Power Sources

 

Maximizing Battery Life

The eTrex 20 can provide up to 71 hours of power from a single pair of AA batteries. Alkaline batteries loose a significant amount of their capacity as temperature decreases. Use only lithium batteries when operating the eTrex 20 in sub-zero temperatures. If not planning to use the eTrex 20 for an extended period of time, store the device with the batteries removed. Several options are available to extend battery life:

• Turn the Backlight off when not absolutely needed
• Decrease Backlight Brightness
• Reduce Backlight Timeout
• Disable GLONASS
• Disable WAAS/EGNOS
• Set Map Orientation to 'North Up', not 'Track Up'
• When permissible, use the Compass or Trip Computer pages while navigating, not the Map page.

Hot Swap

On occasion, you may encounter situations where your eTrex 20 battery reserve is running low and you need to replace the batteries without rebooting the GPSr. For example, when [Setup > Altimeter > Pressure Trending = Save Always] is selected, the device displays "WARNING: Do not remove batteries while this feature is active."

In these circumstances, a Hot Swap can be accomplished using any device with a powered USB port. On grid, this may be a home or laptop computer, an AC to USB adapter, or similar devices. Off grid, a portable computer or auxiliary power source designed to power/recharge USB enabled mobile devices should be sufficient (Our favorite off grid solutions). If connecting to a device capable of communicating with the eTrex 20, a non-data power only USB cable will be required to prevent the eTrex 20 from entering Mass Storage Mode.

Performing the Hot Swap is a quick and easy process:

• Remove the battery cover
• Connect external USB power source
• Allow the GPSr several seconds to register the external power source
• Carefully remove and replace the GPSr batteries
• Ensure replacement batteries are properly seated and oriented
• Remove external USB power source
• Select [Stay On] when prompted
• Replace the battery cover
• Check GPSr for proper function

Battery Display

• The eTrex 20 battery icon provides information about the current power source and battery charge level.
• Remaining battery capacity is updated dynamically based on current battery load conditions.
• A reduction of indicated battery capacity may be observed while using high current draw features (see Power Consumption).
• The eTrex 20 battery icon reports current power information in the Status Page, Small Data Field, and Large Data Field:

 

Power Options

• Multiple options are available to help keep your eTrex 20 running for as long as you are:

Rechargeable NiMH
		Most environmentally responsible solution Multiple manufacturers and capacities available Amazon Basics or Panasonic eneloop pro are recommended For best results, choose LSD or Pre-Charged batteries Configure Setup > System > Battery Type for Rechargeable NiMH
Alkaline
		Most economical single use option Multiple manufacturers and capacities available Capacity is inversely proportional to the load applied For best results, reduce GPSr current consumption Configure Setup > System > Battery Type for Alkaline
Lithium
		Provides the longest single use runtime Best solution for use in extreme temperatures Multiple manufacturers and capacities available For best results, choose 2000mAh or higher capacity Configure Setup > System > Battery Type for Lithium
External AC
		AC USB Charger with International Adapter Set Order Garmin Part Number 362-00072-00
External DC
		DC Vehicle Power Cable Power your Garmin eTrex 20 from any 12v power outlet Includes 1.5 amp replaceable fuse Order Garmin Part Number 010-10851-11

 

Power Consumption

• Calculate your eTrex 20 battery consumption by selecting one value from each applicable category and adding them together.
• Estimated total run time (in hours) = (Battery Capacity mAh / Calculated Consumption mA).
• Garmin eTrex 20 measured energy consumption figures will be posted here in the future.

 

Battery Test

First, a word about battery consumption testing. Outside of a precisely controlled laboratory environment, no battery test result can be absolute. In real world scenarios (where we like to use our GPSr) many variables can and will affect battery consumption rates, and therefore two seemingly identical units with identical settings and identical batteries may not exhibit identical performance.

For the purpose of these tests, a eTrex 20 was adjusted for minimal operational status (Our test simulated using the GPSr primarily for tracking purposes) in an attempt to record best case scenario results. Combining this information with the power consumption chart above, one can approximate the useful lifespan for a chosen power source.

During each battery test, the following conditions were observed:

• Ambient Temperature: 80ºF
• GPS lock active
• GLONASS disabled
• WAAS/EGNOS disabled
• Backlight disabled
• Track Log Recording enabled

At the beginning of each test, brand new or freshly charged batteries are installed, the current track log is reset, and a new track log recording is initiated at a rate of one track point per minute. During each test period, the eTrex 20 is checked periodically for activity. When it is discovered the GPSr has stopped functioning, the batteries are removed, the Current.gpx track log file is imported into BaseCamp, and the total run time is recorded.

eTrex 20 Battery Test Results: