Pieps DSP Battery Power Meter?

[Jonathan S.]

Various posters and reviewers have commented (negatively) on the Pieps DSP battery life.

During my own testing (http://www.beaconreviews.com/transceivers/shefftz.htm and scroll to: “Electronics Issues: Battery Life”) I found no significant differences in battery life.
But that was based on starting with fresh batteries, then searching continuously for three hours.

I recently ran a somewhat controlled, albeit accidental test of sorts.
While getting ready to fly out for this trip:
http://www.tetongravity.com/forums/s...d.php?t=124070
... I decided to take out and test all the AAA batteries from my four beacons and half-dozen-or-so LED headlamps. (Not that I was planning on using all that for this trip! Just seemed like a good time in the season to see where everything was at.)
Anything below 50% I discarded, then I set aside some >50% batteries for the first two daytrips of my upcoming visit to Oregon, then planned to use fresh batteries for the three-day/two-night camping portion.

I started testing the remaining battery power with the S1, because, well, it’s the coolest-looking beacon ever, right!

Anyway, I took a set that registered a little over 60% in the S1, and put them in the DSP.
I turned the DSP on just to check, and it was at . . . 0%?!?
I discarded those batteries to be on the safe side.

Then I took two sets of batteries that were about 80% in the S1, and they tested about 60% and 70% in the DSP, so I set those aside for the first two days.

Each of those two days was not terribly long, but I like to put on - and turn on - my beacon first thing in the morning as soon as I get dressed (one less thing to forget at the trailhead!), so with a long drive from Portland and a casual breakfast, etc., total elapsed time each day from turning on the beacon to turning it off back at the car was very roughly seven hours.

Those approximately seven hours of transmit time (with maybe just a few seconds of search, to check for my partner’s transmit frequency drift, or to see if the DSP was affected by electronic interference in a car – try this with the S1, wild!) caused the battery strength to drop about 30 percentage points, i.e., from ~60% to ~30% for the first set of batteries on the first day, and then from ~70% to ~40% for the second set of batteries on the second day.

The final three days ended up being daytrips. (Threat of overnight thunderstorms cancelled our camping plans at the base of Middle Sister.)
I put in a fresh set of batteries, and waited until we were at the trailhead each day to turn on my beacon.
After about seventeen-and-a-half hours over those three days, the battery indicator had gone from 100% to about 80%, which is typical of my experience with other beacons using batteries starting at any strength level.

I’m not sure what the conclusion is from this, but here’s a chart for the visually inclined:

[pechelman]

not that any of this will help, but my battery meter is very erratic on my peips

Ill start at say 87% one day and when im done that day, be at 74%.
The next day, Ill turn it on, it will be again at 87%.
its definitely not a strong point in the beacon imo

could using partially discharged batteries, in a device not make this data significant?
perhaps the computer in the Peips has some sort of "learning" or "conditioning" that it goes through when it sees new batteries and then calculates it by that?
im no electronics engineer, and far from it, but just an idea
id always say to use fresh batteries if you can, though I understand this being an issue in an emergency case when using "spare" batteries from your headlamp.

this is definitely worht talking to peips about imo.

[Jonathan S.]

The DSP meter definitely jumps around a lot more than any other beacon, although perhaps this is because it's *always* flashing the battery strength in transmit mode (as opposed to other beacons that display it only upon start-up, or in menu mode like with the S1).
Its "rebound" from the end of one day to the beginning of the next day (having been off overnight of course) is also a bit higher than other beacons, but still not that far out of line.
But the 30% drops though over about seven hours, and the 60% vs. 0% reading in the S1 and DSP (respectively), that is puzzling.
My practical conclusion from all this is:
- continue using the 50% standard for daytrips in all other beacons
- DSP daytrip standard should be more like 70%

[Hugh Conway]

Without specifying what brand of batteries, how old they are, or other factors related to the batteries this data isn't worth wiping my ass with.

[Jonathan S.]

