I've been using a 62S for a few weeks now and have been very pleasantly surprised with it's battery life.
Since I'm a battery nut and stumbled across this thread I figured I'd share some of my experiences and the run-down tests I've been running.
I used a pair of 2600mah Ni-MH, a pair of generic low self discharge (LSD) 2200mah Ni-MH cells, and a pair of very high quality japanese Duracell 2100mah NiMH cells (they are the famous Sanyo Eneloops rebranded for Duracell and are sometimes dubbed "Duraloops" )
I also used a pair of the PowerGenix NiZn just for shiggles since these cells are designed for high discharge rates such as digital cameras, motor powered toys and so on and actually have a fairly SMALL capacity of about 1500mah. As a trade off, they can produce amazing amounts of current. In fact, that's how I found out my battery load tester, while rated to 30 amps, wasn't CAPABLE of handling even 25 amps lol!!!
However, since a GPS uses fairly little current, their benefit is minimized... They also have a shorter cycle lifespan, require a special charger and are now quite expensive. I don't see much of a reason to use this type of battery technology in any GPS. Though feel free to use them in sub-freezing tempuratures since Alkaline and NiMH cells take a HUGE performance hit under 32 degrees F. Frankly, I just use lithiums when it gets cold
Some information about my testing methods and equipment:
I used my LaCrosse BC-9009 (No issues with fires on this model and it's now replaced by the BC-1000) to ensure all the NiMH cells were charged correctly and how much charge capacity they each had. The cells used for testing were all "matched", this means they have VERY similar capacities (I accept no more than 200mah (2%) difference) and discharge curves (meaning they "go dead" at the same time)
For the NiZn batteries, I used the standard 4 cell charger provided from PowerGenix. Please note, I read earlier that people were wondering about the chargers for the NiZn batteries, there are TWO MODELS, one will ONLY charge 2 or 4 cells at a time and one can charge 1-4 cells at a time. A quick way to tell the difference between the two is the one that will charge only 2 or 4 at a time will have 2 red LED's on the front, the "one-at-a-time" model has a red and a green LED.
I also used only three pair of Energizer alkalines. I really don't use disposable cells, sorry!
Each run down test was timed from the moment I turned it on, to the moment the device shut off. I used the 62 normally, navigating both on road and off, tones on, battery saver off, WAAS on, mag. compass on. For the backlight tests, it was set to 'Always on"
The Results:
Covering the NiZn cells first, they had somewhat shorter run times than the 2100mah Duracell NiMH, but the difference was only about 1.5 hours give or take a few minutes
NiZn 1500mah - 2 runs/each
No BL: 13.9 hours
50% BL: 11.3 hours
100% BL: 7.9 hours
Not exactly impressive.
The generic and the brand name LSD NiMH cells performed so closely to each other that I'm just going to lump them together
NiMH (Low Self Discharge) 2100mah - 4 runs/each
No BL: 15.6 Hours
50% BL: 12.9 Hours
100% BL: 9.2 hours
Better Finally, my high capacity cells...
NiMH 2600mah - 2 runs/each
No BL: 19.1 Hours
50% BL: 15.5 Hours
100% BL: 11 hours
Excellent Last and least, the disposable one's for completeness sake.
Alkaline - 1 run/each
No BL: 19.8 hours
50% BL: 14.9 hours
100% BL: 9.1 Hours
The backlight was the biggest hit on all these run tests. If you are finding your 62 is eating batteries use the power button to turn off the backlight and leave it off as much as possible if you're in conditions where you have plenty of light. Also, turning off the shaded contours helps greatly with the screen visibility requiring you to use the backlight less.
Other things to keep in mind:
- A worn out rechargeable will provide only a fraction of the run time expected despite a "full charge".
- A defective rechargeable cell in a pair will also cut your run time to mear hours or even minutes depending on how bad it is.
- Rechargables don't last forever AND a poor charge makes then die even sooner!
A good charger is ALWAYS a worthwhile investment if you use Ni-MH's! My LaCrosse BC-9009 cost almost 50 bucks and the new BC-1000 model pushes 60 on Amazon as of this writing. It's a good sized investment IMHO, but is VERY worth it when your $5 charger is continuously destroying $15 packs of rechargables many hundreds of cycles early while giving you lousy run times. Mine has paid for itself 7 or 8 times over now... TBH, I've lost track lol!!
Btw, people also like the PowerEx C9000, I do not. Too hard to use.
bcblues, it sounds as if you have a defective 62, I suggest using your warranty...
Hope this helps all! Happy Caching!
**I know the data here shows alkalines experiencing an exponential drop off in run time, this is not an error despite only a single sample set. This is just the nature of the beast. The more current you try and draw from a disposable battery, the shorter it's life. They are most happy around 100mah draw current and will provide a capacity of nearly 3000mah, unfortunately, even with no backlight, the 62 draws more current than that