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Home > Archive > Electrical Engineering > June 2005 > Battery Charger Blues
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Battery Charger Blues
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| Bob Tyrka 2005-06-25, 11:25 pm |
| I made the mistake of buying a Chinese-made battery-operated electric drill,
which worked fine until I tried to charge the batteries. I emailed the
manufacturer but needless to say, I have received no response.
The rechargeable batteries are rated at 18V. The charger consists of a
small receptacle with a few electronic components in it, and a plug-in
transformer 120v. AC, 60 Hz to 22v. DC, 500mA, 11 VA. The transformer does
not get warm no matter how long it is plugged in, and the pilot light on the
charger that should indicate when it has charged the battery, never lights.
I've spent a couple of hours googling for transformers of similar
specification, with no success, and I refuse to spend more for a variable
voltage transformer than I've paid for the entire drill. Any suggestions as
to a commonly available transformer that would get the job done, even if
slowly?
Bob
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| Brian 2005-06-25, 11:25 pm |
| www.dewalt.com
"Bob Tyrka" <rtyrka@cavtel.net> wrote in message news:palve.95$I96.33189@news.uswest.net...
I made the mistake of buying a Chinese-made battery-operated electric drill,
which worked fine until I tried to charge the batteries. I emailed the
manufacturer but needless to say, I have received no response.
The rechargeable batteries are rated at 18V. The charger consists of a
small receptacle with a few electronic components in it, and a plug-in
transformer 120v. AC, 60 Hz to 22v. DC, 500mA, 11 VA. The transformer does
not get warm no matter how long it is plugged in, and the pilot light on the
charger that should indicate when it has charged the battery, never lights.
I've spent a couple of hours googling for transformers of similar
specification, with no success, and I refuse to spend more for a variable
voltage transformer than I've paid for the entire drill. Any suggestions as
to a commonly available transformer that would get the job done, even if
slowly?
Bob
| |
| TimPerry 2005-06-25, 11:25 pm |
|
"Bob Tyrka" <rtyrka@cavtel.net> wrote in message
news:palve.95$I96.33189@news.uswest.net...
quote:
> I made the mistake of buying a Chinese-made battery-operated electric
drill,
quote:
> which worked fine until I tried to charge the batteries. I emailed the
> manufacturer but needless to say, I have received no response.
>
> The rechargeable batteries are rated at 18V. The charger consists of a
> small receptacle with a few electronic components in it, and a plug-in
> transformer 120v. AC, 60 Hz to 22v. DC, 500mA, 11 VA. The transformer
does
quote:
> not get warm no matter how long it is plugged in, and the pilot light on
the
quote:
> charger that should indicate when it has charged the battery, never
lights.
quote:
>
> I've spent a couple of hours googling for transformers of similar
> specification, with no success, and I refuse to spend more for a variable
> voltage transformer than I've paid for the entire drill. Any suggestions
as
quote:
> to a commonly available transformer that would get the job done, even if
> slowly?
>
> Bob
>
1: measure the charger voltage with a volt meter.
2: make sure the battery is making contact with the charger terminals
3: use an auto tail light to simulate a load. briefly bridge the tail light
across the charger. it should glow brightly.
4: sometimes there is a device in the battery which senses heat. this opens
up when charge is complete. this could be bad on your battery pack.
| |
| daestrom 2005-06-26, 12:25 pm |
|
"Bob Tyrka" <rtyrka@cavtel.net> wrote in message
news:palve.95$I96.33189@news.uswest.net...
quote:
>I made the mistake of buying a Chinese-made battery-operated electric
>drill, which worked fine until I tried to charge the batteries. I emailed
>the manufacturer but needless to say, I have received no response.
>
> The rechargeable batteries are rated at 18V. The charger consists of a
> small receptacle with a few electronic components in it, and a plug-in
> transformer 120v. AC, 60 Hz to 22v. DC, 500mA, 11 VA. The transformer
> does not get warm no matter how long it is plugged in, and the pilot light
> on the charger that should indicate when it has charged the battery, never
> lights.
>
> I've spent a couple of hours googling for transformers of similar
> specification, with no success, and I refuse to spend more for a variable
> voltage transformer than I've paid for the entire drill. Any suggestions
> as to a commonly available transformer that would get the job done, even
> if slowly?
>
In addition to some of the ideas mentioned by others, I'll ask just how far
discharged is the battery. Some small battery chargers are designed to
*not* turn on unless they see a certain voltage from the battery. It is to
help prevent reversed polarity and such. A little-league score-board
controller we have that is battery operated will not charge at all if the
scorekeeper leaves it on overnight. We 'jump-start' it by using temporary
hookup from a car's cigerette lighter. Once the charger 'sees' a voltage of
the correct polarity, it starts charging and brings the battery up to full
charge.
daestrom
quote:
> Bob
>
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| Bob Tyrka 2005-06-26, 6:25 pm |
|
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:BOyve.54614$g5.34262@twister.nyroc.rr.com...
