Team Toad: Battery Tests

18V XR+:

3.02 AH @ 1 hour rate
Excel spreadsheet  

2.40 AH @ 30 minute rate
(two in series for this test)
Excel spreadsheet  

Panasonic 3000 mAhr:

2.96 AH @ 30 minute rate
(using 4 packs in series)
Excel spreadsheet

Runtime vs. amps and voltage droop
Excel spreadsheet

Panasonic 3000 mAhr NiMH vs.
DeWalt 18V XR+ Nicad
at 42 amps (8 NPC 60438 motors)

30 seconds more with NiMH
Excel spreadsheet

What's the AH capacity of the DeWalt 24V XR battery? The forum has ranged from a low of 1.7AH to quote from DeWalt of 2.0AH to a guess of 2.4AH.

Okay, there's nothing like empirical observation to settle this kind of argument.

Using the DeWalt 24V XR pack that came with the $299 kit (hammerdrill, charger, and 1 battery pack), I measured 2.44 AH running an actual NPC 60522 wheelchair motor. Using the same method, we tested the 18V XR+ battery at 3.02 AH.

Here's how I came up with that number:

1. First I drained the battery completely by running the motor. That took almost an hour.
2. Next I hooked up an ammeter with a 50 AMP shunt and the NPC 60522 motor.
3. I ran the motor for 57 minutes, taking periodic voltage and current readings.
4. I made an Excel spreadsheet and added up the interpolated amp-hour numbers for each time segment.
5. Those totaled 2.44 amp-hours from 27 down to 23 volts.

So who's right? You tell me.

The battery provided only 1.81 AH before dropping below 24 volts.
It provided 2.25 AH down to 23.61 volts.
My number is 2.44 AH down to 22.41 volts.

We ran the same tests for the DeWalt 18V XR+ pack with 1 motor (for 80 minutes) and 2 packs in series running 2 motors in parallel (for 20 minutes).