Part 2 of American Survival Guide’s exclusive two-part guide to batteries
In part 1 of our battery series (which appeared in our January issue), we took a brief look at the 200-plus-year history of batteries and discussed some of the different battery chemistries and how they determine the voltage and power characteristics of voltaic cells. In part 2, we will look a little deeper into both single-use ("primary") and reusable ("secondary") battery types we commonly use in our gear. We also test several batteries from different manufacturers to see which ones are the best choices to include in your preparedness and survival supply locker. AA cells make up 50 percent of the roughly three billion alkaline batteries sold in the United States annually, followed by AAA at 30 percent. C, D and 9-volt batteries make up the rest. A look at the battery shelves in a retail outlet supports that breakdown, but it also shows a fairly wide range in prices among brands. A couple of name brands are very popular and are among the most expensive batteries to buy. One would think that premium pricing would imply premium products that surely must be better than the less-expensive varieties ... but is that the case? The only way to find out would be to test them in a controlled experiment. As it turns out, there is not much difference between the premium-priced batteries and the less-expensive brands. However, there is a significant difference in cost per hour of operation (see page 46 for our test results). Marketing adds to the price of batteries, and the two leading alkaline battery manufacturers spend a boatload on advertising. This cost is passed on to the consumer. So, just because a battery costs more at checkout doesn’t mean it will last any longer in your device. In fact, the “longer-lasting” claim does not refer to usage at all; rather, it refers to the battery’s shelf life when stored properly.
EFFECTS OF TEMPERATURE ON BATTERIES
Alkaline batteries exhibit very little power loss when stored in a cool, dry environment (68 to 78 degrees [F]). Typically, alkaline batteries have a shelf life of five to 10 years and will retain at least 80 percent of their original charge under the right conditions. Elevated temperatures will accelerate loss, but it is not necessary to store batteries in a refrigerator unless ambient temperatures are excessive. The suggested temperature range for use of alkaline batteries is 0 to 131 degrees (F), making them suitable for year-round use in most environments. If you frequent more-extreme conditions—arctic cold or Death Valley hot—lithium batteries are better bets. The Energizer Ultimate Lithium AA battery, for example, has a recommended temperature range of -40 to 140 degrees (F). Besides the much broader temperature range, the Ultimate Lithium offers a couple of other benefits over alkaline cells: Shelf life at room temperature is up to 20 years—double that of most alkaline cells; and the lithium battery has considerably more energy that remains more consistent (less voltage drop) under heavy-current demand. As a result, your Aa-powered flashlight can stay nice and bright up to the point of battery exhaustion!
LITHIUM VS. ALKALINE
Although the Energizer Ultimate Lithium AA costs more than alkaline batteries, the additional energy it packs brings its cost per hour of operation to about the same. Besides the longer operating time, the extended temperature range performance makes the Energizer Ultimate Lithium an excellent choice for gear that is stored inside a vehicle, summer or winter, where it will be exposed to extreme temperature swings. Several batteries that find use in our gear are only available as lithium. The CR123 (or 123A), CR2 and the CR2032 coin cells are common examples. These batteries are often chosen by manufacturers for night vision devices, illuminated reticles in rifle scopes, laser range finders, tactical flashlights and many more gadgets due to the high energy density-to-size ratio lithium cells provide.
BENEFITS OF RECHARGEABLES
All the alkaline and lithium batteries discussed so far are “primary” cells—single-use, disposable batteries—and cannot be recharged to any useful extent. “Secondary” batteries are reusable and much more cost effective, especially if you tend to go through a lot of batteries. They do, however, require that you have the means to charge them. NIMH batteries. The most common rechargeable dry cell battery for our portable gear is the
MUCH OF OUR GEAR REQUIRES ONLY THE MIND, EYE AND HAND OF THE OPERATOR TO USE AND MAINTAIN—AS IT SHOULD BE. BUT SOME OF OUR GEAR DEPENDS ON SOMETHING OFTEN IN SHORT SUPPLY WHEN AN EMERGENCY ARISES: ELECTRICITY.
