I am using the NCR18650B 3400mAh Cells.
They are rated to 2C.
90% of the flight time, I will use the cell for not more than 0.5c or even less. But for climbing, I am near to 2.5C for 20sec.

What about higher C rates than 2 C?
Will it damage the cell really or can I go to 2.5c or even 3c, when it is limited in time for 15seconds? What is your experience?

Originally Posted by grizewald

...
I use lithium manganese batteries in my electronic cigarettes. These are designed for high discharge rates. For example, the one I have in front of me now is an eFest 2500mA/h 18650 cell. It can be discharged at 14C, allowing a maximum current draw of 35A. One of these cells weighs 46g. Three in series would give me a 3S battery with 35A maximum current and 2500mA/h capacity for a weight of 138g.
A similar 2200mA/h lithium polymer Turnigy 3S battery pack weighs in at 199g, but has a far higher maximum discharge rating of 35C or 77A.
To achieve a 70A discharge rate with the 18650s, I'd need six batteries in a 3S2P arrangement. While that would give me a 5000mA/h battery capable of 70A discharge, it would also weigh 276g.

In the end, LiMn chemistry cells are great for many things and would be superb for a multirotor with lower current requirements, but for really high current applications, there's nothing that beats a good quality LiPo.

In the end, they are just a hype, claiming performances without any real life support, posted my quick findings here:
https://www.rcgroups.com/forums/show...8#post33481034

Originally Posted by renatoa

In the end, they are just a hype, claiming performances without any real life support, posted my quick findings here:
https://www.rcgroups.com/forums/show...8#post33481034

Exactly! Lithium Ion cells are essentially just LIPO's roll up into a tube for convenience and protection. There may be some chemistry changes between brands and makes but the same can be done to LIPO's as well.

Hi,

Any experience maybe with the Efest 3500mAh /20A battery, or with the LG 18650MJ1?
Are these suitable for a hexacopter?
I'm planning to build a Li-Ion, but need more info, others experince using in multicopters.
I've 360KV motors, motors draw about 15Amp.
A 6S3P pack would be suitable for this?

The LG cells are only rated for a maximum discharge current of 10A and you say you have six motors each pulling 15A?

Originally Posted by grizewald

The LG cells are only rated for a maximum discharge current of 10A and you say you have six motors each pulling 15A?

Not each. Total 15A, if the Pixhawk powermodule is reliable...

Get over it guys! LIPO packs are hard to beat for use in multirotors.

Tested the 3000mAh LG high drain and they are not delivering even 10Amps without a severe voltage drop.
Check my posts history for more details, there are links to discharge curve, me I am in a hurry now.

Originally Posted by renatoa

Tested the 3000mAh LG high drain and they are not delivering even 10Amps without a severe voltage drop.
Check my posts history for more details, there are links to discharge curve, me I am in a hurry now.

Thanks! I will check it out. The tech is just not there yet. Actually, I'm not sure it ever will be. Lipos are just much better for what we need because of its form factor.

Hi guys,

I'm flying a 6S setup with rewound 5010 pancake motors (information can be found here: https://www.rcgroups.com/forums/show....php?t=2469874 ) and 17,5x5 carbon fiber props on a Tarot 650 frame.

The current pack is a Zippy compact 6S 5000 mAh (weight is 710g). The setups total hoover current is between 5-7A. The absolute max current when throttle is 100% in stabilize mode is 22A.

I am looking to purchase a LiON pack with at least 10Ah and stay in the same range regarding the weight of the pack. There were some suggestions on this thread but I just wanted to ask: which cells would be the best to achieve good results? I don't care about the C-Rating as a max output of 1C with a 10Ah pack (and peak up to 2C) is more than enough for the quadcopter so I am only looking to maximize the Ah here. Is there a cheap way or will the packs necessarily cost over 100$?

-Is there a vendor that sells finished packs, or do I need to solder those myself? Anything I need to pay attention to when soldering those packs?

-Is there an option to those 18650 packs? E.g. those normal, low current discharge LiPOs they use in cell phones or notebooks? I like the form factor better and as said, a C rating of 1-2C is more than enough for my quadcopter. Are there any 10Ah flat cells out there that fit my needs?

EDIT: I just found those guys: http://www.ebay.de/itm/A-3-7V-12000m...-/321138832637
Any thoughts on this? No words on the discharge rates unfortunately...

EDIT2: I contacted the seller, he said 3C continuous, 5C burst. This is more than enough. If we deduct chinese honesty from this, 2C continuous should be possible at least - and I only need 0,5-1C.

Thanks!

Originally Posted by Nerox

Hi guys,

I'm flying a 6S setup with rewound 5010 pancake motors (information can be found here: https://www.rcgroups.com/forums/show....php?t=2469874 ) and 17,5x5 carbon fiber props on a Tarot 650 frame.

The current pack is a Zippy compact 6S 5000 mAh (weight is 710g). The setups total hoover current is between 5-7A. The absolute max current when throttle is 100% in stabilize mode is 22A.

I am looking to purchase a LiON pack with at least 10Ah and stay in the same range regarding the weight of the pack. There were some suggestions on this thread but I just wanted to ask: which cells would be the best to achieve good results? I don't care about the C-Rating as a max output of 1C with a 10Ah pack (and peak up to 2C) is more than enough for the quadcopter so I am only looking to maximize the Ah here. Is there a cheap way or will the packs necessarily cost over 100$?

