It is vitally important to use only high-quality Li-ion cells with built-in protection circuitry.
Lithium-ion batteries are rechargeable and energy-dense, allowing for longer deployment times than alkaline or NiMH batteries. High-quality lithium-ion batteries are generally very safe, but the battery market is flooded with counterfeit or otherwise low-quality 18650 batteries that carry much greater risk of combustion.
Do not sacrifice safety to save money. Follow our recommendations to find batteries that will be safe, reliable, and long-lasting.
- Batteries must be both "button-top" and "protected."
- Batteries must be approximately 69±1 mm in length.
- Product listings should name the manufacturer of the original cell.
For example, a battery sold by Brand X may explicitly state in the specifications that the battery uses the Panasonic-Sanyo NCR18650GA as the battery cell.
Additionally, 18650 lithium-ion batteries are available in multiple charge capacities, measured in milliamp-hours (mAh). The 18650 batteries sold by Wildlife Acoustics have a nominal charge capacity of 3,500 mAh. Batteries with lower capacities will not last as long, but may still be otherwise suitable.
What Not to Buy
The following are indicators of an unsuitable battery you might find on a product page:
- Batteries listed as "button-top" but not as "protected"
- Specified length less than 68.0 mm
- No indication of original battery manufacturer and model
- Unrealistic advertised capacity, such as "9900 mAh"
High-quality 18650 batteries have a nominal capacity of roughly 3500 mAh.
Protection Circuitry
The SM5 is only compatible with protected 18650 Li-ion batteries. Protected batteries contain both the battery cell itself (sourced from battery manufacturer like Panasonic, Samsung, Molicel, or Murata) and a small protection circuit board wrapped together into a cylindrical package. The protection circuit extends the battery's length to about 69 mm.
The protection circuit protects the battery from over-charging, over-discharging, short-circuits, and extreme temperatures.
Reliable Suppliers
We recommend only purchasing lithium-ion batteries from Wildlife Acoustics resellers or well-reviewed, specialty battery retailers. Batteries sold for very low prices on large, multi-seller e-commerce platforms may feature misleading specifications and poor manufacturing tolerances. Poorly manufactured batteries are significantly more likely to experience catastrophic failure.
Specialty battery suppliers often source battery cells from a small number of manufacturers and package a cell and protection circuit together into a protected battery sold under their own brand. Look for suppliers who are transparent about the manufacturer and model of the battery cell used in each of their products.
Recommended Battery Manufacturers
The following are some examples of battery manufacturers whose 18650 cells are well-reviewed and available as protected batteries from specialty battery retailers.
- Panasonic (formerly Sanyo)
The protected batteries sold by Wildlife Acoustics and Faunatech use the Panasonic NCR18650GA cell.
- Samsung
- Molicel
- Murata (formerly Sony)