nickel-metal hydride, or NIMH. Available in sizes from AAA to D cell and 9 volt, NIMH batteries are much more capable than the older nickel-cadmium (Nicad) batteries, and they don’t exhibit the “memory” phenomenon that plagues Nicad batteries. While it might be best to let them completely discharge before fully recharging them, NIMH cells can be removed and charged at any state of charge ("SOC") without concern of reduced capacity. Properly charged and cared for, rechargeable batteries can go through hundreds of charge cycles (charge-discharge) before they eventually start losing their capacity. They can also be discharged quite deeply. NIMH cells, however, do not store well for long periods. A fully charged NIMH cell will lose 10 to 15 percent of its charge within the first 24 hours and then about 10 percent per month in storage. It is recommended to top off the charge before using the battery and fully charge it approximately every six months in storage. NIMH batteries should be stored at room temperature and typically have a usage temperature range of 14 to 122 degrees (F). However, they should only be charged when the battery temperature is between 32 and 104 degrees (F). Rechargeable batteries brought in from extreme cold must be allowed to reach room temperature before charging. As with alkaline batteries, it is important to make sure all rechargeable batteries used in a device are of the same brand, capacity and state of charge. Mixing batteries of different types, capacity, age or charge level can permanently damage or diminish the charge capacity of NIMH cells and can cause them to overheat or rupture—which could also damage your device. NIMH batteries are available in a variety of capacities (even from the same manufacturer). Aasized NIMH batteries can range from 1,350 milliamp hour (mah) to 2,500 mah, so it’s a good idea to read the battery labels to ensure they are all the same capacity before charging or using them. Lead acid deep-cycle batteries. The big, heavy, lead acid deep-cycle batteries used for boating or recreational vehicle applications are excellent off-grid power sources for homestead or bug-out locations. While not very portable, they can provide a long-lasting energy reservoir for recharging the smaller batteries we use in our devices. Kept full by utility power or a wind or solar charging system, they are safer and more convenient alternatives to gasoline-powered generators. Automotive-starting batteries are not well-suited for this purpose, because they are designed to provide a brief high-current burst to start an engine. Long, low-current loads can quickly discharge them. SLA batteries. Smaller, sealed lead acid (SLA) batteries are a good alternative to the larger, wet-cell deep-cycle batteries. Their lighter weight and spill-proof design allow them to be transported easily. LIFEPO4 batteries. However, if portability is a primary concern, consider the newer lithium iron phosphate (LIFEPO4) batteries. Often called “lithium phosphate,” these batteries are less toxic and safer than other lithium ion chemistries, and they can be discharged very deeply, up to 90 percent, without any damage to the cells. Compared to lead acid batteries, which should not be discharged below 50 percent, lithium phosphate batteries of the same rated capacity can provide nearly twice the useable power at half the weight. Yes, they are considerably more expensive to buy (how much is your back worth?), but they can supply so much more power and undergo many more cycles than lead acid batteries. They are a bargain in the long run.
RECHARGING THESE BATTERIES
All rechargeable batteries benefit from cycling (charge-discharge cycles), and they all display some level of self-discharge. Long-term storage will require an occasional topping charge to keep them “healthy,” but the biggest killer of secondary batteries is overcharging. Once a battery is completely charged, continued charge current will be converted to heat and can cause the electrolyte to dry out (among other issues). Lead acid batteries held at a high charging voltage will produce excessive gas due to electrolysis (splitting the water in the electrolyte to hydrogen and oxygen), and eventually, the electrolyte needs to be replenished by adding distilled water. Maintenance-free wet-cell batteries have covers over the cells that are designed to recombine the gasses to reduce the loss of water, but they cannot recombine enough to keep the solution in the cells at the appropriate level over time. Removal of the covers to inspect the electrolyte level could be difficult. But this should be done periodically and carefully, and distilled water should be added as necessary if the battery is connected to a charger continuously.
PROPERLY CHARGED AND CARED FOR, RECHARGEABLE BATTERIES CAN GO THROUGH HUNDREDS OF CHARGE CYCLES (CHARGE-DISCHARGE) BEFORE THEY EVENTUALLY START LOSING THEIR CAPACITY.
Charging secondary batteries should be done only with a charger designed for the voltage, size and chemistry of the battery to be charged. The companies that manufacture batteries for the portable use (AA through D cell sizes) market will often include wall or other chargers for their batteries. Smart chargers. While these manufacturer-provided chargers might seem to work acceptably, the best cycle life usually comes when smart chargers are used. Smart chargers monitor each cell individually and can adjust for optimal charge rate. Additionally, they are less likely to overcharge or overheat the battery; and some will even recondition batteries that are showing diminished capacity. Wet-cell batteries usually require more-substantial chargers—especially the high amp hour-capacity deep cycles. Again, smart chargers can tailor the charge rate to give the deepest charge without the worry of overcharging. Chargers that are designed only to maintain a full charge are often underpowered and might never be able to fully recharge a depleted battery. Off-grid power generation solutions, such as solar or wind, are the best bet for any condition. Solar or wind charge controllers can directly maintain 12 volt rechargeable batteries, which can then be used to charge portable batteries. So, there isn’t any reason to be without battery power … ever.
... THE “LONGER-LASTING” CLAIM DOES NOT REFER TO USAGE AT ALL; RATHER, IT REFERS TO THE BATTERY’S SHELF LIFE WHEN STORED PROPERLY.
Above: Buying batteries in large quantities can save big bucks.
Right: With all the battery-powered devices we depend on, consider reducing your expenses and storage space requirements by using secondary (rechargeable) batteries,
Above: The Garmin etrex Venture HC is a very popular handheld GPS device ... but it’s a battery hog.
Far left: Smart chargers monitor the charging process of each cell individually, ensuring a full charge without harmful overcharging.
Above: Mission-critical gear needs to work in any environment. The last thing you need to worry about is whether your batteries can take the heat or the cold. The Energizer Ultimate Lithium will outperform alkaline batteries in both operational time and temperature extremes.
Near left: All these batteries will fit in the same device, but they are incompatible with each other. Never mix battery brands, types, chemistries or capacities.
The Renogy Voyager Solar Charge Controller can handle 20 amps of solar panel input and can charge several different battery chemistries, including LIFEPO4. (www.renogy.com)
Below: Smart chargers that come with 12 volt automotive power connectors allow you to charge batteries on the move and can be connected to solar charging systems for grid-free operation.
The NOCO Genius Smart Charger series comes highly recommended and is very affordable. (https:// No.co)
Above: LIFEPO4 (lithium iron phosphate) batteries provide nearly twice the power as sealed lead acid (SLA) batteries of the same amp-hour rating—and they weigh half as much.
Left: Plastic enclosures offer impact protection and will contain any spills or leakage when servicing lead acid batteries. The top of the enclosure covers the terminals, reducing the chance of short circuits across the posts.