What is a Cycle?

JC777 said:

Are you saying that the life of LFP batteries are indefinite?

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Simply put, yes.

smoothJoey said:

I believe they have a calendar life.
Much better than cottage cheese but still...

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It's nice to know how many miles are on a used car, but without know if it was a grandma grocery getter or a weekend drag race champion, it's always a crap shoot with anything used.

10 year 80% guarantee with 100% cycles that's 3000 cycles.

Over build a battery and under use it, and you are setup to have a 20, 30, 50 year battery. There are NiFE batteries in use right now that were put in service 70 years ago.

Now that "Lithium" batteries are becoming mainstream with dozens of other types of batteries available, with full on 20000 cycle warranties (flow batteries). Being concerned about how long the battery will last is now turning into what chemistry has the most power density.

Humbly, I would argue that with technology advancing at such a pace these days, planning for a battery system to last 10+ years is becoming a nonsense. In three years we'll be pulling CO2 out of the air and converting it directly into electricity, in 5 years fusion power will render local generation obsolete, in 10 years we'll be powering everything from quark-gluon plasma. We'll look back on LiFePO4 and say, "How quaint, we really didn't know any better at the time...".

tictag said:

Humbly, I would argue that with technology advancing at such a pace these days, planning for a battery system to last 10+ years is becoming a nonsense. In three years we'll be pulling CO2 out of the air and converting it directly into electricity, in 5 years fusion power will render local generation obsolete, in 10 years we'll be powering everything from quark-gluon plasma. We'll look back on LiFePO4 and say, "How quaint, we really didn't know any better at the time...".

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And I have magazines from the 1950's saying how we would all be in flying cars by now. I have no doubt better technologies are out there in the future I'm just gonna plan for the worse. We all also bought $5000.00 computers that have less capabilities than a raspberry pi

tictag said:

Humbly, I would argue that with technology advancing at such a pace these days, planning for a battery system to last 10+ years is becoming a nonsense. In three years we'll be pulling CO2 out of the air and converting it directly into electricity, in 5 years fusion power will render local generation obsolete, in 10 years we'll be powering everything from quark-gluon plasma. We'll look back on LiFePO4 and say, "How quaint, we really didn't know any better at the time...".

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Solar Grown Honey

Craig said:

We all also bought $5000.00 computers that have less capabilities than a raspberry pi

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I guess we really are all the same nerds.
The bill of materials for my for my first new PC(Pentium Pro 150) was ~$2000.00.
Assembled by me of course.
That case now holds a DIY UPS assembled by me of course.
I thought OS/2 was the neatest thing until I found yggdrasil linux.

UPDATE: I mis-remembered it was a 486dx2 and that case will house my next project.

some good info here. i have something to add, i hope it is useful.

to get a base for a percentage of lifespan left, (it may be crude but usable to some extent) can't you just run a capacity test and then calculate the difference with a known new source's rate/spec?

Also, a charge cycle life rating is at a specified temperature, and we must also factor in calendar aging and charge/discharge cycle bandwidth for long term aging. And the c rate. I think for solar use (very low c rate requirement) charging to 90% and down to 10%, and keeping battery below 80 degrees Fahrenheit, your cells should last a crazy long time. Long enough for solid state batteries and small thorium based mini reactors to come out. And possibly fusion. I wouldn't worry about cycle life for this reason ?? we just need them to last long enough for next technological breakthrough.