Dewalt Battery Woes

[LI-ghtcycle]

Hello all, I am sorry to report that we have tried to make our first warranty claim on a Dewalt 36v battery pack, and discovered something very unsettling. First off, now according to both the local service center and over the phone with Dewalt directly, the batteries have a TOTAL of only TWO years warranty (This is whether the batteries sit on a shelf or are in use, only 2 years maximum. The TOOLS have 3 years, but not the batteries) After much difficulty getting the batteries in the first place, we have had one of them start to give us the "flash of death" on the charger, and learned that our "3 year" warranty is actually only 2, and this one is no longer covered .

I'm hoping this will be an exception to the rule, none of the other 2 batteries we have (or my 4 28's) have seemed to have any trouble, but just wanted to mention this since Dewalt's site isn't very helpful and leads us to believe the batteries have a 3 year warranty.

I'm hoping since this pack still has voltage, even though the Dewalt chargers (we have 2) still won't charge it, that we can get either another BMS or dissect the battery and find the faulty cell/cells and replace them. This was a new out of the package battery, however the manufacture's date is 2006.

From now on, I'd recommend that we all get the date stamp from sellers of these batteries before you buy.

 

[Icewrench]

Too bad on the warranty thing. You might be able to open it up , after reading goodrums 123 threads,
check the cells voltages, if any are too low use a single cell charger to bring it up.
Some cell phone chargers can be made to work for this. Good luck.

 

[GGoodrum]

I'm guessing it might be fine, but just a bit below where the charger trips off, and you get the flashing LEDs. Try taking a full pack and connect it in parallel with the one that gets the error. Leave them connected for ten minutes, or so, and then see if the charger will now start charging.

I had problems all the time, in the early days, when I tried to use DeWalt packs directly, where the chargers wouldn't work. I had eight packs, and four chargers, and eventually none of the packs would charge, on any of the four chargers.

-- Gary

 

[LI-ghtcycle]

Wow, thanks for the advice and condolences, I will definitely try hooking up a few in parallel. I have since checked the 28v batteries and fortunately they are still under the 2 year warranty, hopefully they will not have similar problems.

 

[LI-ghtcycle]

Hello again, no luck with running a parallel set-up to revive the battery (unfortunately dad ran it down after it started having trouble) so now I think we will need to open things up and charge individual cells. Anyone have a link handy to cellphone chargers that will charge up the cells? I know I saw something here once, but I can't seem to find the thread again.

Thanks again!

 

[vanilla ice]

Cell phone chargers run up to around 4.2v, I think the voltage is too high? But you know what, the current is very low so it might be ok if you keep an eye on it.

Edit: Whoa I just hit my "3.7v" celly charger with a DMM and it says nine volts. I always thought the BMS chip was inside the phone and the wall wart was just a dumb step down, maybe not.

 

[MitchJi]

Hi,

Why not use a Single Cell Charger designed for LiFePO4?:
https://p10.secure.hostingprod.com/...talog/product_info.php?cPath=3&products_id=28

Single cell chargers for LiFePO4 batteries. These are constant current constant voltage (CCCV) chargers for 3.2V LiFe batteries. Max charging current of 2 amps. Terminated with a 5.5mm DC power plug. You can cut this and put on your own connector if desired. Fully isolated, meaning you can hookup multiple chargers to balance charge a series pack of LiFePO4 cells.

Chargers are not reverse polarity protected, do not connect in reverse.

Note, these chargers cannot be left permanently connected to battery, as chargers will slowly drain the battery.

Can be plugged in side by side on an outlet strip (as opposed to our previous version which was too wide).

CCCV to 3.65V, float charge at 3.7-3.8V.

AC input: 100-240V/50~60Hz 0.35A MAX