Lithium-Ion batteries

[badger1]

it's Fri afternoon & things are quiet at work, so I was looking at 21700 4Ah Li-Ion batteries on AliExpress which you can get for about £2.50 (I don't know whether these are horrible quality - probably).

they're ~70g each, so you could make up a 4S2P 8Ah pack weighing ~560g (plus cabling) for £20.  they claim to be good for 3C continuous / 5C burst, so double that as it would be 2P, so that would be 24A / 40A, which is no use for racing/freestyle, but ample for cruising around.  all in a 42x84x70mm pack.

the cheapest 4S 4Ah 30C LiPo HK do is £30 & weighs 450g, so double that for 8Ah to give 900g total & 148x50x58mm pack size.

so weight for weight you get ~50% better from Li-Ion than LiPo, although obviously they're no good if you want to pull much current.  also waaay much smaller pack size.

has anyone played with Li-Ion for long-range stuff?

[ched]

Have a look at these:
34 min flight on 7" quad:
https://youtu.be/u8EkRS_c3MM
and
https://youtu.be/zyStUt4TaP8

[atomiclama]

Yeah I made a 5S1P pack out of those cells.

As long as you are just taking it easy and keep the current well down they are ok.

But start pulling some amps and they get warm and saaaagggggg lots.

I got bored pootling around watching the amps. So don't tend to use them any more. Use them to power me goggles and TX.

[badger1]

I think, with the C-ratings of current Li-Ion batteries, the pack would really need to be 2P to make things a bit more interesting.