How about 18650 Li-Ion battery pack over the Li-Po packs?


#1

Paracell is an electric paramotor with a single large engine and prop, made in Spain.
http://paracell-products.com/

They use a Battery Pack made out of an array of the standard 18650 Li-Ion Batteries, that are widely and cheaply available (for around 2-10 dollars per piece, depending on brand and amount purchased).
For example: https://www.ebay.com/p/2pcs-Samsung-Inr18650-25r-20a-Rechargeable-Battery-2500mah-for-Vape-Modes/4012277288?iid=302669666192

Advantages and Disadvantages of Li-Ion Batteries over LiPo Batteries:

However the 18650 Typ of battery is widely used in tons of applications.

Would it not be an option to use these for the OpenPPG project ?


13S15P Battery Pack Build
#2

This short video explains very well the basics of how to create a battery pack (even though for the OpenPPG project a larger pack will be required)

What do you guys think ?


#3

I’ve always wondered why its taking so long for 18650 to catch on in this segment. They almost have twice the energy density / kg.

You have to purchase quality batteries (a lot of rip offs that don’t meat advertised specs), and make sure you are not drawing too many amps, or if you are drawing too many amps, then find a way to cool the batteries.

Some of these cells can discharge at 20 amps!

Relative to Lipo, I don’t see any cons.


#4

From what I have read is that LIPO has a lot higher output required over LiOn.

I checked the video and if I understand correctly he uses LION batterys to output the same voltage as a LIPO ?


#5

I like LifePo4 batteries - less energy density but longer life, from what I read
Cheers


#6

Is the energy density per Kg really that much better? In a previous comment I calculated the energy density of Paul’s Multistar batteries to be 7.5Ah/Kg, with an output voltage around 22.2v. Based on the Samsung datasheet, I calculated that for an output voltage around 22.2v you would have a density around 9.25Ah/Kg. This doesn’t include any housing or protection for the batteries, which would probably drop it down to the same or worse energy density as the LiPos. Am I messing up my math somewhere?

There are however more-expensive graphene based LiPos with casing and a higher energy density at 8.33Ah/Kg, and Paul’s been using some pretty high capacity, high discharge Bonka batteries with an advertised density of 8.75Ah/Kg.

Of course manufacturers could be fuzzing the numbers somewhat, and I could be making mistakes in my Math, but that seems to be where we’re floating around right now: 8Ah/Kg. It would be fantastic if we could find some particular chemistry that takes that number up, but right now I’ll be skeptical until I see evidence strong enough to support a major claim like that.

Finally; we need to make this project simpler, not more complex. People have enough to worry about- wind conditions, staying alert for other air traffic, and everything else needed to fly safely. We need the most reliable, simplest batteries we can get so that people can put cycles into safe aviation decision making and not into worrying about whether their cells are all charged and balanced.


#7

I wrote above that each 18650 Battery costs anywere from 2 to 10 dollars.
Apparently one can get them for 1 dollar or less with 2500 mAh capacity

so an equivalent of 6S with 16000 mAh LiPo

would be a 6S7P setup (6x7) = 42 pieces (that actually has 17500 mAh)

Add the cost of a BMS (found something for around 30 dollars) plus those Vruzend Connectors ( http://www.vruzend.com ) and you are getting away with a lighter, more powerful but cheaper battery (less or equal 100 dollar)

Also: the Li-Ion have a lot longer life span than the LiPo.

and not into worrying about whether their cells are all charged and balanced.

I absolutely agree, the less I have to worry about stuff shortly before launch, the better!! am 100% with you on that !

But If you have such battery pack with BMS (Battery Management System) then there is nothing to worry about. It’s even less to worry about adding two or more of those Multistar or Bonka LiPo in parallel mode (one battery charging the other, if they don’t have equal voltage).

I watched a few videos on those 18650 batteries on one popular youtube channel, that has tons of videos about building and using those packs: https://www.youtube.com/channel/UCRMrqzsrPIWvY3PINkLKs-Q/videos

However, I am just a noob and don’t have any experience whatsoever other than a few hours of reading on the internet and watching some youtube videos.


#8

CMIUTA Electric Company makes batteries using 18650 and 20700 cells: https://uavfpvbattery.com

The owner is active on DIY Drones, for example: https://diydrones.com/profiles/blogs/6s8p-22-2v-28ah-80a-panasonic-ncr18650ga-battery-pack-for-large


#9

Deleted - the video’s content was an April Fool

damn


#10

Without seeing your actual calculations, one point of possible confusion is that 18650 cells dont have a standard mAh rating. Compare 18650 cells with 3000 mAh’s. The calculations I reviewed were using that #. I believe Panasonic makes 18650 cells that actually do even better than 3000. I think they hit 3400 mAh’s. I’ve see other cells as low as 1500.

If any of you decided to go the 18650 cell route, than one thing I can’t stress enough is buy reputable, reviewed batteries. There are so many rip offs out there…SMH. On youtube you can find great reviews fo different brands / sellers by Richard Lloyd.


#11

when I first found this project the first thing i thought was what about 18650s.


#12

Well we could talk all year or someone could make a pack of 30, charge them, and discharge at 300A to see how many Ah we can pull from these things, and finally weigh the pack. Anyone volunteering?


#13

It would be nice if the system was 6S to accommodate a single module. Pdwhite said its 48V which could mean either 12S or 13S. Two of these in series would give you 12S and over 10 kWh. This might be a great setup for trikes. Assuming 4 kW for average power usage, that is 2.5 hours of flying or 2 hours plus a 30 minute reserve.


#14

Yeah, wow! Of course 55lbs is really pushinig it, but still a pretty cool find. You’re correct; OpenPPG is 12s.


#15

The tesla modules are 24 volt.


#16

Did I not make that clear in my post? I said they were 6s aka 24v and it would take 2 to make the correct voltage.


#17

18650’s are an option, but there are a few problems:

  1. You need a LOT of cells. For example, to get 2 kWh of capacity, that is approximately 180 cells @ 3Ah.

  2. Most 18650 cells do not come with tabs welded on them. Soldering to the cell is difficult and dangerous. You must confirm that the cells that do come with tabs (that can be easily soldered) are rated for the current they will see in flight.

  3. Fixtures made to hold non-tabbed 18650 cells are probably not suited to carry the current PPG requires.

It would be a lot of hassle to build such a pack. Large format pouch type cells in premade packs will be easier for the DIY operation.

BTW, energy density, or specific energy should be quoted in Wh/kg, not amp hours.


#18

oops, you are correct.


#19

These would be great for a trike or quad solution. if a higher thrust pack is developed, carrying capacity is significantly increased for the wheeled paraglider. So maybe there could be 2 battery solutions. One for a wheeled rider with a larger motor and another battery for the foot take off crew.


#20

There are packs being made with special wire bonding technology. Pack technology is rapidly improving… Here is an example. These batteries are not on the scale of what you need, but you will get the idea. 18650 Samsung 30Q cells would be a good cell for packs. 15amp per cell rating and almost 3000mah. 12S8P. Someone else will have to tell me how many of these size packs would be needed. You could wire them parallel, then amp load would definitely not be an issue. and they could be separated and charge separately to decrease charging time. https://www.electricbike.com/luna-cycle-announces-wire-bonded-ebike-battery-packs/