Garmin GPS III Plus powers up on car power adapter but not on batteries

[Morrisrh]

An older Garmin unit has worked fine for years. Over winter the 4 AA batteries died in the unit. Replaced the batteries, unit did not power up. Immediate thought was the internal coin battery foe memory was bad. However, unit did power up when plugged into car power adapter. All waypoints and routes intact.

Could the internal battery still be causing the problem ? Or is there another possible issue ?

Thx for any and all help, Rick

 

[Nuvi-Nebie]

The first thing to check is that the battery terminals aren't corroded, this is very common because dead batteries can leak chemicals onto the terminals. However, I have seen reports of brand new batteries in a unit being reported as very low on power, due to the internal battery needing replacement

This link may be of some use, if you decide to replace the battery :-
http://www.n7cfo.com/vhf/GPS.pdf

 

[Morrisrh]

The first thing to check is that the battery terminals aren't corroded, this is very common because dead batteries can leak chemicals onto the terminals. However, I have seen reports of brand new batteries in a unit being reported as very low on power, due to the internal battery needing replacement

This link may be of some use, if you decide to replace the battery :-
http://www.n7cfo.com/vhf/GPS.pdf

Navi-Nebie:

Thanks for your reply. In summary, I replaced the internal battery and reassembled the unit. It now works on both AA batteries and car power. Some things I found:

The battery springs in the compartment for the AA batteries were not corroded by old battery leakage. So I discounted that as the problem.

Some documentation I saw on the internal battery and in the link you referenced, refer to the internal battery as VL1220/VCN. Which is soldered directly to circuit board using the tangs connected to the battery. I ordered a couple from Mouser. When I cracked the case, however, I found the internal battery was a BR2032/VBN, attached to the inside of the case with 2 sided tape and 2 wires soldered to both the battery tangs and circuit board. I desoldered the old battery, soldered in the wires for the new battery and reassembled.

Connected unit via serial port to my computer and to a 12V power source. Powered up unit. First made sure the version was still the most current (2.06) and it was. I had to apply the GPSEOW fix again to get the unit to pick up the correct date from the satellite (post Y2K issue for old units), that also worked, and date was correct. Apparently, this fix is used in internal memory and not to the ROM firmware itself. So I guess I will have to apply every time the internal battery goes bad. From MapSource, then downloaded my backed up 300 waypoints and 20 routes from the PC to the GPS. All reloaded fine. Then disconnected the unit, powered off, put in 4 AA batteries, and unit powered up on it's own. So success. Now works on both external AA batteries and 12V power in the car. Rick

 

[Nuvi-Nebie]

It seems quite common for Garmin to use different internal batterys, the strange thing is that they switch between rechargeable and non-rechargable types, the BR2032 is not rechargeable, so you wouldn't expect to find any charging circuitry for it, the VL1220 is rechargeable so you would expect to find circuitry to charge it from main batteries.

If you fitted the VL1220 it may not last very long without backup power, because it probably has less capacity than the BR2032 and you would have to charge it before you fit it, because it won't get charged in the unit

 

[Morrisrh]

It seems quite common for Garmin to use different internal batterys, the strange thing is that they switch between rechargeable and non-rechargable types, the BR2032 is not rechargeable, so you wouldn't expect to find any charging circuitry for it, the VL1220 is rechargeable so you would expect to find circuitry to charge it from main batteries.

If you fitted the VL1220 it may not last very long without backup power, because it probably has less capacity than the BR2032 and you would have to charge it before you fit it, because it won't get charged in the unit

Nuvi-Nebie

I actually did order the BR2032/VBN battery from Mouser and installed that, and not the VL1220. I bought this GPS III Plus new a long time ago.However, I had some some documentation I found where I apparently sent back to Garmin for repair soon after I got it for power problem. What they did was not documented on the return shipping notice. So possibly they changed the battery type out at that point. This is over 20 years ago. The battery has lasted that long before this past year.

Use this unit on motorcycle handlebar mount from Garmin and also in car with windshield suction cup mount. These mounts fit this size unit and not newer units, which are different in size....I also have an extension cable with an antenna on it that I use on airplanes to track route, as the small antenna on the back does not usually pick up satellite signals on the plane. The extension antenna has a suction cup on it I put on the plane window. Works great.

Biggest drawbacks to unit are lack of color and limited memory that limits the amount of very detail maps I can download from Mapsource CD. But contrast is good for bright days. And I like having buttons and not pressing screen, especially with gloves on when on motorcycle. I guess I could get their application for my iPhone, but for $50 I have to press screen of course and I have heard mixed reviews on it. Their Zumo GPS unit is like $800 for motorcycle. I'll stick to what I have.....

 

[Nuvi-Nebie]

I also have an extension cable with an antenna on it that I use on airplanes to track route

Does the unit display the speed when you are in airplanes ?, Garmin used to limit the speed on non-aircraft models to 99 MPH, so that they could not be used to navigate in airplanes, you had to pay for the more expensive models, I'm not sure they still do this

 

[Morrisrh]

Does the unit display the speed when you are in airplanes ?, Garmin used to limit the speed on non-aircraft models to 99 MPH, so that they could not be used to navigate in airplanes, you had to pay for the more expensive models, I'm not sure they still do this

Yes, it displays airspeed over 99 mph. and of course I have heading information as well as altitude. And of course the moving map. Maybe this unit is so old that this limitation came in after this unit was released. Screen is pretty small so not sure even Garmin would have seen a lot of usage as a flight navigator. But I am sure some people keep this type of unit as a backup to their iPad or in dash avionics. Now, of course, seat back screens can display this same info, although you may have to pay for it, and if you pay for internet access then you can use something like FlightAware to track the flight on your phone. This option is free and back in the day was the only option. Of course, pre 9/11 no one cared that I had this gizmo with a cable running to the window (antenna). After, every once in a while you get a freaked out passenger who thinks there is some sinister purpose to the unit. But I like not having to pay for tracking options.