Category: Dewalt

Recently the Bluetooth battery status on my DCF888 impact driver was being reported as poor in the Dewalt Tool Connect app and then I noticed it wasn’t connecting anymore. I decided to ignore the warning that it wasn’t user replaceable and have a go at replacing the coin cell myself.

Disassembly was easy enough, there are eight T10 Torx screws and they’re all the same length so no need to keep track of where they came from. One of the lower screws is set fairly low into the enclosure so you’ll need a dedicated T10 driver rather than a 1/4″ Torx bit. The only other trick is to peel back the “Brushless Motor” sticker at the back and “Tool Connect” sticker at the bottom back 50% so the two halves of the case will separate.

But upon peeking around no coin cell to be seen! The Bluetooth module is a rectangular module above where the Li-Ion battery fits with the nameplate on the bottom but the top was filled with white potting compound and I feared the coin cell was within the hard potting mix. After some searching I found that this was the case and the following gives the part number:

Dewalt DCF888B Parts List

The part required is number 26 and simply labeled as “Module” with part number N559222. The only place I could find the part for sale was on E-Bay at $US58 + $US38 shipping and charges to Australia = $US96 or $AUD150 at the moment! The module has a 4-pin connector and would have been easy enough to replace but I decided to pass at that price.

While searching I found a few references to people having problems with the DCF888 not operating at all with a dead Bluetooth cell. However in my case it continues to work well and with a Li-Ion battery installed I can connect and configure the tool so I think I can live without Bluetooth when the main battery isn’t installed.

I recently purchased a Dewalt DCL050 light and while reading reviews there seemed to be a lot of questions about current draw / battery life. Dewalt claim a maximum of 22 hours but that’s about all I could find in official documentation so I thought I’d attach it to a lab power supply and measure what it actually draws. I had the PSU set to 18V which is the nominal voltage and results were as follows:

Low setting (250 lumens) = 240 mA
High setting (500 lumens) = 460 mA

With the low setting the instantaneous current draw skips around because of the PWM used to dim the LEDs so the above is a 10 second average. The largest Dewalt battery is 5 Ah and 5 / .24 = 20.8 so the 22 hour maximum sounds plausible given that batteries are normally rated for a 10 hour discharge and often perform a little better at lower discharge rates. Here’s a little table of roughly what it would be for the common battery capacities that I know of:

Capacity (Ah)   Low setting    High setting
1.3                 5 hrs           3 hrs  
  2                 8 hrs           4 hrs
  3                13 hrs           7 hrs
  4                17 hrs           9 hrs
  5                21 hrs          11 hrs
  6                25 hrs          13 hrs