Test Power Drill Battery Charger

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.

Reply to
TheKeith
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Run the drill until the battery is exhausted & then charge it. This will answer your question.

Reply to
Patch

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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.

Reply to
TheKeith

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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

Reply to
Rich Grise

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