should it not be logical that as example Samsung 30Q gets hotter as 25R at same continuous discharge rate because 30Q has more energy in it therefore the discharge time and energy turend into heat is more. or do i miss something?
Samsung 25R/LG 18650HE2/ Sony VTC5 high power 18650 battery
- Thread starter Ebikebert
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i believe most people will not push even these high power cells at theire limits because who really builds an e-vehicle with only 10min travel time?
if i look at my bikes i have on one 12P 25R and the other has 11p 25R. another has 9P VTC4.
even if i set Max-E controller to max amps it would only be 17A for 9p VTC4 and 13,5A for 11p 25R per cell - much more on peak side than continuous. During ride i have an average consumtion of about 3kw (usually 70-80kmh) what means about 3,5A per cell continuos. These cells will laugh over these currents and hopefully will thank me with high lifespan^^
if i look at my bikes i have on one 12P 25R and the other has 11p 25R. another has 9P VTC4.
even if i set Max-E controller to max amps it would only be 17A for 9p VTC4 and 13,5A for 11p 25R per cell - much more on peak side than continuous. During ride i have an average consumtion of about 3kw (usually 70-80kmh) what means about 3,5A per cell continuos. These cells will laugh over these currents and hopefully will thank me with high lifespan^^
ridethelightning
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This is a good point maddin.madin88 said:
and may your packs live long and prosper
I am currently deciding on which course to pursue for a similar pack, but there is another thing that I take into account , and that is the voltage sag.
for a high performance set-up its most fun to be able to draw large peak of perhaps max 20A/cell from time to time, even only just a second or 2
when your lvc trips off after you have only reached 40-50%dod, due to sag cause your cells have too much IR to give you the peak current , it takes a lot of the fun away.
I wish it would be a beast all the way down to 30%
I have noticed this only too much, with a lower c rate lg pack, how much less of a bike this equates to.
i will either get the samsung 25R or 30Q in 20s12p i think, but The deciding factor will be the sag at high amps, which im still trying to get info on....
Allex
100 MW
To compensate for voltage sag you can build with more P or have a bit lower power
When I had 14p HE2 I never thought about sag when pulling 130DC Amps even at 30% SOC
When I had 14p HE2 I never thought about sag when pulling 130DC Amps even at 30% SOC
ridethelightning
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Its more p all the way im afraid allex 
if only i could stuff another p or 2 into the nyx frame, but its actually not quite as big as i thought.
I think 12p 25r should be good for some punch, but the 20% extra capacity is tempting with the 30Q. i just dont want to compromise on that wingsuit feeling
if only i could stuff another p or 2 into the nyx frame, but its actually not quite as big as i thought.
I think 12p 25r should be good for some punch, but the 20% extra capacity is tempting with the 30Q. i just dont want to compromise on that wingsuit feeling
okashira
10 kW
ridethelightning said:Its more p all the way im afraid allex
if only i could stuff another p or 2 into the nyx frame, but its actually not quite as big as i thought.
I think 12p 25r should be good for some punch, but the 20% extra capacity is tempting with the 30Q. i just dont want to compromise on that wingsuit feeling
I think the 30Q is better then 25R. Same resistance more cap.
Downside is cost
markz
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Whats the cost per Ah for 30Q and 25R?
ridethelightning
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currently its 3.95(30Q) vs 3.25(25R)/cell
so not really a huge difference.
so not really a huge difference.
ridethelightning
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I think the 30Q is better then 25R. Same resistance more cap.
Downside is cost(quote)
[/quote]
according to this chart fer example, it looks like the 30Q is a little higher IR than the 25R.
@Oshikira, what have you observed in your tests when it comes to sag under load for the 30Qvs25R?
Downside is cost(quote)
according to this chart fer example, it looks like the 30Q is a little higher IR than the 25R.
@Oshikira, what have you observed in your tests when it comes to sag under load for the 30Qvs25R?
Hillhater
100 TW
I doubt you would see any difference in sag, ....and certainly hard to measure accurately.ridethelightning said:
Once you have so many cells in parallel, the IR is barely any different between the packs ( less than 0.5 mohm), and even if the 30Q was a 10P pack to give the same capacity, the IR difference is still much less than 1 mohm
ridethelightning
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Hillhater said:
thanks for the info HH.
Im tipping more towards the 30Q now, just trying to figure out how to stuff the maximum number of p in there before i order..
okashira
10 kW
ridethelightning said:I think the 30Q is better then 25R. Same resistance more cap.
Downside is cost(quote)
according to this chart fer example, it looks like the 30Q is a little higher IR than the 25R.
@Oshikira, what have you observed in your tests when it comes to sag under load for the 30Qvs25R?[/quote]
I don't have any 25R unfortunately, but if I had a couple, I could easily do a A/B test setup as I actually have a proper test rig (kelvin connections, calibrated tester) unlike most testers....
My testing of the 30Q was pretty inline in terms of "sag" of tests of the 25R by reputable reviewers (e.g. HJK)
ridethelightning
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well looks like ill get 244 30Q cells, good for 22s12p.
was thinking 20s might be better for the max-e controller at high phase amps, but if i get 22s and only charge to 88v,4.0v/cell, should get great cycle life from them, and there is the extra capacity with 22s too.
seems like the 30Q go for 3.5usd quite often on aliexpress sites, so ill try for a better price with evva.
