Thanks, I was looking at your table earlier and just wasn’t entirely sure the e-score was 100% applicable as i was imagining that the way a cell is used for a vape might not exactly translate to an eskate so I figured id ask specifically incase I’ve missed something.
if someone could go over assumptions here: my motor peak wattage is 3300 (170kv apex 6384) and my battery nominal voltage of 64vdc I shouldn’t do anything more than about 104a (3300watts x 2)/64v) so 104amps/8parallel sits me at 13amps peak per cell, making me think i can draw from the 10a column as constant discharge should be closer to 40-50a.
This makes the 50S the clear winner at an e-rating of 13.7 I just not confident because E-rating is a derived score that I don’t fully understand in the same way I understand watts/volts/amps. actual power density at a given output is the shadow it is casting on the cave wall but that is as far as the metaphor goes for me
It is a pretty specific product so I might consider it if there is nothing else I choose before the end of the day. I’ve also been thrown a ton of knockoff pinecil soldering irons but I didn’t bother with them since I have one already and it is the real version
My recommendation from experience with shitty welders is run the other way, but it seems like you have your mind set on buying it anyways, so good luck.
Mooch’s E-Scores are actually relatively simple, it’s the energy delivered in Wh when discharging down to 3.2V
Capacity testing in mAh is done at a very low current, down to a very low voltage of 2.5V, and represents current and time but not voltage. It’s useful if you can assume voltage over time is constant between the cells you’re comparing, but we don’t have that luxury. The low current doesn’t reflect real world use where sag and internal resistance mess with the numbers. So if a cell outputs 4000mAh at 10A but the voltage sags a lot, the total energy in Wh could be lower than a cell that puts out 3900mAh at 10A but maintains a higher voltage for much of the curve. E-Scores are just Wh delivered at the specified current, no guesswork about whether a rating in mAh needs an asterisk. 3.2V is also much more realistic for eskate use
Re: the rest of the assumptions, yeah the 10A column seems like the right place to look and the 50S looks like the right call. Do you have any boards with a similar power level, to verify if you will draw 6.6kW at peak load, and how close to that your sustained load is? Your maths make sense but it’s hard to know how a given rider will actually use their stuff, I ride much much gentler than many here so the right cell for me would definitely be the 5600mAh guys. My main board peaks at barely over 1000W, so I really would be pulling 2A per cell if it was 18s8p, but that’d be a terrible choice for most folks
Ok i think it finally clicked, thanks for breaking it down for me.
Ok so i have a board that is similar, same size motors on 12s with a comparable gear drive that i will be riding in the same terrain that i have a davega and lots of logs on and a metrPro BUT I haven’t been able to get consistent data out so I don’t trust it. If i did trust it i show peak 90
Starting with the davega- i have gone over the settings carefully and believe my w/mile are accurate (35-40) but the range estimate is only ever 2/3 of what I actually get. Full charge shows 20-23 miles but I consistently get 28-30. I ride hardish, lots of stops and acceleration with much carving and hills so 40ish w/mile seems good and my battery total capacity is probably in the 1200-1300wh range with the number of cycles on the battery. I have quite a few logged sessions to average these numbers in the davega but because of the range discrepancy i can’t figure out i have been using my estimates over the logged data.
The MetrPro data is also weird but in a slightly different way. It haven’t been able to figure out how to get the logs to record wattage per mile/kilometer correctly so I once again tend to manually calculate my stats. Most of my logs show 250ish watts per mile most records but then occasionally ill have a record show 25w/mile. Ive kinda given up on getting good telemetry and just manually calculate everything which involves a lot of approximations and estimates.
The battery i made, 12s8p p42a pack, recovers a lot when resting. I try to take a good break at the 10&20 mile mark and the pack voltage will recover 2-3 tenths of a volt per cell, though i usually only ride about 20mi a session. Maybe 800-1000 miles on the pack so maybe 50-60 cycles
As @mr.shiteside mentioned, the table tells us (in the legend) that E-Scores are just the actual Wh delivered down to 3.2V. It is not a unitless derived number. The table also never mentions that the data is limited to vaping devices.
There’s essentially no difference between any different uses of a cell. All of them run the cell “continuously” for various lengths of time. The total Wh delivered is very close for all possible uses, including one continuous discharge down to empty versus lots of shorter pulses.
For any li-ion cell, any use over a few mS long is pretty much continuous as far as the cell is concerned. It only takes that long for the ions to get set up and after that it’s just a continuous stream of ions flowing the exact same way, whether for 10mS or 10 hours.
In my testing I only got about a 3% difference in the delivered Wh between one continuous discharge and a series of five second discharges. For mixed use like esk8, where there is a constant low level of discharge mixed with bursts of higher power, the difference would be less than that 3%.
