Hi V-22,

Yeah, I have been looking at all of those motors. Those 1303.6 motors or even the 1204 motors might be good on a sub-250 gram build. Maybe an option for my Quest250-LR quad if the motors that I already have don't get the results I want. Right now, I am trying to figure out what I want to do for an FC...something with BLHeli_32.

https://github.com/bitdump/BLHeli/issues/244

Worth a read regarding the cutoff -

(23-Jan-2021, 07:57 PM)kaitylynn Wrote: https://github.com/bitdump/BLHeli/issues/244

Worth a read regarding the cutoff -

Hi Kaity,

Good Find. THANKS 

I will read it all 

(23-Jan-2021, 07:57 PM)kaitylynn Wrote: https://github.com/bitdump/BLHeli/issues/244

Worth a read regarding the cutoff -

Thanks! EVILsteve posted this earlier as well. I think we still need to test each BLHeli_S ESC to verify, but hopefully we'll find plenty that work without issue. It's still not clear whether this only affects 2S setups (eg is it actually a 7V cutoff)?

(23-Jan-2021, 08:29 PM)V-22 Wrote: Thanks! EVILsteve posted this earlier as well. I think we still need to test each BLHeli_S ESC to verify, but hopefully we'll find plenty that work without issue. It's still not clear whether this only affects 2S setups (eg is it actually a 7V cutoff)?

Hi V-22,

Yes, Thanks to EVILsteve. I apologize for not reading it thoroughly at that time. 

My empirical data shows shows that it is clearly per cell and NOT a 7V per pack cutoff.

I pretty much always "Fly Till I Die" just to see how much I can get out of the batteries. In fact, when the "Low Battery" warning appears, I fly back close to me and fly in circles until the quad drops from the sky. That pretty much says that I am taking it down to the limit. In fact, I set the Minimum Cell Voltage in Betaflight to 2.5 just to see if I can get there.

Regardless of which quad I fly, I get the following documented results with LiPo batteries:

When using a 3S pack, the quad drops out of the sky leaving  9.8 to 10 volts in the pack; the per cell voltage is between 3.24 and 3.5.

When using a 4S pack, the quad drops out of the sky leaving 13.80 volts in the pack; 3.45 volts per cell.

Now, I also parallel wire 2 1S 650 cells together for a 2S package. When using this setup, I measure each cell individually and have gotten the following results:

Per cell voltage between 3.48 and 3.60 which translated to 6.96 and 7.20 volts respectively.

Now, if you really think about it, the LVC is to protect the battery rather than the ESC. The only real way to protect a LiPo from being abused would be to have the limit on a per cell basis since there would be no way to know what battery a pilot might use. 

If the pack limit was set to 7 volts, 
then you could draw down a 4S pack to 1.75 volts and a 6S down to 1.16 volts.     
                                             
"  BAM  "   ...there goes your battery. 

(23-Jan-2021, 09:43 PM)iFly4rotors Wrote: Hi V-22,

Yes, Thanks to EVILsteve. I apologize for not reading it thoroughly at that time. 

My empirical data shows shows that it is clearly per cell and NOT a 7V per pack cutoff.

I pretty much always "Fly Till I Die" just to see how much I can get out of the batteries. In fact, when the "Low Battery" warning appears, I fly back close to me and fly in circles until the quad drops from the sky. That pretty much says that I am taking it down to the limit. In fact, I set the Minimum Cell Voltage in Betaflight to 2.5 just to see if I can get there.

Regardless of which quad I fly, I get the following documented results with LiPo batteries:

When using a 3S pack, the quad drops out of the sky leaving  9.8 to 10 volts in the pack; the per cell voltage is between 3.24 and 3.5.

When using a 4S pack, the quad drops out of the sky leaving 13.80 volts in the pack; 3.45 volts per cell.

Now, I also parallel wire 2 1S 650 cells together for a 2S package. When using this setup, I measure each cell individually and have gotten the following results:

Per cell voltage between 3.48 and 3.60 which translated to 6.96 and 7.20 volts respectively.

Now, if you really think about it, the LVC is to protect the battery rather than the ESC. The only real way to protect a LiPo from being abused would be to have the limit on a per cell basis since there would be no way to know what battery a pilot might use. 

If the pack limit was set to 7 volts, 
then you could draw down a 4S pack to 1.75 volts and a 6S down to 1.16 volts.     
                                             
"  BAM  "   ...there goes your battery. 

What ESC is this with? There is another possibility that the MOSFETs used in the ESC cannot operate below a certain voltage level, making testing of the specific hardware critical.

(23-Jan-2021, 07:57 PM)kaitylynn Wrote: https://github.com/bitdump/BLHeli/issues/244

Worth a read regarding the cutoff -

The last post on this link is gold... (if true) this shows that LVC/BLHeli_S problem lies in the hardware...
(I’ve done a similar modification on a servo MCU in order to produce a brushed ESC with failsafe... (just yesterday!!))

I know you guys are anxious to get 10km with DJI on 3"

I have the Apex 1303.6 5555KV. One of firsft flights was hover for 16.2 min on 500mah 14.8V. Sadly I roasted a bell doimg hot air rework - magnets prob toast.

I dont see 10km happening anytime soon
Can't you just wait 2-3 years for new Quantumscape or SolidPower battery tech.

