Small power banks/chargers
Like most hikers, Three Points of the Compass takes a number of electric devices when backpacking- phone, camera, LED light, occasionally an MP3 player. Other hikers may be carrying even more devices. Only three years ago I made the total switch to rechargeable headlamps, first to the Black Diamond ReVolt, that can run on either standard AAA or rechargeable AAA batteries that can be charged in the headlamp. Then I switched out to either the Olight H1R Nova, with proprietary rechargeable RCR123A battery, or the Nitecore NU25. The former is for longer winter hikes or where more night hiking is planned, while the NU25 is perfectly adequate for the remainder of the year.
For shorter hikes where I am also carrying a power bank, I may carry either a Nitecore F1 battery charger or the double sized version- the F2. These will take many Lithium-Ion batteries including the 18650 batteries I favour. The F1 is a simple, minimalist charger with Micro USB in-port and USB out-port. It has a nifty little LED array that identifies the voltage of the battery inserted and informs degree of charge and the F1 allows through charging, so it is possible to charge the battery at the same time as charging a device.
The Nitecore F1 charger weighs 34g including two ranger bands which hold a battery securely in place when in use though I often only take the one. The F1 is not the swiftest of chargers and is not suitable for a brief halt in town of an hour or two and expecting to quickly charge up, but is fine for an overnight stop where there is access to mains power for a few hours. There are a lot of these little battery chargers and power banks available and a little care needs to be taken when choosing one, do your research because a few are downright dangerous. The F1 is a great lightweight option for a day or few, however I feel that the F2 is more suited to longer treks as it gives a greater degree of flexibility and functionality.
The Nitecore F2 has 0.5A USB 3.0 Micro-B input and two USB outputs, giving 1x 2A or 2x1A. The F2 charger/power bank weighs 47g, 54g with two ranger bands. The little 170mm charge lead that comes with it weighs 12g but I normally carry a more robust longer lead.
Depending on the length of trip, I often carry one, two or three Nitecore Lithium-Ion rechargeable 18650 batteries. 3.7V 12.6Wh. The 18650 batteries from Nitecore (and Olight that I have also used) are both built on the Panasonic NCR 18650B, with additional circuitry. The ones from Nitecore each weigh 48g and have built in PCB/IC protection (short circuit and battery overcharge protection and discharge protection circuits) so are a little longer than most other 18650 batteries being 68mm long instead of 65mm. Mine are the 3400mAh batteries which give the best size/weight/power ratio for rechargeable batteries. Though in truth they probably deliver no more than around 3200mAh. When not in use, or in the charger, I keep each 18650 battery in a 6.4g silicone sleeve. This removes the danger of any shorting out while packed. If you have any doubt as to the efficacy of 18650 batteries, it is worth noting that Tesla has been using Panasonic 18650 cells in their Models S and X cars since 2013. Their most common battery pack originally contained 7104 18650 cells, more recently 8256 cells.
Another good charger that can also act as a power bank and has attracted a lot of interest in recent years is the Miller ML-102. There have been a number of versions of this USB charger produced and some earlier models introduced a few faults, however at the time of writing (January 2020) the current version- the 32g ML-102 v9, seems to have reintroduced a reliable charger to the market place. However these will only work with unprotected 65mm long 18650 cells, it won’t accept the longer protected 18650 cells, so I cannot use this on trail with my favoured Nitecore batteries. Unprotected cells should not be left unattended when charging for obvious reasons.
In the eventuality that the battery/power bank does give up and all my 18650s are drained, I usually have just a little backup for light. I often carry two of the fantastic little LRI Photon Freedom Micro button lights. One has a red beam to preserve night vision, or to be just a little more discreet and less conspicuous if wild camping where I ought not. The other has a white beam. I have written elsewhere about these great little lights, but for just 10g each, including battery, you can’t go wrong with these. Spare button batteries are carried for any Photon carried (CR 2016 or 2032 depending on if white or red LED). I also have a light on my phone but better to keep a phone battery charged for emergency use. Finally, I have a minuscule USB LED light with dimmable facility that can be plugged into either my power bank or a room wall plug.
For any hike of a week or more I am usually carrying an Anker PowerCore II Slim 10 000mAh power bank. This weighs 209g, so is the heavier option but I swap out for this for one reason- convenience. With a charger that can only charge one (F1) or two (F2) 18650 batteries at a time, I would need to keep swapping batteries to keep them all charged. Not what I want to be doing. I want to be eating, drinking, washing and resting, not hovering over a charger. With the Anker, I can stop overnight somewhere, plug it in and leave it plugged in until fully charged.
