Change batteries in your beacon below 80%?

Z · 12-10-2006, 11:05 PM

Myth or what?

I was told this in relation to tracker specifically, but later heard that you should do it with all current models. What's the consensus?

**Vicious** · 12-10-2006, 11:10 PM

I've heard and read 50%, but I always change before they even get that low.

Better sooner than later...

Z · 12-10-2006, 11:24 PM

Originally Posted by Vicious

I've heard and read 50%, but I always change before they even get that low.

Better sooner than later...

Yup. Got no problem doing it, just seems odd. My batteries were new at the beginning of the season and now I should change em? You'd think with the technology nowadays, 80% would mean 80%....

**summit** · 12-10-2006, 11:26 PM

80% is what I've been told for the Tracker.

My beacon I change the batteries when the little flashy light tells me to change the batteries.

**iskibc** · 12-11-2006, 02:16 PM

A Tracker will run effectively for 500 hours on a full battery in transmit mode.

Those hours drop a little when the beacon is switched over to search mode.

The Tracker is designed to meet the European standard for all avalanche transceivers, meaning it will search for at least one hour after transmitting for 200 hours.

Switching out your batteries at 80% is a waste of batteries. The beacon is designed to operate effectively all the way down to 0%. Once it hits 0% the beacon will pull power from a reserve.

**summit** · 12-11-2006, 02:30 PM

Originally Posted by iskibc

A Tracker will run effectively for 500 hours on a full battery in transmit mode.

Those hours drop a little when the beacon is switched over to search mode.

The Tracker is designed to meet the European standard for all avalanche transceivers, meaning it will search for at least one hour after transmitting for 200 hours.

Switching out your batteries at 80% is a waste of batteries. The beacon is designed to operate effectively all the way down to 0%. Once it hits 0% the beacon will pull power from a reserve.

Negative, batman!

500 hours at 75F maybe... you beacon gets a bit colder and Rx mode takes a LOT more juice than Tx mode and that is harder on the batteries especially when cold. The beacon will only get colder during a search. What your beacon reads for power levels when it is nice and warm is not what it will read when its been under your shell in 10F with wind for a while (think about your cellphone dying in the cold of a jacket pocket). That is why the recommended replacement levels are higher... they are assuming that users will take their reading in the parking lot after getting out of a warm car.

Originally Posted by BCA Website

•Battery life: minimum 1 hour in search mode after 200 hours in transmit mode (approximately 250 hours in transmit only or 50 hours in search only)

The Tracker manual says absolutely replace before 20% which makes sense with the statistics above. (1hr Rx function on high draw based on alkaline discharge curve at cold temperatures after 80% of usable Tx battery life)

I think something more conservative than 20% is worth considering because of temperature considerations between your check when the beacon is warm and actual life with cold batteries. 50% might be reasonable.

SAR replaces their Tracker batteries at 80%.

**Hacksaw** · 12-11-2006, 06:26 PM

FWIW = I change out my battries when they reach 50%. I figure my life and my partners life is worth at few dollars....

Besides, I have a RC helicopter I can use the 50% depleated batteries on.

**iskibc** · 12-11-2006, 11:25 PM

Originally Posted by Summit

Negative, batman!

500 hours at 75F maybe... you beacon gets a bit colder and Rx mode takes a LOT more juice than Tx mode and that is harder on the batteries especially when cold. The beacon will only get colder during a search. What your beacon reads for power levels when it is nice and warm is not what it will read when its been under your shell in 10F with wind for a while (think about your cellphone dying in the cold of a jacket pocket). That is why the recommended replacement levels are higher... they are assuming that users will take their reading in the parking lot after getting out of a warm car.

The Tracker manual says absolutely replace before 20% which makes sense with the statistics above. (1hr Rx function on high draw based on alkaline discharge curve at cold temperatures after 80% of usable Tx battery life)

I think something more conservative than 20% is worth considering because of temperature considerations between your check when the beacon is warm and actual life with cold batteries. 50% might be reasonable.

