Voltage limits where set lower for my Li-ion pack than for my Lipo pack. The problem was that my Li-ion pack sagged so much and depleted so quickly under high load conditions. My first build was with Lipos, charging them with a hobby charger. Then I switched to Li-ion thinking they would be safer and more convenient with a BMS and expecting the same or better performance as the Lipos. But I was terribly disappointed with there lack luster power and ridiculous voltage sag under load. So I went back to Lipos but this time with a BMS. Now I have power and convenience. And the only time that my Li-ion pack had more range was when cruising the flat boardwalk at no more than 10mph. Even though the Li-ion pack had more watt hours, It depleted so much faster than my Lipo pack under more challenging conditions that they even out in range with the Lipo pack delivering more power throughout that range.
Unles your efficiency changed your statement makes no sense. Energy is energy - it canāt just disappear. So there must be more to this story: You either used only mediocre cells or had wrong cut-offs. 5000mAh from a Liion HAS to get you as far as 5000mAh from a Lipo (at the same voltage obviously).
Voltage drop is an issue yes - but that would just mean you did not use up all the energy in your liion pack. How much did you actually charge it?
The problem is that your voltage should not sag 30-40% ever unless you were drawing like 5kW which is highly unlikely. That is super weirdā¦ Maybe you got bad cells? Thatās kind of why I only buy Samsung, LG, Sony or Panasonic cells. They got way more to lose if they produce crap cells since theyāre used in industrial applications.
Do you still have this pack? Would you like to fix the issues with it? I could probably help you with troubleshooting if you can log data. If you donāt really care for it then, no worries.
E: Check out Kalyās thread, heās got a 12S4P LG pack on his mtb with dual 6374s that he rode 20 miles in just over an hour.
5000mah from Liion SHOULD get you as far as 5000mah from Lipo
But in practice you donāt get 5000mah of any of them. Part of the energy disipates in heat and a lot of energy is just wasted on drivetrain and so on. When you have a big sag you are wasting more energy. (For example, full throttle for 1km, sag of 1v in one battery and 3v on another battery, the first will be using less energy than the second)
So that is why I said that in practice, Liion seems to be making a lot less range than it should when compared to LiPo, and Namakasi is not the only person having this, there are a couple of threads with a lot of people telling their ranges and people with 6s5000mah lipo are getting unbelievable long ranges.
Kind of agree but not really. The issue with @Namasakiās pack is that itās sagging way more than what it should be. The issue with most others that have this issue is that they use 25R cells which as I explained are not great.
Here is a good comparison from another thread:
from this thread:
We discuss in detail the pros and cons of LiPo vs Liions. I suggest you read it.
That is why I said that unless his efficiency changed this is impossible. voltage drop has nothing to do with this - sure we could assume that the heat generated by the Liion is higher than Lipo but I highly doubt that this happens in meaningful amounts. If we would have to dissipate an additional 100Wh via the battery our enclosures would be HOT and the VESC would shut off due to overheating. Ever touched a traditional 60W light bulb while on?
Very interesting reading @PXSS, itās a pity that they are not showing real range
I guess it all depends on the quality of the cells and lipos.
One thing that I know for a fact after years in rc cars and multirotors is that C rating is bullshit in lipos, so if it is in 18650 too we can only trust real tests
Iām at work now so Iāll have to resume later
I had the same thing. Started out using x2 Zippy 3s 30c 5kmAh Lipos in series. I went to a 10s3p lion pack made with 25rās. Did not like the loss in torque that resulted in the voltage sag. So I went back to my lipos. I am now trying another 10s3p, if I can get the damned thing to fit. I also have a 30q 10s3p pack in the works. Im hoping the 30qās prove to be as resilient and beastly as the lipos :).
Iām interested in hearing how your 30Q pack compares to your Lipos
Ill let you know when I get there, still a couple of weeks away at least.
