Samsung cell options: 40T, 50E, 50S, etc

[Electric Dreams]

Just wondering what results other riders have had with their 40T or 50E wheels? What are your thoughts on these different cells. 

 

 

Edited December 6, 2023 by RagingGrandpa
(clarified title)

[mhpr262]

Differences between wheels, riders, riding styles, use cases, charging habits and environmental factors will likely play too big of a role to allow for any meaningful assessments.

[goatman]

ive got a batch 1 master with 50 E packs, i ride the beeps pretty hard on the streets with about 12,000 km's on it over the last year. it gets charged every night, overnight. its probably not the smartest thing to do but theyre perfectly balanced, thinking to retire this wheel at 20,000 kms after this winter and put those packs in my kids ebikes so that if they fail they can still pedal home instead of me going splat. i think its cheaper to buy a new master than to buy replacements packs. was looking for replacement packs and i saw one pack for $1350 on alibaba and you need 4 of them and a new master is $2700.

for my riding style i wish i had the 40T packs

the 50 E will be lucky to go 400 cycles at these amps

the 40 T if you ride hard will go 800 cycles and you can rejuvenate them

what i want to see euc makers start using are the Molicel P45B batteries

after saying all that,

if i had an ex30 with 50E packs id probably retire that wheel at 40,000km's

a master with 40Ts id probably retire at 40,000 km's

 

[Bizra6ot]

@Electric Dreams I don't think you're accelerating enough to see a noticeable difference, the typical SAG for a fast 0-60kph on a 50e 4P configuration is closer to 12V than 6V that you get on your video

You should have done your comparison on a long uphill road which would have been less risky for you and the SAG would have been higher to ensure a real difference between 50e and 40t

Edit, here's a good illustration on a Master 50e I've set the timestamp

 

Edited September 10, 2023 by Bizra6ot

[Punxatawneyjoe]

I think i'm confused about the "350 amp firmware" . What does that mean exactly? Looking at your accelerations, you don't exceed 59 amps.

[alcatraz]

8 hours ago, goatman said:

ive got a batch 1 master with 50 E packs, i ride the beeps pretty hard on the streets with about 12,000 km's on it over the last year. it gets charged every night, overnight. its probably not the smartest thing to do but theyre perfectly balanced, thinking to retire this wheel at 20,000 kms after this winter and put those packs in my kids ebikes so that if they fail they can still pedal home instead of me going splat. i think its cheaper to buy a new master than to buy replacements packs. was looking for replacement packs and i saw one pack for $1350 on alibaba and you need 4 of them and a new master is $2700.

for my riding style i wish i had the 40T packs

the 50 E will be lucky to go 400 cycles at these amps

the 40 T if you ride hard will go 800 cycles and you can rejuvenate them

what i want to see euc makers start using are the Molicel P45B batteries

after saying all that,

if i had an ex30 with 50E packs id probably retire that wheel at 40,000km's

a master with 40Ts id probably retire at 40,000 km's

 

Damn. Take it easy. Riding the beeps hard on a Master, and you have kids.

Not every wheel can do that reliably. So swapping for a new wheel might cause the next "splat".

[alcatraz]

50S cells are becoming affordable quickly so the tradeoff between 40T and 50E is basically a moot point. Just get the high current AND capacity cells.

[alcatraz]

Love all your videos by the way. @Electric Dreams

 

[FunTech4Real]

14 minutes ago, alcatraz said:

50S cells are becoming affordable quickly so the tradeoff between 40T and 50E is basically a moot point. Just get the high current AND capacity cells.

50S cells are only rated to keep 60% of their capacity after 250 cycles.... which is extremely low compared to almost all other cells on the market. 

[onkeldanuel]

37 minutes ago, YourAubsome said:

50S cells are only rated to keep 60% of their capacity after 250 cycles.... which is extremely low compared to almost all other cells on the market. 

Yeah thats the tradeoff there....not sure if i want this cells....will be 400-500 cycles at 10A Discharge or something like that...

