[SML] battery charging protocol

[Jerry Durand]

Carefully.  :)

Lithium batteries do best if you don't drain them, just top off as needed.

Modern NiCd batteries normally don't need to be drained, in theory,
according to the advertisements.

That said, lithium is slightly tricky to charge and there's a range of
chargers that range from excellent to good fire starters.  The same goes
for the batteries themselves.  You've probably heard about a certain
brand of electric car that sometimes bursts into flames while charging
while other brands rarely, if ever,  do that.

Lithium batteries should always have a "protection circuit" built in to
the package.  This is essentially a solid state circuit breaker that
trips on over current, over voltage, or battery too low.

Some battery chargers depend on this and simply feed current into the
battery until the protection trips.  "Done!"  Not the best idea but very
cheap.  If combined with a battery with no protection circuit or a
defective one, a bloated battery or even fire can result.

Better (term used loosely) chargers charge up to a certain voltage and
just hold it there.  Works fine as long as you manually turn off the
charger within a few hours of it being "done".

Best chargers monitor battery temperature, voltage, current, and TIME.

I've worked out a lithium charge method implemented in a small processor
for a customer that works well.  Charge the battery to a preset voltage,
stop and wait for the voltage to drop below the cutoff and start
charging again.  Do this for up to xx minutes and then shut down until
the battery falls below a lower trip voltage.

There's a third voltage where the processor shuts down the device and
goes into low power sleep until the charge circuit gets power again.


On 11/13/20 8:05 AM, Paul Guncheon via Stagecraft wrote:
> Aloha,
>
> What is the current thinking (no pun intended, but I'll take it) with
> regard to charging the various rechargeable batteries and devices one
> runs across these days? It used to be one was to drain the battery as
> much as possible before charging. Then I was informed that this could
> result in reversing the voltage in one or more of the cells, rending
> the battery useless.
>
> Then I was told to charge a battery at the first sign of a fall off in
> tool performance, but to let the battery cool first.
>
> I am under the impression that one should not keep the battery in the
> charger nor should one charge a battery 'before' it demonstrates that
> fall off in performance.
>
> So what's the real deal?
>
> Laters,
>
> Paul 1
>
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-- 
Jerry Durand, WhatsApp, Telegram, VK, signal
www.DurandInterstellar.com & www.Durandinterstellar.ru

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