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Dewalt battery question

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Heritage

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Discussion starter · #1 ·
I have a DeWalt XRP with two 12 v batteries and charger (3 yrs old). My drill still works fine but when I try charging the batteries the charger will show the flashing light (as usual) for about 1 min...then it starts flashing 2 or 3 times faster and I get no charge off the batteries. Has this happened to anyone?

I have the bad habit of running my batteries until they are completely dead.

My question is ( if anyone has experience with this)...is it my charger or the batteries? How could I find out? The batteries are around $150 for the pair and the charger is around $90.

Thanks in advance:thumbsup:
 
#2 ·
Battery
 
#3 ·
yep- the batterys give out over time and won't hold a charge
you might look into getting the batterys rebuilt- it's a bit cheaper than new batterys, but I don't know how well the rebuilt batterys would really work- anyone have any experence with rebuilt tool batterys?
 
#4 · (Edited)
The chemistry of NIMH and NICADS is such that they will drop off sharply after they give up their nominal voltage. NIMH is a better chemistry than NICAD's, however, both are prone to memory and sharp drop offs after their nominal voltage.

The voltage of any given battery will be higher upon full charge. If you dont believe me use a voltmeter and check for yourself. You can actually check the true voltage or juice left in a battery by using a loaded volt meter.

Either battery, regardless of chemistry, only has so many useful cycles before it is no good.

The amperage that NICD's or NIMH will deliver is awesome. That is the only downside to using a Litium Ion or Lithium Polymer.

Lithium Ion's (LION) or Lithium Polymer (LIPO) are a much better battery in that they have no memory. In other words you could use them to half of their rated voltage, recharge, and not effect the ability to charge to full capacity in later cycles.

Here are some downsides to either Lion or Lipo. In a multiple cell pack they need to be balanced evenly. You CAN NOT discharge them below 3Volts per cell or you will render them useless. Lion has a protective casing around it, Lipo is in a plastic wrap case. Both when exposed to water will exploed. When either type is compromised they can burn at in incredible rate and cause fire and damage.

There are much more advanced chargers that will allow you to monitor the health of your batteries and also cycle them to keep them at their best. I would recommend one of these at some point.

If you so desired you could create your own packs out of say 4200 Sanyo sub C cells or whatever the actual cells are in your battery packs at a significant savings. More than likely they would be better then what you would purchase from a store.
 
#5 ·
TempestV said:
... anyone have any experence with rebuilt tool batterys?
Click to expand...
I've had several of my 18V DeWalt batteries rebuilt by:

http://www.voltmanbatteries.com

Prices are cheaper than replacing them, turn around time is pretty quick, and they seem to perform as well as the new batteries I once bought.
 
#6 ·
Ask anybody that's into R/C racing, they build their own battery packs. It's not that big of a deal, the kid a few doors down used to do mine, unfortunately he now has a car and has discovered girls. :cry:

Opening the packs can be a bigger challenge than replacing the cells, on lower priced tools the cases are sonicly welded and hard to access.

You can find the cells at hobby shops.
 
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#7 ·
ATH said:
I've had several of my 18V DeWalt batteries rebuilt by:

http://www.voltmanbatteries.com

Prices are cheaper than replacing them, turn around time is pretty quick, and they seem to perform as well as the new batteries I once bought.
Click to expand...
Thanks for the link, no more throwing them out for me.
 
#8 ·
I had 2 chargers and 5 batteries for my 14.4 Dewalt and the same thing happened to me a while back. I took the battery that didn't want to be charged out of the charger and put it in the other charger and it charged fine! Therefore my charger was toast. Try to troubleshoot yours and see what happens?
 
#11 ·
Heritage: Here is something I have read in several forums, since the batteries are dead anyway: take one put it in the freezer overnight, take it out next day and just let it "thaw out" till back to room temp, then put it back in charger and see if it charges. This is supposed to work. Try it let us know.If it does the freeze em all :thumbsup::party:
JackM
 
#16 ·
Dewalt battery answer

Try hooking up a wallwart type adapter to the battery , positive on the
the trigger side of the battery and negative on the back(short side).
Leave it on for a minute or two. You should see a voltage on the battery with a volt meter. Then place in charger and charge.
 
#17 ·
Dewalt Battery

Hey everyone,
I just wanted to let people here know that I rebuild the battery packs for all corldess tools and I use the highest quality and amperage cells with no complaints from any customers. One thing to do to a battery that won't hold a charge is try to hit it with high amperage to burn off the so called wiskers that begin to grow between the plates in the cells as they are recharged. This can be accomplished by connecting 2 -18v packs together (positive to negative on the packs leaving 1 positive and one negative pole open, this can be accoplished by using aligator clamps as leads) this will create a 36v pack with approximatly 9 amps of DC power, then momentarily touch the positive and negative terminals with leads from the two packs, several times, then test the voltage in the bad pack.
If it accepts the charge, connect the cell to a light source and kill it, then place it in your charger, this will allow the pack to accept a full charge and you will get an increased runtime from the pack from when it was bad but the run time will not be as good as a new one because you are dealing with used cells.
If it will not accept a charge the pack will need to be rebuilt or repaired, I offer these sevices and the prices I offer are very competative and I off a guarantee (60 day warranty) with every recell. I pay return shipping and shipping for all warranty repairs if the issue is due to my work. It doesn't matter the battery make or model I can fix it and I am begining to off the recell of Nicad to NiMH cells, I haven't had any issues in my packs with Nimh and I have been running them and charging them in my original Nicad Equipment so this is also an option. If anyone has any questions please contact me or review my website for all info on Nicad recells. Hope the little trick above works for you, this how I originally got my dead packs ressurrected and had them begin working again.
Please check out my site walkers battery repair
 
#18 ·
You may look into getting the new Dewalt nano battery...

Its their version of Li...its nano-phosphate (like they use in electric/hybrid cars) It will work on there old tools...

But yeah...You never want to run your NiCad's or Ni-MH totally dead...If the drop below .5 volt they will not charge at all because they need that little bit of voltage for the charger to recognize the battery.
 
#19 ·
12v pack is made of 10 1.2v cells. To avoid memory effect, you should avoid charging NiCd repeatedly with only slight use, but complete discharge is very harmful.

Since the cells are not perfectly matched, there's always one cell with the weakest capacity of all. Once that cell is drained, the other cells keep pushing the current and cause that weak cell to start charging "backward".

Since the weak cell becomes drained first every time, you repeatedly stress that one cell if you discharge it all the way. One dead cell = dead pack as it becomes a burden to flow of current, just like a road block.
 
#20 ·
I did not know that batteries could be rebuilt. I to have a dewalt 14.4 drill that has went through a couple of batteries at $75 a pop. Will have to check into that. Although most of my power tools are dewalt ,i have found that the Ryobi 18volt 9 piece kit at $169.99 to be the best value ( i whould not buy anything cheaper than that). The original batteries lasted as long or longer than dewalts and can be replaced at $40 pair at HD.They still take a charge and can be used right away but wont hold charge over night. My charger went out and after paying $20 for a new one cuz i needed it right now, i opened up the old one an found a 3 amp fuse burned out. Look at your dewalt chargers may also be a fuse.
 
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