Don't Trash that Old Garmin 48 GPS!

Posted by Darrell Nicholson at 09:40AM - Comments: (13)

The dreaded “Memory Battery Low” error in your old Garmin GPS 48 doesn’t mean the unit is doomed . .

I was rummaging around the dead letter office at Practical Sailor and came across this bit of advice tucked away in our old Mailport files. Knowing that many Practical Sailor readers, like me, are quite content with a set of charts and a basic GPS showing position, course and speed data, I thought it would be a good idea to resurrect this handy tip. Hopefully, it reaches you before that ye ol’ Garmin gets chucked out during some overzealous spring cleaning.

Introduced more than 10 years ago, the GPS 48 was one of Garmin’s best selling handheld GPS units. I like to think of it as the first nail hammered into mighty Magellan’s coffin.

Sadly, the unit wasn’t meant to last forever. Or, should I say, Garmin did not intend to support it forever? Doesn’t matter. Sooner or later, the lithium battery required by the internal memory peters out, leaving all but the most industrious owners with a worthless piece of plastic and a bad taste in their mouth.

Fortunately, Practical Sailor readers are the industrious type, and they also have no qualms about sharing their wisdom.

A few summers back, reader Rick McLaren, owner of the 1970 S&S Swan 37, Dulcinea, pointed out that you can replace the GPS 48’s internal battery with a your basic CR 2032 lithium battery.

If you want to go really high tech you can order a battery holder to avoid soldering directly to the lithium cell, and also to facilitate future replacement.

The parts required for the battery holder are available from Digikey, so is the battery. Last time I checked, the battery holder was less than a buck.

BS-3-ND Battery Holder—68¢

Step 1: Crack open the GPS casing around the perimeter of the GPS.

Battery in Garmin 48 GPS

Step 2: Unplug the wiring to make it more accessible.

Step 3: Remove the existing soldered-in dead battery. Both wires should be green, note which one is on the top, that should be the negative conductor – at least it was in McLaren’s GPS.

Step 4: Solder your new battery holder in place, making sure to connect the negative to negative and positive to positive (see Step 3 for correct identification of wires).

Step 5: Install the new CR 2032 battery. (You may still get the “memory battery to low” warning.)

Step 6: Install new AA batteries. (The warning should disappear.)

Step 6: Check for proper operation.

Step 7: Reassemble parts and seal with silicone.

Nope, you don’t get 3D contours of the bottom. Nor does the GPS 48 tell you where the nearest Dominos Pizza is. But if you have a chart, it will tell you where you are, and if you know where you are going it will tell you when you’ll probably get there. Nothing fancy, but it gets the job done.

For our report on the newer Garmin Colorado and Oregon GPS, see this GPS test article.

Comments (12)

So I opened up my GPS 48 and quickly found the battery. I then decided not to replace it but just remove it. I then unsoldered the leads from the speaker, and attached them to a holder for a 2032. Yes the top lead is the positive. I installed a fresh 2032 in the holder, taped it up to prevent shorts. The GPS worked normally. I created a couple of waypoints and then turned it off. Just to be sure i removed the main batteries. After several minutes, I reloaded the batteries and turned it on. My waypoints were still there. I conclude this technique will work on any 48 and the 45. I strongly believe I could use it on the 12, 38, 40, and others that use the same style case.

The 2032 has a higher amphour rating than the original. It should last longer, but since it's installed in the wrong place, I don't know yet.

Posted by: Bowhunter8 | April 28, 2019 9:12 PM    Report this comment

So I had to chuckle when I saw the speaker ID'd as a battery. It sounds like more than one person suggests that works. If so, I can only guess the 3vdc on the speaker leads somehow feeds the needed power to the memory. I've not bothered to ask Garmin for a schematic of the GPS 48. It would make no sense for them to provide such sensitive info. I've recently bought a GPS 48 with a bad memory batt. They come pretty cheap. I was thinking to put a CR2032 in it. It has significantly more amp/hour capacity the the 1220, but the charging circuit feeding into the CR2032 does have me spooked on the choice. So I will price up the 1220, and probably just go with that. There is MUCH open area where the antenna would go in a GPS38 or 40. Multiple batteries could be placed there, but they must be WELL CHARGED before installing or they will likely overload the charging circuit. So my thought of multiple batteries may be much more trouble than help.

Posted by: Bowhunter8 | April 14, 2019 3:24 PM    Report this comment

The method I used was emailed back to Darrell so not posted yet. It works. Neil and myself are the only ones who are not on hallucinatory substances. Solder a battery into a speaker circuit and see if it works. I attached a few photos and if they get posted, see for yourself. So far the unit still thinks it is 1997. If there is no firmware update it might be pointless anyway. I have not checked it againts another gps yet. I will keep updating progress if any.