SAR replaces their Tracker batteries at 80%.

Like I said above, the Tracker is manufactured to operate down to 0% effectively. I don't think there is anyone in backcountry skiing who would want to try that out in a real life situation, but if it came down to it the beacon would operate effectively. Now, putting cold weather into play and whether or not you have it in transmit or search mode is another story. Of course those factors will drain the batter much quicker.

I typically switch my batteries out around 50% or so. They are cheap and not a hassle when it comes to switching them out.

Talking with Steve Christie over at BCA, I learned that the digital readings given for battery life are accurate at any temperature. Doesn't matter if it's 75 or 0 outside. Will the batteries drain quicker at colder temps? Yes, they are alkaline.

I've tested and practiced with my beacon at levels lower than 50% and it operates just fine. I've tested it at levels less than 20% and again had no issues with it in transmit or search. Of course you are running the chances of running out of power if you happen to get buried and you are under the snow for days on end. Keep in mind that the temperature underneath the snow is no lower than 32F, so the drain on the battery would probably be slower than if you were standing in the parking lot in zero degree weather.

I was just pointing out that the lifespan of a set of batteries is pretty darn good for a beacon. Even at 50%, you are still going to get more than a couple of continuous days of life out of it in transmit mode and at least 6-12 hours of continuous search mode use in sub-freezing weather.

**LeeLau** · 12-11-2006, 11:32 PM

How about for Barryvox? I change out at 70% and switch them over to headlight duties. Frankly I picked that number out of my ass but would like to hear from others. At 70% my receive range seems to be as good as at 99%

**mrkristofo** · 12-12-2006, 12:10 AM

I never let them get below 85% in my Barryvox. Maybe I could get more life out of them...but I use them in other things and recycle my batteries anyway.

For some reason I feel compelled to mention (in case someone comes stumbling across this in a future search) never, never, ever use rechargeable batteries in your beacon, NiCd, NiMH, Li-poly, Pu or otherwise.

**summit** · 12-12-2006, 01:34 AM

Ogre note, all nerd speak in italics for ease of skimming.

Originally Posted by iskibc

I've tested it at levels less than 20% and again had no issues with it in transmit or search

Nobody said it wouldn't work below 80 or 50 or 20%, just that one should change batteries at a higher indicated power level than 0% and that it is probably a good idea to change at a higher reading than 20%. You agree with this and so do I!

Now, putting cold weather into play and whether or not you have it in transmit or search mode is another story. Of course those factors will drain the batter much quicker.

You mean... using the beacon for the purpose for which it was designed?

Keep in mind that the temperature underneath the snow is no lower than 32F,

I am certain that you know that is a completetly incorrect statement because I am certain that you passed 6th grade science. What happens to snow when its temp "is no lower than 32F?" IT TENDS TO BE MELTY! C'mon Dave...

(there is a negligable change in water freezing point with increased altitude)

Talking with Steve Christie over at BCA, I learned that the digital readings given for battery life are accurate at any temperature. Doesn't matter if it's 75 or 0 outside.

Yes, a simple battery tester reading is generally accurate at a given temperature FOR THAT TEMPERATURE. That is physics.

(You can make a complex tester that utilizes a temperature sensor and have a computer run the measured temperature and battey test result with an assumed discharge curve for the measured temperature against an assumed discharge curve at an assumed worst case temperature.)

It would make some sense if beacon manufacturers had something like that built in, but it would increase the price of the beacon. However, I sincerely doubt beacons include such features. I've seen several beacons give different battery power indications depending on their temperature. Also: "The battery percentage is approximate, depending on battery manufacturer and operating temperature." -BCA Tracker Manual

The other way to compensate for test temp vs working temp is to assume worst case testing vs working conditions when reporting battery levels:

Did the user just turn on the beacon just after getting out of the warm car into 0F? Or did the user leave the beacon sitting out in 0F until it equalized to the outside temperature before testing it? Which situation should you assume when providing information which a user will use to determine when to change the battery?

