DIY EPIRB Battery Replacement

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Replacing emergency beacon or EPIRB batteries is not difficult with a few parts and basic basic soldering and mechanical skills but is it a safe or viable option?

In February 2016 ACR released their new ACR 2831 GlobalFIX V4 with a 10-year battery life and user replaceable batteries. Prior to this most EPIRBs included batteries that needed to be replaced after 5-years by “factory trained personnel with OEM parts” at a typical cost of about $250.

Since the cost of a new EPIRB is about $360 it is hard to justify spending $250 replacing the batteries of a 5-year old unit that will likely last only 5 more years.

Replacing EPIRB batteries yourself is a viable and cheaper option but it is neither safe nor recommended. Does it perhaps make sense for a backup EPIRB?  Maybe – but only if you know what you are doing and only as a backup unit.

Proceed at your own risk!

Replacing the Batteries in an ACR RLB-37 EPIRB

New batteries and parts for my ACR RLB-37 EPIRB cost about $70 and took about an hour to replace and test.

Parts List


  • Soldering iron and solder
  • Screw drivers
  • Long nose pliers
  • Hot air gun
  • Multimeter

The battery packs inside the ACR RLB-37 are not available to purchase and need to be assembled using individual CR123A Lithium Manganese Dioxide Batteries (Li/MnO2) with solder tabs. Batteries with solder tabs are harder to find and more expensive than regular batteries but, unless you own a battery spot welder, solder tabs are the best option as it is not safe to solder directly onto lithium batteries without tabs.

The batteries are replaced by unscrewing four screws on the lid of the RLB-37.  The battery compartment is in the base of the RLB-37 and the battery packs are connected to a battery PCB.  Removing the two screws on the battery PCB releases the PCB and provides access to three battery packs that are connected to the PCB by wire and small connectors.

The following photos provide step by step instructions on how to remove and disassemble the battery packs, rebuild new packs and install them into the RLB-37.

The final step is to perform a self test of the unit following the instructions in the RLB-37 manual.