Flying on 18650 cells

[pure3d2]

i did the 21700 4800 3s3p 14400mah 470grams. I guess we'll see if it lands or falls to the ground at the low voltage,,, or if it even gets in the air...The DJI battery is just the shell with no cells inside...It looks like one of those cake fireworks, i hope it ain't with report!..now i just have to get the weather and time to fly...

Did you hook up the 18650 cells to the balance lead on the DJI battery or did you just hook up the + and - leads?

 

[Blade slap]

i did the 21700 4800 3s3p 14400mah 470grams. I guess we'll see if it lands or falls to the ground at the low voltage,,, or if it even gets in the air...The DJI battery is just the shell with no cells inside...It looks like one of those cake fireworks, i hope it ain't with report!..now i just have to get the weather and time to fly...

Sorry Chazz but if you add 3s3p 21700 the delta weight will be 67 gr x 9 = 603 gr + something for wire so the total weight will be 750 + 720-730 (including delta wire)

 

[Blade slap]

Sorry Chazz but if you add 3s3p 21700 the delta weight will be 67 gr x 9 = 603 gr + something for wire so the total weight will be 750 + 720-730 (including delta wire)

with your configuration (mavic + 3s3p 21700) I am really afraid that you can even flight in a right condition I add my table estimation for different configuration if you look watt/kg parameter are in red area end also the ratio disk load is even too high for the mavic

 

[mavicpro1000]

That poor little Mavic how could you.

 

[chazz]

with your configuration (mavic + 3s3p 21700) I am really afraid that you can even flight in a right condition I add my table estimation for different configuration if you look watt/kg parameter are in red area end also the ratio disk load is even too high for the mavic View attachment 21703

Thanks Blade you are correct the battery weighs 67 x 9 = 603...what i said in my first post was misleading. I meant to say added weight 470 grams because i am not using the dji cells..I took them out of the battery...
The 21700 bat weighs 652 grams (complete) minus 188grams (dji batt cells) = 464 grams added to the mav...I've flown with more i just hope the batteries can supply enough juice to keep it in the air..

 

[chazz]

Did you hook up the 18650 cells to the balance lead on the DJI battery or did you just hook up the + and - leads?

Yes i hooked up the balance lead connected to the battery board..

 

[CyberNate]

Thanks Blade you are correct the battery weighs 67 x 9 = 603...what i said in my first post was misleading. I meant to say added weight 470 grams because i am not using the dji cells..I took them out of the battery...
The 21700 bat weighs 652 grams (complete) minus 188grams (dji batt cells) = 464 grams added to the mav...I've flown with more i just hope the batteries can supply enough juice to keep it in the air..

It will fly no problem. It's less weight than my dual 4000s which 550grams. The only thing that may come into play is the reduced voltage of li-ion. There is less power available, so hopefully it's enough for stable flight, especially on the low end of the battery. I assume you are lowing the cutoff voltage to somewhere around 2.5 -2.8V. I don't think mavic will fly well at 2.5v per cell.

 

[action]

Can you guys tell me if I set the battery_type=2 in Assistant 2 Software I can get rid of the *intelligent* battery board or is it just a tweak for the battery voltage?? I want to use some batteries by just connecting XT60 or whatever.... On my previous P3P I've ripped off the intelligent board and mounted it inside the P3P in order to use third party batteries. I'd be so thankful for this information prior to getting deeper into this topic. Thank you all in advance

 

[CyberNate]

Can you guys tell me if I set the battery_type=2 in Assistant 2 Software I can get rid of the *intelligent* battery board or is it just a tweak for the battery voltage?? I want to use some batteries by just connecting XT60 or whatever.... On my previous P3P I've ripped off the intelligent board and mounted it inside the P3P in order to use third party batteries. I'd be so thankful for this information prior to getting deeper into this topic. Thank you all in advance

Battery type 2 (non-dji type) just gets rid of force auto landing with low battery and the flight time projection bar which helps you gauge when to go home. The battery percentage remains, but you MUST have a Mavic smart battery connected or you'll get no battery details.

 

[chazz]

I did a hover test with the 21700 batteries and i got about 41min..It went into autoland at 3.5V and i had to hold it in the air with about 1/4 stick up. By the time the voltage was at 3.1V i had to hold it up with full stick. It didn't want to be up there...Maybe the battery can run to 2.5V but the bird couldn't handle it with that weight..If I try another flight with this im going to do what DB said and mount it to the bottom..

Airdata UAV - Flight Data Analysis for Drones

 

[CyberNate]

I did a hover test with the 21700 batteries and i got about 41min..It went into autoland at 3.5V and i had to hold it in the air with about 1/4 stick up. By the time the voltage was at 3.1V i had to hold it up with full stick. It didn't want to be up there...Maybe the battery can run to 2.5V but the bird couldn't handle it with that weight..If I try another flight with this im going to do what DB said and mount it to the bottom..

Airdata UAV - Flight Data Analysis for Drones

You didn't change voltage settings in DJI assistant parameters? Auto landing mode cuts current to the motors. You need to avoid that if possible.

41 minutes is very good, but the early auto landing mode is not good.

Have you tried these parameters:

g_config_bat_config_emergency_voltage 3000 -> 2600
raw_bat_level_1 3960 -> 3250
raw_bat_level_2 3600 -> 2800
g_config_bat_config_bat_limit_limit_vol_min 3300 -> 2700
g_config_bat_config_bat_limit_limit_vol_max 3700 -> 3500

 

[chazz]

I didn't change "g_config_bat_config_emergency_voltage 3000" because i wanted to see if it had an affect at 3V. but i might now.

I didn't change " g_config_bat_config_bat_limit_limit_vol_max 3700" because i wanted to see what it does at 3.7V and i didn't notice anything but I may change it

I did change "g_config_bat_config_bat_limit_limit_vol_min 3300" to 2700

It wont let me change the "raw_bat_level_1" or "raw_bat_level_2" parameters. Are you able to?

Autoland and annoying beeps started at 3.5V and 8%..I had to listen to that chit for 20min!

 

[dirtybum]

why does it show bat takeoff at 88%?

 

[chazz]

Honestly i have no idea why the 88%. It was charged to 4.2V per cell and the initial capacity shows 3730mah. It dropped to 0% somewhere around 20min and i ran it for another 20min after that...I wish someone could tell me what to do to make everything just work...

 

[chazz]

does anyone have results for the dual 4lihv's hover time? I would like to know if this is worth any more my time..

 

[dirtybum]

well if I got 36 outta those crappy (2)Thunderpower 4.5's then a couple multistar 4's should match or offer a lil more

 

[50Devastator]

Does anybody have a discharge curve of the original battery to see how this compares to different 18650s based on current?

 

[Zotiss1989]

Hello,
I made a 3s2p 18650 but how did you turn it on

 

[mavicpro1000]

Take it that controllers bricked?

 

[Zotiss1989]

No just hooked cells up in holders soldered heavy wires and small ones so it could read the voltages cause I am using nitecore charger to charge 18650's only didn't know that it wouldn't turn on