Perhaps still barely ok cycle life for euc 

Edited September 10, 2023 by onkeldanuel

[Jason McNeil]

Yeah, but this is not a like-for-like comparison for the 50E/GB, which is ~5A discharge & 2.5A charge. These testing conditions are >5x more/25A on the discharge side & >2x/6A for charging—that's pushing it hard by any standard. I don't think there's any like-for-like comparative data for longevity on the 50S yet, e.g. lifecycle @ 5A 500/1000 cycles. 

1 hour ago, YourAubsome said:

50S cells are only rated to keep 60% of their capacity after 250 cycles.... which is extremely low compared to almost all other cells on the market.

Each cell chemistry/model is going to have it's unique characteristics, there is a direct relationship to the rate of charge/discharge & the cell's useful cycle-life, as illustrated in this graphic, from Battery University. 

https://batteryuniversity.com/article/bu-501a-discharge-characteristics-of-li-ion 

Edited September 10, 2023 by Jason McNeil

[alcatraz]

I suspect most Samsung cells promise that.

But remember that with these big companies, they'd rather err on the side of caution.

Edited September 10, 2023 by alcatraz

[goatman]

50E cells dont like regen whereas 40T cells like regen. if you do battery cycle testing and play with the continuous cycling you will see it in the charts

https://endless-sphere.com/sphere/threads/desulfate-40t-and-30q-and-vtc6-and-p42a.109601/

if you follow Roger EUC youll see his 50e packs are overheating, i think its because of cell resistance aka the cells are pooched, he was charging which meant he was pumping heat into the packs also (endothermic)

 

[RagingGrandpa]

From the V14 megathread:

(Context: " 1 C " discharge means you ride your EUC from 100% to 0% in one hour of riding... a good sanity check since most modern EUC's have typical runtime exceeding one hour.)

On 10/1/2023 at 3:24 PM, Vanturion said:

What is somewhat more applicable are the discharge tests in the 1C/2C/3C discharge range where most performance wheels operate, and the value of these kinds of comparisons are basically only in the direct comparison to other cells since the concern is "did we spec the best cell for the application."

Happy to say Pajda generously shared his excel data with me and so I plotted the 1C discharge comparison:

TL;DR: 50S = slightly more better in this artificial lab test.

Some other thoughts and clarifications for battery nerds:

• Every 50 cycles Pajda ran a 0.2C nominal capacity test which doesn't stress/heat the batteries allowing them to cool, I removed these low stress capacity cycles from the dataset
• Interestingly you can see in the data how much more the 50E and 50G cells were affected by temperature/heating even at 1C in the capacity spikes (temporary capacity healing if you will) every 50 cycles
  • If you only look at the spikes for each cell (which are more relevant than the rest of the data as no one is continuously cycling, that is riding-charging-riding-charging without breaks) the capacity degradation is almost identical between all 3 cells with the 50S having the advantage in most of the cycles with the 50E/50G only gaining the advantage after ~800 cycles or so in these artificial tests.
• Some lingering battery nerd doubts I had was cleared up, the 50S looks like a great fit given the data on hand, particularly accounting for use in less temperate climates.

On 9/30/2023 at 7:46 PM, Vanturion said:

On 10/2/2023 at 11:59 AM, RagingGrandpa said:

Side note: M50LT looks ~10% better than Samsung based on above! 
(I think 2C aged capacity is most relevant for fast 4P EUCs.)
I'll have to start putting my mental aversion to LG in check. 

Edited November 1, 2023 by RagingGrandpa

[Jason McNeil]

Sent a pair of 50E/50S packs, 30s2p, to an independent lab for validation under three constant loaded conditions: 10A/20A/30A—30A was the upper limit of the 50Es. Still a bit of a work in progress for the presentation, temperature probe placement was not perfect, but here's the initial comparison graph. 

 

Edited November 1, 2023 by Jason McNeil

[alcatraz]

21 hours ago, Jason McNeil said:

Sent a pair of 50E/50S packs, 30s2p, to an independent lab for validation under three constant loaded conditions: 10A/20A/30A—30A was the upper limit of the 50Es. Still a bit of a work in progress for the presentation, temperature probe placement was not perfect, but here's the initial comparison graph. 

