I noted that the nominal Ah of 18650 cells can vary a lot. Typically everybody is using 2500 mAh as the standard, but some can have 3000 mAh or above, which should in theory give you a better range if put in parallel. But I assume there is a price to pay for that (and I don’t mean the price of the cell itself…), considering you can find these cells at a very competitive price. So where is the catch?
Voltage sag. Higher capacity usually means lower discharge rate. Unless you’re making a 8p pack you’ll face voltage sag.
oh dear, would that plague a setup such as using two of these 6s 8000mah packs in series?
I still cannot determine weather these are as good as 18650s
Higher capacity cells usually have lower discharge capabilities. Which is why when you find one that has high capacity AND can handle high currents you usually have to pay for it. In the end we typically stick to a couple of proven cells and choose the one we can afford.
Forget 18650. If you want decent discharge and high capacity, I’ve found 26650 cells to be more than adequate. Basen 4500 is the best way to go
Ah! now we are back on the debate 18650 vs 26650. i remember reading not so long ago that it was still better to use 18650, even though I could not remember the excat argumentation. But I must have that somewhere. i am open to using 26650 if it’s really better, I do not have space issue.
Simple answer is to use what fits in your design parameters.
I think the 26650 is generally more expensive… There’s also these ‘huge’’ headway cells which are really easy to connect (screw terminals) but they also cost quite a lot $$$
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Look up samsung 30Q.
These seem to be good cells. Some even say they are /somewhat/ - '‘derated’’ and can reasonably be used or compared to 20A cells…
I can totally agree on this one:
So you should ‘‘chain’’ enough in parallel to make ‘‘decent pack’’ I think 4P is a good recommendation / start point…
great battery find! cheap.
I wonder about these. only 15c rating but the graphene are touted as really stout at high discharge and maybe it’d be a true 15c all the way down to 3.5 volts. If it’s true 15c, an 8ah pack would be 120amps and good enough for sure. get them and hook up the vescs to data log and tell us how you do going up steep stuff when your pack is already low please! 48mm for 6s and could be cut down to 2s and slimmer than a typical 2s lipo. super cheap for a graphene battery which has a life cycle ability similar to li-ion but with power output ability of lipo. these are a dream come true at that price…if they do 15c
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The issue is that for some reason it became the standard to use 25R cells, they are rated to 20A but are just horrible as far as voltage sag or capacity goes. They perform worse than Sanyo GA cells which are only rated to 10A and have 3500mAh capacity.
I honestly don’t know how this cell became the standard. It’s got nothing outstanding in its spec sheet other than its “rating”…
Good high capacity cell: Sanyo GA LG MJ1 Samsung 35E These cells suffer from some voltage sag but a 4P pack is great for up to 20A avg with bursts up to 50A.
Good high power cell: Sony VTC6 Samsung 30Q LG HG2 These cells sacrifice capacity for power. Voltage sag is non issue and a 4P pack should be good up to 40-50A avg with bursts up to 100A.
IMO, LiPos belong in places where very high power density is really required (rc airplanes/multi-rotors). Not the case in longboards unless you live in a SF hills kind of area or are just trigger happy.
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I’m gonna call bullshit on that. I’ve run an 8s n x2 10s lion packs and multiple lipo packs. Hands down lipos give more raw power.
Sure you can only charge them a third as many times as a decent lion packs. But they cost a third as much and sometimes less.
Yes you have to balance charge…But noone out here is ‘building’ a good board that can’t handle balance charging.
Plus…Voltage sag is non-existent, they are incredibly easy to replace, offer many more customization options and can save you $200 on a total build.
The only thing lion has is more watt hours, on average, and any 3 year old can charge them.
Thanks @PXSS for these indications. That’s what I was looking for. @mmaner I had a look at Lipos and you have quite good deals at the moment on HK so it was tempting, but I have the impression that Lipos are too sensitive to handle for a dummy like me, especially in terms of charging. My objective is also to build a modular battery that can travel by plane, and I have the impression Li-ion offer more flexibility from that point of view. The idea is to have a 10S5P on the model of what @okami did with XT60. As it is to go on a large board with pneumatic wheels, I want to ensure I have enough capacity to do a significant distance. No big hills where i am.
oh lord i do not have nearly the spare cash at the moment to grab a cell, a VESC, and a motor and a remote to test the voltage sag they seem like very interesting cells though
They really aren’t, they are no more sensitive than lion. You just have to balance charge, which is very simple.
