my drill seems weak, bogs down really easy in wood that my old drill handled fine, battery is full.

Diagnosis

The loss of power in your DeWalt DCD800B is typically caused by the tool operating in the wrong gear ratio or a failure in the electronic torque management system. The DCD800B features a two-speed brushless transmission; Gear 2 is designed for high-speed drilling into soft materials or driving small screws, but it lacks the mechanical advantage (torque) needed for boring large holes in hardwoods. If the gear selector is set to "2," the motor spins faster, but the drill will stall or "bog down" the moment it encounters significant resistance. Another possibility is that the gear selector switch is stuck in a "half-way" position. Because the DCD800B uses a sliding toggle, it is common for sawdust or debris to lodge in the switch housing, preventing the internal gear from fully engaging. When the gear isn't fully seated, the motor may spin, but the power isn't efficiently transferred to the chuck, resulting in a perceived loss of strength. You can confirm this by attempting to drive a large 3-inch lag screw; if the drill stops immediately despite the battery being fully charged, you are either in the wrong gear or experiencing a mechanical slip.

How to Fix It

To restore full boring power and torque, follow these precise steps to ensure the transmission is correctly engaged:

1. Remove the battery from the base of the drill to ensure the tool is completely powered down before adjusting mechanical components.
2. Locate the gear selector switch on the top of the drill housing, directly behind the chuck.
3. Firmly slide the switch to position "1". You should feel a distinct, tactile "click." If the switch feels spongy or doesn't click, use a can of compressed air to blow out the crevices around the toggle to remove any sawdust or metal shavings.
4. Reinsert the 20V Max battery.
5. Set the torque clutch (the numbered ring behind the chuck) to the "Drill" icon (the bit symbol). If the clutch is set to a low number (e.g., 5 or 10), the drill will stop spinning as soon as it hits a specific resistance level, which mimics the feeling of the motor bogging down.
6. Apply steady, firm pressure while pulling the trigger. In Gear 1, the RPMs will be lower, but the torque will be significantly higher, allowing you to penetrate dense wood without stalling.

If That Didn't Work

• Check for "Battery Sag" or Voltage Drop. Even if the battery shows a full charge on the LED indicator, an older or damaged cell can cause a voltage drop under heavy load. Swap the current battery for a high-capacity 5.0Ah or 6.0Ah battery. If the drill suddenly regains its strength, the original battery has internal resistance issues and needs replacement.
• Inspect the Chuck for Slippage. If you are using a non-hexagonal bit or a worn-out driver bit, the chuck may be slipping internally. Ensure the bit is centered and tightened fully. If the bit is spinning inside the chuck while the motor is still humming, the issue is grip, not motor power.
• Verify Bit Compatibility. Ensure you are using a "Brad Point" or "Forstner" bit for wood. Using a standard metal twist bit in hardwood creates excessive friction and heat, which can trigger the DCD800B's internal thermal protection, causing the brushless controller to limit power to prevent the motor from burning out.
• Reset the Electronic Controller. Remove the battery and hold the trigger down for 30 seconds to discharge any residual capacitance in the brushless controller. Reinsert the battery and test again. This can occasionally clear "ghost" errors in the electronic speed control.

Heads Up

• Avoid "feathering" the trigger when boring large holes; a consistent, full-pressure pull prevents the controller from fluctuating the torque output.
• Never switch gears while the drill is spinning; this will strip the internal planetary gears and permanently damage the transmission.
• Keep the air vents on the motor housing clear of debris. Brushless motors rely on efficient airflow to maintain peak torque; if the vents are clogged, the tool will throttle power to prevent overheating.
• Periodically check the battery terminals for carbon buildup or debris, as a poor connection can limit the current flow to the motor during high-load tasks.