Keeping those power-hungry but every more useful Devices charged can present a problem outdoors, with the battery life apparently shortening with every advance.
Currently I am aware of Three reliable methods that are sufficiently portable and reliable
1. Carrying Charged Batteries
Disposable alkaline, or Rechargeable NiMH(*1) for my Head Lamp.
- Simply and probably the most light weight option.
- Common batteries easily swapped between low and high priority devices as required.
- Low Set up cost.
- You need to make sure your batteries are full charged before you leave home using a Battery Tester. / Charger.
- How many batteries should you carry?
- Regular trips can make disposable batteries expensive.
- Temperature changes can greatly affect how long Batteries last, particularly NiMH.(hotter shorter/ cooler – Longer)
- You must carry all batteries out with you.
2. Power Bank
They come in two types:
a) Simple USB charged, Closed Case Cell.
- Simply and light weight.
- Low to Moderate Set up cost.
- Depending on the device you are charging – can hold a number of charges.
- Recarged via Computer USB or Solar panel or charger.
- re charges limited / by the device.
- Only able to charge USB compatible devices
b) A Charger /Power Bank Combination
- Can act as both a Power bank and Charger.
- In Power bank mode any A class batteries (NiMH or Alkaline) fuel the recharge of USB capable devices.
- Combined with an external Goal Zero Solar Panel, it acts as a charger for A class batteries as well as a power bank / buffer to cut power fluctuations in the charging of dual charing USB device(*2)
3. Solar Charging
There are some good quality Solar systems around now days, most or which are a joint panel and a battery charger/ power bank.
- Requires only UV light, and there is plenty if not to much of that in New Zealand. Modern Panels will charge well in most conditions including light rain…
- Generally greater weight than carrying batteries or a power bank
- You still have to carry at least 4 -6 AA batteries to allow rotation and USB charging if you are using other electronics beyond a smart phone.
- You need all of your outdoor electronics to use compatible batteries or USB charging.
- Greater Set up cost
My Power Picks
All of my outdoor electronics/ devices either use AA or AAA batteries or are compatible with USB charging from AA Batteries.(*3)
Single Day Hikes;
- I carry 6 freshly charged AA NiMH batteries, 2 in the GPS, and the 4 spares, which can also be used to run the UV Water steriliser .(very low power requirement)
- 4 x AAA Disposable Alkaline Batteries in my Head Lamp, and 4AAA as spares(*4)
- A Power bank for emergency recharge of phone (gives me approx 3 days on flight mode.)
Overnight or Multi Day Hikes;
- Goal Zero Nomad 7 Solar Panel with the Guide 10 Plus – Charger /Power Bank combo))
- 6x NiMH AA Batteries, 2 in GPS, and 4x in the Guide 10 (which keep charging until rotated out in pairs)
- 4 x AAA Disposable Alkaline Batteries in my Head Lamp, and 4AAA as spares.
Battery Maintenance and Organisation
- Before I use new NiMH Batteries I always add a label defining when i got them. (this proofs invaluable later for calculating a replacement date.)
- I carry all charged batteries in Battery Containers which help to prevent accidental discharge.
- To avoid mixing charged with discharged, I colour code pairs.
- Power Banks and NiMH Batteries need regular charging when not in use to keep their performance ( just like your smart phone)
- Try and find a NiMH charger that also has a discharge cycle. Even better a charger with a capacity to charge different size batteries and a digital readout.
- The most Reliable brand of NiMH I have found is Eneloop.
Goal Zero Performance
- In the New Zealand high UV; it takes approx 4 hours to charge 4x NiMH A class batteries via the Nomad 7 Panel under a clear sky(although be careful to shade the charger well)
- Walking in and out of sky cover (Bush and clearings) it takes the same combination about 6-8 hours to get a full charge.
- The Power Bank requires 4 AA or 4 AAA to start charging, it doesn’t matter what state of charge the batteries are.
- In the absence of good UV conditions, the Power Bank can charge from a USB power source
- Charge just batteries or divide the charge between the batteries and a USB device.
- The Power Bank has an LED light – always handy when your head lamp batteries need changing.
- The solar panel also works perfectly fine through the deck of my plastic sea kayak! I just strap it across one of the dry bags in the sealed gear compartment.
- Goal Zero Solar
- Batteries: Discharging at High and Low Temperatures
- The Best Rechargeable Batteries and Chargers Of 2019
(*1) Currently my favourite NiMH batteries are the Panasonic Eneloop,(slow discharge) which are good for around 2000 charges, although I see there are now Eneloop Pro batteries sold with a longer discharge life.
(*2) When charging a Modern USB smart device from a solar panel walking under shade or a cloud passing over the sun will cause charging power to fluctuate in a way that will cause the device to recognise it as an unsafe charging source and stop / prevent charging.
(*3)Using a common battery type between electronics has the advantage that you can swap batteries around depending on which device is in priority device when conserving power.(ie: taking batteries from your charger and GPS to for to run a UV water filter for a drink bladder fill, and then putting them back into the original devices.
(*4) While the batteries in my Head Lamp simply last for ages, its less that I need to carry spares, more that they will always run out on that day that becomes an unexpected night – when i am not carrying them:-)
(*5)The Goal Zero Nomad 7, while still listed on the Website, was superseded in 2018 by the with the newer generation Nomad 7 Plus in New Zealand outdoor stores.
(*6) When buying Goal Zero Gear, make sure that the solar panel and Power Bank has the correct output power for your device. (The Nomad 7/ Guide 10 has and output of 1 amp, with the Nomad 7 Plus/ Venture 30 Power Bank being greater.