One should probably assuming a likely worst case scenario for testing conditions versus working conditions. The worst case scenario is that user is going to:
Test the beacon warm (eg room temperature)
Use it cold (eg the bottom of the standardized operating range)
Use a high power draw mode (ie search mode)

Perhaps the design engineers took a similar approach to the reporting system. I need to call Steve about something else this week anyhow. I'll try to remember to ask him if their manual is incorrect and the Tracker truly utilizes temperature compensated battery level readings or whether they used a worse case test vs work assumption or something else entirely. Worst case s a great way to do it as long as a user stays close to the ranges of the standards the beacon is designed for.

I was just pointing out that the lifespan of a set of batteries is pretty darn good for a beacon...

All beacons have to meet the minimum standards for transmit and receive time at given temperatures. EN 300-718 requires 200hrs Tx at 10C then 1hr Rx at -10C. The Tracker's battery life is good but nothing remarkable.

Standards are standards. Do you and mother nature always operate within the EN300-718 standards? No, we don't (although most of the time we probably do). We don't know the exact details of the Tracker design. We don't know the design engineers' thought processes. We don't have a stated operational lifetime for an indicated battery level on the DTS. Tracker users only have a statement that, "The manufacturer reccomends replacing the batteries before reaching 20%." (BCA Tracker Manual). Therefor we come up with our own threshold of how much before 20%. You use 50%. That seems like a good enough idea to me.

My beacon doesn't give a %. My beacon has a "change battery" light that blinks red when the batteries have enough life for 100hrs Tx or 5hr Rx (a "reserve level"). I think that is conservative enough for me, so I follow the "change the battery" light.

**summit** · 12-12-2006, 01:36 AM

Originally Posted by mrkristofo

For some reason I feel compelled to mention (in case someone comes stumbling across this in a future search) never, never, ever use rechargeable batteries in your beacon, NiCd, NiMH, Li-poly, Pu or otherwise.

Very good point!

Please send all your Pu batteries to me... I always wanted an RTG of my very own...

**dewam** · 12-12-2006, 12:10 PM

A couple years ago I ran battery tests on two Trackers and a Pieps DSP. The Trackers did not behave the same. One Tracker was able to send and receive for over 24 hours after reading 0, but the other one quit within one hour. Although I don't expect anyone to let their battery get that low, I have found it is a good idea to run a battery test on your own beacon. My first battery test was begun when the wife said "is your beacon supposed to be on?" I had forgotten to turn it off the last time out.

From the Pieps site:
According to the standard, every avalanche beacon should have built-in flat-battery detection. If a flat battery is displayed, a beacon must be able to transmit for at least another 24 hours at +10ºC and ready to receive for 1 hour at -10ºC according to the STANDARD.
The PIEPS-DSP indicates a flat battery by displaying 01% i.e. after which the unit can still function efficiently for at least 24 hours in transmit mode and 1 hour in reception mode.

When a trip is started, there should be a display of at least 01%. There is no problem whatsoever if e.g. more than 70% or only 5% is displayed.

When testing the Pieps DSP I was able to get more than 14 days of use with a 0 battery reading on the original software. Den

**grskier** · 12-13-2006, 12:00 PM

I change mine out at 50% and keep the batteries for my xbox and tv remotes.

**jfost** · 12-14-2006, 03:25 PM

Originally Posted by LeeLau

How about for Barryvox? I change out at 70% and switch them over to headlight duties. Frankly I picked that number out of my ass but would like to hear from others. At 70% my receive range seems to be as good as at 99%

this point I think deserves some discussion...

Maybe the beacons are "functional" with lower levels of power, but do the x-mit and rec. distances decrease?? That could be reason enough to keep batt's fresh. I know my TV remote has trouble at extended range when the batt's are low, is this possible with the beacons as well!?! (IR vs. RF - paging enginerds)

edit: the obvious reason to not use rechargeables is their sudden cut-off when out of power, vs. the alkaline "fade-out" - but when does the "fade-out" start to functionally restrict the operation?!?

