Is it possible to discharge cordless drill battery packs?

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Hi,
I have recently purchased an 18volt Ryobi cordless drill with two
battery packs and was wondering if there is a simple way to fully
discharge the battery packs before placing one of them into the charger
unit?

I previously owned a Makita 12volt cordless drill (which was stolen from
the rear of my ute) and that particular drill had a discharge button on
the charger which you pressed as soon as you dropped a battery pack into it.

I only ask about discharging the battery pack before re-charging,
because it's supposed to increase the life expectancy of the cells by
doing so.

thanks.

Re: Is it possible to discharge cordless drill battery packs?



"dude"

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**  Yep  - open up the pack and discharge each cell in tern with a 1 ohm
resistor until the voltage is 1 volt.


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**  Then what ????

 Some overweight tooth fairy arrives in a tutu and does the dance of the
Sugar Plum Fairies ??



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** Fraid it is far more likely to do the exact opposite.

Beware what is actually a genuine technical feature and what is merely a
cynical sales gimmick designed to hoodwink the gullible.




.....   Phil






Re: Is it possible to discharge cordless drill battery packs?


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With a good design charging circuit, it should make no difference
whether you start with flat or part discharged cells.

Whether the charger in the unit in question is 'good' or not is another
matter...


--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Re: Is it possible to discharge cordless drill battery packs?



"Adrian Jansen"

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** Likely to use a timer circuit to cut off the charge -  hence the apparent
need for the pack to be flat.

The  PROBLEM is that one cannot discharge a series pack of cells reliably by
loading the whole pack, especially one with 15 cells in it.



.......   Phil



Re: Is it possible to discharge cordless drill battery packs?



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charger
from
on
into it.

If this is one of Ryobi's "budget" or home handyman drills then
neither the battery pack or the charger is worth a pinch of salt
unless things have changed recently. I had an experience with one of
their cheap drills and the battery just wouldn't hold a charge (the
cells were cheap chinese junk) and the charger was crap. They finally
decided to give me a free higher quality so-called professional model
as a replacement and this was very good quality. It used Panasonic
(Japan) cells and the charger, while still not state of the art, was
adequate.

Re: Is it possible to discharge cordless drill battery packs?


Fortunately my experience with one of those drills has been quite
positive - bought it about 8years ago, and the battery is still going
fine - holds its charge well and gives me no grief - maybe they have
changed batt suppliers, or you were just unlucky

David

Ross Herbert wrote:

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Re: Is it possible to discharge cordless drill battery packs?


On Thu, 01 Mar 2007 15:23:42 +1100, quietguy

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Techtronic Industries (HK), I think only started to take over Ryobi
brand power tools divisions for North America, Europe and Australia
around 2000 so you were probably lucky and managed to get one of the
"genuine" Japanese Ryobi drills before Japan stopped supplying these
markets. My brother has one of the Japanese Tradeline (blue thermo
plastic) power drills from pre 2000 and it has performed faultlessly
in all regards.

Ross

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of
finally
model
was

Re: Is it possible to discharge cordless drill battery packs?


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That would gell with what I was told in Bunnings, that a German had
bought the Ryobi name and almost nothing else, before setting up
with entirely different manufacturing in China. Just hearsay, but
it adds up.

Re: Is it possible to discharge cordless drill battery packs?


Leave it in the drill and tape the on/off switch to on?


David

dude wrote:

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Re: Is it possible to discharge cordless drill battery packs?


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That is only relevant with nicad batteries.



Re: Is it possible to discharge cordless drill battery packs?


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Supposed to help a bit if the packs arent balanced....

Re: Is it possible to discharge cordless drill battery packs?


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I'm pretty sure if you peeled open a battery pack, you'll find nicads in
there.  Not sure about the professional range of cordless drills though.

Thanks all.  Judging by everyone's comments, i shouldn't worry about
"memory effect" as it's probably just a marketing gimmick and there's
not much i can do about it anyway.

Re: Is it possible to discharge cordless drill battery packs?


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If your really worried by it ( I am not) then discharge the pack with an
incandescent bulb and throw it in the freezer for a couple of hours ,
then warm it in air before charging.

Re: Is it possible to discharge cordless drill battery packs?


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DONT throw it in the freezer. It can blow the seals.
Cool it in the tray under the freezer. Its less likely to do so.
Its slightly warmer.



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