Even if there was a bigger difference the table’s data can be used to compare the performance of once cell to another without regard for how it’s being used. There won’t be big differences in how one cell handles continuous vs pulsed versus how another handled it so they can be directly compared using only one type of discharge.
sorry, i didn’t mean to imply that the E-Score was not an empirical measurement, just that as a measure of capacity i have a sort of intuition about mAmp hours as a part of total capacity testing at low draw in the traditional testing of cells but not any about of how E-Score translates. This is a feelings thing, so I’m asking all the dumb questions so I don’t drop $1000 on cells until I understand it well enough that i can explain it.
Obviously a higher E-Score is better but what about my fee fees? Can i just add three zeros to the score? I think this is where I’m hung up. I’m going to say the 50S has an E-Score of 13,700mwh. also going to add three zero’s to everything now, where did I put that 2000 micro meter Allan?
This is really interesting, i wonder if the total time of the test would affect the available capacity. Say the average discharge c rating was kept at .5c. - as an example instead of drawing 1 amp for an hour constantly, run 2 amps on a 50% duty cycle for an hour, or 4A on 25% and so on. It would be interesting to know if the recovered voltage from letting a pack rest partly through a full discharge cycle actually has an effect on usable wattage. I don’t think it would be too hard to come up with a test rig, but will I do it if I don’t add three zeros to the end of the name? Only time will tell
The increasing voltage sag (as current increased) would immediately shorten the run time since one of the higher current pulses would hit the low voltage cutoff sooner.
But the total run times, if not allowed to reach the low voltage cutoff would be very close for different duty cycles as that’s essentially the same thing as what different applications do with a cell.
A flashlight is often 100% duty cycle.
Vaping varies between perhaps 10% and much lower percentages.
ESK8 has a complex hi/low power profile.
Adding up the total Wh used for each thought would result in about the same run times (ignoring when the low voltage cutoff is reached). What affects run time a bit is the temperature the cells reach.
Warmer cells have lower internal resistance (IR) and will hold up their voltage for longer. This means that higher duty cycle applications (assuming all else is equal) can result in longer run times. This is the primary cause for the 3% or so max difference I saw in run times for my testing, how the cell temp affects run time.
I do like this better but Nano is kind of out of fashion. Need to figure out what it is in Planck energy. Slap the word Quantum on that bastard then express it in scientific notation and we will have come full circle. Doesn’t the term Quantum E-Score just ring nicely?
This Jives with my anecdotal experience, getting low = go slow. at least when I’m trying to squeak out my absolute max range. I do wish ev charging infrastructure was a little farther along - taking a break and charging would make my current board’s range turn so many “there and back” trips into loops.
Ebike community (Onyx specifically) is dying for real battery makers. They are relying on Chi at this point in time and they’re finally realizing that the “upgraded range” packs Chi is selling can’t even output more amps than the stock Onyx pack due to the 50E cells used. Dude has a full corner on this market and it’s infuriating. Just had another company coming in promising upgraded batteries and they’re just pumping up the capacity and providing cells that can’t even deliver the amps needed (cough cough Powerful Lithium)
Any trusted battery builders in the US open to building quality ebike batteries and making some money off old farts pretending their bikes are motorcycles?
I called out ChiBattery for their shit packs and I’m getting a lot of support from other owners wanting to actually see some batteries before they get wrapped in black tape and shipped out (so basically they want to be like us and know their packs are being made well).
I’ve been in calls this past week with the Onyx ambassador, Mr John Angel himself and we would like to bring some esk8 batteries and vescs into the ebike world. To be clear, I want no money from you maggots. Just want people to be able to buy reliable batteries from not-Chi.
I’ve found Eon Lithium that’s the supplier for electro & co batteries. they sell E-moto conversion kits and such so the batteries should be powerful enough for onyx bikes or any class 2/3 ebikes. I suppose that if you contact them and ask they would prob consider doing it for some ebikes if there is enough people buying
judging from their pics it seems better than chinesium batteries even tho like Evwan mentioned there was an issue with one of the batteries but I believe it was resolved
ofc they wont beat some of the builders we have on here with an absolute work of art
Sadly no. The ebike forum took a big split when the faster bikes showed up. A lot of purists saying they don’t belong and it just got dumped. So now it’s facebook groups and discord chats. I’m trying to get the FB group more involved and interested in asking the questions they should be instead of just buying whatever new item gets posted and promises +5mph
Any picture I can find does not show something that is of a quality that should be on sale.
All I can find is badly cut nickel, inadequate welds and some fairly sloppy soldering.
The heatshrink game is on point though.
I do like this better but Nano is kind of out of fashion. Need to figure out what it is in Planck energy. Slap the word Quantum on that bastard then express it in scientific notation and we will have come full circle. Doesn’t the term Quantum E-Score just ring nicely?