@namasaki is your li-ion experience only with basen cells?
Also c ratings are numbers pulled from thin air, there is no standard way of measuring c ratings. Lipos are overrated in their specs, especially hobbyking, still more discharge than li-ion of course. 18650s weight less per capacity and with enough parallel cells have decent discharge. 18650 cells are probably the best for cruising and getting max range. Lipos are better for performance and can pull lots of amps. So that being said I might go back to lipos (from 25r’s) because I pull 80 amps on very hard accelerations and don’t need capacity as much as I need amps. Or I might switch to 30q cells or 20700a cells
True my only experience with Li-ions was with Basen 4500 cells which claimed 40a continuous per cell.
Maybe they where overrated. They got good range going slow on flat ground but lost more than half that range charging up hills. Maybe 25R’s are overrated as well.
All I know is that my 5ah 60C Lipos have as much range or more on hills as my 9ah Li-ion pack did with a lot less voltage sag and the Lipo pack is smaller and lighter.
Do you have some basis for this claim?
If so, I would really like to see it.
Some may be overrated as some Li-ions are but it seems they must have some way of determining C rating besides “pulling it out of thin air”
Anyway, I have personally compared 5ah 25C Lipos in a 12s config with 5ah 60C Lipos in a 10s config.
The 10s 60C lipo pack had much less voltage sag and just as much range even though the 12s config had more watt hours.
This is pretty typical and is better than lipos IIRC. Keep in mind this measurement is measured with full charge/discharge cycles from 4.2v to 2.5v, which is way below what we typically discharge to. Also, with every .1v we cut short from max charge we also double the cycle life of the cell.
I find it hard to believe that under charging 1/10 of a volt will double the number of full charge cycles in the life of a lithium battery.
Has anyone here actually proven this theory.
I have been using my Lipos and fully charging them for about 8 months now and I wish I would have kept a log of charge cycles. I honestly can’t even guess how many times I’ve charged them.
I do know that if you fully charge your lithium battery and only discharge it to half empty and them recharge it. that only counts as 1/2 of a charge cycle off the life of the battery.
Table 4: Discharge cycles and capacity as a function of charge voltage limit. Every 0.10V drop below 4.20V/cell doubles the cycle but holds less capacity. Raising the voltage above 4.20V/cell would shorten the life.
Basen is not a good representation of li-ion as they are not made by a trusted battery company
What I mean for lipos is there is no standard on how to calculate c ratings. Any company can claim what they like. They can claim 100c and still use 12awg wire and 60amp rated connectors. If you get lipos of the same specs from different manufacturers they will perform differently. Your example imo shows this as the 12s pack would be 125amps, Im pretty sure you’re not pulling close to that many amps continually. I like lipos, just don’t believe their ratings. My main concern with lipos is they’re more sensitive and risky over 18650 li-ions.
I think the biggest problem with them is that it would take too many of them in parallel to substantially reduce voltage sag in situations that require heavy current draw.
in milder situations they performed just fine with excellent range.
I went 28 miles on a 10s2p pack with Basen black 4500 cells just cruising on flat ground.
From what I’ve heard they may be better than Samsung 25R’s
Lipos or Li-ions, I think it comes down to a matter of choice that depends on individual needs.
For some Lipos are the best fit, For others, Li-ons are the best fit.
There lots of factors to consider. Basen weigh just over twice as much as 18650 according to specs. So less capacity per weight. According to mooch testing there is also more amps available with something like 30q cells per weight.
I’m not hating on lipos. I might use them for my next board if I can find the right size packs from good manufacturer for my enclosure. What I don’t like is the c rating. It’s not accurate so it’s not useful for comparing packs between manufacturers. Also my experience with turingy 60c is I puffed them first couple of days. So no hobbyking lipos for me
I didn’t realize that the Basens weight twice as much as the Samsung 18650s seems odd since they’re only 1/4" larger in diameter and the same length.
They do have 1 1/2 times the capacity as 30Q and almost twice the capacity of 25Rs. Just their discharge rate is overstated like 25R’s
Don’t know why your Turnigy 60C’s puffed in 2 days. Mine have been going for 8 months with no issues.
Isn’t Hobby King just a retailer? A pretty large one at that, They obviously aren’t going to test every Lipo pack they get from the manufacturers. So I always check them as soon as they arrive and before putting them in use.