**hutash** · 12-14-2006, 11:20 PM

according the info provide with the Pieps it is at a very low level. They say they operate within euro standards at low temps, and will function for X number off hours(can't remember the number) at 1%. I would certainly not go that low, but they appear to have a totally functional beacon at low temps with that low a value. I assume they test it down that low, or they would have one hell of a liability issue to deal with.

**Cirquerider** · 12-15-2006, 02:15 AM

The Barryvox has an acoustic alarm when battery power drops below 20% and the unit is switched on. The manual claims 20 hours in send mode and 1 hour search mode at this depleted condition. I agree with the concensus of the Traker guys that 50% makes a good place to change over. Anyway, Mammut also claims 200 hours of send time at 99%, so they assume linearity in battery life. No doubt you have a lot of time in send mode between 50% and and the 20% warning level, but why go there.

**danhikeski** · 12-15-2006, 09:01 AM

I agree with most, somewhere between 75 and 50% is when i change them. anyways, how many remotes, handheld game systems, mp3 players, headlamps, water purifiers etc. do you have that use aa or aaa bateries. they probably won't go to waste.

**dewam** · 12-15-2006, 10:51 AM

[QUOTE=jfost;1039746]this point I think deserves some discussion...

Maybe the beacons are "functional" with lower levels of power, but do the x-mit and rec. distances decrease?? That could be reason enough to keep batt's fresh. I know my TV remote has trouble at extended range when the batt's are low, is this possible with the beacons as well!?! (IR vs. RF - paging enginerds)

QUOTE]

I have tested the Pieps for transmit distance and ability to recieve multiple beacons. There was no difference in the way the beacon functioned from 99% down to 0% After running for two weeks at 0% the beacon could still function at the same level as 99%. This was version 2.4 They must have built in one hell of a "safety" factor into their battery reading. I have not done tests on the newer software versions. Has anyone worked wit the new 4.0 version? Den

**summit** · 12-15-2006, 02:39 PM

I spoke with Steve today and he said that their people changed their batteries at a variety of levels, all of them seemed to be above 20%... some were higher than 50% some lower.

The Tracker battery tester is not temperature compensated but their designers took possible temperature differentials into consideration with battery level reporting.

Every time I talk with BCA I'm reminded how much on top of their game they are. Great company and a great product.

**brendodendo** · 12-18-2006, 02:05 PM

Good heads up. Was looking at gear after seeing this post... M2 had E2 (lithium Ion) batteries in it. Also has old battery cover. Glad I caught it at home and not in the field. The BCA tracker has good old Energizer AAA's functioning @ 80%. They are from last season and cold, but holding steady at 1.12 volts. (tested on high quality volt/ohm meter)

**abraham** · 12-21-2006, 12:43 PM

I have no experience with any of the beacons though I am looking to get one soon. So, why should you not use a rechargeable battery?

**KnuckleDragger** · 12-21-2006, 01:07 PM

Originally Posted by shitonastick

I have no experience with any of the beacons though I am looking to get one soon. So, why should you not use a rechargeable battery?

Read this thread:
http://tetongravity.com/forums/showthread.php?t=69591

**abraham** · 12-21-2006, 03:54 PM

Ok thanks, thats good to know.

**Buzzworthy** · 12-28-2006, 05:19 PM

Also, the properties of an alkaline battery are way different than a rechargeable battery, Ni-CAD, NiMH, Li Ion, Poly Ion......

I could site many webpages showing you all the ins and outs of why and I am sure you all can google that too.

Bottom line: If you want the beacon to function properly, use alkaline batteries only. Others can/will fail on you!!

For best battery life in your beacon, leave the beacon inside as well. I left mine in the garage for a week on brand new batteries, tracker read 100% and now it reads 97%. Cold will degrade battery charge. (many of you know this anyway).