Appliances Faulty DeWalt Battery charger for power tools

DaveC426913

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I've replaced the charger for my DeWalt tools several times, and now I may have to go out and get a fourth one.

One of them flashes a fault warning (steady slow flash), the other two do not light up at all.

Now, I do not take care of my tools. All three of these chargers may have been exposed to a light spray from rain getting into the slot where the terminals are (the chargers are protected, but wind carries mist). The terminals are not rusted; they look shiny.

The charging slot has a "drain" hole in the bottom, and the terminals are raised above the bottom, almost as if it's designed to prevent water from getting at the terminals.

I'm using the battery, so it's not entirely dead.

I find it hard to believe that a relatively simple device (it's just a transformer) could fail so easily.

Can anyone suggest some checks I might do to see if any one of these chargers can be resuscitated?


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One question Dave, have you tried the "charged" batteries with more than one tool? I assume you have but had to ask.
 

DaveC426913

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I only have the one tool. I've been using my drill for the last week on the same charge, but it finally ran down (not all the way).
I've tried charging it with all three chargers and I get a little action out of it, but it's not actually charging.

So I don't think the drill is the problem. It is behaving fine.
 

anorlunda

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I'll bet one of your neighbors has a Dewalt charger. See if they can charge one of your batteries.
 

DaveC426913

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I'll bet one of your neighbors has a Dewalt charger. See if they can charge one of your batteries.
Ugh. The thought of asking my crazy neighbor for anything...

But seriously, I'm pretty certain the batteries are fine. I've been using them for a year with no trouble - until the charger gets a little misty.
 
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Now, I do not take care of my tools. All three of these chargers may have been exposed to a light spray from rain getting into the slot where the terminals are (the chargers are protected, but wind carries mist). The terminals are not rusted; they look shiny.
If moisture was able to get into where the terminals are, maybe it could also get into the guts of the charger, and corrode some of the connections or components inside. It might be useful to connect a voltmeter to the thing and see what voltage it's putting out. If the charger isn't working correctly, I would see what things look like inside.
Also, I wouldn't leave it anywhere it could get wet.
 
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Mark makes a good point. Can you take it apart and check for moisture-related corrosion/damage or it it one of those things where the instruction manual says something like "this excellent device can only be broken into by a qualified special person with a three-pronged framis, which if you have one do not use it or the device will probably explode and kill your entire family, including the goats" ?
 

berkeman

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I'm using the battery, so it's not entirely dead.
But seriously, I'm pretty certain the batteries are fine.
Singular or plural? Both of my batteries slowly died over the years, so I bought new ones from Amazon recently and all is good now. My battery charger has never been left out in the rain, though...

Maybe borrow a compatible battery from your crazy neighbor to see if it works more normally in your charger(s)?
 

DaveC426913

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If moisture was able to get into where the terminals are, maybe it could also get into the guts of the charger, and corrode some of the connections or components inside. It might be useful to connect a voltmeter to the thing and see what voltage it's putting out. If the charger isn't working correctly, I would see what things look like inside.
I will have to. But I swear it's not that bad.

Also, I wouldn't leave it anywhere it could get wet.
That's crazy talk.

Singular or plural? Both of my batteries slowly died over the years, so I bought new ones from Amazon recently and all is good now. My battery charger has never been left out in the rain, though...

Maybe borrow a compatible battery from your crazy neighbor to see if it works more normally in your charger(s)?
I already have some newer(ish) batteries. That's what I've been using. But I'll try that to rule out one factor.


So the gist that I'm getting is that there isn't some 'I got wet!' fuse in these things.
 

Wrichik Basu

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Can anyone suggest some checks I might do to see if any one of these chargers can be resuscitated?
The best is to check whether the output terminals are giving the proper voltage, with a multimeter or voltmeter.

If you get no reading (0 V), then a fuse has perhaps tripped. Otherwise you have to check each and every component to see if they are working.
 

Tom.G

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Aww, come on. Google finds over 400 000 'dewalt charger schematic' (they make a LOT of different ones!) 'dewalt charger service manual' finds 1 970 000 hits.

The label in your photo shows that one is good for a wide range of different batteries; which probably means it has a rather smart IC in it that also senses what battery is inserted.