Posted by: Crusty yauchty | March 5, 2017 2:58 AM    Report this comment

I just successfully completed this fix and as "Neil" suggests those other guys are on drugs. The memory battery is indeed a Panasonic VL-1220 which I bought on ebay from Germany and cost about $14. It can be a little tricky and a small tipped butane solder iron is all that's needed and calm nerves. I have some photos and a recommended method but it's not massively hard and I can't figure out how to post photos yet.

Posted by: Crusty yauchty | February 23, 2017 4:12 AM    Report this comment

This "repair" is someone dreaming and sending readers on a wild goose chase.
The item shown at the top with the two green wires is a piezo speaker (where the beeps come from) and NOT a battery.

Removing the piezo speaker and soldering a battery in it's place is a waste of your time and efforts and can damage your GPS.

The battery you are seeking to replace is soldered to the circuit board and is a Panasonic VL-1220 and is available from places like Mouser for around $5. It's the battery looking object sticking up off the circuit board with the brown edge. The VL-1220 is rechargeable. The suggested CR2030 is NOT RECHARGABLE and could be damaged ...but since the author suggests soldering it in place of the piezo speaker there is little change that 1) this mod will ever work and 2) that the CR2030 would ever be recharged.

Replacement requires a small tipped soldering iron and the ability to de-solder the connection without destroying the board, from the opposite side of the board. This is not something you can do with the gun type soldering irons. If you are not skilled at board level repairs - do not attempt to solder the (correct) battery into the place of the failed battery. Find someone who is skilled and slip them a couple buck or a six pack - total time to repair - with the correct VL-1220 battery - is ~30 minutes

Neil Schwanitz - Marshall Islands
Retired Broadcast Engineer
Present Radar Field Engineer and solder slinger.

Posted by: Neil Schwanitz | June 22, 2015 9:17 PM    Report this comment

Awesome article on the GPS48. I have a GPS75 that also gave me the dreaded low internal battery message. Anyone know if the same procedure for the 48 would work on the 75?

Posted by: Unknown | April 8, 2015 6:33 PM    Report this comment


Posted by: onm2014 | November 17, 2014 4:35 AM    Report this comment

Thanks for your very helpful comment.

I have two Garmin 48's. Both were kind of trashed by leaking AA batteries, probably trying to keep charging the internal batteries. As a result the ends of all the AA battery chamber end (with spings mounted on them) broke off in pieces. Somehow I will need to recreate that end. Any ideas?

Opened one of my mine and found it has the VL-1220 battery on the circuit board like yours. Also found the Digi source for replacement, as you advised. I have no idea how would accomplish desoldering/soldering in such a tiny area. All I have is a pencil tip soldering iron. Again, any advise would be welcome.


Posted by: Unknown | April 7, 2014 12:24 PM    Report this comment

Thank you for posting this article. I have a Garmin 48 very much in need of this procedure! The 48 was my first hand held GPS and I was sad to see it fade away. I will order up the parts and bring it back from the dead as soon as they arrive!

David Cooper, Traverse City, Mi

Posted by: David C | November 22, 2013 10:27 PM    Report this comment

I think we may still have one of these aboard as a backup backup backup. Guess we should dust it off and check the battery. Will definitely save the article info for future reference if we need it. Thanks!

Posted by: DAVID M | November 22, 2013 9:48 AM    Report this comment

Darrell, just a note of thanks on the piece regarding the GPS 48. I've owned this unit for about 12 years and it finally gave up on memory...all wiped clean. After many frustrating searches on Google I stumbled upon a link to this website and the article. Well, I opened up the case and followed the instructions and decided to order the CR2030 battery holder from Digi-Key. I ordered a second one just in case I ran into a problem. Those folks are outstanding...the total order was $5.23 for two holders and postage. Gracious, what service for such a small order. Anyway, I sat down and went through the checklist and installed the holder/battery. I have since logged in about 20 waypoints, which included several shutdowns of the GPS 48. Memory is just fine, as they all appear intact when the 48 is booted. What a gift. BTW, the top wire is negative as pointed out. Many thanks again to you and Rick McLaren. Without that help the 48 would be history as a decent navigation instrument.

Hank Wood
Durham NC

Posted by: Tarheel | December 6, 2012 1:30 PM    Report this comment

thanks for keeping yet another piece of electronic gear out of the landfill. It was heartbreaking last year (Feb 2010) to finally de-install my Loran and toss it when I read about E-Loran (whenever!) not being compatible.

Posted by: PeacheyKeen | March 27, 2011 11:20 AM    Report this comment

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