(16-Feb-2023, 03:42 PM)amped_fpv Wrote: Glad to help!

I measured both those resistors at 9.65 k ohms.


Good luck!

Can I ask you to take another measurement between the USB port housing and the +5 volt USB connector? I marked in the picture. Thank you!

(17-Feb-2023, 02:59 PM)Gumilev Wrote: Can I ask you to take another measurement between the USB port housing and the +5 volt USB connector? I marked in the picture. Thank you!

18.75 k ohm

Hi there, very intrigued by your build and its achievements. I currently have a build of my own, but am having problems with it falling out of the sky at only 3.2V. (Thread here: https://intofpv.com/t-1s-nanolongrange-f...#pid204135 )

I just wanted to ask, would it not be more beneficial (maybe only in my case) to power the entire drone from the 5V step up? i.e. not just the camera and vtx.

Hi Panda,

Yes, depending on the FC, most of them have a cutoff somewhere between 
3.0 volts and 3.5 volts.

Take a look at this thread:  Li-Ion 18650 Batteries and Low Voltage Cutoff

Now, the concept of powering the whole FC from a +5 Volt BEC is very interesting.
Keep in mind that most of the small BECs with amp ratings at 2A or less will likely
NOT work because the amp draw for the entire FC board and motors is much higher
than that. An FC board rated at 5A (which is per motor) will actually draw up to
20A at full throttle and more if motors are used that will pull more (yeah, that will
burn out an ESC). So, the BEC needs to have an amp rating of at least 20A for
a 5A FC board. We are talking a much larger and heavier board than what is
needed just to power 1 component. It will ADD quite a bit of weight to the craft.

If you want to try it, be sure that the BEC is rated for at least 20 Amps for a
5A FC board. Yeah, if the FC is rated higher and you are using maximum draw
motors, then an even larger BEC will be required.

Please let us know how it works out. In fact, maybe start a thread in the 
"Tips & Tricks" section of the process, the components used, and how it works 
or doesn't. I will also allow for others to comment specifically on this process
and offer considerations. 

It will be a good experiment. 

(23-Aug-2023, 01:27 PM)iFly4rotors Wrote: Hi Panda,

Yes, depending on the FC, most of them have a cutoff somewhere between 
3.0 volts and 3.5 volts.

Take a look at this thread:  Li-Ion 18650 Batteries and Low Voltage Cutoff

Now, the concept of powering the whole FC from a +5 Volt BEC is very interesting.
Keep in mind that most of the small BECs with amp ratings at 2A or less will likely
NOT work because the amp draw for the entire FC board and motors is much higher
than that. An FC board rated at 5A (which is per motor) will actually draw up to
20A at full throttle and more if motors are used that will pull more (yeah, that will
burn out an ESC). So, the BEC needs to have an amp rating of at least 20A for
a 5A FC board. We are talking a much larger and heavier board than what is
needed just to power 1 component. It will ADD quite a bit of weight to the craft.

If you want to try it, be sure that the BEC is rated for at least 20 Amps for a
5A FC board. Yeah, if the FC is rated higher and you are using maximum draw
motors, then an even larger BEC will be required.

Please let us know how it works out. In fact, maybe start a thread in the 
"Tips & Tricks" section of the process, the components used, and how it works 
or doesn't. I will also allow for others to comment specifically on this process
and offer considerations. 

It will be a good experiment. 

Hi iFly,

You have just pointed out a complete oversight of mine, I never considered the current limit of the Set-up that I had in mind. It's only 2.8A, which as you say would obviously not be enough to power an entire array of ESCs. Looking at other options that are rated for this higher current, it seems that they begin to get quite large and much too heavy for this nano build.

I have also made sure that none of my batteries have a cut-off like you mention. I have tried the popular VTC6 batteries, and have had no luck getting them below 3.2V. This is fine, but seeing other builds happily draw them down to 2.8V - 2.6V, really makes me feel like I have wasted potential. I have even tried the most powerful 18650s that I could find, the Molicel P28A, and did get better results. However, it is very unpredictable, dropping out of the sky as soon as it hits any voltages between 3.4V - 2.9V. Some predictability would be very much appreciated at the moment 

(25-Aug-2023, 12:33 AM)panda0323 Wrote: Hi iFly,

You have just pointed out a complete oversight of mine, I never considered the current limit of the Set-up that I had in mind. It's only 2.8A, which as you say would obviously not be enough to power an entire array of ESCs. Looking at other options that are rated for this higher current, it seems that they begin to get quite large and much too heavy for this nano build.

I have also made sure that none of my batteries have a cut-off like you mention. I have tried the popular VTC6 batteries, and have had no luck getting them below 3.2V. This is fine, but seeing other builds happily draw them down to 2.8V - 2.6V, really makes me feel like I have wasted potential. I have even tried the most powerful 18650s that I could find, the Molicel P28A, and did get better results. However, it is very unpredictable, dropping out of the sky as soon as it hits any voltages between 3.4V - 2.9V. Some predictability would be very much appreciated at the moment 

Hi panda,

It is NOT the batteries that have the low voltage cutoff (they don't care). It is actually the circuitry 
on the FC board itself. As indicated in the other thread, some FC boards can be modified to allow 
the board to operate at a lower voltage. This is soldering between things that are not normally 
soldered and you need to know the schematic of the FC board and the chip that it uses. The
components are very tiny and there are no pads. The process is soldering super tiny pins.

Do keep in mind that the CPU chip operates at 3.3 volts. Now, I don't know if the regulator for 
the 3.3 volt rail is a step-down only or has step-up/step-down capability. 

Another interesting thing, is that this low voltage cutoff seemed to be based on the per cell 
voltage rather than the whole pack. From my experiments, a 2S pack would cut off before the 
pack drained down to 6 volts. Now, this is not normally an issue on multi-cell battery packs. 

Later, iFly