

Treat Li-Ion batteries like people to make them last - andyrebele
http://www.purewatercraft.com/to-care-for-lithium-ion-batteries-treat-them-like-people/

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codys
The article lists percentages of capacity as if every battery (or battery
controller) reports the full range of capacity (or allows charging to actual
full capacity or discharging to completely empty).

I had thought that many manufacturers (at least Apple) had added things that
specifically limit the amount the battery is charged to less that "100%" while
(of course) still displaying 100% to the user (essentially, users see the the
capacity as dictated by policy, not by physical characteristics).

Is this article only talking about "dumb" Li-Ion batteries? I note it's a
"watercraft" related blog, does that mean the same mentioned percentages don't
apply to non-watercraft/consumer Li-Ion batteries?

Further, we get some numbers, but we don't get the data those numbers are
from. I presume they are just "these seemed to make sense to us from our
anecdotal evidence".

~~~
andyrebele
I put a link to Battery University at the end. Some of the numbers came from
there. Others come from cell data sheets (best ones from Panasonic). A lot of
this is synthesis over many data sheets and white papers, none of which would
by themselves be illuminating to the average battery user, because so much of
the data would be cell-specific.

You're right that device manufacturers choose what to name "100%". Generally,
cellphone makers are most attuned to people running out of power, so their
100% is pretty close to the real top charge level (not overcharge). They are
rated and tested and reviewed based on tests like Walt Mossberg's run standard
processes and see how long it runs until empty. The incentive provided by such
make-or-break tests is to allow users to fully charge and fully discharge.

Better control and information would be provided if you gave the actual
voltages and chemistries, but both are beyond what a normal user would be
comfortable using on a daily basis. Internally, we almost always refer to
state of charge in cell voltage terms.

Tesla and BMW provide the ability for the user to know and adjust the top of
the charge. Tesla's approach is fairly user-friendly, and BMW's is a little
more powerful, albeit less user-friendly.

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Guvante
This is about watercraft, not consumer devices. These kinds of things are
managed automatically for you in your phone, tablet, or even PC.

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cabirum
I think the title should include 'boats' somewhere.

> get the most out of batteries for electric boats > Mostly full is a LOT
> better than fully full > Don’t leave them full > Don’t empty them all the
> way

I've been under impression that all modern li-ion batteries are equipped with
some kind of controller preventing overcharges and empty batteries, monitoring
battery performance, etc. Users can actually leave their devices plugged
indefinitely and it won't cause batteries to degrade faster.

~~~
andyrebele
This post was not about boats; it's about li-ion batteries in general. We
learned the lessons when developing our outboard motor battery pack, but the
batteries we're using are the same cells used in laptops, and the same
chemistry as used in cellphones, tablets, etc.

There is no specific charge level at which battery use becomes costly. It's
just more costly to charge the higher the voltage to which you charge. Of
course, overcharging (over the rated voltage) is extremely costly (and
dangerous). Under that level, the device maker has to make an arbitrary choice
about how to balance cycle life with calendar life, and that choice is usually
near (but not at) top voltage.

Our tests have found that charging a cell to 80% instead of 90% can extend its
life by more than 50% under the same conditions of use, sometimes much more
(lots of factors: charge/discharge rates, temperature, time between cycles,
etc.). I'm sure no cellphone/tablet maker is limiting charge to 80%.

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abandonliberty
This is something people really don't seem to care about. The lack of
awareness of how to increase battery life combined with non-replaceable
batteries baffles me. Perhaps the effect isn't immediately obvious, or
overstated?

Though it's actually best to starve people a little bit.
[http://en.wikipedia.org/wiki/Intermittent_fasting](http://en.wikipedia.org/wiki/Intermittent_fasting)

~~~
Guvante
All of these things are built into consumer devices already.

0% maps to about 5%, 100% maps to 90-100% depending on where in the charge
cycle the device is (it will stop charging for a while to discharge some of
the battery before starting charging again).

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andmarios
Or just buy a device with an easily replaceable battery.