That said, first step is substitute the charger, then substitute the battery. (cuts the search universe in half. 😁)
 

berkeman

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The best is to check whether the output terminals are giving the proper voltage, with a multimeter or voltmeter.

If you get no reading (0 V), then a fuse has perhaps tripped. Otherwise you have to check each and every component to see if they are working.
I'm not all that familiar with charger circuits, but I don't know if a no-load voltage check will work. It may be that the charger needs to sense a battery before it applies a charging voltage. I think that my 12V lead-acid battery charger (small one for motorcycles) behaves like that.
 

anorlunda

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DeWalt is a quality product. Have you considered their customer service. You could recite you sorry history with multiple chargers. You might get tips from them, or you might get a free charger.
 
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I'm not all that familiar with charger circuits, but I don't know if a no-load voltage check will work. It may be that the charger needs to sense a battery before it applies a charging voltage. I think that my 12V lead-acid battery charger (small one for motorcycles) behaves like that.
what he said (very small).jpg
 

Wrichik Basu

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I'm not all that familiar with charger circuits, but I don't know if a no-load voltage check will work. It may be that the charger needs to sense a battery before it applies a charging voltage. I think that my 12V lead-acid battery charger (small one for motorcycles) behaves like that.
Many chargers behave like that. Trickle chargers for vehicle batteries are examples, as you have said.

But I don't think it would be difficult to connect the battery to the charger via two words wires, such that the charger terminals are still accessible by the probes. Once the charger senses the battery, the multimeter can be used.

If the battery is in good condition, but the charger cannot sense it, then there can be a chance that the sensing circuit is faulty.

Edit: fixed typo.
 
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NiCd? Maybe time to jump on the Li-ion band wagon. NiCd and NiMH base power tools never really lived up to the "power" part, always found them lacking and very short lived in terms of charge so never bother with cordless. Then I tried a friends Milwaukee M18Fuel tools, was quite impressed and been replacing all my corded tools with Dewalt XR brushless, nothing wrong with the red, I'm just a little OCD in that respect, so already having some black and yellow, couldn't go change color scheme now!

Difference between NiCd tools of yesterday and the Li-ion+brushless is night and day, the brushless recip I have gives my corded one a solid run for its money.
 

DaveC426913

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I'm not all that familiar with charger circuits, but I don't know if a no-load voltage check will work. It may be that the charger needs to sense a battery before it applies a charging voltage. I think that my 12V lead-acid battery charger (small one for motorcycles) behaves like that.
They do work like that. I watched a DIY video of a DeWalt charger not charging an extremely dead battery and it did exactly that. His trick was to give the dead battery a goose from another battery. Just enough so the charger could sense it.

DeWalt is a quality product. Have you considered their customer service. You could recite you sorry history with multiple chargers. You might get tips from them, or you might get a free charger.
Alas, that would be pretty dishonest. There isn't really a slippery slope here, where I could blame it on something else and simply neglect to mention the water exposure. I'd have to outright lie.
 

anorlunda

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You don't have to lie to ask questions. They should have better answers than PF.
 

DaveC426913

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You don't have to lie to ask questions. They should have better answers than PF.
Sure, but the first question they're going to ask is: Are you storing them properly and keeping them dry?
And I'll have to say "Well..."
And then they'll say "Great. Anything else we can help you with today?"

That's what I mean by no slippery slope. There's really nothing to ask that doesn't immediately provoke the obvious question.
 
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Sure, but the first question they're going to ask is: Are you storing them properly and keeping them dry?
And I'll have to say "Well..."
And then they'll say "Great. Anything else we can help you with today?"

That's what I mean by no slippery slope. There's really nothing to ask that doesn't immediately provoke the obvious question.
Yeah, but that doesn't mean they won't have an answer (possibly preceded by, "Well, you're not supposed to DO that").
 

Wrichik Basu

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Alas, that would be pretty dishonest. There isn't really a slippery slope here, where I could blame it on something else and simply neglect to mention the water exposure. I'd have to outright lie.
You don't have to lie. You can tell them, "Yes, it got wet. But can you tell me how I can repair it now?"

If you open the charger, a close look will tell you if the water has had bad effects - corrosion. If you can confirm that none of the components/soldering is corroded, you can surely ask the customer service how you can repair it.
 

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