I did get a couple bad Zippy packs from them once but they replaced them promptly.
i use samsung li-ion 18650s. 12S at 4P and 5P, both 25R and 30Q cells. I leave that choice to the buyer but honestly i can’t tell the difference on the street. My boards use a 60 amp BMS and burn urethane on launch. Even kegals, as sticky as they are, lose traction when i hit the throttle hard enough.
lion 18650s last longer. They’re safer. They don’t puff, they just vent. They seem to be able to completely fail within their own p group and not take the rest of the cells with them somehow. I’ve had multiple occasions where a dead p group was reading less than a volt and nothing dangerous was happening. They’re less puncture prone, far more configurable as far as shaping the over all pack, and store more easily for the same reason.
trying to find prismatic cells that fit every application as far as shape and size goes is annoying as fuck.
Also C ratings are distorted at best and grossly exaggerated to the point of fraud at worst, even from reputable sources.
Lipos are cheaper, that’s thier only real advantage other than power density per cell, which can be had with any prismatic. Their cycle life sucks and they come in awkward sizes that don’t allow me to get as much juice in the same space.
but they’re pretty much perfect for DIY and hobby boards that you don’t have to ship to customers and support over the long term.
If you compare cell to cell it’s not the whole story. According to specs a 10s2p (20cell) basen pack will weigh as much as a 44 cell 11s4p 18650 pack. (Not including wire weight)
I did test the turnigy. Don’t remember ir but it wasn’t to high and capacity was not accurate to usable voltage. My point is hobbyking lipos imo are not the best, i personally like gens ace.
But thats the problem with lipos, there are just too many to choose from and there is no standard unit of measure. Lipo manufacturers lie. Just try pulling 300amps from your pack continually. Also feel hobbyking lipos give lipos a bad name. I want to see more discharge graphs with lipos across different brands. The community seems to always compare cheaper lipos to 18650s, I want to see other high end lipo packs into the mix. It’s hard to know whats a good lipo tbh, I’m not 100 percent sure either, I just know it’s not hobbyking.
@longhairedboy do you monitor your rides with something like ackmaniacs firmware and phone app to know things like voltage sag and amp draw? And what brand lipos are you talking about?
I have not used Gens Ace but have heard that they are good quality.
I have used Venom Lipos and they performed very well but they are very expensive.
Now that I think about it, a 300/600 amp rating is rather ridiculous, especially considering that the wires coming out of the battery are rated for 75a.
I do think that C ratings can be used as a relative guide for Lipos of same brand or similar quality.
I wouldn’t expect a turnigy 60c to be equal with a Gens Ace 60c or a Venom 60c
I think it reasonable to say that if your going to use Lipos, get the highest C rating possible for the best results.
I don’t think that 18650s are that much expensive. Ofc if you buy it as a pack like bajarali sell. But for example to me 10s4p with 25Rs is aprox. 160e including sells, wire, nickel strips, welding heat shrink…
There’s plenty of threads where I’ve detailed the difference between 25Rs and 30Qs. 30Q cells are far superior than both 25R and Basen cells. GA cells by Panasonic rated at 10A sag slightly less than 25Rs and have 40% more capacity. The ratings take a lot more than just ability to deliver power, like life cycle expectancy so you can’t just take that number.
Lipos are cheap. That’s their main advantage. A 4P 30Qs provide plenty of power for a mtb imo so the extra power gain from Lipos is useless and the capacity density is not worth it imo.
i have in the past enough to know that 60 amps is plenty and 99% of the time you’ll never see it unless you’re deliberately trying to get there. Casual riding won’t ever see that and hard hot dogging might once in a while, racing and bombing uphill may see it more often. To make my point, my BMSs are supposed to trip if held over 60amps for a small period of time and they don’t. Ever.
I have a 12S4P with dual 6355s on a 16/32 ratio on kegels. With proper vesc settings I got on it full throttle from dead standstill with enough force to put your face onto the back of your head on no more than 57 amps total between both motors. Also my motors are rated somewhere around 3000 watts but i’ve never seen more than 1200 watts go into either of them.
doing that on a half charged pack like that might get you 2%-3% sag on the volt meter. the worst case of voltage sag i’ve ever seen on one of my packs was 12% and it had broken welds.
12-20% is apparently common and somewhat forgivable on an Evolve Bamboo GT for some fucking reason. I had one in my shop that below 40% would sag down to as low as 25% when you tried to take off.
I’m moving to 5P packs as they virtually eliminate voltage sag. 6P sag doesn’t seem to happen at all but i’m not going to start building hollow core decks.
over build and the components will last longer because they stay cool and comfortable while still putting a smile on your face.