I think a battery set that reads 60% in an S1 and 0% in a DSP is a potentially important issue.
I also think that a drop of 30 percentage points over a seven-hour period is a potentially important issue.
The batteries had expiration dates ranging from 2012 to 2014.
They had all put into use at some point during the current ski season.
The batteries were all regular alkaline (of course) and were a mix (though not mixed within each set) of Energizer, Duracell, and generic/off-brand.
(I've used the same mix of batteries in prior seasons, and also swapped batteries back-and-forth between different beacons, yet never before seen such disparity in readings among different beacons, and never experienced such a big drop over only several hours.)

[pechelman]

i still think its important to ask Peips about this and the electronics as it might not be an issue at all for a beacon that uses fresh batteries....
(the emergency "spare" battery case is still an issue)

Ive used *fresh* batteries fine throughout a whole season with no issues. (over the course of 3 seasons)
I dont think I dropped below 73% on any of my 3 seasons using them.
Admittedly, I may not tour as much as others, but I will always wear my beacon everyday I ski, and ski on average about 40-50days a year. Each day is probably an average beacon transmit time of ~6hours. Combine that with probably ~2hrs or practice every season and thats my usage.

This has been the case over both versions of firmware ive used on the same beacon.
I want to say 2.6 or 2.8? and whatever the most current one is...maybe something stupit like 6.0? (it was upgraded last summer if that helps)

also
when you were testing this, did you notice and issues with functionality?
could you still pickup the beacon?
could the beacon still find a signal?
what happened to range?
multiples?
other functions like flagging and reading signal deviation +/- Hz?
what firmware?

[Hugh Conway]

I think a battery set that reads 60% in an S1 and 0% in a DSP is a potentially important issue

until there's some standard for Alkaline battery discharge performance, no, it's not.

[Jonathan S.]

Beacon has the older button configuration, but the latest firmware:
http://www.libertymountain.com/uploa...gradeForm5.pdf
No impact on functionality *except* that I did not test the beacon when it diplaying 0%. (It still seemed to be transmitting though.)

[Jonathan S.]

until there's some standard for Alkaline battery discharge performance, no, it's not.

I'll admit to having no EE background, but shouldn't 60% mean that some non-negligible % of the original spec transmit hours (with final search reserve) still remains, and 0% mean that it's going to shut off any minute now?

[Hugh Conway]

I'll admit to having no EE background, but shouldn't 60% mean that some non-negligible % of the original spec transmit hours (with final search reserve) still remains, and 0% mean that it's going to shut off any minute now?

To implement such functionality the digital camera industry has needed to include circuitry in the battery itself (see Nikon en-el3e batteries which can record shots taken/battery and give you information regarding when the battery will no longer hold a charge in addition to some rough indication of charge remaining).

All you get from AAs is a Voltage/Current out, all you can do is compare it against some modeled discharge. The discharge will very battery to battery making the % numbers an approximation of varying accuracy. This curvefit is part of the reason they suggest you don't use LiIon batteries in your beacon - the % indicator will always be screwy.

[Jonathan S.]

Okay, thanks.

And that also matches up with the reply I got from someone who has been testing different beacon models with, umm, some sort of tester. (Told ya I didn't have any EE background!)

*****
"The conclusion is that as I've documented for a someday TAR article,
there is no standard for reporting battery life, no consistency, and
the DSP is the most conservative, showing 0% when there are DAYS of
life left. From 70% to 40% indicated by the DSP is a change in total
battery voltage (3 cells) of 4.15V to 4.05V."

[Dobish]

i have done a couple of different tests on beacons and batteries, from a variety of companies. I have run my DPS with 3% batter life for 4 hours transmitting and 45 minutes of searching. I ran a Pulse for about 3 hours searching and 7 hours with 5% life. I tested the difference in strength signals from fresh batteries to weak batteries, and that was actually where there was the most difference (although not statistically significant, it made sense to me to have newer batteries) Just don't leave them in there unused, they will leak.