How to Manage Electronics and Batteries in the Backcountry (Member Q&A)

What are the best and affordable GPS systems? Can I use my iPhone to make calls in the back country?  Can I use my iPhone as a gps system in back country?

What is the best battery management app for an android based mobile phone, or what other techniques do you recommend to extend battery life while backpacking and using the phone for navigation, the occasional photo, and the occasional text message while bluetooth linked to an inreach mini. BTW the navigational use is limited to checking waypoints at critical junctions or route transitions that aren’t obvious or subject to some other confusion. I do not track or navigate by gps to obvious destinations and so limit gps power use to points that must be hit and aren’t obvious except maybe to check a point as a way to double check progress and manage time or effort.

Along these lines is it better to sort of ‘sleep’ or hibernate the phone to avoid the power used in boot-up or just turn it on and off especially if there’s not likely to be a photographic subject in the offing; which situation is of course often difficult to predict!

Most of my lights, Steripen Opti use CR123. Is there some sort of battery pack that will allow me to charge my phone/camera with these, too?

James – Someone had posted a couple months ago about the Miller ML-102 charger.  With it you can either charge an 18650 battery with an external power input OR use an 18650 battery to charge other devices (via a standard USB-A output).  I’m pretty sure that one 18650 battery is the same as two CR123 batteries, so, if you can find one, this might be your answer.  I did some digging and they seem to be discontinued everywhere, but there might be something similar out there.

Wish I could participate but I’ve got church at that time.

Howsomever… while looking for  a Garmin InReach (not the Mini) I see that it is well over $500.!! Guess I’ll be sticking to my SPOT Gen. III and its limitations.

OK, Thanks Kevin!

Other than putting iPhone in Airplane mode, what Setting changes should be made to minimize iPhone battery consumption on backpacking trip?

What is the best way to charge SLR camera batteries in the backcountry?  Typically, the chargers that come with the camera are meant to plug into 120v AC…is there an adapter that will work off a solar panel, for example, that puts out a safe charging current for the camera battery?

How well do portable solar arrays work in overcast or rainy environments?

Diana – for camera battery chargers check out Nitecore. I use one for my Nikon batteries. It’s smaller, lighter, faster and cheaper than Nikon’s charger, charges 2 batteries at a time, and charges from USB.

https://photo.nitecore.com/CAMERA_BATTERY_CHARGERS

Just an advisory on Kevin Babione’s post above on the ML-102….it will only work on unprotected 18650s.  The protection circuitry will add 2mm to the cell length, and will not fit.

I’m way out of my league here, but it seems crazy to me that the “same” (in this case, 18650) battery could come in different lengths!  How do manufacturers like Zebralight and Fenix deal with that?  A bigger spring?

I don’t have anything that uses an 18650 so I can’t check, but James was asking about CR123 batteries originally.  Any idea if two CR123’s would fit in the ML-102?

Protected/unprotected 18650s are just a fact of life.  If your device has protective circuitry, then you can use either…if they fit.  If your device does not have protective circuitry, then you are at risk using an unprotected cell.

Kevin, regarding your question on charging two CR123s, the Miller charger was designed for 18650s and not CR123s, regardless of fit.  I wouldn’t.  There are chargers for a CR123 rechargable out there, but not as compact as the Miller.

Also, the Miller charger has several versions out there.  I’ve got a v3 & a v6, and I see there is a merchant selling now v9.

James (and to a lesser extent me) wasn’t looking to charge CR123 batteries – we were looking to use CR123 batteries that we were carrying anyway as an option to charge a phone (or other device).  My UV water treatment uses two CR123 batteries and I typically carry 2 spares.  I don’t always carry a power bank and it would be nice to have the insurance for just a couple of grams.

So – my question is this (and I see that I wasn’t clear at all):  Could I put 2 CR123 batteries in a Miller ML-102 and use it to charge my phone?

Could I put 2 CR123 batteries in a Miller ML-102 and use it to charge my phone?

No.

I would disagree with the opinion regarding solar power is not a viable/reliable power supply for backpackers.  Solar can provide a stable power source over the course of a long-distance hike for those of us who are travelling in sunny environs or at higher elevations, alpine zones.   The best approach is to have the solar panel charge a small battery during the day and use the battery to charge your devices in camp.  I do NOT recommend directly charging devices especially phones as they a sensitive to any variation in voltage levels and often do not charge if solar exposure varies.  The battery is securely mounted to the back of the panel and the power cord must be supported where it connects to the battery.  My panel (Lixida, 102 grams via Amazon) and battery assembly weighs 181 grams and cost about $45.  The panel is best attached to the top of the pack for those whose packs have lids or top pockets.  I use three simple clips to attach the paned to the top of my Osprey Levity Pack.  Mounting the panel in this manner does not impact my activity, as I often spend a significant portion of a hike off trail, moving through brush or rock scrambling.

The battery is fully charged by the end of the day without any special effort.  As the panel trickle charges the battery, direct or indirect sunlight over the course of the day provides current to the battery.   I then charge the devices that need power that evening from the battery.  I typically carry an iPhone 8, Garmin Fenix, Garmin Inreach-mini, steripen and headlamp which utilize USB charging.  I have not had any issues keeping my devices and my wife’s devices charged during long hikes using a single panel.  I first tried this approach on the John Muir Trail in 2019 which was 19 days on trail with no town visits or off trail nights to charge devices.  I have since used the arrangement on many 10 day trips in Wyoming, Nevada, Colorado and Utah.  A solar panel allows longer trips without carrying significant battery weight.  The only failure I experienced was the power cord was not supported properly where it connected to the battery, the differential movement disconnected the plug from the battery’s circuit board.  A secure mounting of the battery and supporting the cord are best practices when assembling your panel.  I disconnect the battery from the panel and place the battery in a dry location in case of rain.  I hope this information provides an additional option for those out on longer trips to avoid carrying excess battery weight.

Thanks for your real-world info on the use of a solar panel in the backcountry, Bob.

Battery Bench has been published for a while — might want to change to a link in the Additional Resources section of this.