Tools, Sharpening and Power Machinery - Dewalt 18V battery question

Hello all...Long time lurker, first time poster!

Anyway...I own an older Dewalt 18V drill and was looking into other Dewalt cordless tools. All the newer Dewalt 18V batteries are "XRP". Are they interchangable? Can I use my two standard 18V batteries in the newer XRP tools? Thanks guys for a wonderful site!

Welcome, Finleyville. Sounds like a town in Ohio!

yes, they are interchangable. The XRP batteries came out after the originals and are just extended-run time batteries. If you can get new batteries w/ your tool, go for it- thats the cheapest way to get them since they are about $119 for a two-pack if you have to purchase them seperately. Your older batteries won't last forever. One of mine died recently. They will just quit taking a charge after a while.

Hello all...Long time lurker, first time poster!

Anyway...I own an older Dewalt 18V drill and was looking into other Dewalt cordless tools. All the newer Dewalt 18V batteries are "XRP". Are they interchangable? Can I use my two standard 18V batteries in the newer XRP tools? Thanks guys for a wonderful site!


Dewalt is stating they have a 40% longer run time. Dont know if that is true or not, But as stated they are interchangable.
You will start to see a lot of new batteries in the next few years. everyone is trying to get away from the nicad batteries.

Welcome, Finleyville. Sounds like a town in Ohio!


Actually, Pennsylvania... It's not where I'm from, only my nickname... :rolleyes:

Thanks guys. I guess I will be looking into their cordless power tools soon then. I'm sure they will be fine for this occasional "weekend warrior."

My batteries, some of which are only one year old, just fail without warning. How do you repair therm, is there a trick? Thanks.

Batteries fail and any time after a year is when. They are best replaced, not repaired.

Thanks, but there has to be a way to rejuvenate/repair these batteries. Shelling out $90 every year is ridiculous.

Go ahead and look into it, but you're going to find that replacement is the best answer.

I've read - either on this forum - or the one in UK (screwfix) - someone suggested leaving dud batteries in the freezer for a day or so then recharge. Never had to test this idea tho!

Well, it's -10F here, and one of my "dud" 14.4 Dewalt batteries still won't take a charge. I won't say that theory is pure bunk, but it doesn't work for my battery.

I live in southern UK & we never get such low temps! Since batteries tend to work better when warm what about sticking it on top of the boiler for a few days? Anything's worth trying (if safe!) rather than fork out the extortionate sums for replacements.

The frozen battery trick is a throwback from the carbon battery days.
I remember this from my youth when it was the thing to do.
Freezing this type of battery would give you an extremely shortlived amount of power but today's alkalines or NiMh do not respond to this fix.

If you can get two batteries in the price range of $100.00 I don't think you would be doing too bad.
I am faced with the dilema of having to replace two Milwaukee 18 volt batteries at a cost of $110.00 EACH!
Normally I wouldn't consider spending this amount of money on power tool batteries but they are for my 18v Sawzall which happens to be one of my favorite and most usefull tools.
For the less than the cost of the replacement batteries I can get a new 18v recip saw in a cheaper make but the Milwaukee's quality and ease of use cannot be matched.

So, unless you have a personal attachment to a tool like I do, it sometimes does not make sense to replace batteries.

Land o lakes, I posted this under the "Bad battery or bad charger?" thread, but it might help.

It will take some doing, but you can repair cordless drill batteries. An 18 volt battery pack is made up with 12 "C" sized rechargable cells. These are available at Radioshack or any place that sells rechargable batteries. After your battery pack has been on the charger long enough, take the cover off the pack and identify the positive end of the first cell in the chain. Using a multimeter, check and make note of the voltage reading between that point and the negative end of that cell and then from the negative end of each cell in sequence. From cell to cell you should see a 1.5v jump. If the voltage jump is less than .8 volts, the cell your checking is bad. Mark the cell and keep checking the cells until you get to the end. You will probably have to cut or de-solder the leads going from cell to cell to be able to extract the bad cells. Be certain, when putting new cells back in, that the polarity is correct. Again, you will have to solder the leads back on. Warning, this can be tricky.

I just ressurected a pair of 12v DeWalt batteries ($56 each new) for $9 in rechargable batteries and an afternoon of fussy work. For me, being a cheap S.O.B. who likes fixing things, it wasnt so bad.

If a battery pack is allowed to go very dead, the cells holding a higher charge will actually start recharging the weakest cells and reverse the polarity of those cells. For my 12v Dewalts (9 - 1.5v cells) having 3 bad cells each, it meant that I wasn't even getting the benefit of the remaining 6 good cells, because they were giving up their charge to the the three bad cells with reversed polarity. Essentially I was only working with 4.5v of power. :coffee:

You'd think (and maybe someone has) someone would invent a battery shaped adapter with a power cord sticking out, so in the worst case scenereo you could just plug it in.

I was wary of battery powered tools at one point, i think my parents had some cheap-o black and decker .5 volt drills or something, and they were horrible.. but I caved in durring my 1st remodeling job and got a dewalt 18v combo set saw and drill.. the batteries lasted into about 2/3 of the project, I was impressed!

But, thinking ahead to when my 1st battery dies (i now have 3 of them) is going to suck a little, it's almost better off buying a new tool that comes with the battery, then selling the tool to account for the high cost of the battery :)

You'd think (and maybe someone has) someone would invent a battery shaped adapter with a power cord sticking out, so in the worst case scenereo you could just plug it in.

I played around with your idea (and it's a really great one) and the result was a 9 lb "anchor" duct taped to my cordless drill. Making 12VDC from 120AC is easy, a small transformer, a rectifier, capacitor and a few other bits and wha-lah. Sure, it's not a regulated supply, and the amps are barely enough to spin the drill, but at least it fits inside the stock DeWalt battery case and best of all, no smoke. In order to get the necessary amps to make some real torque, I had to use a huge 24VDC transformer rated for 35 amps. I pulled from the center tap, thus 12VAC, but it too was unregulated and actually put out just under 18VAC. To regulate it down to 12VDC, it took a chunky bridge rectifier, a few big filter capacitors (think 35mm film capsules) and a pair of high end MOSFETS along with some IC chips and and a handful of other bits to build a PWM controller. OK, some creative PC board work, lots of electrical and duct tape and...hold on...this thing is getting really hot. No prob, just add a couple well placed heat sinks and a muffin fan and ...

It worked, drove the drill as well as or better than a new fully charged battery and looked pretty snazzy too (it looked a bit like the CO2 filter cobbled together in the movie "Apollo 13"). I'm sure there's a whip smart EE out there who can design a small, cool running 20 amp DC power supply that weighs only a pound or so. Until then, when time allows, I plan to rework my "anchor" to be a benchtop supply with a long output cord that plugs into the battery socket (what a great idea, where did I hear that before?) and keeps the work going until my Dewalt doorstop, I mean battery, charges.

Again, and I'm being serious, it's a really great idea.
:coffee:

imagineer, you sound like the kind of guy I'd like to talk to during halftime over beer & chips. :thumbup: