I purchased a 12V Makita drill (6216D) about 2 years ago. It came with
two of the gray 2.2Ah Ni-MH batteries and a charger (DC1411). From the
very beginning, it did not seem to me that the batteries were holding a
charge very well. I could charge a battery until the green light came
on, remove the battery put it in the drill ... and come back 2 weeks
later and there was very little power left in the "fully charged"
battery.

I previously owned a Craftsman Professional 9.6V drill with NiCad
batteries (which I suspect were nowhere near 2.2Ah) ... and it would
hold a charge for several months. I think I've read that Ni-MH
batteries will lose their charge quicker than NiCad batteries ... but I
wouldn't expect a "fully charged" battery to lose most of its charge in
2 weeks!

My problem now is that I can't seem to get either of the Makita
batteries to fully charge. I've tried only leaving the battery in the
charger for an hour ... and I've tried leaving it for a week. Neither
way seems to fully charge the battery. One thing that seems strange ...
after charging a battery for a couple hours, I can remove the battery
.... wait a few minutes ... and then plug it back in to the charger ...
and the blinking green light turns red and stays red like it is doing a
full charge cycle. (I have not timed it to see how long it stays red,
although I suspect it's not very long.)

So ... my questions:

(1) could the charger have been "bad" from the very beginning?
(2) is there anyway to rule out the charger as the problem with a v/o
meter?
(3) is it more likely that the batteries are "bad" (and maybe were from
the beginning)?
(4) what's my best course of action to diagnose my problem?

One last question ... does it harm the battery or the charger to leave
a "fully charged" battery connected for weeks?

"Bankerjohn" wrote in message
oups.com...
I purchased a 12V Makita drill (6216D) about 2 years ago. It came with
two of the gray 2.2Ah Ni-MH batteries and a charger (DC1411). From the
very beginning, it did not seem to me that the batteries were holding a
charge very well. I could charge a battery until the green light came
on, remove the battery put it in the drill ... and come back 2 weeks
later and there was very little power left in the "fully charged"
battery.

Crappy cells. Yes, it can happen.



My problem now is that I can't seem to get either of the Makita
batteries to fully charge. I've tried only leaving the battery in the
charger for an hour ... and I've tried leaving it for a week. Neither
way seems to fully charge the battery. One thing that seems strange ...
after charging a battery for a couple hours, I can remove the battery
... wait a few minutes ... and then plug it back in to the charger ...
and the blinking green light turns red and stays red like it is doing a
full charge cycle. (I have not timed it to see how long it stays red,
although I suspect it's not very long.)

It is checking for charge. No, i t will not stay on long.


So ... my questions:

(1) could the charger have been "bad" from the very beginning?

Possible, but I think it is the cells, not the charger.


(3) is it more likely that the batteries are "bad" (and maybe were from
the beginning)?

Yes, very possible. Too late now though.

(4) what's my best course of action to diagnose my problem?

Check each cell. Of course, you have to open the pack to do that. If you
check the voltage right after charging, if you are getting less than 12V you
can be sure cells are dead.



One last question ... does it harm the battery or the charger to leave
a "fully charged" battery connected for weeks?

Depends. Not on most new equipment.

You can always have the packs rebuilt better than new at www.primecell.com
See http://www.primecell.com/pctools.htm the 12V is $33.

only have 1 real comment to make here, the last point of what to do
now.
go buy a rigid from home depot
not as good as dewalt, milwalkee, or porter cable, but free replacement
batteries for life makes a big advantage for the rigid brand name.

Empress2454 #124457


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Bankerjohn wrote:
I purchased a 12V Makita drill (6216D) about 2 years ago. It came with
two of the gray 2.2Ah Ni-MH batteries and a charger (DC1411). From the
very beginning, it did not seem to me that the batteries were holding a
charge very well. I could charge a battery until the green light came
on, remove the battery put it in the drill ... and come back 2 weeks
later and there was very little power left in the "fully charged"
battery.

I previously owned a Craftsman Professional 9.6V drill with NiCad
batteries (which I suspect were nowhere near 2.2Ah) ... and it would
hold a charge for several months. I think I've read that Ni-MH
batteries will lose their charge quicker than NiCad batteries ... but I
wouldn't expect a "fully charged" battery to lose most of its charge in
2 weeks!

My problem now is that I can't seem to get either of the Makita
batteries to fully charge. I've tried only leaving the battery in the
charger for an hour ... and I've tried leaving it for a week. Neither
way seems to fully charge the battery. One thing that seems strange ...
after charging a battery for a couple hours, I can remove the battery
... wait a few minutes ... and then plug it back in to the charger ...
and the blinking green light turns red and stays red like it is doing a
full charge cycle. (I have not timed it to see how long it stays red,
although I suspect it's not very long.)

So ... my questions:

(1) could the charger have been "bad" from the very beginning?
(2) is there anyway to rule out the charger as the problem with a v/o
meter?
(3) is it more likely that the batteries are "bad" (and maybe were from
the beginning)?
(4) what's my best course of action to diagnose my problem?

One last question ... does it harm the battery or the charger to leave
a "fully charged" battery connected for weeks?