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Test Power Drill Battery Charger

T

TheKeith

Jan 1, 1970
0
I just got a new 15.6 V craftsman drill and noticed that when charging the
nicd batteries, the do *not* get warm at all, but in the instructions, it
says the batteries do get warm. They seem to be charged, but then they
already had juice in them when I charged them for the first time, so I'm not
completely sure the batteries are charging. Is there a way I can check the
charger? I have a multimeter, if that helps. Thanks.
 
P

Patch

Jan 1, 1970
0
TheKeith said:
I just got a new 15.6 V craftsman drill and noticed that when charging the
nicd batteries, the do *not* get warm at all, but in the instructions, it
says the batteries do get warm. They seem to be charged, but then they
already had juice in them when I charged them for the first time, so I'm not
completely sure the batteries are charging. Is there a way I can check the
charger? I have a multimeter, if that helps. Thanks.
Run the drill until the battery is exhausted & then charge it. This will
answer your question.
 
T

TheKeith

Jan 1, 1970
0
Patch said:
Run the drill until the battery is exhausted & then charge it. This will
answer your question.


that's what I ended up doing--it works. I was just wondering if there was
another way where I didn't have to do that, but it's already done
so--thanks.
 
R

Rich Grise

Jan 1, 1970
0
TheKeith said:
that's what I ended up doing--it works. I was just wondering if there was
another way where I didn't have to do that, but it's already done
so--thanks.
Actually, any real test that's any good does essentially the same thing
anyway.

I once made $1000.00/week + rental car + $350.00 expenses (which all went
to expenses, imagine my surprise!) for a 2-week assignment out of town
(in Tooele, Utah, actually - pronounced Too-Ella, not Too-Lee) where they
had a bank of my client's battery chargers that had failed to properly
charge about eighty-seven 55 AH fibrous ni-cd's one day. Nobody had a
clue what was wrong, and when I asked the two guys who seemed to be running
the show "Who's in charge here?" they each pointed at the other guy and
said, "He is." Anyway, it turned out that the ambient temp. was about 110
deg. F that day, and the charger/battery banks were in a metal shed. After
a week and 4 days of basically trying to look busy, somebody (me) thought
to ask the battery mfr's rep, and it turns out that if the batteries are
over about 90 deg F, they won't hold a full charge. They'll _take_ a full
charge, but only keep part of it. (I'm not sure, but it's ridiculously
small, like 20%.)

Anyway, these things were "battery charger/analyzers" and used a 68HC11.
They'd charge the batteries and record the charge AH, discharge them
through a dummy load that consisted of about 6 big heat sinks with about
6 or 8 MOSFETS each, measure how many AH they could get out of them,
and then charge them again. By this time, of course, so when you pour
1.2C into them after having just pulled out 1C in about 2 hours, they
heat up, and wind up with about a .2C charge. 'Course, if I'd asked
the battery rep the first day, I'd have cut myself out of 2 weeks of
gravy. :)

If you want to be fanatical about "under operating conditions," you
could come up with some kind of clutch/brake thingie to load the
drill to a normal operating torque, as well.

Have Fun!
Rich
 
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