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Flying on 18650 cells

RolandS888

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Set this up using the original battery monitoring board from a destroyed battery and 3 new LG HG2 18650 cells. I couldnt get the mon board to turn on so I powered the Mavic through one of the battery plugs I installed on the side. The mon board was plugged into the balance wires on the 18650 pack and was reporting cell voltages and total voltage accurately throughout the flight.
I reduced a volt min parameter down to 2.5v to allow the 18650 cells to go down that low. As you can see from the screen shots I got 16 minutes and I had one cell faulty. I ran it down to 2.11 and the other cells were still at 2.8v (and had 600-700mAh remaining). This setup could proably get 18-19 minutes on just 3 cells.
After the flight the cells were warm but not hot1. Mav2 Desk 18650.JPG 2. Mav2 Start Screen.JPG 4. Mav2 In flight 18650.JPG 5. Mavic 18650 End of flight.JPG . I'll get some more cells and go 3S2P next.
 

CyberNate

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Set this up using the original battery monitoring board from a destroyed battery and 3 new LG HG2 18650 cells. I couldnt get the mon board to turn on so I powered the Mavic through one of the battery plugs I installed on the side. The mon board was plugged into the balance wires on the 18650 pack and was reporting cell voltages and total voltage accurately throughout the flight.
I reduced a volt min parameter down to 2.5v to allow the 18650 cells to go down that low. As you can see from the screen shots I got 16 minutes and I had one cell faulty. I ran it down to 2.11 and the other cells were still at 2.8v (and had 600-700mAh remaining). This setup could proably get 18-19 minutes on just 3 cells.
After the flight the cells were warm but not hotView attachment 19942 View attachment 19943 View attachment 19944 View attachment 19946 . I'll get some more cells and go 3S2P next.
Yes, I'm looking forward to more or your testing. I've considered getting a spot welder to make 18650 packs. With the use of the smart battery board and tweaked low voltage settings, I think the high capacity 18650GA/18650B cells could be the key to longer flights in the right parallel configuration. They have a low max current, but if you had them wired lets say dual 3s2P packs, that would distribute the current over enough parallel cells to avoid over taxing these cells. I believe that this configuration will be the very best for the mavic with 14AH capacity and lighter than my dual 4000 multistar setup due to removed mavic battery. I envision near 50 minutes flight times at distance run speeds (32ish mph). The titan 7AH packs are already setup this way. Just need someone to test a pair of them wired into the smart board sans mavic cells.
 
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wrapter

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A samsung 21700 battery can run cooler with just 3S1P, hard to find them.
There is also the sanyo 20700B which is a 4.2Ah battery probably same chemistry has 18650B.
 

Progenite

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Gran trabajo con estas baterías. Podría ser el paso definitivo para obtener un mejor tiempo de vuelo con el mismo peso o similar. una vez terminadas las pruebas y el número de baterías a utilizar es definitivo, se puede hacer una caja en impresora 3d que se adapte al Mavic para que encaje perfectamente.
 

marcini

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Mind sharing where to find the voltage parameter in DJI assistant?
 

ede h

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Use ijoy 20700 vape batteries.. They are available and give 40 A
 

Blade slap

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Dear Roland you wrote I reduced a volt min parameter down to 2.5v, exactly witch parameter you ar referring , because in assistant mod. where is several parameter voltage , personally i made several test with 18650 , 1p , 2p , 3p but clearly that with 3.5 volt as mininum i cannot use full capacity. , my setting i no dji battery.
 

chazz

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I think i'm going to try this...It seems that people that do try this with the bigger setups like 3s3p don't talk about how much flight time they're getting because either 1) don't know what parameters to change to make it work 2) it sucks really bad or 3) its so great and they are flyin for days straight and cant put the RC down to post results ... So I'm buyin some 21700 Samsung 4800 and give it a shot..I don't know much about these batteries and have a few questions...the plan is to do the 3s3p and just using the board from the DJI battery. I think after i build it i should have a max continuous discharge of 30amps. Is that enough? I hope so because i already ordered them but I AM willing to hear bad news...How do you charge these? i have a LiIo setting on my charger but maybe i can use the Lipo setting for 4.2V? and how many amps would i charge this at? Also does anyone have some good pics of when they were building it or pics of the tops of the pack before all the tape or shrink tube was put on it? Or maybe there's a link to somewhere that will answer all my newbie questions? I attached the data sheet if anyone wants to look at it...
 

