LiPo batteries are chemically the same as Lithium-Ion batteries used in cell phones and laptops. The main difference in the battery types is the housing. What RC model and drone enthusiasts refer to as LiPo batteries are really Lithium-Ion batteries in a polymer casing vs. the hard shell one typically finds in other lithium cells. This makes LiPo batteries advantageous for several reasons. First of all, LiPo batteries have one of the best charges to weight ratios of all batteries on the market today. Secondly, LiPo batteries have a relatively flat voltage curve as they discharge. What that means is the voltage remains fairly constant under load, up to a point. While the chemistry of the battery gives us a favorable capacity to weight ratio and a high discharge rate, there are a few issues to be aware of when using LiPo batteries. LiPo batteries produce hydrogen (a very flammable gas – see Hindenburg Disaster) as a result of the discharge. Under normal conditions, the amount is minimal and poses little danger. However, damage to the battery can easily result in a fire. Overcharging, discharging, and physical damage can all cause internal shorts facilitating rapid discharge of the battery’s stored potential, resulting in a buildup of heat and hydrogen: a recipe for disaster. (Take a look at this link to a youtube search for Lipo Fires for some samples of the carnage). Special care is required for extending the life of your batteries and precautions should be taken to minimize the risk when using LiPo batteries.
The first rule for LiPo batteries is to never leave them unattended while charging. A battery left unattended while charging can easily overcharge and catch fire. Secondly, a LiPo battery should always be charged and stored in a LiPo bunker. A LiPo bunker is a fireproof bag or box that will contain any battery fire, should one occur. LiPo batteries should never be completely discharged. This can cause the battery to short internally and/or cause it to fail to charge. Never leave the battery charging unattended. Overcharging is a sure way to cause problems: At best, the battery can be rendered useless, at worst the battery could cause a fire, and many have. Never use a battery that is puffy. The puff comes from the cells breaking down internally and can release flammable gases. A ‘puffy’ LiPo has a reduced capacity to store charge and can result in your remotely operated vehicle losing power and crashing or catching fire. Never use a battery that has visible external damage. Anything that punctures the cells can cause internal shorts. The high charge density of LiPo batteries means that the cell can rapidly discharge across that short, generating intense heat and releasing toxic fumes. Always balance charge multi-cell LiPo batteries. Doing so will extend the battery life and reduce the potential for individual cells to over-discharge and short internally. A good balance charger is a relatively inexpensive step to take to minimize the risk to you, your equipment, and, most importantly, to other people around you.
Taking care of your batteries will save you in the long run. You will save money, in terms of extended battery life, but also, you will save yourself from increased risk of damage to property, equipment, and human life. Cars and remote control trucks are a fun and rewarding hobby, but proper precautions are essential to keep yourself and those around you safe.