Dewalt drill battery replacement

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My Dewalt 18 volt corless drill died. A new battery is 80 bucks. I read somewhere I can take apart the battery case and replace the internal battery packs much cheaper. Is this true and can I save alot of money doing it this way? Is it hard?

Reply to
stryped
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Not hard if you can solder, but bear in mind that there's gonna be 15 of those suckers in there, probably C size, but maybe one of the odder sizes like R14. By the time that you've found that many cells in a decent quality that's going to last more than a few months, you might not be much in compared to buying the genuine article complete with a shiny new DeWalt warranty.

Arfa

Reply to
Arfa Daily

How did it die, just low voltage? If that is the case, then some of the cells have shorted. If it is a nicad battery, you can burn open the shorted cells with a 3 - 12 volt battery. You need a voltmeter to see which cells are shorted after you open the case, Then you put the shorted cell across a voltage source for 1 second to blow the short open. If you don't have experience with batteries and voltmeters and burning cells open, find someone who does as you can cause the cell to explode if you reverse the voltage or leave the source applied for more than one second.

I suggest googling on the battery part number, there are many sellers of batteries on the web who charge about 60% of the manufacturer's battery prices. I just did that for a 12 V battery for my Ryobi drill. The original battery pack had been repaired several times, but wasn't holding a charge any longer,

H. R. (Bob) Hofmann

Reply to
hrhofmann

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It just quit working. Even after charging overnight. I got some sort of error beeping on my charger too.

I have a voltmeter and know how to use it. I can solder but am not the world's greatest although never "blew" a battery open. Can you explain how that works one more time?

What are the chances that just one cell is bad and needs to be replaced? Seems like that would be a cheap fix.

Right now the drill w> stryped wrote:

Reply to
stryped

Reply to
stryped

You can, but buying the 15 cells needed is unlikely to save you much money, if any. Remember the maker buys them by the million and gets big discounts. Not all cells are of the same quality - and I'd expect DeWalt to use decent ones, so take this into account when pricing.

The size you need is an industrial size - Sub-C - and you'll probably have to get them from an electronics supplier. Tagged cells are easier to solder to without risk of damage - the originals will be spot welded. You might find a supplier who will weld them for you.

It can be cheaper to buy another maker's battery which is on special offer and rob it of its cells.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

IF you are looking for replacement cells, E.H. Yost (Batteries America) in Middleton, Wisconsin not only can supply the cells - BUT will spot weld the tabs IF required (a very nice service - that not all suppliers / distributors offer)

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They have a large catalog of the Sanyo cells Ni-Cad and Ni-MH (high capacity, fast charge. standard capacity) - in a wide variety of sizes.

g. beat

Reply to
g. beat

They charge $4.95 each for Sub-C 2400mAh Sanyo Ni-Cads, so that would be $74.25 before postage etc. ;-)

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

Dave -

That is correct - if all cells are bad (or if you wish to replace all). With the British Pound Sterling and US dollar exchange rates - it should be a bargain :-)

Sanyo does have manufacturing facilities across the globe, and you can find a specific regional or country distributor on their web site.

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g. beat

Reply to
g. beat

It's common for a single cell to fail, usually by going into reverse polarity or by developing an internal short.

Reverse polarity can be fixed by charging just that cell alone. You'll need a source of DC voltage higher than the 1.25V of the cell and a resistor in series with it to limit the current (50-200mA for a C-cell). You can even use an alkaline cell with a 5-10 ohm resistor in series with it by connecting them for about 30 seconds and then charging the whole battery pack normally.

A shorted cell can sometimes be fixed by zapping it with brief pulses of higher voltage, like 12-50V, from a capacitor (connect "+" of cap to "+" of cell, "-" of cap to "-" of cell) to vaporize the short, but almost always the short grows back in a few days. I zap until the popping sound from the arc weakens, which I think indicates that the short has disappeared.

To solder in a new cell you'll need an iron with plenty of power, at least 40W, but 45-50W is better, and it helps a lot to sand the ends of the cell and apply some rosin flux (not acid flux) to it. I would tin any wires before soldering it to the cells, but it's possible that there isn't enough room inside the battery case for decent size wire, so you may have to instead use strips of copper or brass (from a hobby shop or real hardware store). Try to complete the soldering quickly, to prevent damaging the cell from heat. This is why you want to use the 40-50W iron, sand the metal, use rosin flux, and tin the wire or metal strips.

