PLB battery replacement?

I think it depends on the features you wish for.   I’ve had two Garmin (DeLorme) devices and currently have a Mini.   It goes with me, and is turned on, on long day hikes where there is spotty cell signal.  It goes with me on long hikes also.  I charge it up when it drops to 50 percent post-hike.

I pay $12 a month for an InReach Mini.  Plus $400 to buy it.

I’ve been using it for a few years.  Mostly, I just send a nightly message to say where I’m camping.  The only problem is sometimes it’ll take even a couple hours to acquire and send a message.  Other times 5 minutes.

I’m looking forward to satellite communication on phone.  Samsung is working on it.  Maybe S25 will have it.  I think iphones have limited capability currently.

Thanks for that perspective. I also backpack alone, and I chose an Inreach Mini for the same general reasons. I like being able to communicate as well as sending an SOS. The charging really isn’t much of an issue because I leave it turned off until I want to send a message. But the monthly charges are significant. I’ve only used the SOS feature once, but on that occasion it was really helpful to be able to get information from the dispatcher, and it avoided the need to send help in-person.

Thank you for this post and for the responses.  The only time I used a PLB, it was a heavier Garmin, and it worked.  There was an injury, and we ended with a free ride to the nearest hospital.

For less than $30 did order a new battery for the Ocean Signal PLB1, a much more compact and light item.  Also carry it for day hiking.  Only problem is, would not rely on it without a reliable test of the battery, in the PLB.  Without that, I would not carry the device, except as a back up in areas where my cell phone would be in range of a 911 call.  Otherwise, think I’ll see what Garmin is offering these days for a light PLB.

Have been in plenty of jams as a younger and more fearless soul, and got into several situations that at my current age, I probably would not survive or would at least be immobilized.  So if not in cell range, which can readily be tested, I would want something I could be sure of.  In the meantime, I’ll remain in cell range.  Having actually needed a PLB, gave me a permanently different outlook.   It doesn’t bother me a bit being a wuss these days.  In my mind’s eye, I can still see the looks on the faces of those two grizzlies in the Canadian rockies.  Not to mention a 50 foot slide down a bumpy shale bed.  Was in tip-top shape then.  Happy Trails.

I’ve owned an InReach SE (originally from Delorme) for close to 10 years.  And I recently acquired an ACR ResqLink PLB off of eBay.  Its battery expired in 2022 and I’ll probably do a similar “DIY” replacement.  I see that the battery can be found on Amazon.

Why did I buy a PLB if I already have an Inreach?  I run Map & Compass skills workshops through my local outdoors club, and just finished offering a Caltopo/GPS/PLB workshop as “Part 2” for those looking to take their skills to the next level.  I wanted a “Show and tell” PLB to pass around and so we could discuss the pros and cons of each.

This is a really interesting case study for how PLBs work and serves to highlight some of its drawbacks.

https://blog.oplopanax.ca/2011/08/personal-locator-beacons-from-the-rescuer%E2%80%99s-perspective/

• Rescuers may not get accurate coordinates with some older PLB models.
• Rescuers have no way of knowing the nature of your emergency.
• The party calling for help has no way of knowing when they will be rescued.
• The party calling for help has no way of knowing in what form the rescue will take.  Will it be a helicopter?  Or will it be a small SAR party on foot?
• PLBs can only be used for absolutely life & death SOS scenarios.

there have been several cases where I personally, or a friend who also has an Inreach, has used them to get out of a bind in a non-SOS scenario.

1. Case 1:  Hiker in a group on Isle Royale sprained her ankle and couldn’t continue with the multi-day trek to reach the far end of the island.  This was not worthy of a SOS activation.  InReach owner messaged contact back home who called the Ranger’s office on the island to explain the situation.  The park service agreed to pick up the injured hiker via boat at McCargo Cove the following morning.   Crisis averted.  What would their options have been with a PLB?
2. Case 2. Three of us were hiking a big out & back loop up near Banff but one of the guys started having knee problems.  We wanted to cut out a portion of our loop that was a big descent into a valley and climb back out again, but part of our itinerary was on National Park land with designated campsites.  Using the InReach, I contacted someone back home who called the park office and changed our permit itinerary so that we could take our time making our way back to the Trailhead using different designated campsites along the way.   Without the InReach, we would have run the risk of encountering a ranger and being “off permit” needing to explain our situation.