Namasaki 26650 cells arenāt as good as name brand 18650 cells. A lot more R&D was put into 18650ās since they were heavily used in laptops for a long time. 18650 was the only size battery that had enough manufacturing infrastructure already built around it for use in electric vehicles. This is why Tesla chose this size cell. They had the best specific energy, and could be manufactured in larger quantities with tighter manufacturing tolerances more quickly than any other size cell.
The other issue is name brand cells from reputable suppliers vs off brand Chinese or recycled cells. A lot of chinese suppliers take old Samsung, LG, Panasonic etcā¦ cells and clean them up re-wrap them and cell them as new cells. A lot of chinese suppliers also buy cheap knock off 18650 cells from Chinese factories and sell them as legit name brand cells.
The vape community has done extensive testing around 18650 batteries and how much a single cell can handle in terms of current draw and voltage sag. This information is all out there publicly. If youāre interested search for posts by ābattery_moochā or maybe ābattery_m00chā on reddit his name is something like that. Heās put out a wealth of information about 18650 cells some of which are of interest to us.
The TLDR of my post, 18650 cells produced by Samsung, LG and other name brand companies have spec sheets which are accurate. These figures may be inflated by resellers, but go look at the manufacturing spec sheet for real info. If you buy cells made by someone other than Samsung, Panasonic, LG and Sanyo you can expect the specs to be inflated.
If you buy cells from a disreputable reseller, you can expect there is a good chance they will be re-wrapped chinese or recycled cells not the real cells.
18650ās are great for our purposes, but there are a TON of fake resellers of cells. Be careful and know your supplier.
I Appreciate the offer but unfortunately I had stored it in my safe for safe keeping and my safe was taken during a burglary. How ironic is that?
A 10S3P pack is always going to sag some when you pull more than 45-60 amps from it. Iām not sure how much amperage you guys draw, but Zippyās are capable of more amp output.
They probably had fun when they used a blow torch to open that thing 
Ya, Iām thinking that the Basen 26650 cells where overrated. I went with those because of the 4500mah in an attempt to build a compact battery with good range. And its range was exceptional under very mild conditions but not under more demanding conditions.
Itās my understanding that Tesla doesnāt use just any 18650 but theirs are special. From what @PXSS has stated, it sounds like those 30Q cells may be the best available option for A Li-ion battery. As for me, Iām happy with what Iām getting from my Lipo packs so Iām not looking for other options at this time.
The other thing with these batteries is as capacity increases, current draw decreases. Typically a good 2500mAh cell from the same generation as a 3000mAh cell will be able to handle more load with less heat and voltage sag.
I donāt know as much about 26650 cells as I do about 18650 cells, but the current generation 18650ās absolute top of the line cells for capacity are 3500mAh. Those arenāt suitable for our uses though. They might be in something like a 10P config, but realistically for us 3000mAh cells like the Samsung 30Q and LG HG2 are about the best weāll get in terms of capacity.
Iām thinking about either reconfiguring my 12S5P pack or building another 10S6P pack with cells from the same supplier to see if I get more torque because my only experience so far is with my 12S5P pack and 16AH Multistar batteries. People have said the Multistar batteries are lackluster in terms of voltage sag under load and donāt give enough torque. Both seem fine to me, I get comparable range and speed from both. The 18650 pack sags slightly less under load.
Iāve yet to top out either pack. I cruise around at probably 18-22mph top speed. I didnāt realize how fast 25+mph would feel on a board when it is that high up. Most of my longboarding experience was on drop throughs or dropped boards. I owned one top mount which I turned into the esk8 and with the angled risers, itās very high up from the road. I might try putting stiffer bushings on it but I like the carvy feeling I have now.
I am just wondering how manufacturers like Inboard can sell their boards with 12S1P 18650 configs and get away with it. The voltage sag must be HUGE on those packs.
I would not even consider building a10s6p or 12s5p battery out of 18650 cells because of the size and weight of it. I mean 60 cells, thatās gonna be over 22" long in a low profile configuration. We have tall speed bumps where I live so ground clearance matters. What I needed was plenty of power in a compact low profile light weight battery and since my rides are usually 10mi or less, range is not my main concern.