By Gwen Mathis, AMA Education Development Coordinator | gwenm@modelaircraft.org
As seen in the December 2024 issue of Model Aviation.
IF YOU LIVE in a place that gets cold during the winter, you probably know how dangerous low temperatures can be for your batteries. If you’ve never noticed this before, pay close attention to your cellphone battery the next time it’s outside in cold weather. You will be able to observe how quickly the battery level drops.
The effect that cold temperatures have on batteries can be summed up with a simple explanation: Cold temperatures increase the internal resistance of batteries and lower their capacity. Cold batteries produce less power than usual, experience slower chemical reactions, and are unable to retain their regular charge.
Is there anything that you can do to keep your batteries safe and healthy? There are, in fact, many things!
Note: This article discusses care for LiPo batteries. If you are handling a different battery type, we recommend doing careful research about specific storage, charging, discharging, and maintenance.
Safe Storage
Batteries need to be stored in temperatures between 40° and 70°F. Temperatures that are too cold or too hot can damage them. Batteries temporarily lose capacity in freezing temperatures, but the temporary capacity loss leads to reduced long-term storage as well. It is important to keep batteries away from areas with direct, constant sunlight and hot surfaces, such as car hoods on hot summer days.
You must be extremely careful with where you store your batteries. You can’t just toss them in a toolbox or your pocket. Batteries should also be stored in a firesafe bag or nonflammable container. These containers should not have sharp objects that could pierce the battery packaging.
Safe Charging and Discharging
You do not want to store your batteries at charge levels of 100% or 0%. The ideal storage charge level is 50%. It is important to know the nominal storage voltage per cell when storing your batteries. Each battery cell should be stored at a charge voltage of roughly 3.8 volts. A 2S LiPo battery would be stored at 7.6 volts, a 3S LiPo battery would be stored at 11.4 volts, and so on.
When charging batteries, it is important to closely monitor them. In the unlikely event that one catches on fire, do not attempt to put the fire out using water. You will need to use a Class D fire extinguisher because common household extinguishers are unable to control fires caused by LiPos. If a Class D fire extinguisher is unavailable, throwing sand onto the fire can help calm it.
Use High-Quality Batteries
High-quality batteries might be more expensive, but they’re also more reliable. Low-quality batteries typically require more upkeep and expenses, which can really add up over time. Although they might cost more up front, high-quality batteries can save you more time and money over their lifetime.
Safe Disposal
No matter how well you maintain your batteries, they will eventually reach the end of their lifetime. Some signs to dispose of your batteries include puffiness, losing 20% of their capacity, and/or if they’re no longer able to hold a charge.
Before disposing of your battery, you should discharge it. After discharging the battery, submerge it in saltwater for two weeks. If the battery is damaged or puffy, do not discharge it; skip straight to submerging the battery in salt water. When the battery has been submerged for two weeks, you can dispose of it.
When it is time to dispose of batteries, a simple option is to recycle them through a free battery recycling program called Call2Recycle. There are more than 16,000 public drop-off sites throughout the nation, all of which can be found on the Call2Recyle website (www.call2recycle.org) or by calling (877) 273-2925.
When handling damaged batteries, make sure to use personal protective equipment, such as gloves and safety glasses. If a damaged battery leaks onyo your skin, immediately wash your hands with soap and water. If any battery leakage gets in your eyes, immediately flush them and seek medical attention.
Conclusion
Batteries are very useful. We use them to drive in our cars, send texts, and fly our favorite model airplanes. Modelers and non-modelers alike rely heavily on batteries. Cold weather can damage them, but well-maintained, clean, high-quality batteries are able to prevent capacity loss and retain their regular charge.