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What is their cycle life?
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#1 (permalink)      4/24/2014 8:12:52 AM US Central   quote/reply + tips
sirol
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What is their cycle life?
What is their cycle life at 1/3c charge and 2c discharge?
#2 (permalink)      5/1/2014 6:45:33 AM US Central   quote/reply + tips
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Jock73
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It depends how you treat them!!
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#3 (permalink)      5/1/2014 10:13:53 AM US Central   quote/reply + tips
iinweed
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As with most lithiums, 300 cycles should give about 70% capacity remaining, depending on how you treat them.

Why anyone would want to buy a high discharge cell and use it like a standard cell is beyond me though. Just buy a higher capacity standard cell for the same price - if you are going to use it at those rates you can even have a protection circuit on it should you desire. Higher capacity will give a longer effective life if that is your concern.

Edited on 5/1/2014 at 10:14 AM. Reason:
Never underestimate the power of human stupidity. All opinions expressed are my own.
#4 (permalink)      5/1/2014 3:19:14 PM US Central   quote/reply + tips
Str.bean
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My jerk housemate used my 20R and discharged well below where it should have been. Now it has half the capacity. QQ
#5 (permalink)      5/1/2014 8:48:56 PM US Central   quote/reply + tips
sirol
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It depends how you treat them!!


I wrote. 1/3c charge and 2c discharge

Why anyone would want to buy a high discharge cell and use it like a standard cell is beyond me though.

Standard cells has bad cycle life at 2c.
For example sony US18650NC1:

After 200 cycles about 2320mah.
This is at 6a and only 1A charge.
Here is sony US18650VTC5:

At huge 4A charge rate.
Over 1/3c charge rate is harmfful for standard batteries.
These new high rate batteries has little lower energy density at beginning, than standard batteries and it deacrease slowly if using them under 2c, at 150-200 cycle capasity is about same, after it smaller. Also standard batteries require low charge rate.
I want use high rate batteries for short (under 30 km) and middle (30-50 km) trips. Average electricity consumpion at me is 15 wh/km and 18 wh/km at windy weather, so i need 540 wh battery pack for short trips. I have 30A controller. If i will build 12.5ah pack, then it means 2.4c at full throttle.
Significant part of electricity consumpts at me at current over 20A. It is over 1.6c if using 12.5ah pack, it is too high to standard batteries. I can use standard batteries for long trips only, because i need over 20 AH pack for long trips. For long trips i will use 2 packs in parallel, for example 15AH pack sony US18650VTC5 and 10AH panasonic NCR18650PF pack in parallel. At 20A current it is 0.8C only, which is not bad for panasonic NCR18650PF.

you can even have a protection circuit


I will use fuse or fuse + bms. If i will use them without BMS, then i will use small lipo alarm device for protect them from over discharge.


Edited on 5/1/2014 at 8:50 PM. Reason:
#6 (permalink)      5/2/2014 11:28:00 AM US Central   quote/reply + tips
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Jock73
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@sirol... Treat em right and they will last... Treat em wrong they will go bang!!
In Karanka We Trust!
#7 (permalink)      5/2/2014 1:12:26 PM US Central   quote/reply + tips
sirol
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Treat em right and they will last... Treat em wrong they will go bang!!

If you can not answer to my question don't write off topic.

#8 (permalink)      5/2/2014 3:59:02 PM US Central   quote/reply + tips
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Jock73
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Stop posting stupid questions!!!
In Karanka We Trust!
#9 (permalink)      5/2/2014 5:13:14 PM US Central   quote/reply + tips
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johnny_469
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It's not stupid :-P It's good information that is now easier to reference because it is here...
Woah, mama!
#10 (permalink)      5/2/2014 7:22:31 PM US Central   quote/reply + tips
sirol
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Stop posting stupid questions!!!

Is question:

What is their cycle life at 1/3c charge and 2c discharge?

stupid?

#11 (permalink)      5/3/2014 1:16:26 PM US Central   quote/reply + tips
iinweed
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I wrote. 1/3c charge and 2c discharge



OK, but the point I was making was how low are you going to take them, and what capacity are you going to charge them to?

Charge and discharge rates are only part of the equation.

If you take them low and charge them all the way back up you will shorten the life. If you only take them down to, say 50% and recharge them to 90% capacity they will last considerably longer.

Hence my comment that it depends how you treat them.

You might find better answers on one of the electric vehicle forums.


Edited on 5/3/2014 at 1:17 PM. Reason:
Never underestimate the power of human stupidity. All opinions expressed are my own.