GPSrChive Discussion Forum

I do a hell of a lot of hiking by myself and with groups of people.
We are are all day long hiking in the woods and geocaching.
Been able to go 3 or 4 days straight on one set of batteries.
If you want to go longer on your batteries you can switch to Expedition Mode.

Expedition Mode places the GPSMAP 66sr into a low power state and can extend battery life up to 21 days.
Only GPS (L1) satellites are used while Expedition Mode is active (Multi-GNSS and Multi-Band are disabled).
The Status LED next to the power button will flash green once every 5 seconds to indicate Expedition Mode is active.

I have no idea how you have your 66 setup.

If I use it in my car I am running on the car battery via the the old cigarette light power and have no need to use the batteries in the 66.

The adapter is the one that goes between the 2 batteries that lets you charge the 66 without having to take the batteries out.


In the GPSrChive store

Garmin NiMH Battery Pack (with the adapter)
or
GPSrChive NiMH Adapter (sold alone to be used on other chargeable batteries.

asprin624 wrote: Thu Oct 12, 2023 9:59 am Why are you charging your batteries that many time per week?
I can go days of heavy use and still have lots of power left in my batteries even if I let it sit for weeks without using the 66.

Why not? The quoted battery life is "up to" 16 hours. If you used it for an 8 hour day they would be half empty so putting in a fresh set for the next day is entirely reasonable. And if you only used it for 3 days in a week there is the 3 replacements already.
How you may choose to use your device was not the question asked.

asprin624 wrote: Thu Oct 12, 2023 9:59 am You no that charging batteries to many times does reduce it's life cycle.

That is not correct in this case, the data you are quoting refers to full charges and in this case it's partial charges. Life of the chemicals is related to the overall total charge capacity and (other than other common factors like charge temperature) it makes no difference in this use case how that amount is broken up over time.

I had access to a GPSMap 66s for a bit, and just wanted to comment that the battery compartment does feels very very tight.

Not sure if it's unit to unit variation, but initially I couldn't remove the battery without using a small pry tool to gently remove the 1st one. After some use, of putting batteries in, and taking it out, it has gotten a tiny bit better, but I still have to rotate the battery for a bit before I can remove it, and my fingernail still hurts after doing so.

This is drastically different from the 60csx battery compartment, which the battery can be removed very easily and smoothly. I was going to use a micrometer to measure the compartment size and compare with 60csx, but didn't get around to do it when I had the 66s.

I am not surprised with repeated use, the battery connector may be broken. That battery compartment feels like it needs to be a tiny bit bigger. This is with Eneloop and other NIMH batteries.

Note for future Garmin AA GPS device, please enlarge the battery compartment by a tiny bit so the battery can be more easily put in and removed, without causing excessive stress to the connector/springs. It's not like you are running out of space on the 66s like devices, given how bulky it is..

ps. On the eTrex SE, it seems ok, but still pretty tight compare to how smooth the 60csx is.

You can always place a small felt ribbon under the batteries to aid in removal, similar to much older devices.

Also, measure the batteries.

Not all AA batteries are manufactured to the same tolerances. The specs for AA batteries actually allow some variation.

The Garmin AA battery compartment must be tight enough to still hold smaller AA while also accommodating larger AA cells.

And they must all be tight enough to prevent unintended power loss when used under harsh conditions where vibration can be an issue.

GPSrChive wrote: Fri Apr 11, 2025 8:14 pm similar to much older devices.

AFAIK Garmin never used such a felt ribbon...