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Blade slap

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I think i'm going to try this...It seems that people that do try this with the bigger setups like 3s3p don't talk about how much flight time they're getting because either 1) don't know what parameters to change to make it work 2) it sucks really bad or 3) its so great and they are flyin for days straight and cant put the RC down to post results ... So I'm buyin some 21700 Samsung 4800 and give it a shot..I don't know much about these batteries and have a few questions...the plan is to do the 3s3p and just using the board from the DJI battery. I think after i build it i should have a max continuous discharge of 30amps. Is that enough? I hope so because i already ordered them but I AM willing to hear bad news...How do you charge these? i have a LiIo setting on my charger but maybe i can use the Lipo setting for 4.2V? and how many amps would i charge this at? Also does anyone have some good pics of when they were building it or pics of the tops of the pack before all the tape or shrink tube was put on it? Or maybe there's a link to somewhere that will answer all my newbie questions? I attached the data sheet if anyone wants to look at it...
Even if seems 3s3p for 21700 the best probably will be to heavy , look the image of my excel file in the other discussion ....better to charge the li-io with their program not the one of lipo , I already made mainly for error , because I forgot change charger program and a part the first 3 time charge that i was happy because you can charge with success ...soon or later the battery start to loss their capacity if you over charge in voltage . But I confirm that is possible if you want to perform special for 2-3 time . Li-io better to charge at 1C
 

chazz

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Even if seems 3s3p for 21700 the best probably will be to heavy , look the image of my excel file in the other discussion ....better to charge the li-io with their program not the one of lipo , I already made mainly for error , because I forgot change charger program and a part the first 3 time charge that i was happy because you can charge with success ...soon or later the battery start to loss their capacity if you over charge in voltage . But I confirm that is possible if you want to perform special for 2-3 time . Li-io better to charge at 1C
Thanks Blade. I know they're a little heavy but my external 8000mah and the dji 3830mah total 11830mah weigh 696grams and i get pretty good time with them and this battery will weigh maybe 630grams at 14400mah. Hopefully i can make it stay in the air at the low voltage with the extra weight...I guess we'll see.
You don't happen to have pics of your battery where you connected the tabs? I like to see others work before i dig in ;)
 

CyberNate

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Thanks Blade. I know they're a little heavy but my external 8000mah and the dji 3830mah total 11830mah weigh 696grams and i get pretty good time with them and this battery will weigh maybe 630grams at 14400mah. Hopefully i can make it stay in the air at the low voltage with the extra weight...I guess we'll see.
You don't happen to have pics of your battery where you connected the tabs? I like to see others work before i dig in ;)
I'm looking forward to your results. I'm very interested in the li-ion batteries. Could be the key to longer distances if the Mavic can fly at lower voltages and the battery meter can function predictably.
 

mavicpro1000

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Should have my li-ion 7000mah setup tommorow on the mavic. Will the mavic handle the extra 310g? Any ideas on a flightime for just cruzin about?
 

CyberNate

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Should have my li-ion 7000mah setup tommorow on the mavic. Will the mavic handle the extra 310g? Any ideas on a flightime for just cruzin about?
The dual 4000 multistar lihv are 550grams together. 310grams is cake.
 

mavicpro1000

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The dual 4000 multistar lihv are 550grams together. 310grams is cake.
Nice. Know what? I hate that mavic battery all cased up like that and cooking away at 55degrees every flight! Im gonna strip the case off and allow some cool air to extend the life of the pack.
 

mavicpro1000

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So how do we reduce those voltage parameters to accomodate the 18650?
 

chazz

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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...
 

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dirtybum

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**** Chazzdog, thats next level shizz! It'll fly weight-wise I bet(although I would strap on the belly to give it a fighting chance), hand launch/catch. I dont expect much out of it but you got my attention more than a cliffhanger on my fav bing watch
 

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