Charge leads and plugs
Charge rate can be severely affected by the cable used. Both internal cable structure and length will alter the charge rate. Also, the quality of the end pins/plugs is of concern, the last thing you want is the end pulling off while on a hike. To ensure I don’t end up totally scuppered, I carry at least two USB/Micro USB charge leads with me. My main charge lead is usually a 900mm 28.4g USB / Micro USB Anker Powerline. This is a good quality charge lead made with Aramid fibre and double braided line. It will take a lot of the wear that charge leads are subject to.
If I have my iPod Nano mp3 player with me (I have no other Apple products), then I include a tiny little Micro USB/Lightning adaptor. It is only 20mm long and weighs 1.2g. However, it is much more likely I will be carrying my little SanDisc player. This has a built in rechargeable battery, the USB/Micro USB cables I am already packing will work with this.
Other charge leads carried are a very short, silicone coated lead, just 67mm in length and 5g in weight made by Lifemall. Again, this is USB/Micro USB. It originally had a loop for hanging from a key chain but I removed that. Output is 2.4A maximum. Carrying this little extra charge lead means that I am not left bereft should the longer main lead give up the ghost. The very slight weight penalty is acceptable to me.
A rather nifty feature on the Olight H1R is the simple, magnetic tailcap to which the USB charge cable connects. This means that, if need be, the headlight can be charging while being worn. So if I am carrying the Olight headlamp rather than the Nitecore NU25, I also carry the magnetic Olight charge cable for the HR1 Nova head torch. This weighs 14.5g. The tail glows red when charging and switches to green when fully charged.
In the past, the necessity of carrying one particular charge lead has been a source of annoyance. My Olympus Tough TG-4 camera cannot be charged via normal Micro plug, instead, this requires the inclusion of a proprietary connector. This extra 700mm lead weighs 48.5g. However if I am carrying a camera these days, I am normally taking my Sony RX100v, which can be charged with the standard micro USB.
Three Points of the Compass has a liking for the ingenious folding plugs from Mu (Greek for small or micro). It is not only weight that can be an issue in the pack, but bulk too. The 51.1g Mu Duo has double USB ports with a fixed split of 1.2A per port. Input: AC 100-240v, 50-60Hz. This accompanies me on shorter trips up to a week. For longer trips I have the 50.4g Mu Tablet, this has a single USB port with a DC 5V 2.4A outlet and AC 100-240V, 50-60Hz input. It may seem counter-intuitive to take a single outlet plug for longer trips but it is the higher, faster charge rate that I want then. Though of course, this is nothing compared to the newer connectors coming through as I write this. There is, for example, a Type-C connector Mu plug available.
The higher output single and dual port Mu both measure 73mm x 55mm x 14mm when folded, there is also a lower 1A output Mu that is a little smaller at 60mm x 55mm x 14mm. This is the open white one shown below.
The above leads mean that I can be charging two 18650 batteries in the Nitecore F2, while simultaneously through charging my phone and Olight or camera. If I have the Nitecore F1, I will also have the double port Mu plug, so can charge a single 18650 battery and also the phone, Olight or camera from the second port.
Mu folding plugs are not cheap and I have used the cheap ‘n’ cheerful TH31 folding dual USB adaptor from Aulola in the past. This has a 5v 2A output, but that is split across the two ports. Slightly larger at 67mm x 49mm x 20mm, these weigh 57g.
I recognise that while I have been slowly bringing all my electronics in line with each other, utilising micro USB charge ports, the wave of change is sweeping by and I shall have to make a further change in the future to keep up as micro USB is eventually going to become obsolete.
The size of power bank carried on a hike, or rather the amount of mAh, is very much a personal choice and should be influenced by a number of circumstance- cost, weight, availability, bulk, number of electronic devices carried, opportunity for recharge, duration between said recharge opportunity etc.
When Three Points of the Compass completed his 2000 mile hike across the UK in 2018, the lightweight Nitecore F1 was carried for the first 800 miles as there was opportunity to recharge every day or two, by the time Scotland was reached, with far less opportunity to charge a power bank, I had switched out to the larger 10 000 mAh Anker which was completely adequate for the remainder of my hike. The longest I went without opportunity for a partial recharge was five days.