When do you replace your tranceiver batteries?

Thanks Jonathan. Looks like your recommendation there (for folks who don't read it) is to replace at 50%. Some good info in there.

Thanks for the info.

Wish there were more technical references to the reasoning. This especially since he references meter performances that vary widely. Amazingly so. Also, he prudently does not id those that perform at the extremes. 50% reasoning seems to come from the same source as the values chosen by everyone else on this thread. That is, better safe than sorry and what the heck, its only a couple of bucks to replace and it is your life that may depend on it...

Given the statement that different brands have wildly variable performance with their meters (never mind the potential for variability within a brand that was not referred to and not even sure that was tested) I personally would do some testing of my gear to see how well the meter actually meters. But the easy solution is to change earlier. It would be interesting and actually pretty easy to take a battery that meters at 80%, or 50% or something and then leave it on at room temp and test range, compared to new batteries. Also see how quickly it decays to 10% or so and how long an acceptable range is achieved with what the meter claims is a dead battery.

Doing a repeat at low temperatures would be nice, but then how to choose? A meter that is transmitting "ought" to be doing so from the confines of a warm body. On the other hand, a meter being used to receive very well could be very cold as held in a hand.

The article still only reflects the mantra that the manufacturers print on their lit. regarding battery types. Still like to know "exactly" why it is so. The "I don't need to remind you..." appears to not be an informed reason. Searching for wisdom to this question on line (itself not a wise thing to do!) results in only rather acid responses to the question from those who feel that the question should not even be asked. Most seem to suggest that it is a problem with metering. Some suggest that the device will not operate properly. All are clearly speculation.

A related question arises as why not design them to be able to use rechargeable batteries? Maybe rechargeables are too variable in type (i.e. NiCad, NiMH, Li, etc.) to be able to design to. Maybe too variable in quality or capacity? Also maybe the fact that they do not cycle forever and have declining performance over their lifetime would put too much risk in the hand of an unaware user?

If any of the above from the preceding paragraph is true, then I will resign myself to the fact that I will never get an answer to my original question simply for the reason that no one would want to accept the liability of appearing to approve of such use off-label. Still just curious.

Alan

All the detailed testing and spreadsheets end up defaulting to my advocacy of the standard 50% guideline (for daytrips) b/c it’s, well, a really good guideline! By contrast, a 90% guideline means changing batteries 5x as often for no benefits. Similarly, an 80% guideline means changing batteries 2.5x as often for no benefits. I mean, if you head out with a 50% reading, any beacon is going to function fine for a full day (plus an expected overnight) and still carry out a search. (One model in particular might start displaying very pessimistic readouts by then, but it will still work.)
Heading out below 50% will also work fine, but it becomes a question of where to draw the line, plus diminishing benefits. If you really wanted to, you could chart in great detail your personal beacon’s typical consumption curve with your typical batteries over the course of a season, combined with indoor tests, then determine exactly how far past 50% you can go head out with on a daytrip. All of which will probably save you a few battery changes each season.

As for the correlation of range and battery %, having performed thousands of range test trials, the variation in range from day to day, or even from back-to-back trials, far exceeds any range differentials that can be attributed to battery %. So range (search and also transmit) is unaffected for well past 50%.

The prohibition on non-alkaline battery chemistry includes both 100%>0% dropoffs (e.g., Li) and various disfunction (“PowerPix”). This is not speculation (e.g., I’ve personally experienced this same effect with Li batteries in other devices, and a certain beacon company rep personally tested PowerPix). Given the negligible advantages of any non-alkaline batteries for this application, hence the general prohibition. Also, the reason for the acid responses found on line is often because the questioner seems to be unaware that only alkaline are to be used, and hence the questioner is posting about blindly on-line w/o having reading the user manual first. (Note that I’m not suggesting that is the case here, but rather just explaining why such questions usually engender such responses.) And none of this is related to liability.

I appreciate your answer and quite agree with what you say with regards to both when to change batteries and also to your response to my questioning the use of batteries other than alkaline.

Mostly I am curious, but also realize why such an answer is not forthcoming from the engineers who actually design these things. To many worms to let out of the cat, so to speak. But I am still curious.

Even if most would adopt the 50% rule for battery changes, I still think that it is a good, if not fun, thing to do is to test of battery function/longevity on ones personal beacon. Knowing its capability or just demonstrating that a beacon with a very low battery is more than capable of doing the job is somehow comforting. (Learning the opposite, should there be a defect is also very useful to find out.) Careful, since very low batteries are prone to leak.

Unfortunately I do not have a meter on my beacon, so I am out luck. I have left the beacon on for many days on purpose to see how it worked and now feel very comfortable about its capability.

thanks again,
Alan

I have an older analog transceiver, with no battery indicator on it.

Whch is now widely regarded as being obsolete and should be retired....

www.avalanche.ca/cac/gear/obsolete

"Single antenna beacons. I know lots of people are hesitant to upgrade because they’re “faster with their old beacon”, they’re waiting “for the dust to settle” as new technologies standardize, or they just “don’t get out much”. Here’s why you should upgrade now …

Three antennae digital beacons generally won’t find single antenna (analog) beacons as well as digital units. That means if two people are buried close together, the one with the digital beacon is likely to be isolated first. Bad news if it’s you under the snow wearing the old analog beacon!

In a multi-burial scenario, signal overlap can be a significantly bigger issue with old beacons in the equation. Modern digital beacons are slowed down and again, it’s you under the snow who bears the cost.

Old analog beacons send out fewer but longer signals. That means in any given period of time there is less information available to process. This slows down a digital beacon. Consequently search speed slows down. Again, it’s you who pays the piper.

False maximum and complex deep burial problems aren’t an issue with modern three antenna beacons except for extreme cases (where burial depth is greater than probe length).

Multiple burial problems are generally easier to solve with modern three antennae digital beacons. And it’s only going to get easier as fewer old units remain in service.

Even in simple scenarios search times are faster with digital units – once you’ve practiced and learned how to use it effectively.

Most manufacturers require preventative maintenance every three years to ensure they function properly. This is important because frequency drift, a broken antenna, or a myriad of other problems can affect performance causing the beacon to fail. Your old beacon should be costing you money. (It could be more economical to just get a new beacon – and learn how to use it effectively!)"

Seemed to work fine when we did practice using two old units along with some new digitals.

Frequency drift not currently an issue with these units. They were picked up well and searched well. I hate to throw something away that I know works. If the unit is so bad why are they still for sale or were so at least a year or two ago?

Alan