problems when batteries are being recharged by GPSr

[steerage250]

I had a friend make me a little piece of plastic on his 3D printer that slips between the 2 rechargeable batteries and presses the little switch down so the GPSr knows it has rechargeable batteries and will recharge them in the device.

It works great in that the batteries do recharge.

However, the GPSr becomes VERY sensitive to power dips (eg when I start or stop the car) and very frequently shuts-down and will not restart until I have removed and replaced the batteries. (Needless to say, this is VERY annoying when you've just started the car and are ready to drive away.)

If I remove the piece of plastic, the problem goes away (start & stop the car no problem).

Is anybody else using this same configuration, or a genuine Garmin rechargeable battery pack ?

My batteries are getting a bit long-in-the-tooth, and I'm wondering if that might be contributing to the problem?

[GPSrChive]

What equipment are you using between your vehicle 12v DC and your GPSMAP 66?

[bonstetten]

I also use such a piece of plastic (see https://podcast.paravan.ch/2019/09/garm ... aet-laden/) and never noticed such a problem. But I also have to say, that I never use it with external power.

[steerage250]

What equipment are you using between your vehicle 12v DC and your GPSMAP 66?

I've tried the old Garmin-supplied cigarette lighter adapter I bought with with my old GPSMap 60csx, and also some 2 amp 12V-to-USB sockets that I fitted to the car. Both behave about the same. When you crank the engine, accessory power is briefly removed, frequently causing a voltage dip and a GPSr lockup. However, it also locks-up sometimes when I turn the engine off.

There has been times it has been quite reliable (I suspect when the batteries are fully charged).

[GPSrChive]

What happens when you connect and disconnect the unit from your Computer USB cable while the GPSr is powered on?

[asprin624]

I have never ran into any of these problems being plugged into the car system.
Been using a Garmin Micro USB kabel and a GARMIN quick multi auto charger in my car.
I also use the Garmin NiMH Battery Pack. Can not be troubled to add this so called bypass so other batteries
can be charged. I top off my 66s while driving and even when I stop the car and the 66s stays on. As for other batteries I use a charger and they are fully charged and ready to be put in the 66S if I need them. As of yet have not had to pull the Garmin NiMH Battery Pack and replace it will other batteries and have been out all day. When I get to the hotel I just plug in my 66s to a Garmin NIMH Battery Charger. Leave it in over night and it is ready to go the next morning. Yes it charges very very slowly but who cares it is over night being done. If I need a quick charged batteries I have it as a backup but have yet to use them on the 66. I have it for my eTrex HCx as you can not charge it with the unit.

I think it is very important to have the correct items that work with the 66s or any other Garmin you have and not some off the shelf cable or car charger.
There are lots out there but why risk to screw up your Garmin.

[steerage250]

What happens when you connect and disconnect the unit from your Computer USB cable while the GPSr is powered on?

I initially had some locking-up problems, but lately, no problems.

[GPSrChive]

Modern electronic devices are very sensitive to AC voltage, and vehicle 12v DC power ports can suffer from AC voltage spikes from the vehicle electrical system.

I would suggest trying a quality 12V DC power port to USB adapter (Garmin 010-10723-17) and see if that helps. You may also want to have your vehicle electrical system tested by a competent technician for any electrical anomalies.

[luvvinbird]

I charge both my 66s and 66st via the USB port on my car. Both have the Garmin battery pack installed. I've never had any trouble charging either device this way even with power interruption such as ignition off or me suddenly disconnecting. On a disconnect, I always see an option to Shut Down the GPSr or Stay On. But one thing I have done is I've changed both interfaces to "Garmin Spanner" so when plugging in, I'm asked the question if I want to go to Mass Storage Mode, which I don't accept. I also have a 12 Volt Garmin charger in my glove box but rarely use it for these two devices. For what it's worth, maybe it's something to try.

[GPSrChive]

Excellent observation and suggestion, all my Garmin GPSr are also configured to use the Spanner interface mode.