Keeping Battery Devices Running In An Austere Environment, by Snaketzu


We all have at least a handful of battery-powered devices that can be very handy in an emergency or even a TEOTWAWKI situation. Weapon sights, flashlights, GPS, handheld radio, a tablet loaded with books and PDFs, night vision gear, and possibly even a cell phone are all things that could be very useful. Although everyone must be prepared to do without these devices, depending on the scenario there is no good reason to believe that these items must be discarded after the initial battery charge fails. Counting on scrounging more batteries or a power source to charge with is a recipe for failure. Luckily, the solution is neither difficult nor expensive.

First off, you must be discerning about equipment if you want to keep it working. Items that use exotic batteries that aren’t rechargeable are out. Basically, you should stick to AA or AAA batteries and also devices that use internal batteries that can be charged via USB. There are rechargeable CR123 batteries out there, but just how important is that high lumen flashlight? You can get close to the same performance with a AAA battery-powered light without adding an additional battery to your supply chain and another charger to keep them going. Likewise, there are many quality options available for weapon sights and NVG that use AAA and AA batteries. The gear that uses coin type batteries is simply not sustainable.

Second, how will you keep your batteries charged in an austere environment? A plug in or 12V wall charger is great for Plan A at the retreat, but what about Plans B and C? Your handheld devices will be even more critical if you have to leave the retreat either temporarily or permanently. Solar energy is free and abundant, but a truly portable solar charging system takes some careful thought and selective purchases.

Luckily, packable solar panels and lightweight charging equipment have coalesced around the USB standard. USB has transformed charging the batteries in small personal electronics. As long as you have a cable that fits your device and has a USB A connector on the other end for connection to a variety of power sources, you can charge your device. Something that most people don’t know, however, is that not all USB chargers are created equally. Some will only charge 2.5 watts, some will charge 5 watts, and some will charge 10 watts, and the higher the output, the faster (most) things charge. In the interest of making the best use of available sunlight and time, for a portable charging system it is obviously best to avoid any bottlenecks and stick with equipment that can and will work at the faster 10 watt level. USB works at 5 volts and the faster charging systems are rated at 2100 mA (milliamps) or 2.1 amps. The best way to tell if you are looking at equipment capable of fast USB charging is to look into the specs and see what the max output rating is. It should show a max output of 2.1 amps for one port or 3+ amps for two ports . (Dual port 4.2 amp chargers are wonderful but hard to find.)

Third, there is a variety of other equipment that can be very handy for opportunistic use of available power to do some charging. These various adapters could aid in scrounging power from generator-powered systems, vehicles during driving, or even automotive batteries from abandoned vehicles. While not absolutely necessary, such items add a lot of utility for a small trade-off in space and weight.

Specific, Basic Equipment Needs

Batteries: Panasonic Eneloops are widely regarded as the best rechargeables out there. This is not the time to stick with your favorite alkaline brand; apparently Energizer and Duracell don’t want to create too much competition for their throwaways. The standard gen4 Eneloops are the ones for most applications. They are rated for 2100 discharge cycles (that’s once a day for nearly six years), 2100 maH, and will hold 90% of charge at six months and 70% at five years, assuming a relatively stable storage temperature. Don’t be tempted by the more expensive Eneloop Pros; they have a higher 2550 maH capacity and higher charge retention but are only rated for 500 discharge cycles.

Solar Power: There is a pretty good selection of packable folding solar panels for personal charging on the market, and the prices have come down into the range of downright reasonable. GoalZero is of course a well known but expensive brand, and RAVPower, Anker, and Suaoki all have highly rated products. Most reviews of USB charging with solar panels use 15w panels, but a 20W panel is better. The reason is simple:  you can’t count on ideal conditions. My real world testing indicates it’s still not a sure thing to get 10W output (2 amps @5V) from even a 20W panel. For fast charging, you need your panel to maintain that full 5 volt 2.1 amp output as much as possible. Theoretically, a 20w panel can run two such charging circuits, so you’ll have a lot of headroom to account for cloudy conditions and/or less than ideal placement. The difference is a couple of inches in width, about 4 ounces, and around $10. It’s worth it.