-Is there a vendor that sells finished packs, or do I need to solder those myself? Anything I need to pay attention to when soldering those packs?

-Is there an option to those 18650 packs? E.g. those normal, low current discharge LiPOs they use in cell phones or notebooks? I like the form factor better and as said, a C rating of 1-2C is more than enough for my quadcopter. Are there any 10Ah flat cells out there that fit my needs?

EDIT: I just found those guys: http://www.ebay.de/itm/A-3-7V-12000m...-/321138832637
Any thoughts on this? No words on the discharge rates unfortunately...

EDIT2: I contacted the seller, he said 3C continuous, 5C burst. This is more than enough. If we deduct chinese honesty from this, 2C continuous should be possible at least - and I only need 0,5-1C.

Thanks!

I had to make the packs myself. I used wide solar panel tabbing wire to connect. You can find high drain li ion 18650 batteries that discharge at 35A and in reality do 22A. still more them enough. they are at 2500-3000 mah at 45grams a cell. you have to connect in series then parallel to get the size battery you want.

so a 2500mah cell connected in 6s4p would get you 10000mah by using 24 cells for a weight of 1080 grams. The Lipo you found for 12000mah would be 1260 grams.

Originally Posted by Nerox

Hi guys,

I'm flying a 6S setup with rewound 5010 pancake motors (information can be found here: https://www.rcgroups.com/forums/show....php?t=2469874 ) and 17,5x5 carbon fiber props on a Tarot 650 frame.

The current pack is a Zippy compact 6S 5000 mAh (weight is 710g). The setups total hoover current is between 5-7A. The absolute max current when throttle is 100% in stabilize mode is 22A.

I am looking to purchase a LiON pack with at least 10Ah and stay in the same range regarding the weight of the pack. There were some suggestions on this thread but I just wanted to ask: which cells would be the best to achieve good results? I don't care about the C-Rating as a max output of 1C with a 10Ah pack (and peak up to 2C) is more than enough for the quadcopter so I am only looking to maximize the Ah here. Is there a cheap way or will the packs necessarily cost over 100$?

-Is there a vendor that sells finished packs, or do I need to solder those myself? Anything I need to pay attention to when soldering those packs?

-Is there an option to those 18650 packs? E.g. those normal, low current discharge LiPOs they use in cell phones or notebooks? I like the form factor better and as said, a C rating of 1-2C is more than enough for my quadcopter. Are there any 10Ah flat cells out there that fit my needs?

EDIT: I just found those guys: http://www.ebay.de/itm/A-3-7V-12000m...-/321138832637
Any thoughts on this? No words on the discharge rates unfortunately...

EDIT2: I contacted the seller, he said 3C continuous, 5C burst. This is more than enough. If we deduct chinese honesty from this, 2C continuous should be possible at least - and I only need 0,5-1C.

Thanks!

Wide solder wick works well for connecting cells. Rosin flux and some 60/40 or 63/37 LEAD rosin core solder. Dont buy the lead free crap! Also buy some rosin flux.

You will need a soldering iron with a large tip. The tips mass needs to be enough that it won't cool when you try to apply solder to the cell. When soldering 18650's, no more than a few seconds should the iron be on the cell, any more and its permanently damaged.

You will ruin the cells with a dept store/ big box store iron, they just dont have enough mass. Even a hakko type soldering station is iffy unless you find a tip with a lot of mass. Weller sells a iron and tip combo that is great for making packs. here's the link. http://www.mouser.com/ProductDetail/...6A2dJQAvdlI%3d

Seriously though, unless your dead set in using lion cells its much better to just use lipos.

Originally Posted by CommandAir

Hi,

Any experience maybe with the Efest 3500mAh /20A battery, or with the LG 18650MJ1?
Are these suitable for a hexacopter?
I'm planning to build a Li-Ion, but need more info, others experince using in multicopters.
I've 360KV motors, motors draw about 15Amp.
A 6S3P pack would be suitable for this?

Check out my realtime flight video with telemetry data on the left to corner of the video flying my Volantex RANGER 757-4. I'm using LG 18650MJ1 li-on pack 3500mah per cell and clump it into 10,500mah (3s3p) flight time of 51 minutes, constant avg consumption of 7.5A and total capacity consume is 50%, still have some more juice left in the tank after landing. Watch the video below and observe the telemetry data as i flip the menu around:

Video:

36km Delta Shoreline - UAV Volantex RANGER 757-4 using Li-On (LG MJ1 18650) (53 min 18 sec)

Very interesting ican3d. I am working on a similar arrangement in an hk/vq stick 1500. How many flights do you have on your pack and where did you get your cells? I'm running basen 3.1ah 40a cells in a 4s3p arrangement. I have used them in lower draw applications with good luck.


Note: battery bars, like the rc car guys use, work very well for building packs but they do add some weight.

Originally Posted by ican3d

Check out my realtime flight video with telemetry data on the left to corner of the video flying my Volantex RANGER 757-4. I'm using LG 18650MJ1 li-on pack 3500mah per cell and clump it into 10,500mah (3s3p) flight time of 51 minutes, constant avg consumption of 7.5A and total capacity consume is 50%, still have some more juice left in the tank after landing. Watch the video below and observe the telemetry data as i flip the menu around:

Video:
https://www.youtube.com/watch?v=m9WxZQjNjoI

Nice! Ive always wanted to do this type of flight.