Hello, I'm a bit confused on how the power specs work  .... The Runcam Link is rated at 7.4-26.4 V@ 4-9W........ Does that mean I need to use  lipo that can match the 26.4 V high end, or better? The lipos get real big and heavy at that range. I wanted to go with the Lumenier N2O 1250mAh 5s 120c Lipo Battery, but it's voltage only goes to 18.5 volts. 

Can you help set me straight?  

The RunCam Link VTX has an onboard voltage regulator so whether you feed it 7.4V or 26.4V (or anything in between) it will internally regulate the voltage down to 5V. If you have an 8-10V voltage regulator on your FC then it's highly advisable to connect the RunCam Link VTX to the pads for that which provides added protection from voltage spikes. If you connect it directly to LiPo voltage then make sure you solder a good quality 1000uF 35V low ESR capacitor across the ESC pads that the LiPo pigtail are soldered to.

Thank you ... I am going to connect the Link VTX directly to the luminair lipo battery. 

"across the ESC pads that the LiPo pigtail are soldered to."     by ESC pads, you mean the Link VTX correct? The positive and ground on the Link correct?

So it would go:

1) lipo (Lumenier N2O 1250mAh 5s 120c Lipo Battery)
2) soldered to a good quality 1000uF 35V low ESR
3) and then somehow these two components connect to the Link VTX .... positive and ground.

I just need to connect the positive and ground for this to work correct?

I've never soldered a capacitor before, so please forgive my ignorance. I'm just not certain I understand how #3 is going to work. 

I suppose I need to unscrew the first layer of the VTX to get at the pads correct?  It's not like they provide ANY directions whatsoever..hahah!!!    

    

(24-Jan-2023, 08:49 PM)Sgroche Wrote: Thank you ... I am going to connect the Link VTX directly to the luminair lipo battery. 

"across the ESC pads that the LiPo pigtail are soldered to."     by ESC pads, you mean the Link VTX correct? The positive and ground on the Link correct?

So it would go:

1) lipo (Lumenier N2O 1250mAh 5s 120c Lipo Battery)
2) soldered to a good quality 1000uF 35V low ESR
3) and then somehow these two components connect to the Link VTX .... positive and ground.

I just need to connect the positive and ground for this to work correct?

I've never soldered a capacitor before, so please forgive my ignorance. I'm just not certain I understand how #3 is going to work. 

You can solder the capacitor across the positive and ground terminals of the RunCam Link if you want but it is usually easier to solder it onto across the larger pads on the ESC board. The end result is the same because it means you will have a capacitor across the LiPo positive and negative wires at one of the points in the circuit which is what matters because it absorbs / smooths out the voltage feed thus reducing the risk of a voltage spike. You can see how they are connected to an ESC in one of Oscar's articles HERE.

Make sure you use a decent make capacitor and not just any old budget no-name brand capacitor. It must be a low ESR capacitor otherwise it will be useless. I use Panasonic FR or FM series capacitors.

(24-Jan-2023, 08:49 PM)Sgroche Wrote: I suppose I need to unscrew the first layer of the VTX to get at the pads correct?  It's not like they provide ANY directions whatsoever..hahah!!!        

No. You don't need to dismantle the RunCam Link VTX. All the solder connection points are easily accessible and can be soldered from the side. You just need a small tip on your soldering iron. See the image below.

Thank you so much for this helpful info!! Do you think 35v is big enough or should I go 50v based on a 5s build?

Here's the list from Oscar that I'm considering ..... size matters...hopefully the measurements are in mm!!! I'm runni g out of room.

I'm accually installing the Wasp Nano camera and unit into an RC racecar ,,,, a 1/28 scale Mini Z to be specific. It has an ESC but it's for a racecar. It might be an OS ESC whitelable. I could do exactly what you say and run the WASP through it, but it will drain the 4 aaa battaries powering the car too quickly. 

This is why I want to simply add a completly separate power supply, by soldering the capacitor directly to the pos and ground on the smaller pads on the air unit. Just as I saw it in Oscars depiction. Then I would solder the pigtail wires going to the lipo battary, directly on top of the Capacator and Air Unit solder.

Dumb question (but not dumber than frying my gear .... since the three components mentioned above would be on a three way solder, what's to stop the electical current from bypassing the Capacators function and moving directly to the Air Unit? Sorry for this, but I'm not an engineer.

You CAN mod a mini z to run on any battery source, so my final version will most likely change as technolgy progresses, but for now I need to get the car up and running so i can test and improve it. 

I'm also doing this in my giant scale Lysander plane gas powered plane, and will be building a race drone soon!!! The new Walksnail Avatar kit is in the mail, and I'll be testing that against the DJI v2 goggles and Wasp with new light air unit.

I appreicate all of your help. I'm researching a new business model that could help FPV  pilots /drivers/ people take advantage of this exciting and fun technology worldwide.

Here's the list of capacitors for consideration .... is low impedance better than high?            

[size=undefined]
[color=var(--pcheading-cl)]1000uF – For PDB Main Power

[color=var(--pcheading-cl)]35V[/color]
Brand
Series
Size (D X L)
Impendance (Ω/100 kHz)
Panasonic
FM
12×25
0.015

Panasonic
FM
12.5×20
0.018

Panasonic
FC
16×20
0.029

Panasonic
FC
12.5×25
0.03

[/size][/color]

OK, that explains the confusion around the ESC I just automatically assumed it was a quad.

I run a 1000uF 35V capacitor on 6S (quads) without any issues but if have space for a 50V one then that gives more headroom but limited space on a quad usually prevents that, or you have to go down to 470uF if you want a 50V capacitor which is generally the same size as a 1000uF 35V capacitor. Once you go over 1500uF the minimal additional benefits you get from the higher capacitance tend to outweigh the physical size of it.

Having the capacitor across the positive and negative connections isn't to throttle current, it's to smooth out voltage delivery to the components on the circuit whereby some of the supplied voltage will sink to ground until the capacitor is fully charged after which it then continually discharges/recharges while voltage is present on the connections. You can get a voltage rush/spike during initial plug-in of a LiPo (notable by the spark produced, especially on 6S and hiher) so the presence of a (discharged) capacitor will absorb some of that initial excess voltage and sink it to ground. After that the capacitor then continues to act as a voltage smoothing device / filter.

Out of those capacitors you listed get the FM series ones. They have a lower ESR (which is what you want) than the FC series and are generally smaller in size by comparison for the same voltage / capacitance specs.

Thanks Again!!

You explained that perfectly!!!