External Power for Garmin GPS Receivers

If you intend on using a connector to build your own cable to provide power to your Garmin GPS (whether as a combined data/power cable, or just a simple power cable), please make careful note of the maximum voltage that your GPS unit can handle without being vaporized. The eTrex/eMap/Geko receivers can deal with no more than 3.25 volts. Some common older Garmin GPS units (such as the GPS 38 and GPS 12) require 5-8 Volts. If 12 Volts (the standard voltage provided by a car battery) is applied to any of these models of GPS receivers, they will be destroyed. Some Garmin units are fine for up to around 40 Volts, but check the specs on your unit first before building a power cable and hooking your GPS up to it. If you have one of the units that must have less than about 15 volts (a car battery can reach a few volts more than 12 while being charged), you must build a regulated supply into your cable. Schematics for a 6V regulated supply are available in the documentation of how to construct a cable with one of the round connectors. Note that if you are building a cable for the eTrex, eMap, or Geko, these schematics will not work for you, since even 6V will destroy your receiver. Instead, you may want to look at the Mobile Power Supplies section on the web site of fellow Pfranc, Mast of Estonia, or consider the purchase of a power inserter cable that provides a regulated 3V supply to eTrex/eMap/Geko receivers, as well as an unregulated supply voltage to receivers that can handle a voltage range up to about 15 volts, or a combined eTrex data/power cable if you'd rather only deal with one cable. Keep in mind that our power inserter cable only works with the data cables we carry - it will not work with any other data cables, including Garmin's own.

The following table provides the voltage ranges acceptable for the numerous GPS receivers that Garmin makes. Note that although there is a fairly large variation in acceptable voltage ranges, most of the Garmin GPS units in common use can be used with a 3, 6, or 12 volt supply.

Since Garmin is always coming out with newer models, this chart may not be completely up to date. In addition, as errors may be present in the table, it is always best to check with the specifications in your user manual first - we cannot be held responsible if the construction of a cable from information in this table damages your GPS, computer, power source, or yourself. Note also the two styles of connector we offer may not fit all GPS receivers in this table - we only offer rectangular connectors that support the eTrex/eMap/Geko series, and round connectors with 4 pins (with or without a 5th centre plastic post) on receivers such as the GPS 38, GPS 12XL, etc.

3-3.25 3 eMap, eTrex, Geko, Rino
5-8 6 GPS 12, GPS 38, GPS 40
5-40 12 GPS 95XL
6-40 12 GPSMAP 175, GPSMAP 195, GPSMAP 295
8-40 12 GPS 89, GPS 90, GPS 92
9-33 12 GPSCOM 190
10-18 12 GPSMAP 168 Sounder
10-32 12 GPS II, GPS II+, GPS III, GPS III Pilot, GPS III+, GPS 12CX, GPS 12MAP, GPS 12XL, GPS 45, GPS 45XL, GPS 48, GPS 60C, GPS 60CS GPS 120, GPS 120XL, GPS 126, GPS 128, GPSMAP 130, GPSMAP 135 Sounder, GPSMAP 162, GPSMAP 180, GPSMAP 185 Sounder, GPSMAP 205, GPSMAP 210, GPSMAP 215, GPSMAP 220, GPSMAP 225, GPSMAP 230, GPSMAP 235 Sounder, StreetPilot, StreetPilot ColorMap
11-33 12 GMA 340, GPS 100AUD, GPS 100PRT, GPS 100STD, GPS 150, GPS 150XL, GPS 155TSO, GPS 155XLTSO, GPS 165TSO, GPS 400, GTX 320, GTX 327
12-18 12 GPS 125 Sounder
14 14 GNC 250, GNC 250XL, GNC 300, GNC 300XLTSO
28 28 GNC 420, GNS 430, GNS 530

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