Eight days backpacking with a DeLorme inReach SE

[Edit: removed question]

Great information.

Thanks.

Sorry, let me try again:

The battery life gauge read 7% at the end of the trip.
5% of the battery life was used that day.

I'll edit to clear the confusion.

— Rex

Rex – Thanks for posting your detailed trip experience with your inReach. Your results seem to verify what I had estimated with my use of the inReach on shorter trips. Certainly shows that real world usage of the inReach gets you far less than the 100 hours of usage claimed by Delorme.

I find it interesting that our usage pattern is similar in that I fought with the screen brightness (wanted to shut it off but ended up leaving it on), and have forgotten to turn on tracking quite often.

Certainly justifies the exhaustive quest for a light weight power supply that has been going on in your other inReach thread.

As for a screen protector… the solution I came up with was to buy an Invisible Shield screen protector for an iPad and custom cut a piece to fit my inReach. I've also managed to cut a piece for my iPhone, GPS and camera from the same iPad protector and still have a nice sized chunk left over.

Rex – thanks!

This also mirrors what I had with mine as well. I frequently forgot to turn on tracking…but I'm getting better as I've gotten used to having it with me. I really, really like looking at the maps I create when I get home :)

I've kept the screen at 50% and find that it works well enough…but the one time I needed to stretch it for 10 days without a charge I turned the tracking to every 4 hours (not a nice map at the end…), kept the screen at 10% (since after a while you pretty much know where the presets are…and if I were going to actually converse with someone with messages I generally did it in my tent at night so the 10% was fine for that).

But I'm one of the ones seriously thinking about what to do about charging during longer trips and I've pretty much convinced myself I need SOMETHING. Just haven't decided yet.

Suntastics 5s maybe????????? Too many decisions.

Rex, your report was interesting, and rather thorough. In addition, it happens to be quite timely for me. Tomorrow night, our Boulder Lightpackers meet-up group will be discussing "Communications on the Trail." The main speaker will be our local DeLorme representative, who will do his presentation on the inReach SE. In addition, we will be discussing PLBs, the Spot system, ham radios, and satellite phones. Your initial field-test report will better equip me to ask decent questions of the DeLorme rep. Thanks for sharing your expertise.

Gary,

These BPL articles and discussions might be useful for your meet-up:
Two-way Satellite Communications for Backpacking: Part 1 – Introduction
Two-way Satellite Communications for Backpacking: Part 2 – Satellite Phones
Two-way Satellite Communications for Backpacking: Part 3: Satellite Texting
DeLorme inReach SE announced, ships mid to late April

— Rex

If you look at my day-by-day battery life in the original post, you'll see some days that used over 20% of battery life, and some that used barely 10%, on very similar days. At the end of the first day, with several hours of "on" time (no tracking), and several messages exchanged, the inReach SE showed 100% battery life! This makes predicting battery life very difficult.

Either true battery drain varies dramatically with similar usage, or the battery life indicator is not very reliable. In my experience, most devices have unreliable battery life indicators, so I'm guessing that's the problem.

Now the engineers can explain why battery life indicators are unreliable.

— Rex

Actually, Rex, I will be taking copies of those to the meeting, and I will be paraphrasing your words extensively. A year ago, Ryan gave me the OK to photocopy the 3-part series for handouts to the group, but he didn't want any electronic versions floating around. No one wanted to pay for the photocopying, so I just suggested that people buy a BPL membership to get to your articles. Your contributions to BPL are impressive, Rex.

"Now the engineers can explain why battery life indicators are unreliable."

First of all, it is not acting like a battery life indicator. It is acting like a battery charge indicator, and that is approximated by it being a battery voltage indicator. Let's say the nominal voltage is supposed to be 3.7V. If you get it all charged up from a 5V source, then the battery might come up to 4.25V maximum. If your battery is fairly new and you gave it a good charge period, yours might come up to 4.3V.

Inside the circuit design, they probably set the "100%" point to be 4.25V, so you might have gotten a bit of overcharge in it. It might take a small amount of usage to settle that down to the 100% point. Once you got into the normal usage pattern for a few days, the battery drain was more consistent, so the percentage scale should have dropped more consistently.

