Very tidy ! 

Hi MomoBrut,

Man, that is one SLICK build.    Very Clean     

EXCELLENT JOB  

Very nice! Looking forward to see how far you can push this!

Thank you, I'm glad you like it. I'm too old to do things I don't like. 
A lot of things need to be done before everything is as it should be. And it probably doesn't belong in this thread. If you're interested, I'll put it here.
So far in BLHeli32 I have reduced the PWM to 16 kHz and the vibrations have disappeared from 99%. So for now I stay with BF 4.2. So far, I only fly VLOS, it already flies very nicely, 7 inches has such a nobility in flight. I started calibrating the current sensor and pulled out the batteries I use on my 60-inch 3D acrobats. That was also the reason why I went to 7 inches. With the 6s3300 battery, the VLOS flight time is around 11 minutes, so BVLOS will be an estimated 8 minutes, which is less than I hoped for. I will have to connect two 6s VTC6 packs in parallel so that I can fly somewhere further.

I flew several times today. I checked the calibration of the current sensor, it still needed to be slightly adjusted. I verified the GPS function and started setting up the GPS rescue. But most of all, I needed to find out how I was doing with that efficiency, and that doesn't seem very good to me. I would like someone to share their experience with the 7 inch.
The quad weighs 770 g including the Gopro Hero8 with its battery. The Turnigy Lipo 6s3300 weighs 504 g, so the total flight weight in the current configuration is 1274 g. The 3.5 V values per cell will be touched for the first time in 7 minutes and 30 seconds. The capacity taken at that time is 2570 mAh. I tried to keep the speed constant somewhere between 85 and 90 km / h. I didn't even try the maximum speed.
I'm a little disappointed I was expecting more, how is your experience?

Today I managed to fly 6 batteries. I have GPS Rescue set up and tested and it works, today the weather was beautiful, I usually had 17 or more satellites.

I tried acro for the first time, I'm still a little afraid to deal with it so that it doesn't break in flight, it's surprising that it almost doesn't have propwash and I've never done anything with PID yet.

For the first time I tried to fly a little further, I was 3.3 km away and I needed 2.2 Ah for the trip there and back. I had an average cruising speed of about 78 to 80 km / h, at higher speeds the current quickly increases above 20 A, and it quickly drains the battery.

As for my antenna and the great Matek R24D receiver at that distance, I didn't get below -78 dBm and that's a really high margin down to -118 dBm, an incredible 40 dBm remains. As for the range of the receiver, I'm completely calm and I have no worries about FS. But what disappointed me is the range of the DJI Air Unit with the best TBS LR antennas, I still have to check everything, but the range seems smaller to me than DJI Vista with HGLRC LR antenna, and that's a shame.

I also tried to work better with the throttle and got on a 9 min flight for 2.5 Ah. However, the cruising speed is less than 75 km / h, which corresponds to a current of about 18.5 A. I am disappointed, my Rekon 5 flies almost 65 km / h for only 6-7 A and moreover only from 4s VTC6, so it is many times more efficient.

And I use Dalprop Cyclone T7056 C Pro. I also have HQProp 7x3.5x3, I will try these propellers next time.

I've had quite a few flights. I've tried quite a bit. Without the Gopro with the relatively light 6s2700 battery, freestyle flying is surprisingly good and it takes about 5 minutes before the battery starts to sagg too much. On freestyle, the HQProp 7x3.5x3 appears to be a better propeller, especially in higher revs. I'm not afraid to fly harder anymore when I'm not flying with a heavy battery and I have to say it's fun.
I also did a few more LR flights. I was surprised that there is almost no difference between the HQProp 7x3.5x3 and Dalprop Cyclone T7056 C Pro propellers when flying at a current between 18 and 20 A, the difference in forward speed is almost negligible. On the contrary, the Dalprop Cyclone T7056 C Pro performs better at higher currents. I write this because the difference with small currents is not really as big as one might think. But when one wants to fly far, one still has to fly at low current, and in this case the difference between a propeller with a small and a large pitch is simply small.
I was thinking over a 6s2p Lion, I couldn't decide between 18650 or 21700. After comparing the weights and voltage sags during a current around 15-20 A I opted for 6s2p18650, which eventually comes out about 200g lighter, which is just a lot. I ordered a total of 12 pieces of original Murata VTC6 from nkon.nl. I hope that with the reserve I will be able to fly in the wind for at least 15 minutes.

Hmm, that was faster than I thought.

(20-May-2022, 09:10 AM)MomoBrut Wrote: Hmm, that was faster than I thought.

I've become super interested in this thread recently as I want to switch to ELRS.  My CRSF performance has been disappointing ever since I built my Chimera 7 back in Nov/Dec; for example, low RSSI, flucuating LQ, and RXLoss/Failsafes under 7km.  

There may be something wrong, but I've tried:
- Different antennas (currently have Bardpole RX and Diamond TX), 
- Moving antennas (front, back, side, up, down, etc...) 
- Swapped the RX Nano
- and I'm using 1W on the TX, so 7km shouldn't be an issue.  

I thought about buying a diversity nano, but for that price I can get an entire ELRS setup which seems to be performing really well and with lower latency! 

So here I am, and curious to see how your longer-range results turn out. 

Regarding Batteries: I've been running 21700 P42a 4000mAh Molicel packs in 6s2p, and they work great, but are a bit heavy. So I've recently purchased P28a cells and will be making a lighter 6s2p pack test out.

Nice work with you project, cheers!

It so happened that I had time, it doesn't happen often. :-) So I worked. I finished the batteries, each 6sVTC6 battery with everything like cables, connectors, foil, etc. weighs 302 g.

