More Cordless Drill Battery Questions.

The second of my Wagner chargers died. They were marked 14.4v but batts came out usually about 15.60ish unloaded.

The wall unit is marked 19v 500ma.

I got inside the charger stand and bi-passed the dead "brain" of it and now pass what goes in out.

After 20 minutes or so of 19V the batt showed 17.30...

I also have a 12V 300ma wall unit. After about 1 hour of that, a batt that started at 13.11ish got to 14.13...

Which would be better, and how long on either voltage?

I won't actually NEED these drills any more, as I'm getting back a batt for a decent Craftsman 14.4 tomorrow.

But I can't help but tinker with it! Maybe I need even a different wall unit?

I think my head may explode! /ubbthreads/images/graemlins/help.gif

These durn things are designed to be replaced, period....

I just got through a three day last try to make my 30 cc. leaf blower work. Four years old. Lost time.

I Tossed it.

My new one works great. Times have changed. The local repair shop charges $ 50/hr. for repair.

The blower cost $ 69.00.

Nuff said.

That's all well and good JohnK, but I hope these aren't the final words on this subject!!!

One of these Wagners, as hokey as they are, has survived at least a month out laying on a patio chair in the weather. Plenty of WD40 saved it.

So they have sentimental value.

Sort of an update. For perhaps 30 minutes today, one pack was getting the full 19V at 500ma. On other occasions I have measured a pack straight out of that configuration at 17+ V. This one sat in that charger for several hours after the timer kicked off. When I got it out and measured it, it read 16.65V. JUST checked it again and saw 16.50V. I think (and the Craftsman charger for 14.4V reads) 15.35ish is what the charger USED to put out. Right now I have a choice of unloaded 17.00V at supposed 500ma, or 15.20V at supposed 300ma available.

I guess the 17.00V is perhaps a bit too much, but for 30 minutes I don't feel hot batteries or anything like that.
The 15.20ish is probably close... however it's coming from a multi voltage wall unit SET at 12V...

I would guess the answer is I need a wall unit putting out around???????V at ????????ma.

Like I said before, it's making my head hurt!!!

Re: More..... 6V Stinger Batt asked and answered!

OH yeah! At Batteries Plus today I asked about getting a 6v stick made for my Stinger. She said they are working on it, and that the problem is the collar at the top of the stick. They have somebody working on it she said, and that I should check back from time to time.

Alternately, I could have my Stinger stick destroyed for the collar....

Re: More..... 6V Stinger Batt asked and answered!

Bump. For two reasons.

I can't believe more interest isn't being expressed about the 6V Stinger Stick.

And...

I'd really like some more info on what to hit these 14.4V packs with.

Re: More..... 6V Stinger Batt asked and answered!

use a 300ma walwart with a oc voltage of 17-18 v
remember that the voltage goes DOWN when a nicad comes to full charge.as for the 6v stinger pack rebuild a dead one with 5 2/3sc cells.

Re: More..... 6V Stinger Batt asked and answered!

Hello there,

Actually 300ma probably isnt too bad for this battery pack.
Your charge time should be about 10 or 12 hours.

Most chargers for these packs run 100ma and you leave it
on charge for about 30 hours.

You can figure the batteries are about 2Ah no
matter what the voltage is, unless they are not
sub C size NiCd's (possibly in 18v drills).
If you are worried, then perhaps a test is in order.
Charge the batteries for 12 hours at 300ma.
Discharge the batteries using a known resistor
drawing about 200ma almost constant.
Start a timer when you connect the resistor.
Stop the timer when the voltage drops to less then
1.05 volt per cell (a 14.4v pack has 12 cells).
Multiply the time (in hours) by the current (200ma)
to get the ampere hour capacity of each cell.

If the capacity comes out lower then about 1Ah you
probably have a bad cell or two.
If the capacity comes out to more then 2Ah you may
wish to repeat the test charging for 15 hours first,
or else just accept a 2Ah rating.

Once you know the rating, you can calc the required
charge time by dividing the rating by the current
the charger puts out and multiplying by 1.4 .

Thus, 2Ah divided by 0.3 amps gives 6.67 hours.
Multiplying that by 1.4 gives us 9.3 hours charge time.
10 hours would be ok too.

Take care for now,
Al

I'd at least put a voltage regulator on it. A 7815 with a heat sink is good up to an amp and would work OK with either of your wall warts. Measure the '12v' one, tho. It needs to be about 3 volts over what you want with this chip. Just about all of these Chinese wall warts seem to be 18-20v these days regardless of the nominal voltage. Anyway, they are about 40 cents and only have 3 terminals to connect. Those NiCads are tough but there is no need to overcharge them. Note that this doesn't give you any thermal overload protection, and the voltage regulation might still give you an overcharge - it will just minimize it. This is the quick & dirty method I use when it's not worth buying a proper nicad charger. I wouldn't do this with NiMH.

Jeez! Now it's all over my head. I have no idea how to pull a measured load.

I figure when the drill starts to sound sick, I'll go about 4 hours with the 15odd voltage and check it. Or maybe about 30 minutes at a time with the 17 odd volts.

This isn't to be a critical application... the Craftsman 14.4V drill works like a champ! (and still has an original charger in good shape).