Battery in expedition mode

It's impossible to test this properly with a stationary device. You have to keep moving for the duration of the test. The device behaves differently when it is standing still - it's periodically testing to see if you're moving yet. Mind you, I have no idea if that results in more or less power drain than the moving situation. I just know it's different.

The other thing that makes a big difference is having a clear view of the sky. When the device attempts to send a track point (every 30 minutes), it's going to retry if it can't connect to the Iridium network. I don't know if it's as aggressive about this in expedition mode as it is normally. But it will retry. This keeps the Iridium radio on for that much longer.

In expedition mode, I am not sure you have any control over the recording interval (for logged points). I thought that expedition mode handled all of that, just like it disables BT, WiFi, the device screen, and so forth. But I could be wrong.

I couldn't find anything more on expedition mode from Garmin than what you find in the manual.

The device offers settings for the frequency of Live Track and recorded track when it's set to Expedition Mode.  I don't know if the setting for recorded track has any effect.  But I can adjust the frequency of Live Track points being sent to the satellite in Expedition Mode.  The default  for Live Track is 10 minutes, but I usually set mine to one hour intervals.

I cannot vouch for the 200 hours.  But I can tell you there is something supernatural about the 66i Expedition Mode.  It gives the device battery life way beyond anything I've seen in older Garmin devices.

On more than one occasion, I've gone a week on a full charge.  I now plan on about one full charge per week.  I turn the device off when I make camp and turn it on in Expedition Mode and Battery Saver mode when I break camp. So it's off about 14 hours per day.  For about five or six hours per day, it is continuously recording and storing a track.  During that time, it is also sending a live track point every hour.  It is in my pants pocket.  So it does not have a clear view of the sky.  And I am typically in vertical terrain under a tree canopy. (The 66i doesn't seem to have the clear sky problem that people talk about.)  I send or receive about five messages/day.  And I have the screen on for a total of at least an hour each day checking maps, planning routes, marking/labeling waypoints, composing/reading messages, etc. 

Used like that, I plan on one full charge per five days.  If I'm going out for three days or less, I don't take any power backup.  If longer, I take a 7-ounce phone charger per five days that I will be out.  The phone chargers are labeled 10Ahr with no voltage specification.  So I don't know how much energy they are supposed to hold.  A fully charged phone charger of that size will fully charge the 66i and still have some juice left for camera, headlamp and Kindle.  Thanks to the 66i, I no longer take a phone or have to worry about charging (or damaging) it. Garmin says the 66i battery holds 9.3 Whr = 33.5 kilojoules, which seems about what I would guess.

USB operates at 5 volts so presumably a 10 Ah USB power bank would hold 50 Wh. However a lot of these power bank manufacturers are really "smart" and use the battery cell voltage instead of output voltage. So for 10 Ah worth of 3.6v lithium cells we are looking at a theoretical maximum charge of 36 Wh :( Other factors come into play like how honest the manufacturer is, the environmental temperature, the discharge speed and voltage conversion efficiency. My 7800 mAh banks tend to at least give me 10 Wh or so, when measured at the usb plug/cable, which is less than half of the rated capacity, however you see it.  

I am just also experimenting with the expedition mode, so far not quite clear how it works and what else I should observe or switch off etc.

Expedition mode is on, 66i most of the time outside, abt 80-90 % of the time however doing not much (stationary).

When ever I leave home, the device goes with me.

First it is in expedition mode, one has to switch it on with the power button, it says restarting. However I first noticed, when I move, after few minutes the unit is on and the display is also on all the time as long as I move.

I then set also the display to turn off after 15sec. However it seems that any time I touch a button, the display goes on  again. The expedition mode is therefore active really only after the unit is stationary for some time.

Is this how it should be or what settings have to be applied to extend the battery life?

I managed to get some 70h sofar, would like to get some 100h (like the old Deloerme), the 200h stated must be under some very strange conditions.

The expedition mode is set to go to sleep after 2min of inactivity. This does it correctly.

When I take the 66i, without doing anything to it, and go for a walk, the 66i will kind of wake up and start tracking, activity and inreach(if I am lucky). The display is then mostly on as long as I am moving. It does mail checks. It goes to sleep after 2min stop however.

In this condition, when I am moving, and have the 66i in my bag, the display light goes also often on, when a button is incidently pressed etc.

If I set also display time out, then the display will switch off after 15sec.

When the unit is stationary and placed outside, it goes to sleep. It tries to send track point very 4h.

In the mean time it seems however to wake up for short time often, trying to make gps fix and making thus spider. I suppose it senses that it is moving, as the spider jumps around 100m.

So yes, the 66i is in expedition mode, in addition display in power save mode. It is placed outside. It still produces endless spider, meaning it wakes up and makes position and stores it.

Is this so meant to be? Or did I forget something?

run just an other test

Have two 66i. Both I did set to expedition mode, auto (=2min). Both have also display set to power save.

After a stationary time, I took both in hand and went for a walk of abt 2h. Initially both 66i did flash the green LED in abt 20sec interval. This seems to be correct notice that units are in expedition mode.

But at some point, one of the 66i stopped to flash the green LED. No idea what is here the difference?

The display remained off on both.

Checked on explore website, both 66i did sent their tracking points approximately at correct intervals.

Something is wildly wrong. The behavior you describe does not make any sense for expedition mode. Look at it this way:

You have expedition mode set up to start automatically (Auto is selected) after 2 minutes of inactivity.

Activity means button pushes. It has nothing to do with whether or not the device is moving, or anything else. Purely button pushes.

SO, after 2 minutes of inactivity the device should go to sleep. If the display was on, it will go out. If the device was connected via BT to your phone, the connection to the phone will break. And so forth. The green LED will begin to flash at wide intervals.

It should REMAIN in this state until you briefly press the power button. NOTHING other than  a power button push should wake the device. During this time, tracking will continue (if enabled). Sent points will be recorded at the specified interval but transmission may be delayed. Mail checks will not occur. Logged points will be recorded at intervals determined by the device, but generally at longer (on the average) intervals than what you set.

It does not sound like it is behaving that way. If not, you might try NOT enabling power save mode along with expedition mode. Might be that these two interact. I can't say that I've ever tried the combination.

Edited to add: I do not know if entry into sleep mode would be delayed by pending iR activity. In particular, if the device is in the middle of a mail check, it might wait to finish that before going to sleep. Same thing if it has pending traffic (messages or points) to send. This tends to only be an issue in challenging conditions (for example, indoors, in a narrow defile, or under heavy wet canopy).

OK, the first 66i will have tomorrow battery empty (~100h continuous operation) , I will then reset it and note what settings I did.

Currently both 66i sits outside (stationary) and flash green every 5sec and seem to send their 4h stationary interval points.

The latter sounds like reasonable behavior in expedition mode.