I don't think that is a problem, is it?

I feel that the bottom end of the scale is much more important, because you really want to know when operation is going to fail from a dead battery. Besides, a dead battery state is kind of hard for the future life of a battery like this.

–B.G.–

Once you got into the normal usage pattern for a few days, the battery drain was more consistent, so the percentage scale should have dropped more consistently.

I don’t think that is a problem, is it?

Yes, that’s a problem for me, for several reasons.

– Before this trip, I really tried to figure out how many days the inReach SE battery would last. I thought the battery would last 9 days, because I was mislead by the charge indicator. I was off by 3 days.

– Here are the daily “% battery charge used per hour” numbers from my trip, dropping the anomalous first and last days:

1.4% per hour (over two days)
2.0% per hour
1.1% per hour
1.7% per hour
1.2% per hour

That doesn’t look consistent to me.

For the last half of the trip I was somewhat stressed over how long the battery would last, especially with the inconsistent charge usage. As it was, I had to turn off the inReach SE on the last day, which caused some communications problems.

If I had known all this before the trip, I could have tried reducing the tracking interval (with unpredictable results), or taken an external battery or charger.

I don’t need more stress from electronics when I’m backpacking.

— Rex

Why did you think that the battery would last for nine days?

I can understand that if the device tries to send a message, but if it can't get an ACK from the satellite, then it will keep trying until it gets the ACK. That could use a little extra battery power. If you have open sky with a good constellation overhead, then it might get the message out on the first try. Or, there could have been some unusually high traffic passing through the satellites right then, and that could have slowed down the ACK.

I'm in a little different boat, because I expect to leave tracking off, so the whole thing will be powered down except for whatever few occasions when I decide to send a message, maybe once per day at most.

–B.G.–

I bet that inconsistency is consistent

Test it a couple times at home – leave it on, keep track of how long and what the battery percent indicator is at a number of points

You could come up with some conversion factors, like when it says 55%, it's really 50% (or whatever)

Or, just time it so the battery indicator will be 20% (or whatever) at the end. Then, if the indicator goes down faster the last couple days, the battery won't die.

Part of the problem is that we (as users) don't really know what is going on inside the device. I mean, we think we know what it is doing by displaying GPS coordinates, or what it is doing when it sends a message, or sends tracking, etc. But, we really don't know the internals. This thing might have to do some kind of internal maintenance on itself.

Jerry, as you suggest, we users need a lot more test data before we really know what we've got.

–B.G.–

The “figure out” link I posted above explains the testing I did, and how I extrapolated to 9 days.

Quoting myself:
Note that realistic testing is challenging, because you must keep moving to keep the inReach SE awake.

So you must test by almost continuously moving for many hours at a time. Testing any black box in varying conditions is especially challenging.

All the more reason an accurate charge indicator would be very, very useful. Too bad the inReach SE doesn’t have one.

— Rex

I've experimented with portable recharging of the SE. Except for extremely long trips without resupply, solar PV charging is both much heavier and much less convenient. This leaves electro-chemical recharging, i.e., batteries.

There are two major styles of batteries (or rather cells): one-shot and rechargeable. The cells with some kind of lithium chemistry are the only ones worth considering for various reasons, including weight and power density.

I have used both kinds of chargers, the Energizer PP-3AAMC which uses 3 AA Energizer Ultimate Lithium AA cells, and the Miller ML102, which uses a single Panasonic NCR18650A rechargeable lithium cell. The Energizer device includes a very short USB micro-B pigtail. The Miller must be supplied a USB cable. With a stout 12" micro-B cable, the rechargeable setup weighs 92g, and the Energizer setup weighs 90g. The Energizer capacity (12.6 Wh) is a bit more than the Panasonic's (11.2 Wh), but both hold enough to double the SE's life (8.8 Wh). Three Ultimate Lithium AA cells weigh the same as one NCR18650A cell, 45g. The ML102 can charge devices at the full USB spec, 5V x 1A. I haven't measured the Energizer charger, but expect the same from it.

