GPSrChive Discussion Forum

I don't know whether I can comment on the apps that can be used by my GPSMAP 66s on this Forum. The one I have been trying out is Charge Monitor to improve the indication of battery level. It is supposed to be compatible with my gps. Well, it isn't. All I get is a static indication of 80% on my display. It doesn't change, no matter what I do: put in NiMH rechargeables, AA, Lithium, whether they are empty or full, 80% that's all I get.

So don't waste your time on this one.

External link

https://apps.garmin.com/en-US/apps/4b1c ... 0eeb676e85

Not sure if it is the same as the 65s, but you can only charge batteries if you use the original chargeable battery pack, or have a trick to click the button under the batteries.
https://www.gpsrchive.com/Discussion/vi ... .php?t=520

I have an original NiMH battery pack myself. And there the Charge monitor does the same thing: it indicates 80% all the time no matter whether the batteries are empty or full. All I want to say is that this app is useless and cannot be used on a GPSMAP 66s. I wish there was a good app because the battery indication of the gps itself is to say the least erratic and not reliable.

To be fair, no app or software can provide battery charge information for AA batteries (Alkaline, NiMH, etc.) in the same detailed way they can for Lithium-ion batteries. Battery chemistry changes from one brand to the next, and even inconsistencies within the same brand make it difficult to provide charge level information in great detail.

It is not uncommon to see the AA Battery power level display 'jump around' during use as high current draw consumers (such as the backlight, etc.) will create a voltage drop sufficient to indicate the battery has lost some capacity, only for the battery voltage to increase the instant that consumer is deactivated, resulting in the charge indicator display increasing.

Devices with purpose built internal lithium-ion batteries will always be able to provide far more detailed battery consumption details.

If you want this type of detailed battery capacity information, you will need to upgrade to something like the GPSMAP 66sr, which has an internal Lithium-ion battery.

See GPSrChive > GPSMAP 66 > Operation > Power Sources and GPSrChive > GPSMAP 66sr > Power Supply for details.