A little-league score-board controller we have that is battery operated
will not charge at all if the scorekeeper leaves it on overnight. We
'jump-start' it by using temporary
hookup from a car's cigerette lighter. Once the charger 'sees' a voltage
of the correct polarity, it starts charging and brings the battery up to
full charge.
daestrom
Thanks for all the suggestions I received. Unfortunately, I don't have the
patience or the equipment available to do troubleshooting and the DeWalt
site doesn't show transformers as separate from the charging mechanism, as
is the one I own. One of my batteries did have a slight charge left, but it
too failed to charge. Does anyone know of a transformer I might buy that
will work for my drill? Would an 18V. 500mA to 1A DC output charge my
batteries?
Bob
| |
|
| Bob Tyrka wrote:
quote:
> "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
> news:BOyve.54614$g5.34262@twister.nyroc.rr.com...
>
> A little-league score-board controller we have that is battery operated
> will not charge at all if the scorekeeper leaves it on overnight. We
> 'jump-start' it by using temporary
> hookup from a car's cigerette lighter. Once the charger 'sees' a voltage
> of the correct polarity, it starts charging and brings the battery up to
> full charge.
>
> daestrom
>
> Thanks for all the suggestions I received. Unfortunately, I don't have the
> patience or the equipment available to do troubleshooting and the DeWalt
> site doesn't show transformers as separate from the charging mechanism, as
> is the one I own. One of my batteries did have a slight charge left, but it
> too failed to charge. Does anyone know of a transformer I might buy that
> will work for my drill? Would an 18V. 500mA to 1A DC output charge my
> batteries?
>
> Bob
>
>
>
Yes, but you need to add a 470 ohm 1 watt resistor** in series.
And it will take a little over 2 days to full charge a
completely discharged* pack. (* - "completely discharged" as
used here means your 18 v pack is depleted to about 13.5 - 15
volts. "Completely discharged" occurs when the battery operated
device shows degraded performance - a drill slows dow, a
flashlight gets dim, that kind of thing.)
** = assuming a regulated 18 V adapter. If it is not regulated,
you need a bigger resistor. Use 2 470 ohm, 1 watt resistors
in series with an unregulated 18v supply. A second assumption is
that the battery pack is rated at 1500 maH.
It should be noted that the above appraoch does not yield
the best treatment of your battery pack - a properly designed
charger requires far more than an 18 v adapter and a resistor.
But is cheap, you can do it without test equipment and a
lot of effort, and it won't overcharge the pack.
One *major* warning: you *must* ensure that the positive
output from your adapter goes to the positive side of the
battery.
Ed
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| Brian 2005-06-26, 11:25 pm |
| BOB! Throw away that Chinese piece of crap and buy a DeWalt!
| |
| TimPerry 2005-06-27, 4:25 am |
|
quote:
> daestrom
>
> Thanks for all the suggestions I received. Unfortunately, I don't have
the
quote:
> patience or the equipment available to do troubleshooting
http://www.qvc.com/asp/frameset.asp...ll?item=H123093!tpl=DETAIL!ref=GOG&ref=GOG&cm_ven=GOOGLEFEED&cm_cat=HOME%20IMPROVEMENT&cm_pla=TOOLS&cm_ite=H123093
or
http://www.overstock.com/cgi-bin/d2...&cid=25608&fp=F
and the DeWalt
quote:
> site doesn't show transformers as separate from the charging mechanism, as
> is the one I own. One of my batteries did have a slight charge left, but
it
quote:
> too failed to charge. Does anyone know of a transformer I might buy that
> will work for my drill? Would an 18V. 500mA to 1A DC output charge my
> batteries?
>
> Bob
>
>
>
| |
| Don Kelly 2005-06-27, 4:25 am |
| What are the chances that the DeWalt charger is made in the US?
--
Don Kelly
dhky@peeshaw.ca
remove the urine to answer
"Brian" <spam@whatisitgood.for> wrote in message
news:9yHve.58763$oK.20533@okepread02...
quote:
> BOB! Throw away that Chinese piece of crap and buy a DeWalt!
>
>
>
>
>
| |
| indago 2005-06-27, 12:25 pm |
| 050626 2236 - Don Kelly posted:
quote:
> What are the chances that the DeWalt charger is made in the US?
My DeWalt charger for my battery drill was assembled in Mexico...
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