Yup picked up HK graphenes for $27 a pop. I’m using a 10s setup right now with no issues at all. they are rated for 90c discharge, I don’t know how true that is I’m waiting on the metr update to get data. But tons of power.
2 Likes
HK Graphenes are the closest to their stated C-rate out of all lipos. Here’s the proof: https://www.rcgroups.com/forums/showthread.php?1767093-Battery-Load-Test-Comparisons
To answer your question @mtuan293 , ALL lipos are below graphenes!!
Edit: I do realize that a 3c multistar is closer to its “10c” label, than a true55c HKG is to “75c”, but you’re missing the point if that’s what you’re concerned with
4 Likes
In a case that small, I’d probably go lipo just for the extra discharge capability. In my opinion, the advantages of li-ion really shine in either (A) large packs, where longevity is a must and extreme power density is not needed, or (B) in small to medium packs where you want the most energy density, but don’t mind taking a hit to power density.
For small packs where you want ALL the power, lipo is king. It won’t last as many cycles or hold as much energy per kg, but it’s cheaper and higher discharge.
For a high power build (anything bigger than a single 6355 or thereabouts) you really need either lipos, or at least 3-4p of li-ion to handle the required current.
3 Likes
I guess it’s because of that “safety”. People tend to afraid lipo pouch can be easily damaged causing fire and all the stuff compared to metal housing of liion 18650 cells. But I feel like using cylindrical cells there’s lots of space wasted compared to squared shaped of lipos
2 Likes
Hmm I’m inclined to bump up my settings now 
True, there is a lot of space wasted. But going by the rated capacity and dimensions of a 2.2ah 4s turnigy graphene, it has a volumetric energy density of just a hair over 200wh/l. A single flat layer of 18650-30Q cells (Including the air space!) has a volumetric energy density of 514 wh/l. Bare cells are 633 wh/l.
1 Like
I thought cylindrical lion cells are less space efficient than squared lipo cells. i.e., you can fit more chemistry into the corners of the square which would have been lost due to the circular shape of lion cells. Looking at your 18650 pack there’s always gap between cells, now imagine you make a battery pack with square corners it would utilize all the gap and give you some extra capacity/discharge.
1 Like
See above. It’s true that there is less room for battery chemicals. But, the battery chemistry is SO much better, that it still way outperforms RC pouch cells in terms of energy/l or energy/kg.
lipos still win in terms of watts/l and watts/kg though.
3 Likes
If you dont switch, @least try lipos.
1 Like
Then why don’t we have squared lion cells instead of the stupid cylindrical cells then!!!
Lipo have a nice discharge curve too staying high before finally out of juice. That’s worth something. And probably can charge them much faster without damaging.
Because the construction of the layers inside is a jelly-roll. Try and make a square cinnamon roll, and you’ll see why.
Another reason is that the layers tend to try and puff up, expanding away from each other during high discharge, etc. The cylindrical shell applies even pressure from all sides and has no tendency to buckle in one direction or another. This is why large packs of prismatic li-ion cells always have some sort of structure to keep the cells compressed. Cylindrical cells have that built in already.
If you made square cans, the flat sides would bulge out due to the forces applied to them simply from the assembly process, much less from the layers trying to puff over time.
6 Likes
You can compress lipo. Think it’s good for them.
I think lipo are safer given the track record here. So many cells and possible points of failure with ion vs plugs and fewer cells. Just scratching off the insulation on ion can be disaster
3 Likes
Yep. But we don’t usually because it’s a pain and takes extra space/weight/engineering to do it.
Buy round li-ion, and they’re pre-compressed.
I think those are like the turds that Evolve use, but I’m not 100% sure. I bet @longhairedboy knows. These seem to be the exact ones they use in Carbon GT. Stay as far away from these things as you possibly can. But if you wanted a pile of used ones to play with, I bet some are available
1 Like
Maybe. What if the round shape allows a machine to roll that sucker up super-tight with thin layers, making it more efficient? I agree with you, but there are known-unknowns and probably unknown-unknowns here
5 Likes
Exactly. All I’m saying is, there’s gotta be a reason so many EVs (And other industries) use cylindrical cells. If they were a shitty idea, everyone would be using pouch lipos for everything.
1 Like
Pouch lipos are in cell phones, tablets and etc. As far as large scale industrial manufacturing goes, companies like the one that makes iPhone batteries have the machines capable of consistent production. This guy, whom I believe is with revoelectric, has some interesting things to say about it: https://www.rcgroups.com/forums/showpost.php?p=29238904&postcount=1774
This is linked in the main article I linked a few posts up. Tldr, it seems that industry is tooled for liion and small capacity lipo manufacturing, but not really for large capacity lipo manufacturing. And as the graphene lipos are fairly new among lipos, commercial adoption may be limited to hobby batteries for a while.
My thoughts anyway, but what do I know. Pretty much thinking “out loud”
3 Likes
But lipos have their cables which take up space as well Its not like you would put something where the empty space of li ions is
2 Likes
The shape of that box, I don’t think you can get interesting lipos in there.
Plus, the diyelectric esc most likely has voltage cutoffs for lithium ion, not lipo.
Plus, if you do the same thing to the lipos that you did to the 10s2p pack, 
The cheapest decent lipos are usually the 30c or 40c hobbyking, zippy or turnigy. Usually 3s or 4s for the shape (makes 10s difficult).
You can hit 10s with 2s or 5s lipos (usually), both of which will be difficult to fit I think.