Lipos disconnect with a single plug, much easier than lion. If you want a 10s battery that is 99wh per pack, then get Turnigy 5000mAh 2S 30C Lipo Pack. A little over $100 and you are ready to go.
Seriously, do what you want, that’s the beauty of this thing. But don’t let people talk you into something that is simple not accurate. Talk to different people, get different opinions, then make up you own mind. You can seriously limit yourself by accepting opinion as fact and acting on that assumed fact.
In this case, I would put x5 2s 30c packs against any lion pack and leave them in my wake.
He’s mostly referring to Li-ion cells which usually have a much lower C rating than Lipos. Those Lipo cells can handle 120a discharge One Li-ion cell will only handle 20-25a discharge and therefore must be multiplied in parallel.
Ok but how far would get me 5000mAh? and how do you charge your 5 batteries?
Was that you just being argumentative or do you honestly not know?
Depends on how you ride, but probably 70-80% as a 7500mah lion, and a third the cost.
WIth either a 10s charger, or make a 15 pin port for each set of P cells. I would opt for the 15 pin adaptor port and use a accucel balance charger.
That’s actually one of the great things about lipos, most people balance charge so every time you charge your packs you KNOW what condition your cells are in. Not so much on lion packs.
I don’t have anything against lion packs, but for people that want less voltage sag, ease of replacement, modularity & lower cost its a win win.
Bullshit? I stated that LiPos are more power dense than Liions, FACT. I stated that they are used where high power density is required. FACT Voltage sag can be just as good with Liions if you choose the right cell, FACT. High power density is not required in longboards, FACT. I can make a 10S6P pack that can easily output 3KW and has a capacity of 18Ah and is smaller than your 8S 5500Ah LiPo. FACT
The only real reason to go with LiPos is cost. They are cheap. Dirt cheap. I just bought 12 3S 2.2Ah packs for $45. That’s the equivalent energy of 27 Samsung 30Q cells which cost ~4ea but I didnt say anything about cost in my previous post
How do LiPos offer more customization than Liions? Have you seen White Pony’s builds? What do you think those would look like if the were made with massive Lipos?? Please explain this one cause I absolutely think you’re just plain wrong.
Liions can be replaced too, theres a user that is using sleds and can swap out any one bad cell. There’s another user that made his pack split in 5, so he can easily replace modules or disconnect them and fly with them. I still cant believe you said that Lipos are more customizable.
My post was not me passing my opinions as facts. It was me using facts to answer someone elses question.
And you can also balance charge Liions. I don’t know why you have the impression it’s any different than LiPos.
10S4P pack with real world max continuous power output of 1000W, burst up to 2000W for a minute and a whooping 504Wh measured. Its charged as 2 5S packs and has balance connectors too.
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For 3 times the cost of a comparable Lipo pack, and the lipo pack wold have a higher discharge rate.
Thats point that I was trying to make. Not that lipos were better, just different but definitely had a place in the powered skateboard community. There are many reasons other than cost to go with lipo packs that just cost…higher discharge rates for a lot less money, easier to install and implement than building a lion pack, you always know your cell health when balance charging, all the points I made earlier.
What I meant was that you can by 2 5s 5000mah lipo packs and have a 10s 5000mah or a 5s 20000mah with the switch of an XT/bullet connector. The same can be said with 3s, 4s, etc. packs.
Of course lion cells can be replaced, never said they couldn’t, just said it was easier with lipos. Pull a pack then insert a pack. No soldering required. Can’t say that about lion packs unless you are talking about sleds, and most people don’t like sleds as they are fragile. I can pull my lipo packs in less than 2 minutes, tape up the connectors and fly with them too, didn’t have to make anything special to do it either.
In closing, I was rebutting you statement of… LiPos belong in places where very high power density is really required (rc airplanes/multi-rotors). Not the case in longboards. I absolutely think you’re just plain wrong.
I was simply offering the “opinion” that you were wrong. I think making blanket statements like something should not be used to someone who is new to this process is irresponsible. Most people can drop $600 to build a powered board, most people will think twice about dropping $1000 to $1200. I’ve built $400 boards with lipos, not great boards, not beautiful boards, but damned fun to ride. My current daily board is great and beautiful (said lush as hell) and it is hovering around a $1000 now…with a 10s3p pack that I got at a heavy discount. My 6s lipo packs were faster, had less sag and still cost half as much. FACT
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