Reply to
larry moe 'n curly

Reply to
stryped

Hard to tell, unless they are marked.

Arfa

Reply to
Arfa Daily

I'd not mix old and new.

They are a good price, but not good enough to import and pay carriage and possibly duty. ;-)

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

This makes think the thermal protection circuit went bad. No voltage at all and the error beeps on attempted charging. Not familiar with DeWalt but the Makitas that I have have a 3rd terminal on them. If this is open the battery will not charge and you get the error beeps. This is usually a thermal relay that opens up if the batteries get too hot while charging or in use. BTW I have used "salvaged" batteries in my bad Makitas. Soldering can be a pain and the post about a big iron is right on. I use a big gun with the tip cut off. Like a poor man's spot welder except I use solder. Keeping the tabs as long as possible. I also keep one union open until the last cell is in the pack. Nothing more exciting than a shorted pack! As far as capacity I usually don't worry about it as the smaller capacities use cells that are shorter so you can tell by the entenders.

I have 15 of them running now. At ~ $60 new that can add up. But I have gotten great deals on eBay. Richard

Reply to
kv888831393ster

Sounds like the thermal fuse inside the pack blew.

Reply to
James Sweet

I have a similar problem

If I charge my battery for an hour, it works like a champ

but ..

If I leave the battery on the charger overnight, it acts like it barely has a charge.

You would think that it would do a quick charge, then drop to a funtional trickle charge.

snipped-for-privacy@hotmail.com (James Sweet) wrote in :

Reply to
Mike_in_SD

On most I've seen it is simply a sensor that shuts down the charger - it's not a cut-out.

Same physical size cells come in different capacities, and the cheaper ones tend to be at the low end.

The performance of a drill etc depends very much on the maximum current a cell can deliver. In many cases a cheap drill can be much improved by using decent cells - but then it's no longer a cheap drill. And decent cells have a longer life - if charged properly. Many cheap drills come with chargers which can easily damage even decent cells through overcharging. But the likes of Makita should have decent chargers.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

Depends. Some cheap drill chargers have no more than a DC source with a resistor in series, and charge in say 4 hours. If you leave them on longer it will ruin the batteries. I'd look inside the charger base for signs of proper electronics.

The best basic charger does a 1/10th capacity constant current charge which requires some 14 hours from flat. This can be achieved by adding one transistor and a few components. It's the kindest way to charge batteries and they will last longer. Even the most sophisticated fast charger will shorten battery life over one of these.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

Actually I've got a bunch right here. This one is made by Klixon YS11A45B-005-T F3AB. It reads 0 ohms at 72=BA F. Another one from a Makita reads the same looks like the same type. However there is another one that reads infinity at room temp. It looks like a bead Tantalum capacitor.

Well the one's I salvaged are all Makitas, exact same cell or Bosch which were brand new but looked like they'd been run over. Also I use Sanyo, Panasonic.

Agreed I'm just recycling batteries that would wind up in the land fill. I pass on batteries that are of an obvious inferior quality. The

9=2E6V Makitas are 1500mAh. I try to match up the ratings of of the batteries that I recover. I did have a test rig that would rate the Ahr capacity of NiCads but I only used that on pro camera belts like Arri. Richard
Reply to
kv888831393ster

Actually I've got a bunch right here. This one is made by Klixon YS11A45B-005-T F3AB. It reads 0 ohms at 72=BA F. Another one from a Makita reads the same looks like the same type. However there is another one that reads infinity at room temp. It looks like a bead Tantalum capacitor.

Well the one's I salvaged are all Makitas, exact same cell or Bosch which were brand new but looked like they'd been run over. Also I use Sanyo, Panasonic.

Agreed I'm just recycling batteries that would wind up in the land fill. I pass on batteries that are of an obvious inferior quality. The

9=2E6V Makitas are 1500mAh. I try to match up the ratings of of the batteries that I recover. I did have a test rig that would rate the Ahr capacity of NiCads but I only used that on pro camera belts like Arri. Richard
Reply to
kv888831393ster

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