The ML102 is also used to recharge its 18650 cell, using the same cable, from any USB power source. It can do both at once, so it would work well with a USB PV panel. Having a battery between a PV panel and an Apple OS device avoids a lot of the charging orneriness they are known for. I carry an iPod Touch (88g) for navigation display, with GPS info Bluetoothed from the SE. A one gram tip adapter permits iPod recharge from the same chargers.

Unlike Rex, I take battery backup with me even on day trips. I think the 3 oz cost is worth it. The total weight of my navigation, communication, recharge, and photography gear is 13.3 oz.

"The total weight of my navigation, communication, recharge, and photography gear is 13.3 oz."

Interesting. Perhaps you have posted the specific of this before but could you again. My inreach SE is 6.8 oz. If you Battery is 3 oz that doesn't leave much room for evenmost point ans shoot cameras.

I currently am working with Inreach SE (6.8 oz) turned off except for once a day, Busnell solar charger/battery pack (3.5 oz) , Lumix camera (4.3 oz) , usb to iphone/micro usb cable (0.6 oz), and this is already 15.5 even without the USB wall unit (0.8 oz) and the camera battery recharge unit (1.2 oz) I need to take with me on the JMT. Extra camera battery 0.6 oz extra too.

Also when I add it all up like that I feel like an ass taking my iphone as well. I should have stayed a Luddite. I have the small consolation that I would only take the camera and and and extra battery on a weekend trip. But on a weekend trip weight is irrelevant anyway, so very small consolation. :-(

Marko, what Lumix do you have? I have the ZS25 and it weights 6.84oz on my scale with the battery and wrist strap but no other accessories. For spare camera power I carry a few extra batteries and leave all the cords and chargers at home.

"I should have stayed a Luddite."

There are still career opportunities for Luddites.

–B.G.–

"Marko, what Lumix do you have? "

I have the Lumix DMC-FH6:

http://www.amazon.com/Panasonic-Lumix-Digital-Camera-Optical/dp/B00728Z8U0/ref=sr_1_1?ie=UTF8&qid=1404760019&sr=8-1&keywords=Lumix+DMC-FH6

I bought it firstly for its weight. Distant second was the Leica Lens (I used a real Leica for many years) though I am pretty sure this thing is nothing like my summicron lenses. Also it was cheap – I am a klutz, and only more so when I'm fumbling for it because a bear just dashed across my path. I have it attached to a bungie lanyard, but I may still find a way to smash it.

Measured weight of 4.3 oz is with the battery in, BTW, and included wrist strap as well. Also with added anti-reflective protector on the LCD. This is BPL after all – I want to be precise.

Thanks for indulging my curiosity. Didn't know they had models that small/light. Luddites have it so easy…

I was poo pooing bringing the damn Inreach, probably even earlier in this thread, until I read some of the missed-resupply stories people related. That was maybe 2 1/2 month ago. Now my brain thinks this rock is a necessity and it TRIES to collect data on why it is needed. Its like a plague, or the invasion of the body snatchers, or those zombies in World War Z that TRY to bite people who will best be able to spread the disease.

"Interesting. Perhaps you have posted the specific of this before but could you again. My inreach SE is 6.8 oz. If you Battery is 3 oz that doesn't leave much room for evenmost point ans shoot cameras."

The iPod Touch 5G is a surprisingly good snapshot camera, too. I enjoy its sweep panorama and handheld HDR features a lot. But the main use for the iPod is for navigation, paired via Bluetooth with the SE. I've been using Gaia GPS on the 'Pod for that. The iPod could also be used as a voice recorder or video camera. Multi-use at no extra weight cost but the juice to run it. Need more juice? Take another battery (either one 18650 or 3 AAs) at 45g. I'm still below 15 oz. That's not much weight for a lot of capability.

Ah, ok.If I could keep my iPhone charged while using it as a camera then I could loose about 6 oz. I could use the iPod trick as well. I think the main trick is not to go on a 47 day trip. I could leave a lot of functionality behind then.

Thanks for the info.