If you live in a place that gets cold during the winter holidays, you may know how dangerous low temperatures can be for your batteries. If you've never noticed this before, just pay close attention to your phone battery the next time it's outside during the winter weather. You will be able to observe how quickly the battery level drops.
The reason for 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. This means that cold batteries produce less power than usual, experience slower chemical reactions, and are unable to retain their regular charge.
This is comparable to the way we work as humans: when our bodies feel cold, they conserve heat in an attempt to keep us warm. We can't do as much when we're cold as we would when our bodies are operating in comfortable temperatures, because bodies spend energy levels in different ways to battle the cold.
You may be wondering whether or not there is anything you can do to keep your batteries safe and healthy. And, in fact, there are many things you can do!
Just a note going forward: this article discusses care for Lithium Polymer (LiPo) Batteries. In the event that 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 a temperature between 40°F and 70°F. Temperatures that are too cold and temperatures that are too hot can both cause damage to your battery. Batteries temporarily lose capacity in freezing temperatures, but the temporary capacity loss leads to reduced storage long term 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 batteries in a toolbox or your pocket. Batteries should also be stored in a firesafe bag or non-flammable container. These containers should not have sharp objects that can pierce the battery packaging.
Safe Charging and Discharging:
You do not want to store your batteries at full or no charge. The ideal storage charge is 50% charge. 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 around 3.8 volts. A 2S LiPo battery would be stored at 7.6 volts, and a 3S LiPo Battery would be stored at 11.4 volts, and so on and so forth.
When charging your batteries, it is important to closely monitor them. In the unlikely event that the battery catches on fire, do not attempt to put the fire out using water. You will need to use a Class D Fire Extinguisher, as common household extinguishers are unable to get fires caused by LiPo Batteries under control. If a Class D Fire Extinguisher is unavailable, throwing sand on the fire can help calm the fire. This is the reason sand buckets are a recommended addition to both your flight line, and your charging station!
Maintain your Batteries Regularly:
Checking on your batteries regularly and maintaining them throughout the year can prevent disaster. You can maintain your batteries by performing visual checks, checking the environment, and charging them when necessary. By performing regular maintenance on your batteries, it is possible to prolong the life of your battery.
Use High-Quality Batteries:
High quality batteries may be more expensive, but they're more reliable. Lower quality batteries typically require more upkeep and expenses, which can really add up over time. Even though they may cost more, higher quality batteries can save you more time and more money over its lifetime.
Safe Disposal:
No matter how well you maintain your batteries, they will eventually reach the of their lifetime. Some signs to dispose your batteries include puffiness, losing 20% of their capacity, and/or are no longer able to hold a charge.
Before disposing of your battery, you should discharge it. Once you've discharged 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. Once the battery has been submerged for two weeks it can be disposed of.
When it is time to dispose of your batteries, a simple option is recycling them through a free used rechargeable battery and cellphone collection program, called Call2Recycle. There are over 34,000 collection sites throughout North America, which can be found on the Call2Recyle website or by calling (877) 273-2925.
While it may seem easier to simply throw batteries in the trashcan, it is important to know that it is illegal in some states to dispose of batteries in the regular trash.
When handling damaged batteries, make sure to use personal protective equipment, such as gloves and safety glasses. If a damaged battery leaks on your skin, immediately wash your hands with soap and water. If any battery gets in your eyes, immediately flush your eyes out and seek medical attention.
Batteries are very useful. We use them to drive in our cars, send texts, and fly our favorite model airplanes. Both modelers and non-modelers alike rely heavily on batteries. The cold weather can cause damage to your batteries, but well-maintained, clean, high-quality batteries are able to prevent capacity loss and retain their regular charge.
If you are curious about safe battery practices and/or would like to read more on the topic, the AMA has other resources for LiPo Battery Basics and Safe Use.