Battery Charger Questions

Posted by Stormin Mormon on October 24, 2009, 9:39 am

From what I've heard over the years the nicad "memory
effect" is that repeated shallow, partial discharges, and
that some how limits future discharges. Different people say
that is real, or not real. I've not had that problem.

Some chargers will dry up the cells due to electrolysis, but
no way to know if your charger does that.

I've not heard of lithium cells having memory effect.

I think you're worrying about tiny stuff, and you are
wasting your worry power.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

I have a cordless drill using NiCad bateries. They died a
few weeks ago and
last week I got two new batteries.

I fully charged one, used it and waited till it was fully
drained, and
started charging again...STUPID ME, I forgotten about it and
left it in the
charger for a full week and didn't realized it until
today!!!

I heard that if you left your battery in the charger after
it has been fully
charged it will create the memory effect again, is this
right? Did I ruin
this new battery by my dumbness again?

One other related question, my cell phone uses a lithium ion
battery. I
have a car charger and a regular charger. My friend told me
I should avoid
charging with the car charger as much as possible because
they create memory
effect on the battery. Is this true? I could not find any
online
references for this.

Thanks in advance,

MC

Posted by SMS on October 24, 2009, 10:59 am

MiamiCuse wrote:

> I heard that if you left your battery in the charger after it has been fully
> charged it will create the memory effect again, is this right? Did I ruin
> this new battery by my dumbness again?

Some of the cheaper drills have chargers that don't cut off
automatically when charging is complete and the instructions warn you to
not leave the drill on the charger continuously. One week probably did
not destroy the NiCad batteries.

In any case overcharging causes voltage depression, not "memory effect."
Every time you overcharge (never leave the batteries on the charger
continuously) you damage the battery a little. You didn't destroy them
with one week of overcharging, you just damaged them a tiny bit.

While you don't want to leave them on the charger continuously, nor do
you want to let them self-discharge after long periods of non-use, which
is worse than occasional over-charging.

If you only use the tools occasionally, hook the chargers to a timed
outlet, and charge them for an hour every week, using a timer like the
Intermatic DT620CL. Unfortunately some charges require that you push a
button to initiate charging (these tend to be the charges with a
micro-controller that monitors charge state and turns the charger off
when the batteries are charged, but it doesn't turn it back on as the
batteries self-discharge).

> One other related question, my cell phone uses a lithium ion battery. I
> have a car charger and a regular charger. My friend told me I should avoid
> charging with the car charger as much as possible because they create memory
> effect on the battery. Is this true? I could not find any online
> references for this.

Your friend has no idea what he's talking about.

Posted by Oren on October 24, 2009, 4:26 pm

wrote:

>While you don't want to leave them on the charger continuously, nor do
>you want to let them self-discharge after long periods of non-use, which
>is worse than occasional over-charging.

The OP has one un-used new battery. How long can it sit on the shelf,
before any potential damage?

Anyone?

Posted by Ed Pawlowski on October 24, 2009, 4:36 pm

> wrote:

>>While you don't want to leave them on the charger continuously, nor do
>>you want to let them self-discharge after long periods of non-use, which
>>is worse than occasional over-charging.

> The OP has one un-used new battery. How long can it sit on the shelf,
> before any potential damage?
> Anyone?

Not sure, but they do lose charge over time. I plug them in every month or
so to keep them topped up. In two months they are near dead otherwise.

Posted by MiamiCuse on October 24, 2009, 7:10 pm

>> wrote:

>>>While you don't want to leave them on the charger continuously, nor do
>>>you want to let them self-discharge after long periods of non-use, which
>>>is worse than occasional over-charging.

>> The OP has one un-used new battery. How long can it sit on the shelf,
>> before any potential damage?
>> Anyone?

> Not sure, but they do lose charge over time. I plug them in every month
> or so to keep them topped up. In two months they are near dead otherwise.

I bought them new, but they may have already sat on the shelf for months,
right?

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Battery Charger Questions - Page 2