here some more information for the A123 M1 FePo4-cells (we are using now for some month in rc-sports)
(specially dedicated to the big scepticer flecc
)
we have the diagramms, we have the data provided by A123-Systems
but - as flecc stated - datas from a manufactor are always very pink...
every-day-flyer has desided to get real-world data for cycle-life.
the datas provided by A123Systems (>1000cycles) are measured at 10C load
(1C = dischargecurrent same as capacity of cell
2C = dischargecurrent 2 times as big as capacity of cell
10C = dischargecurrent 10 times as big as capacity of cell)
every-day-flyer wanted some own realworld - testresults, his words:
Quote:
I have studied all of the vendors graphs, read hundreds of post in many different forums on several different Users Sites including ,RCU,RC Groups ,Traxxas and a few smaller ones. I have read post by car /truck,aircraft ,fixed and rotory wing and even boat RCers.
I have read post of those charging at 6A,10A and even 25A and discharge rates from about 5C (12 min) runs to 10C ( 6 min). flights .
The one thing that remains a mystery is real cycle life data at rates other than 10C max..
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he has used the batts in a rc-car with
7-8C average dischargerate (= 16A - 18A average)
and up to 30C peaks (= 70A peaks)
so no labor-test
(REMEMBER: in a electro pedelec you would use the cells as a 5p-pack (5cells paralleled), so the 40A peaks in the pedelec would be only 8A PEAK for single cell and not 70A like on the test)
here is a graph of the condition of his batts (much more stressed than in a electric bike) at first discharge
and after
185cycles !
after this 185cycles (which - flecc - were FULL Deep-discharge-cycles !)
the battery has
still 96% of its original capacity
oh:
at charge number 168 he even did a
full-charge of the empty pack within
4min 18seconds !!!!!
look here:
even after that torture the cell showed only that ~4% capacity-loose (17cycles later) after 185cycles overall !
so.. considering this and the fact, that the cells would be stressed FAR FAR less in a electric pedelec, i think 1000cycles with over 80% capacity should be possible.
for chargers: i have shown in other thread that a charger for a pack you can use in the bike (for example 12s5p with 11Ah) does not need to be "VERY very big and heavy" as stated here somewere as well..
for the whole ongoing test visit this thread:
A123 pack life in real world uses?
to the end:
this cells are not at all comparable with anything you maybe knew before !
and for sure not with cells, which are sold currently in the e-bike-shops
(for example this cells:
50cycles Electric Bicycle - What you really need to know about Lithium ion battery packs )
the thing which must happen now:
the e-bike-sellers (not the "we build the cheapest in china" once)
have to get this cells in there hand..
build a nice casing
configure the cells in there factories for bike-use (10s4p - up to 12s5p for example)
and develope some easy handling chargers
as well as balancer/equalizer
all this parts are already available but for a easy-to-use-for-also-non-electric-enthusiast there should be a all-out-of-one-hand solution