap into all cells like I mentionend above. thanks.
 
#12
I usually hook a JST to the ESCs battery connector to T off a separate power feed for the VTX. If the VTX can handle direct lipo, I will go that route, otherwise I will use a ubec or other regulator between the JST and VTX. Some ESCs even come with the JST already on it like the FT Power pack A&F ESC
https://www.readymaderc.com/products/details/strix-nano-goblin-replacement-20a-esc

Cheers!
LitterBug
Yes, I have the Power Pack A and it has a JST plug which i suppose is tapped directly off the battery input on the ESC. What happens is the ESC dies? Would i lose the power to my vTX by going through this JST plug? Or is the JST directly connected to the Battery input on the ESC. I can't tell because of the heat shrink wrapping on the ESC...
 
#13
Yes, I have the Power Pack A and it has a JST plug which i suppose is tapped directly off the battery input on the ESC. What happens is the ESC dies? Would i lose the power to my vTX by going through this JST plug? Or is the JST directly connected to the Battery input on the ESC. I can't tell because of the heat shrink wrapping on the ESC...
YES CORRECT...actually to be fastidious regarding ESC & your fail safe, one should cut the red and black receiver wires from ESC to receiver to isolate the power wires.....you should then route those Blk & red wires to your "ubec" "power out" connection points ...now you have constant power to the reciever, should you blow an ESC YOU STILL HAVE POWER TO YOUR RECEIVER AN SERVOS and you can still fly your aircraft under your control gliding it back down safely
 

LitterBug

Troll Spammer
#15
Yes, I have the Power Pack A and it has a JST plug which i suppose is tapped directly off the battery input on the ESC. What happens is the ESC dies? Would i lose the power to my vTX by going through this JST plug? Or is the JST directly connected to the Battery input on the ESC. I can't tell because of the heat shrink wrapping on the ESC...
It is a direct tap off the power input tabs of the ESC, so unless your ESC dies in a way that shorts the battery out in a big ball of fire, you would still have power to the VTX.
 
#16
It is a direct tap off the power input tabs of the ESC, so unless your ESC dies in a way that shorts the battery out in a big ball of fire, you would still have power to the VTX.
strange, I had an ESC in a wing puff magic smoke a year ago and lost servo controls and CRASHED not all ESC are built equal many are not even close to the amps they state they are

but because I powered my FPV gear off the balance lead I had a first person view as I augured in, thats when I began to do this UBEC powering to the RECEIVER, FLIGHT CONTROLLER & FPV gear due to loss of FPV image when another ESC blew a year or so ago....I no longer loose my fpv image or SERVO CONTROL from ESC failure

or a battery connectors like a xt60 cold solder joint fails.....and AGAIN you crash

powering video and RX from a source other than the ESC using a $5 UBEC is cheap insurance....
twocents.gif
 
Last edited:
#17
strange, I had an ESC in a versa wing puff magic smoke a few weeks ago and lost servo controls and CRASHED not all ESC are built equal but because I powered my FPV gear off the balance lead I could watch as I augured in, I began to do this UBEC powering due to loss of FPV image when an ESC blew a year ago....I no longer loose my fpv image from ESC failure

or a battery connectors like a xt60 cold solder joint fails..... you crash

powering video and RX from a source other than the ESC using a $5 UBEC is cheap insurance....
you lost servo control because you used the power coming off the esc signal JR connector that goes to your rx? I would assume that those 3 wires are part of the speed control circuit and fails if you see smoke.
 
#18
you lost servo control because you used the power coming off the esc signal JR connector that goes to your rx?
YES so have many others .....crashing due loss of control from blown ESC's is NOT uncommon.....

bad battery connector plugs, burn up an esc and your likely going down

powering videoTX and radio RX from a source other than the ESC using a $5 UBEC is cheap insurance.... you can still glide it down


edit: I think I have that bad ESC still here, I should open it up use a mulitmeter and make a video showing what risks we take and then show just how easy it is to add a UBEC to power your ESC, FC and videoTX from a separate source
 
Last edited:

LitterBug

Troll Spammer
#19
The bigger the bird, the more options you have for power and control. I have been flying <250g wings that barely have enough room to fit the required gear in it, let alone a second battery to power the servos and ESCs. My bigger wings like the Strix Stratosurfer have a Matek Wing FC with seperate BECs for the servos, camera, VTX, and other gear. It also comes down to how complex you want to get. Sometimes it is nice to just Keep It Stupid Simple.