 

Very interesting!

The temperature seems odd. 80C is usually the limit and even at 3C (15A - 30A for 2P) you barely touched 40C. Ambient temp was 26-27.5C which leads to a delta of only 13C for the 50E. That's inconsistent with other reviews. Maybe using a heat camera would be better next time. 

[Jason McNeil]

28 minutes ago, alcatraz said:

which leads to a delta of only 13C for the 50E. That's inconsistent with other reviews. Maybe using a heat camera would be better next time. 

Yep, I know... This lab was struggling with carrying the test requirements—it took dozens of messages to get this far. They placed the probes on the outside of the insulating foam, not ideal, particularly as there were exposed cell cyclinders in the pack. Planning on another test iteration to address those deficiencies. 

[alcatraz]

No problem. Thank you for sharing your findings and being transparent. 

[alcatraz]

What is a good way to thermally probe a pack in heatshrink?  That's the question I've been thinking about for a while now.

Maybe making a tiny cut and attaching it to the side of a cell in the middle? Hmm...

[RagingGrandpa]

1 hour ago, alcatraz said:

What is a good way to thermally probe a pack in heatshrink?

Relative to the costs of conducting a laboratory test, the cost of the battery pack is negligible. By all means, cut open the shrink and glue a sensor directly to a cell. 

Better if the pack were installed in the real chassis and battery boxes of the EUC... with no fan blowing... to reveal worst-case temperature rise. 

 

And if you're thinking about retrofitting temp sensors to your personal EUC just for monitoring during riding (not a lab test), I think installing the sensor directly against the shrink, under any foam pads, would be good enough for informal monitoring.

[alcatraz]

Sounds good. I would love that by the way. A retrofitted monitoring device for safely using "dumb" packs.

[RagingGrandpa]

On 11/3/2023 at 12:21 AM, alcatraz said:

I would love that by the way. A retrofitted monitoring device for safely using "dumb" packs.

It requires a whole $5 of investment

https://www.aliexpress.us/item/3256805542289008.html  

[Freeforester]

On 11/2/2023 at 11:09 AM, alcatraz said:

Very interesting!

The temperature seems odd. 80C is usually the limit and even at 3C (15A - 30A for 2P) you barely touched 40C. Ambient temp was 26-27.5C which leads to a delta of only 13C for the 50E. That's inconsistent with other reviews. Maybe using a heat camera would be better next time. 

Thermal cameras are routinely used in such scenarios, often with very precise readouts, they’re a great way of detecting any anomalies or early signs of overheating problems developing - in a test and monitoring scenario, though obviously this is less practical for ongoing monitoring during the lifetime and daily use of any pack. Sorry if this is ‘old hat’ for you!

Edited November 5, 2023 by Freeforester

[alcatraz]

8 hours ago, RagingGrandpa said:

It requires a whole $5 of investment

https://www.aliexpress.us/item/3256805542289008.html  

That's a good start, and certainly in the kitchen for getting that steakhouse flavor. 

I saw somewhere what I was referring to but I can't find it right now. It's a pcb/module smaller than the smallest bms' that only monitors voltages, and perhaps it also has a termistor. I can't remember.

I'd like to see more of those. If I come across it I'll post a picture.

[alcatraz]

1 hour ago, Freeforester said:

Thermal cameras are routinely used in such scenarios, often with very precise readouts, they’re a great way of detecting any anomalies or early signs of overheating problems developing - in a test and monitoring scenario, though obviously this is less practical for ongoing monitoring during the lifetime and daily use of any pack. Sorry if this is ‘old hat’ for you!

Please share your thoughts. The more the merrier.

On second thought maybe a heat camera won't work as well as a termistor glued to the cell, if the pack is in heatshrink. If you take off the heatshrink, it wouldn't be realistic. Heat could dissipate faster.

You'd want the delta and from it you could calculate what amp draw is safe for which ambient temperature.

Hey, is battery cooling going to be a thing on eucs soon?