PLB battery replacement?

[John Q]

I have an Ocean Signal RescueME PLB1 beacon that I purchased in January 2015.  The battery in the beacon expired in February 2022.  It’s time to either replace the battery or buy a new beacon.  I have contacted three different “authorized battery replacement” companies recommended from the manufacturer either with no response or that they no longer carry those replacement batteries. I am happy with this PLB because of its size, weight and specifications ( thankfully I never had to use it ).  I’m hesitant about buying a new one because of its inability to be serviced.  Which other PLB would any of you recommend?  Or should I just buy another rescueME PLB1 since its battery life is good for seven years?

[Ray J]

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.

[Jerry Adams]

google “rescueme plb1 battery replacement”

for example https://www.cruisersforum.com/forums/f13/ocean-signal-plb1-battery-replacement-instructions-271251.html

I saw a battery on ebay for $40

maybe just do it yourself?

you might throw $40 away

I changed my Garmin InReach battery successfully, although it was a bit tricky

[John Q]

Jerry, thanks for the link.  That gives me another option of changing the battery myself.

[Dan]

Sorry to derail the thread, but just out of curiosity, what is the advantage of this type of beacon over something compact and lightweight that allows two-way communication, like a Garmin Messenger?  Is it mainly the trade-off of ongoing fees vs functionality? Or are there additional factors?

[Jerry Adams]

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.

[Matthew / BPL]

Dan, my understanding is that a PLB (which is different than a satellite messenger/communicator) has a much stronger signal. Also, you don’t have to recharge it. It just sits there turned off until you (hopefully never) have to use it.

There are many disadvantages of course. All it does is send a very strong signal indicating you need help.

[John Q]

Dan, I generally always backpack solo.  There is almost never any cell service unless I am on a ridge.  I carry the PLB as my last resort to request immediate help if required either for myself or any other emergency situation that may arise.  As noted before, there is no monthly subscription charge, no timely battery recharging required, sends a very strong signal and the PLB battery life is seven years.  I’m close to seventy years old and it gives my wife some peace of mind ( I think that’s the most important factor ).

[Todd T]

All it does is send a very strong signal indicating you need help.

Well, it does send your GPS location (if available) and then starts sending a homing signal on another frequency to direct aircraft to your position.  And it works globally, with access to two sets of satellites.

I don’t carry any kind of SOS device, but if I ever do, I’m sold on the simplicity, reliability, and foolproofness of a PLB.

[Dan]

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.

[Eng-Shien Wu]

I literally just finished replacing my PLB1 battery with one from Ebay… I used this YouTube video.

Warning: it’s trickier than it looks as you have to align the battery, the foam pad, shield, and board back into the case just so. It took two tries–take a picture of the stack when you pull it out. Make sure the battery cable hangs below the top battery or it will get pinched by the post.

I tested it with the test button and even activated/deactivated it inside a metal file cabinet without extending the antenna, but I’m still left wondering if it really will work if needed. Fortunately, it just the backup to my iPhone 15 SOS.

My parents have one that will also need battery replacement and I was thinking of paying to get it done the right way when I came across your post…

[Sam Farrington]

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.

[Jerry Adams]

“Warning: it’s trickier than it looks…”

same with replacing the InReach Mini battery, getting a foam piece right, a couple attempts before I got it to work,…

with the mini, it’s easy to test to see if it works

There’s no way to send a test message with the PLB???

I would be skeptical that it actually works if I couldn’t test it.

[John Q]

Thank you all for your responses.  I’ve decided that the most responsible thing to do is not to change the battery myself and I went and ordered a new Ocean Signal rescueME PLB1 from REI.  Now I don’t have to be concerned about using a non-OEM battery, if it is situated in the enclosure properly or if it actually works, etc.  Thanks again for all your help and guidance.

[Eng-Shien Wu]

Another interesting observation.. the battery inside has an expiration date that is two years after the expiration on the PLB1. I guess they were being conservative.

> I would be skeptical that it actually works if I couldn’t test it.

That is the problem with PLBs in general.. it is one-way so you are left wondering if you are carrying a dud even if brand new. Doubly so if you had to force its contents back into the case…

I am hoping the Starlink T-Mobile will happen eventually to make the InReach pointless. I had a poor experience with the original InReach (Delorme?) on the PCT.. the first died in the desert and the replacement would not communicate reliably even with clear view of the sky. I also found out that I really didn’t need to communicate more often than I got cell coverage.. texting is time you aren’t hiking or eating or sleeping.

[Jeff McWilliams]

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 T]

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

Interesting read.  But it seems that most of the noted drawbacks were related to GPS, not the PLB in particular.  Any of the newer 2-way options would seem to have had the same problems?  And the PLB did manage to make authorities aware of the SOS early, even if the location at that time was uncertain.  It seems odd to me that the rescuers seemed to have little idea how PLBs worked prior to this incident.  (The article is dated 2011, so there was no real alternative to PLB at the time.)

[Inreach devices] don’t need higher transmitting power because the satellites are in a lower orbit.

But isn’t the higher power of a PLB better at cutting through bad weather?  Or does weather attenuate either signal enough that it can’t reach its intended satellites?

[Jeff McWilliams]

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…

 

[Jerry Adams]

my phone (S23) has a much better GPS receiver than my InReach

that is, the InReach can take an hour or two to acquire a satellite.  My phone takes maybe 5 minutes max

[Jeff McWilliams]

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.

 

[Jerry Adams]

i have one called gps status that’s free and seems to work

probably equivalent to gps test

[Moab Randy]

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.

[Jeff McWilliams]

Jerry – Here are two side-by-side screenshots from GPSTest for Android.

I like seeing the detailed list of satellites from the different constellations (GPS, Galileo, GLONAS).

And the “Sky map” is also interesting.

When the app first starts, the list is updated in real time as satellite transmissions are received.

 

[Jeff McWilliams]

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

 

[Moab Randy]

Sorry, Jeff, I don’t have a clear memory of that–it was $100-something. I felt it was reasonable compared to buying a new beacon. Just give them a call, or go through their quote on the webpage.

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