GPS: TwoNav Aventura

[chinoook]

http://twonav.com/?op=2_0&lang=0en&prod=275

Some very interesting properties:

- about any map usable
- unlimited number of tracks, routes and waypoints
- probably very good display

with some disadvantages

- price (three times as expensive as the Garmin Etrex Vista HCx)
- big
- to few information (display resolution, battery life)

Is there any experience here with this device?


-chinoook

[Bryan]

the device can get 10 to 20 hours of operation out of its lithium-ion 3.000 mA/h rechargeable battery pack or 3 AA batteries

Compare that with 39 hours out of 2 AA batteries for the GPSmap 60CSx.

[chinoook]

Originally Posted by Bryan

Compare that with 39 hours out of 2 AA batteries for the GPSmap 60CSx.

Yes, I noticed that later. But 39 hours is impressive. I had about 20 hours with my Etrex Vista but maybe had different usage than you. I would expect the two devices to perform similar in battery life.


-chinoook

[Bryan]

Originally Posted by chinoook

Yes, I noticed that later. But 39 hours is impressive. I had about 20 hours with my Etrex Vista but maybe had different usage than you. I would expect the two devices to perform similar in battery life.


-chinoook

I agree and I wonder why the huge difference. I assume you were using disposable Engergizer Ultimate Lithium batteries? Were you using the compass or WAAS? Here is how I tested:

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.

[chinoook]

Originally Posted by Bryan

I agree and I wonder why the huge difference. I assume you were using disposable Engergizer Ultimate Lithium batteries? Were you using the compass or WAAS? Here is how I tested:

I will someday apply exact the test you performed, then we will know better.

I did

- turn off WAAS
- use compass often (don't know wether turned on permanently)
- took dense trackpoints


-chinoook