Lawrence, i have a bunch of these cells that i want to let go, make me an
offer.
90+ cells total, most still in a 12p8s battery enclosure, can send pics, i
harvested about 10 cells from it, which i still have as well.
Can send pics.
Cor
On Thu, Apr 16, 2020, 7:14 AM Lawrence Rhodes via EV
wrote:
My comments were really only in the context of EV application.
The most knowledgeable people in a particular tech space are usually also
the ones that have the most to gain. Its a common problem. I had a
job where a new-ish product was being made that did not fit the ASTM
standards for the
Michael Ross via EV wrote:
1C huh? That is not stressful at all and only a truly sh#t cell would
have much trouble with that.
Ah, but that is heavily dependent on the kind of cell you are testing.
There are many types of cells for which a 1C rate is a relatively fast
discharge.
Also, 1C
Hi Bill,
Thanks for the commnet. I have no connection with testing the last 5 years
so I was wondering. You probably have more reason to care about this
than almost anyone. 1C huh? That is not stressful at all and only are
truly sh#t cell would have much trouble with that.
Isn't it lovely that
This 1C test is the standard test that allows inter-comparison of cells
from brand to brand. You need some sort of a test under standard
conditions, for different size cells, for different voltage cells, etc.
You need some test that is uniform for all manufacturers. This is the
test everyone
On 4/16/20 6:32 PM, Michael Ross via EV wrote:
As shown by the research at Dalhousie, 16000 cycles is meaningless if the
conditions are watered down.
That kind of cycle count is falsely impressive, and a huge waste of time
and resources.
Assuming you are not referring to a 1C discharge rate
As shown by the research at Dalhousie, 16000 cycles is meaningless if the
conditions are watered down.
That kind of cycle count is falsely impressive, and a huge waste of time
and resources.
Are there any useful testing standards becoming a tradition? As in
standards that actually stress the
The A123 systems 26650 cylindrical cells have a _huge_ cycle life.
Way over 5000 cycles at a 1C rate. 100% SOC discharge. (They have cycled
a 26650 cell more than 16,000 times and still have greater than 50%
capacity.)
The main trouble with higher rates is the elevated cell temperature
The A123 systems 26650 cylindrical cells have a _huge_ cycle life.
Way over 5000 cycles at a 1C rate. 100% SOC discharge. (They have cycled
a 26650 cell more than 16,000 times and still have greater than 50%
capacity.)
The main trouble with higher rates is the elevated cell temperature
Good point but you don't know how much faster it will degrade at 50 amps.
75% in 800, 500, 200 cycles, etc.
I would buy one and test it first.
On Thursday, April 16, 2020, 1:54:04 PM CDT, Michael Ross via EV
wrote:
It is important to figure out what the #cycles means to you
Then you run up against an insignificant sample size. Can you get specs and
trust them? When I was trying to sort this out in the 2014 time frame,
testing was ALL crap. You couldn't believe much of anything. Partly
because no one really know how to test well, and many did not want to know.
The
It is important to figure out what the #cycles means to you personally.
1000 cycles is a lot even daily - for some people.
On Thu, Apr 16, 2020 at 2:39 PM paul dove via EV wrote:
> Cycle Life (retaining 70% capacity) at 20A Discharge, 100% DOD: >1,000
> cycles
>
> This tells me you don’t want
I have a set of such batteries in case you are interested in them, will let
them go for friend price, because they were spot welded into a commercial
battery arrangement.
Cor
On Thu, Apr 16, 2020, 7:14 AM Lawrence Rhodes via EV
wrote:
>
>
Cycle Life (retaining 70% capacity) at 20A Discharge, 100% DOD: >1,000 cycles
This tells me you don’t want to discharge at 50A if at 20A you are down 30%
capacity in 1000 cycles.
Sent from my iPhone
> On Apr 16, 2020, at 4:25 AM, Lawrence Rhodes via EV wrote:
>
>
https://sfbay.craigslist.org/eby/ele/d/hayward-a-battery-cells-33v-2500-mah/7098505376.html
Are these batteries a wise purchase? I am building it for a 40 amp 72v
controller. This would be my first lithium build. I think I could bet by with
one string of 21 but would 2 or three strings be
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