LiPo batteries are difficult to deal and maintain, Can I use Li-ion batteries?
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LiPo batteries are difficult to deal and maintain, Can I use Li-ion batteries?
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That is a good video and does give an insight into li-ion but the ncr is only ok for fixed wing or very light multirotors. For most multi aircraft the newer high drain cells need to be used.
Price of Lipo is higher
LiIon are heavier
LiPo are flexible in size and dimensions and fit tablets, smartphones.
Connecting LiIon tubes in parallel/serial you get oversized pack of tubes and empty spaces between them.
LiPOs come as boxes of any size to fit any drone, copter, mini copter.
I am surprised since LiIon batteries used in smartphones are exactly of the same box shape and dimensions as LiPo batteries.
Any problem to remove tubular shape from LiIon cells ?
Yes the price of lipo is higher.
I do not agree that li-ion is heavier. Our packs are nearly half the weight of a lipo with the same capacity, slightly less c rated admittedly but not by much (as seen by the results of our testing). We will be releasing real world testing info and videos when we start sales, to help potential customers make up their own mind. I am confident (otherwise I wouldn't be doing it) that these customers will see these exact results and enjoy their choice of buying lighter and cheaper batteries that can extend their flight times and improve their handling.
Li-ion are also flexible in size and shape, they come in flat packs but these are not suitable for our use as they just don't have the required specifications, they are made for low drain electronics.
The 18650 size does indeed mean that there are small gaps between the cells, this is a good thing! It allows airflow along all the cells if assembled correctly and makes the cells run cooler and more efficiently. Can a lipo do this? In our aircraft we have a moulded scoop that can direct airflow into the pack, it's works brilliantly. I disagree that these packs are "oversized", as Alasdair has already said our packs are smaller in volume than their lipo counterparts.
We can make packs in a variety of shapes and forms to best fit the individual aircraft. To be fair you can do this with lipo but how many suppliers will make a custom pack for you? There are slim packs etc but the choice is still quite limited and can constrain the creative builder. I do disagree that you can get lipo to fit any size and shape as you stated.
You can remove the cylindrical shape but it is not that big a deal. The most promising developments in batteries are in the 18650 format as this is how they are used in the high end projects (electric vehicles, scientific equipment etc). The new carbon ion should be available soon and looks to be a real game changer.
I am most definitely not trying to tell people what to do, only offering a potential new way for consideration. At the end of the day it is "horses for courses" and people should do what they think best. As I have said, will will publish all the info we can to help people make an informed decision, these will be real world results.
All the best.
Yes, a lipo can have cooling between cells, For very high discharge applications I have incorporated spacers between the flat cells wen building my packs. I don't do it anymore since I've found little benefit.
What would be nice is to have the same chemistry that is used in the 18650 lion cells used in lipo cells. Is there a reason this can't happen?
As I understand it, chemistry aside, a lion is basically a lipo rolled up into a cylinder and inserted into a metal cylinder for standardized form factor and cell protection.
I've been using and building my own lipo and lion for many years, I have a lot of experience with them in high drain applications. The only advantage of lion over lipo that I can see is that the cells can be installed into the arms of a multirotor. Yes, lion cells do have better cycle life but thats the last thing I want to think about while in the air. I would much rather have lipos high current capability any day over worrying about stressing a lion cell too much. Also with lion cells to get the current capacity needed for a UAV many cells will need to be wired in series/parallel. That requires many more connections which can be a failure point, with a quadcopter one failure point can ruin you and your quads day!
IDK, maybe I'm wrong, but I just don't see anything beating a lipo for the foreseeable future. Good luck trying though!
lipo are much lighter
but in either case you need to wire cells in series/parallel
Look for laptop battery packs,
2-3 Liion cells wired in parallel//
than wired in series 3 x 2-3 cells or 4 x 2-3 cells to get voltage
3.7 V x 3
or 3.7 V x 4
Liion cells have to be HV welded and LiPo cells can be soldered.
The primary reason to go to Li-Ion is that Li-Ion carry up to 73% more electrons per gram than LiPo. That gives you:
- a lot more duration in the air (but if you have enough, who cares)
- a lot more acceleration for the same mAh (less mass, but a trade with C rating; so a 20C LiIon is the equivalent in acceleration to a 30C LiPo)
Thanks for the info on the multistar battery, it does look to be one of the good ones going by the specifications. I see by looking at some of the reviews that they get hot occasionally. One user is flying a quad with an AUW of 1.8 kg, he describes his battery as quite hot after hovering for the duration. However this is a very unscientific test as there is no data for load or even the temperature it reached. It certainly did not fail. There are many happy customers on hobbyking with this range so it must be very reasonable. The only complaints are a few failed cells but that is probably down to the manufacturing/testing process. Our packs are a few gms lighter than your projected weight but your summation is correct. The only other thing to consider is the life of the pack. With lipo we are yet to get more than around a hundred cycles, even with careful handling versus at least 500 with li-ion. If the packs were the same price you could see the benefit. I will get some of these packs to test and compare, I'm very interested in the c rating validity and just how long it would last/perform with regular use on an average quad current draw. Thanks!
As mentioned earlier, I have been testing NCR18650GA with partial success. To answer you question, it is indeed possible that my cells are not genuine. I need to aquire some cells that are guaranteed so I have a benchmark to start from.
Perhaps you should start your own thread to dedicate to your hard work.
Thank you.
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