GPS: Energizer lithium batteries

[Bryan]

Originally Posted by Bryan

I tested the life expectancy of Energizer Lithium disposable batteries because they should last longer than any other available battery. They are also lighter weight than alkaline batteries. One AA alkaline battery is 23.7 grams and the lithium is 14.5 grams.

I tested with backlight off, compass off, WAAS off, and battery saver mode off. I tested indoors at about 20°C (about 70°F). I simulated real world usage by changing screens periodically and turning the power off about every 6 to 8 hours. While on, the GPS was logging its track position once every 30 seconds for my first test, and once every second for the second test. The batteries lasted for 40.75 hours in the first test, and 39.75 hours in the second test. This is more than double the usual 18 hours reported for alkaline batteries.

The battery meter did not go from four bars down to three bars until about 35 minutes before all power was lost. Two bars showed at 12 minutes remaining, and one bar showed at 9 minutes remaining. 0 bars showed and the warning beep and message were issued with 6 minutes remaining. These results were observed with the battery selection set to “alkaline”.

Since disposable lithium batteries cost more than twice the price of alkaline batteries, they are not cost effective from a pure time vs. money perspective. But in addition to the convenience of less frequent battery changes, and the slight space savings, the weight savings is very significant. A quick weight calculation for enough batteries to run for 160 hours: 8 lithium batteries at 14.5 grams (0.51 oz) = 116 grams (4.08 oz) vs. 18 alkaline batteries at 23.7 grams (0.84 oz) = 426.6 grams (15.12 oz). The total battery weight factor is about 3.7:1. That’s a huge weight savings when you need to carry enough batteries to last over a month!

Incidentally, rechargeable batteries are a good alternative, but not for long hikes, when one never knows when electricity will be available.

The above test was done in May of 2008. Energizer has since come out with some cheaper lithium batteries which they call Advanced Lithium. They are about 30% cheaper than the original lithium batteries, which are now called Ultimate Lithium, but they have less power and are not any lighter weight. The packaging isn't that different if you aren't looking closely. Be careful not to buy these by mistake (like I did). Make sure to get the Ultimate Lithium batteries.

[Bryan]

Energizer has changed the packaging for ultimate lithium batteries and claims that they are improved.