Today I flew with the 6s2pVTC6 configuration. It was very windy, in gusts up to 60 km/h. I tried to fly still at 20 A. After the wind I flew more than 90 km / h, against the wind then around 65 km / h, still at 20 A. I landed at 2.9 V per cell, I lasted almost 17 min, consumed capacity 5342 mAh. Hmm, that's not bad at all. The temperature of the batteries after landing was not higher than 50 degrees Celsius, so given my previous experience, everything is absolutely fine. Immediately after landing, the cell voltage increased to 3.15 V. Currently, AUW with Hero 8 and its battery is 1430 g. I will do more tests when I want to properly load it with larger currents. I believe I won't get under 12 minutes and that should be enough for what I plan to do.

When the time comes, I'll send photos of how I made the batteries. And I didn't do them for the first time, so maybe it will help someone.

(22-May-2022, 02:17 PM)GiantAntCowboy Wrote: I've become super interested in this thread recently as I want to switch to ELRS.  My CRSF performance has been disappointing ever since I built my Chimera 7 back in Nov/Dec; for example, low RSSI, flucuating LQ, and RXLoss/Failsafes under 7km.  

There may be something wrong, but I've tried:
- Different antennas (currently have Bardpole RX and Diamond TX), 
- Moving antennas (front, back, side, up, down, etc...) 
- Swapped the RX Nano
- and I'm using 1W on the TX, so 7km shouldn't be an issue.  

I thought about buying a diversity nano, but for that price I can get an entire ELRS setup which seems to be performing really well and with lower latency! 

So here I am, and curious to see how your longer-range results turn out. 

Regarding Batteries: I've been running 21700 P42a 4000mAh Molicel packs in 6s2p, and they work great, but are a bit heavy. So I've recently purchased P28a cells and will be making a lighter 6s2p pack test out.

Nice work with you project, cheers!

I was also thinking about 21700 cells, but in the end I stayed at 18650 because of the weight. I don't know yet where the change in efficiency between weight and capacity is with the FR7, but I would say that I probably got closer to it. When you give info on flight times and weights with the 6s2P21700, it will probably be clearer what works better. In any case, high-quality 18650 cells are more expensive than 21700 cells, which are significantly cheaper.

My production of Lion battery pack:

A soldering station is needed that can hold a temperature of over 400 degrees Celsius, with a sufficiently large tip. I solder 18650 cells at a temperature of 420 degrees Celsius, which allows me to have solder time between 2.5 s and 3 s. Such a short soldering time does not cause excessive heating of the cell during soldering. Before soldering the cells together, all surfaces must be sanded with sandpaper. Grit is not decisive, something between 200 and 400 is enough. Immediately after soldering, it is advisable to tin the contact surfaces to prevent their repeated oxidation. If quality solder with lead and inner flux is used, no additional flux is needed, I use a thick flux in the tube to be sure.

1. After sanding the contact surfaces of the cells, I tin them all right away. I use a solder coil as a holder when tinning cells. It must never be soldered for more than 4 to 5 seconds, then the cell will heat up over 80 degrees Celsius, which leads to irreversible damage to the cell. As I wrote above, in my configuration soldering takes less than 3 s.
2. Then I stick a pair of cells with 0.5 mm thick 3M double-sided tape together. Then I stick these pairs with the same tape until I get a 6s battery arrangement.
3. Then I prepare the cell jumpers from the 16 AWG cable with silicone insulation and tin them. The length must be sufficient to connect the adjacent cells and the stripped part must be as short as possible to sufficiently connect and prevent a possible short circuit on the positive side of the cells.
4. Subsequently, I solder the jumpers to the appropriate cells in the 6s configuration and clean the remaining flux from the contact pads.
5. Only from the top side I partially strip the jumpers in their middle so that I can solder the balance cables to this place. The balance cable starts to be soldered from the middle cable, it must always have the longest length. I always try to keep the balance cables as short as possible and at the same time all have the same length on the side protruding from the battery. Finally, I solder the main power cables with a pre-soldered xt60 connector to prevent accidental short circuit of the battery. After soldering all the cables, I first measure all the voltages to be 100% sure that all the cables are correct, and finally I connect them to the charger and check that the charger correctly detects the voltage of the individual cells and the whole battery.

Hi MomoBrut,

I have added the above post to my  [Tutorial]  How to Solder - Principles, Technics, Etc.  

Good Job.    Thanks  

6. Subsequently, the cables must be secured against movement and at the same time the contact surfaces must be insulated. I do this using automotive double-sided foam adhesive tape 1 mm thick. I use two coats where necessary. I don't cover the battery up to the edges, it wouldn't look good later and it's useless. The tape must be placed primarily at the point where the cables will protrude from the battery, so that the shrink film used later does not cut the cable insulation.
7. I finalize the battery using shrink sleeve, to achieve sufficient durability I use a total of three layers. The first layer of sleeve together with the double-sided foam tape secures the cables in place. To make it clear, I used a transparent sleeve for the first layer. The first layer is placed on the battery so that the cables press against the body of the battery from the side. A 120 mm wide sleeve is required for the first layer 6s 18650.
8. I give the second layer mainly to increase the strength and durability of the pack, it is given in the same way as the first layer, so a sleeve of the same width is needed. I want the whole pack in black color, I use black sleeve.
9. Finally, a third layer is used, which pulls the cells together and at the same time completely encloses the set in the sleeve. Here you need a sleeve 100 mm wide, in my case again black.

And in the last picture, both packs are ready, it remains to add a label with a description of the battery pack.

(23-May-2022, 12:50 PM)iFly4rotors Wrote: Hi MomoBrut,

I have added the above post to my  [Tutorial]  How to Solder - Principles, Technics, Etc.  

Good Job.     Thanks  

Thank you. I hope it can help someone.