I think PLBs are great if you don’t want to be tied to a data plan with a commercial 2-way satellite communicator.  But most of the big 2-way sat com. providers offer a way to suspend your data plan during months when you’re not using it.  Which is what I do with my InReach.  Also, the InReach devices have proven to be very reliable devices.  They don’t need higher transmitting power because the satellites are in a lower orbit.  SARSAT now works largely off of the GPS satellites orbiting at 20,000 KM, and some GOES satellites orbiting at 20,000 miles.  Iridium satellites (servicing Inreach and some other devices) orbit at an altitude of 485 miles.   Garmin has some great stats about number of rescues performed, what types of users they were, the reasons for the rescue, etc.

Todd – there seemed to be a lot of confounding factors affecting the location accuracy, as described in the article.

1. Weather
2. Speculation that the 121.5MHz transmission could affect GPS reception
3. Speculation that the GPS in the PLB couldn’t get a fix in part because it couldn’t get a good enough signal to receive all the needed ephemeris data first.

There are other factors that can affect GPS accuracy besides weather as well.  These can include signal multipath issues caused by tall surrounding mountains and high solar/geomagnetic activity.

I believe the transmit power of PLBs at 406MHz is 5W.  The InReach transmits 1.5W at 1.6GHz.  Frequency can also matter.  I know that different WiFi frequencies carry better than others.  I don’t have the background to say which combination of frequency, transmit power, and distance to the receiving satellites yields the best outcomes.

Another performance factor is GNSS Almanac and Ephemeris data.  Having out of date almanac and ephemeris presents GNSS receivers with TTFF (Time To First Fix) times, called “Cold Start” and “Warm Start” times.  A PLB that only gets a “GPS Test” once per year, per the owner’s manual recommendation, will almost be guaranteed to be in a “cold start” scenario when activated because almanac data is only valid for 180 days.  This means that even under ideal conditions, TTFF could be  12.5 minutes, or longer if there are signal quality issues due to weather.  With a device like an InReach, I may send out a “checkin” message every day, ensuring that the GPS receiver in my device has updated almanac data and is only ever in a “warm start” scenario, meaning TTFF is much faster.

It’s difficult to judge which class of devices have the better GPS receiver.  And it may be outright silly to generalize or speculate.   The one I got off of eBay is an older PLB-375 and I can’t find any detailed specs on the GPS receiver chip used by it.  The newer PLB-400 claims to be a “GPS and Galileo GNSS receiver” but again, absolutely no chipset specs provided.  :-(   According to GPSrChive the Garmin InReach Mini2 and InReach Messenger use a newer chipset with pretty impressive looking specs.  (33 tracking-channel and 99-acquisition channel, with a cold start TTFF of 27 seconds! )

Since the incident was from 2011, it was probably an older PLB that was being used.  My older Lowrance Handheld GPS receivers around that era only supported like 12 channels if my memory serves, and it and performed poorly in some areas.  Modern GPS receiver chipsets, combined with the availability of GPS, GLONAS, and Galileo GNSS constellations perform so much better, so long as the device you’re using has one of those modern chipsets.   Then again, my InReach SE is also 10+ years old, and I’m still relying on it.  Someday I will upgrade…

My Pixel 6 has pretty darn good GPS reception too.  Since you’re Android, check out a small free app called GPSTest.  It will show you all the GNSS satellites it “sees” and is using to acquire a lock, your current estimated HOrizontal and Vertical accuracy, etc.

Cell phones benefit from something called AGPS (Augmented GPS).  They can use the cell phone network to grab the current GPS almanac and ephemeris data instead of waiting for it to be slowly fed as part of the GPS transmissions.  It eliminates the cold start and warm start delays.

I have an 8-9 yr-old ACR Resqlink PLB. Year before last I had the battery replaced by Satellitephonestore.com, their San Diego office. Presumably they do other brands as well. You can get a quote online to see if they have your battery. Service was very quick and they provided a full test report etc. Recommended.

Randy – do you recall how much it cost to have the battery replaced in your ACR ResQLink?