I did some testing last night with a regulator  I believe we have a mix of esc's on the market that have LVC and dont but I dont think blheli32 is going to be an easy solution anyway. 

betafpv 20A aio -blheli S used in the photos
I tried this with 2 other unbranded esc's the results where about the same.

Test 1: 7.5v at plug in and I reduced the voltage untill the motors stopped spinning. This was about 6.3v it usually quit, flight controller and betaflight were still operating normally but I could not re-arm the quad until I increased volts to about 6.5v. If I reduced the voltage extremely slowly I could get a bit lower to 5.83V or 2.91v/cell. The motors did not stop at the same time if I went slow enough.





Test 2: 11.6V at plug in. I could reduce voltage well below 2.5v/cell without any issues. LVC not active on this esc.



My test show that I do not have LVC active but the mosfets cannot handle operating below 6v on any board I tried. Im not sure blheli32 would do any better, moving to a 1-2s ESC might be the only solution. None of my blheli_S boards seem to have LVC but ifly4rotor's definetely seem to by his testing. Hopefully we dont have LVC issues with 1-2s boards.

This was with a switching regulator that was extremely noisy I did not try any tests with a blheli32 esc. I need a cleaner power source for any more tests.

I’ve actually heard of the “3s LVC fix” before, although I always equated it to the voltage sag... but you testing shows a different story... great work EVILsteve!!

Found a few more new motors that could be promising. I'm interested to see how the SunnySky 1104s I'm starting with compare to the Flywoo NIN 1404s, and whether one of these 120x or 130x motors will provide a better balance between performance and efficiency. I'm worried that the tiny stators on the 1104s won't have enough torque to reach the performance numbers they would otherwise be capable of, and I haven't found a way to capture stator size in the performance calculations.

Diatone Mamba Toka 1206 6000Kv
https://www.diatone.us/products/mamba-to...cing-motor
https://www.racedayquads.com/products/di...icro-motor

FETtec Motor 1303.6 5555Kv
https://fettec.net/en/shop/fettec-motor-1303.6
https://www.racedayquads.com/products/fe...icro-motor

Phantom-X with 1303 5000kv FPV Cycle motors spinning 4 inch Gemfan Hurricane 4024 props had the following Fly Times:

Using the 3s 1100 mAh GNB battery and AUW of 176 grams, the Fly Time was over 17 minutes.
Phantom-X with 2 18650 3000 mAh cells in a holder and AUW of 226 grams, the Fly Time was over 21 minutes.

Also NOTE:  When I used 3 18650 3000 mAh cells (AUW of 275 grams) the Fly Time was a little over 17 minutes.

Keep in mine that the quad had a totally factory tune and no checking for any Low Voltage Cutoff setting anywhere.

So, the 1303.5 5555kv motors might be a little better. Although it doesn't seem like much, sometimes a little goes a long way.

My curiosity would be how the 1206 6000kv motors compare on a similar rig and spinning 4 inch props.

I am also looking at the BrotherHobby 1402 9500kv 1-2S motors since they are designed for 1-2S builds. The higher kv should generate more thrust with less throttle as long as they spin the 4 inch props.

You hear people talk about the motor being able to spin the bigger props. Well, I have routinely "over propped" the motors just to see if it would work. My thoughts are that it is not really about "spinning" the prop, but rather the thrust it takes to lift the weight. The same motor can spin a larger prop if you reduce the weight of the craft so that you can use less throttle to get the thrust. 

I think "over propping" is fine for an efficient long range build, as you probably won't be flying aggressively and efficiency increases with prop size. The tradeoffs are much higher current requirements when you increase prop size at a fixed Kv, and reduced responsiveness of the motors due to insufficient torque which can lead to lack of control. A multirotor's control authority comes from being able to adjust the thrust produced by each rotor, and by using a larger prop (or smaller motor) the motor response to the flight controller is slowed leading to instability. If you're just cruising around in level flight the reduced control authority won't be a big deal, but it will become extremely obvious if you try to do any acro.

The way I understand it, wider stator motors can produce more torque, giving you improved low-end responsiveness and finer control. More torque allows the props to accelerate faster, thereby producing the requested thrust sooner to change orientation as requested by the flight controller. Taller stator motors produce more power, and can produce more thrust at the top end. It seems analogous to horsepower and torque in a car engine.

If someone has a better handle on this and can explain it more clearly, I'm all ears!

Hi V-22,

Well said; my perception as well. 

That is why I would choose a 1303 over a 1204; or a 1402 over a 1303. 
Those BrotherHobby 1402 9500kv motors are looking better and better the more I think about it.

For me, "slowing" down that authority makes that quad handle better, smoother. I want a craft that doesn't overreact when I do. By now, you probably know that I don't race and don't fly acro, generally - If I do, I will grab the GEPRC Phantom and go have fun. I like easy cruising and smooth flying; I want it to feel like gliding through the air. This endurance quest that we are on, will pretty much mean that we will end up with "MY" kind of quad. You know, ease it off the ground and up to altitude {for me that is over 100 meters}, then cruise steady with just enough throttle to maintain a desired speed...for as long as I can.  

This new T-Motor 1404 should be great for a 4-5" 2S long range build.
https://www.getfpv.com/t-motor-f1404-380...motor.html