I wouldnt trust those other aliexpress sites in a flip
btw. perhaps the 30Q should be added to the title post?
was thinking 20s might be better for the max-e controller at high phase amps, but if i get 22s and only charge to 88v,4.0v/cell, should get great cycle life from them, and there is the extra capacity with 22s too.
seems like the 30Q go for 3.5usd quite often on aliexpress sites, so ill try for a better price with evva.
I wouldnt trust those other aliexpress sites in a flip
btw. perhaps the 30Q should be added to the title post?
okashira
10 kW
I got a quote from a chinese supplier it was around $3.1percell forqty 10,000 shipped by sea.ridethelightning said:well looks like ill get 244 30Q cells, good for 22s12p.
was thinking 20s might be better for the max-e controller at high phase amps, but if i get 22s and only charge to 88v,4.0v/cell, should get great cycle life from them, and there is the extra capacity with 22s too.
seems like the 30Q go for 3.5usd quite often on aliexpress sites, so ill try for a better price with evva.
I wouldnt trust those other aliexpress sites in a flip
btw. perhaps the 30Q should be added to the title post?
Where are you seeing 3.5 per cell? I don't see anything remotely that low on aliexpress
In cold conditions internal resistance of 30Q is higher from 25R. When I get 30Q will be able to tell this with certitude.
Charts:
https://www.dropbox.com/s/x6514tdp5...2500mah 18650 constant-current tests.bmp?dl=0
https://www.dropbox.com/s/nle8ol3eq...q 15a 3000mah constant-current tests.bmp?dl=0
Charts:
https://www.dropbox.com/s/x6514tdp5...2500mah 18650 constant-current tests.bmp?dl=0
https://www.dropbox.com/s/nle8ol3eq...q 15a 3000mah constant-current tests.bmp?dl=0
Hillhater
100 TW
bellfador said:
From those charts, both cells have very similar IRs of 0.024 ohm !... ( and reducing as the capacity drains.. Cell warms ?)
...? I thought you had already had the 30Q cell for testing ? ...for your previous graph of IR vs Capacity ?
ridethelightning
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bellfador said:
interesting... how cold are we talking?
sorry if you have alredy said and i missed it.
ridethelightning
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okashira said:I got a quote from a chinese supplier it was around $3.1percell forqty 10,000 shipped by sea.ridethelightning said:well looks like ill get 244 30Q cells, good for 22s12p.
was thinking 20s might be better for the max-e controller at high phase amps, but if i get 22s and only charge to 88v,4.0v/cell, should get great cycle life from them, and there is the extra capacity with 22s too.
seems like the 30Q go for 3.5usd quite often on aliexpress sites, so ill try for a better price with evva.
I wouldnt trust those other aliexpress sites in a flip
btw. perhaps the 30Q should be added to the title post?
Where are you seeing 3.5 per cell? I don't see anything remotely that low on aliexpress
seemed to be pretty common price on aliexpress. ill find the links when i get a moment.
okashira
10 kW
ridethelightning said:okashira said:I got a quote from a chinese supplier it was around $3.1percell forqty 10,000 shipped by sea.ridethelightning said:well looks like ill get 244 30Q cells, good for 22s12p.
was thinking 20s might be better for the max-e controller at high phase amps, but if i get 22s and only charge to 88v,4.0v/cell, should get great cycle life from them, and there is the extra capacity with 22s too.
seems like the 30Q go for 3.5usd quite often on aliexpress sites, so ill try for a better price with evva.
I wouldnt trust those other aliexpress sites in a flip
btw. perhaps the 30Q should be added to the title post?
Where are you seeing 3.5 per cell? I don't see anything remotely that low on aliexpress
seemed to be pretty common price on aliexpress. ill find the links when i get a moment.
don't see anything even close to 3.5 per cell on aliexpress for 30q, even in qty 500
Hillhater
100 TW
It will be useful to know if the low temp performance is different.bellfador said:
but on those charts 3.8 volts is only relavent at light loads (<10A) and even then only for the first minute or two of use ( leass than 10% of capacity )
..But for most of us, operating in normal temps, and at typical usage situations over the other 90% of capacity, ..those charts show the 30Q has less voltage sag ( at 20Amps and 1.0 Ahr usage ), and even a lower IR ( 15mohm vs 17 mohm ) at its best.
But again, the differences are small and once a few cells are paralleled into a pack, sag and IR would be very similar.
ridethelightning said:
Room temp 20-25*C.
Hillhater said:
Usually Internal resistance not changed in range 5% - 80% of discharged capacity. I'm interested from Internal resistance with minimal influence of temperature. For that I look beginning of discharging charts. 30Q have bigger capacity and is wrong to compare in same capacity usage with 25R. But 30Q is the better cell, no questions.
ridethelightning
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:lol: good to hear bellfador
iv got 244 30Q on the way. Hope iv done the right thing!
iv got 244 30Q on the way. Hope iv done the right thing!
Hillhater
100 TW
?? Im Surprised you think that.bellfador said:
there is a mass of data to show that IR . (discharge ,DC ) varies significantly with state of charge.
Those graphs you linked to above clearly show the IR decreasing as the SOC reduces, as does the LG HE2 data sheet
Whilst it could be assumed that this may be due to cell temperature increasing with discharge,
..(Since we already know IR also reduces as temperature increases)
...but that doesnt explain those other cells which show IR increasing as SOC reduces (eg: Panasonic PF )
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