Portable Battery Bank: Most solar systems are set up to charge a battery bank, which is used as both storage and a buffer. I think it’s very smart to stay with that plan for a miniature system. There are literally tons of small lithium ion power banks out there on the market that are designed to be charged via USB and then allow you to charge your cell phone on the go. As long as they have the right specs, they are ideal for our purposes. The one you choose needs to be rated at a full 5 volts and 2.1 amps output for fast charging. If it doesn’t have this, then your storage battery will become a bottleneck in your charging system. I also recommend at least 10000 maH capacity. I found a Limefuel brand battery with the proper specs, 15000 maH capacity, and a rough service casing with IP66 dust and water resistance rating. I advise avoiding gimmicks like built-in solar panels or hand cranks. It’s best to buy each component separately, buying a quality piece of gear at each stage. Combining functions inevitably leads to making compromises somewhere.

Battery Charger: I only found two good candidates for recharging AA or AAA via USB, although I expect more “smart” chargers will be hitting the market. One of them apparently has a reputation for being very picky about the input voltage, so that made the choice easier. I chose the PortaPow Intelligent USB charger. Intelligent means that it can recharge one to four batteries of any combination of AA or AAA simultaneously because it truly monitors each battery separately. This is an important distinction and a nice feature, because there are a lot of chargers out there that require you to charge batteries in pairs, which is downright inconvenient when you have a flashlight that takes three AAAs.

Additional, Very Handy Gear

  • A plug-in USB diagnostic meter– You can plug these into a USB socket and then plug your device into the back end of the meter and see real time voltage and amperage. This is handy for diagnosing problems, aiming the solar panel, and aso checking overall system performance. At around $10 and the size of a thumb drive there’s no reason not to have one.
  • Extra 3′ micro USB cables – 6′ cables should be avoided, except for bedside chargers. The extra length requires a cable of exceptional quality to maintain the full voltage at the load end. It’s best to stick with shorter cables for high performance charging.
  • An extra dual port USB high performance wall charger – You never know when you might have access to a standard receptacle and you want to be able to make the most of the opportunity, if it happens. The way to tell if you have a charger that can go full speed on both ports is to look at the amperage rating. If it has two ports, it needs a 4.2 amp rating so it can hit 2.1 amps on both ports at the same time. Most dual port USB chargers are only rated around 2 or 3 amps, so beware!
  • An extra dual port 12v receptacle USB charger – The same things I said about the wall charger apply. You never know when you might be in a moving vehicle. If you are, charge something!
  • There are a lot of DC stepdown modules floating around on the Internet that allow you to hook up to a 12V battery and give you a USB output. The better ones have a pretty wide voltage input range (8-22V) and a female USB receptacle; there are even some with a male mini USB output that are autoranging 12/24/36/48V and work down to 8 volts. These are very inexpensive and can be used with  battery clips to scavenge charge off of batteries in abandoned cars.
  • There are even hand crank power sources. They aren’t terribly expensive and don’t take up much space, so if you are trapped in shelter by the weather you can at least put some charge back in your battery bank, even if solar isn’t available.
  • There is a USB charging cable out there for the popular Baofeng UV-5R radio (and variants). This allows charging of the factory LiOn battery instead of using an insert with AAs or AAAs.

Finally, discussion of maintaining use of electronic equipment in a TEOTWAWKI scenario will inevitably run into discussion of EMP or solar storms. While I agree that a handheld GPS is likely to be useless after an EMP or SS event, there’s no reason why your charging kit and other devices can’t be stored such that they are protected. Everything I’ve discussed here fits easily into a .50 caliber ammo can, along with a backup tablet, LED flashlights, and other goodies. Placing everything in quality antistatic shielding bags and then wrapping in aluminum foil before storage in the ammo can should give >50db shielding across the entire frequency range.

Depending on your needs, a portable solar charging kit is probably not appropriate for a tactical loadout or even a bugout bag. When speed and weight are at a premium it is likely better to just pack some extra batteries. However, a portable charging system can easily be included in a secondary cache for potential long term or “plan B” use. It’s an easy preparation to make that could return big dividends.

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