Is it possible to discharge cordless drill battery packs?

"dude"

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

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

** 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

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
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

"Adrian Jansen"

** 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

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.

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

David

dude wrote:

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:

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

of

finally

model

was

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.

That is only relevant with nicad batteries.

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

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.

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.

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.