GPSMAP 66i and external battery pack (charger)

Why all of a sudden will external battery packs not charge my GPSMAP66i?  The same four battery packs (see picture) that used to charge my 66i won't charge it now.  My Windows PC USB outlet will charge it.  Every one of the many AC plug-in USB chargers will charge it.  An automobile cigarette lighter USB charger will charge it. The USB battery packs still charge every other other USB device in my pack (headlamp, kindle, camera, Steripen.)

Is this the result of an update?  Did I unwittingly change some setting?  Will a different lightweight 10WHr battery pack work?  If so, where do I get a couple of them right away?

I need a solution fast.  In two days, I leave the grid and won't have access to AC power, the Internet, cell service or resupply for almost four weeks.  During most of that time the 66i will be my only means of outside communication and my only electronic navigation.  In the past I've relied on the two black Anker chargers in the picture.  One provides a full 66i charge, the other provides about 1.3 66i charges.  Starting with a full charge, that's enough for more than three weeks of 66i use the way I use it.  But now it looks like I have a serious problem.

Just a guess: This has something to do with external battery packs shutting down when there is no current load.  This is to save energy in the external battery.  So it's not necessary for AC chargers.   

  • Hi there Volker

    Just noted your response does you 66i stay on all the time when charging with a power bank. If so does it charge up to 100%?

    When I charge with power bank it stays on and then when I push the power button it shows the percentage and then turns off. Doesn't do that with a charge from a wall plug

  • Behavior on power button push while connected to a power source should not be different between PC, wall wart, and power back. When the device is on and powered, pushing power once briefly will turn the device "off" (no way to tell exactly what that means), display the charging screen with percentage, and continue to charge. I believe that a second power button push will actually shut the device down. I don't know if it continues to charge in that state or not. 

    What percentage of charge was showing? If the unit was near 100%, it was drawing very little current. Meaning that the power bank might have shut down. 

  • Thanks for that. It definitely seems to behave differently.  Percentage is low when it powers down itself. Might be power bank. 66i comes on with power bank and then powers itself down on its own accord

  • Do you know the capacity of the external battery?  In joules or watt-hours? I was told by Garmin support that the 66i battery holds 9.3 Watt-hours, which is about 33,500 joules.

  • I can confirm that charging with power banks is not always simple.

    Example:

    I have one brand XQUISIT model 26022, 1040mAh, 38.4Wh , does it say on it

    It has 2 outputs 2A and 1A

    Power bank charged fully

    66i connected to the 2A output will charge normally until 100% or so

    66i connected to the 1A output will charge to some 40% and will then switch OFF itself

    However!

    I have also a normal USB wall charger , also with 2A and 1A output

    connecting 66i to 2A will charge it, while connecting it to the 1A output will reach max some 50% and the 66i will switch itself off.

  • Are you sure about the quantities of charge and energy?  1040mAh*37V = 38.4Wh.  That's more potential than most laptops need to be charged.  If the mAh were 10400, that would be 3.7V which is more in line with charging USB phones, etc.

  • no I am not sure abt anything. I just copy the text from the battery pack

    https://www.amazon.de/Xqisit-26022-10400-mAh-Schwarz-Akku-Notebook/dp/B01LMK7U86?language=en_GB

    it is just one of the bigger batteries I have

  • There is a fair amount of misrepresentation among battery makers.  But if the 38.4 Wh is truthful, then it should charge a 66i at least twice and maybe even close to three times.  The 66i battery holds less than 10 Wh.  But there is a lot of loss in the charging/discharging process.  

  • yes it does charge. As I mentioned above, the 2A output will charge normal, in fact I have two 66i here and I can charge both with it. But only on the 2A output. The 1A output will cherge only to abt 40% and the 66i will then switch itself off.

  • Open a support ticket. I could understand the power bank shutting down. But NOT the 66i itself. That seems like a bug, particularly when using a wall wart (which takes the whole power bank capacity variable out of play). A 1A source will take longer, but should still charge the device fully.

    Note that the capacity of the power bank is irrelevant as long as it has sufficient remaining capacity to charge the 66i from it's current state to full charge.