I've an "out of curiousity" question. When I'm outside with my smartphone on a sunny day, I have to cover the screen or find a shaded area to read it.
Do the handheld GPSs have the same issue? If so, how do you solve this issue?
Smartphones use backlighting to show the pixels on the screen. They are designed for lower light conditions. The backlight eats batteries and can't ever get bright enough to overcome bright sunlight.
GPS units use transflective screens. Transflective screens are a lot more expensive but they only use backlighting when the light is dim. They use the non-powered reflective quality of the screen to show the image clearly in bright sunlight without the need for additional lighting. Transflective screens are used in better quality devices that are primarily intended for daylight use.
The combination of screen size, number of pixels and backlight or transflective screens determine how much battery energy is used. Batteries last longer with transflective screens of smaller size and fewer pixels.
That's why the Garmin Oregon and other larger touch screen GPS units have less battery life than smaller non-touchscreens. The determining factor for battery life is the type and size of screen. Another battery factor is the type and size of onboard memory.
On transflective touch screens there need to be two more layers of material over the top of the image forming pixels to allow the touch sensitivity. This requires an even brighter backlight in low light conditions which shortens battery life even more. GPS users will seldom see this effect since most GPS use is during daylight. In overcast conditions or when tree cover is extreme the extra backlighting will shorten battery life even more on a touchscreen than a non touchscreen unit.
The GPS manufacturers try to keep battery use as low as possible for each unit. They do this by balancing the desire of consumers for bigger and more detailed screens with the least pixels possible and the smallest acceptable onboard memory. Adding memory or screen size or pixels costs big in battery life. The touchscreen GPS units get about half the battery life and are shipped with about half the memory of the slightly smaller non-touchscreen units.
I prefer the non-touchscreen Garmin units for another reason entirely. A touchscreen requires two hands to operate. The Garmin non-touchscreen units require only one hand to operate. Since I mostly use my GPS unit while hiking or 4 wheeling having a free hand to steady myself on a slope or while jostling in rough terrain is important. The extra battery life and increased memory is just a bonus.
