Rookie Question - GPS battery croakage . . .

[+Wingnumberone]

I'm trying to see how long I can keep a streak rolling - 'till I bag all the caches between the casa, the gym, and the office. I've been picking off C&Ds & LPCs for over a month, and I'm getting to where I have to hike a little to get my daily smiley. I usually roll with a caching kit, containing spare logs, batteries, minimag lite, bison tube O-rings, baggies, tweezers, etc - but when I'm on the way from work to the gym, and just hop off the bike for one, I typically jam the eTrex 20 in my pocket and go.

 

Yesterday was such a day. Parked the bike, and started scrambling back a trail, toward what I was sure would be a relatively quick grab. I've found over 20 of this gal's hides - her coord's are usually spot-on, and they don't require bush whacking, as a rule. GPS puts me 1/8 of a mile in, and over 100' off the trail in some pretty dense stuff - I'm surprised, but follow to GZ, just as I get the "beep" for low battery. I'm not running back to the bike for batteries, so I start working around a promising-looking tree near GZ. I look back at the GPS, and it now has me 80 - 100 feet off, GZ is back out towards the trail.

 

I hustle back out to the trail, and am bearing down on the "new" GZ, when the Garmin goes black - dead as a doornail. I started poking around, and made the grab, but thought it strange that the eTrex would lock in on a false target that far off. Skies were clear, and tree canopy wasn't particularly dense. I also found it strange that the unit would bother to give a low power warning - with less than five minutes left in the tank. This is the first time I ran it totally dead. I usually pop fresh batteries in at the warning beep. Is this weirdness typical when the ol' AAs are in their death throes ??

Edited October 19, 2012 by Wingnumberone

[+WRASTRO]

I have found over the years that my Garmin loses accuracy when the batteries are less than about 50%.

[7rxc]

Me too! I got bit good a few weeks ago, not finding anything at the coordinates so I gave up and went to the second cache... that time it looked better, but nothing. Then I got the beep, looked down and it said low battery and 5 seconds later... bye.

 

That was my map60cx... I do find that there is a bigger occurance of this when I am using rechargables (NiMh), as most rechargables have a quick drop off when getting down to minimum. Alkalines are not like that, just keep fading away. The GPS senses when you are getting to minimum operating voltage and triggers the message and shutdown. Rechargables just do it quicker.

 

IF you do use rechargables of any type, make sure you set the type of battery appropriately, even fully charged NiMh and Nicads are almost down to the point where Alkaline cells show low. Setting the type to NiMH (1.2v) adjusts that setting and the 'meter' bars.

 

Doug 7rxc

[Clan Riffster]

Like Wrastro and 7rxc, I've noticed that battery life has some noticeable affect on GPSr accuracy. I'm not a battery expert, but what I've been able to glean from the Internets is that higher end rechargeable batteries behave quite differently than disposable batteries. Hopefully, someone brighter than me will correct me if I'm wrong, but it seems that the better rechargeable batteries maintain a constant voltage output right up until they are almost dry, whereas disposable batteries lose voltage as they lose volume? I can't help but think that any electronics designed to function at a specific voltage range, would have its abilities reduced as the voltage decreased? Maybe?

[+ras_oscar]

Yeah, I've seen that too but not 80-100 feet away. If you are keeping your GPS in your pocket your body is blocking the GPS signals and giving you a false reading. I discovered this by accident when I was doing a cache run and running a tracklog to enter the trails into OpenStreetMap. When caching I usually leave my GPS in my hand, horizontally oriented with the strap wrapped around my hand to keep from dropping it. On this particular occasion I found all the caches, and left the tracklog on but put the GPS vertically in my shirt pocket to free my hands to get somethting out of my pack. When I downloaded the tracklog I was suprised to find that when I put the GPS in my pocket the tracklog immediately veered to the north about 100 feet and placed the trail in the middle of a lake. The route in was dead on. Same batteries, about 15-20 m inutes apart.

[+redsox_mark]

I've never noticed this. I generally leave the batteries in until they go dead.

Doesn't mean it doesn't have an impact, but I've never noticed it.

Every once in a while I find my GPSr has a "funny moment" - it sends me somewhere 100 ft away, then settles down and changes it's mind and sends me to the right place. But I have not correlated this with low battery.

[+JL_HSTRE]

Every once in a while I find my GPSr has a "funny moment" - it sends me somewhere 100 ft away, then settles down and changes it's mind and sends me to the right place. But I have not correlated this with low battery.

 

I had this happen on consecutive caches 2 weeks ago with my Etrex 30, despite the batteries being almost brand new.

[+TeamTwoStar]

 

Is this weirdness typical when the ol' AAs are in their death throes ??

 

This same thing happens with my magellan...it basically goes from charged to dead with no inbetween..and the accuracy is awful just before they die.

 

We use the Energizer 9x Lithium batteries...they last quite a while...over 24hours of continous use for a single set. but they cost 20 bucks for an 8 pack...I recently found an a bulk sale on ebay for about half the cost..so 10 for 8 batteries.

[+Sharks-N-Beans]

We see this all the time (only use disposables in the Dakota 10). If we are struggling getting a fix on GZ and are below half, we'll pop new batteries and many times have the cache within a minute. Since we usually only use the Nuvi in the car for extended trips, we'll pop the old batteries back into the Dakota to guide us to the next cache until they are completely spent.

[+BAMBOOZLE]

Like Wrastro and 7rxc, I've noticed that battery life has some noticeable affect on GPSr accuracy. I'm not a battery expert, but what I've been able to glean from the Internets is that higher end rechargeable batteries behave quite differently than disposable batteries. Hopefully, someone brighter than me will correct me if I'm wrong, but it seems that the better rechargeable batteries maintain a constant voltage output right up until they are almost dry, whereas disposable batteries lose voltage as they lose volume? I can't help but think that any electronics designed to function at a specific voltage range, would have its abilities reduced as the voltage decreased? Maybe?

 

I believe what you say is true......from the first we've used MAHA PowerX batteries and never had issues. More recently we started using Sanyo Eneloop 2500's and they are simply the best.....you can get a long day out of a 450 and I've never run down the 62S....all with no change in accuracy.