-- Use a balance charger specifically for lipo batteries. We love the SkyRC iMax B6AC-V2 Dual Power 50 Watt Balance Charger, but we sell several others to meet your needs. We wrote an entire blog post on how to charge a lipo battery.
-- Charge your batteries at 1C. In our blog post "12 Steps to Safely Charging a Lipo Battery," we gave you the formula for figuring out what 1C is for your batteries. (Divide the milli-amps by 1000.) While 1C is the recommended charge rate, charging the battery at a lower rate (some of our customers prefer even 0.5C) will cause no harm. It will just be slower. With a new battery, you might consider a slower charge rate for the first couple of charge cycles, as that will ensure proper cell balance on subsequent charging cycles. As noted above, lipo batteries are FLAMMABLE. Charging at a rate higher than 1C (unless specifically noted otherwise by the manufacturer) will result in a dead battery and possibly fire. NOTE: Even if a manufacturer specified a faster charge rate, regularly charging above 1C will shorten the life of your battery.
-- Use a lipo safe charging bag when charging your batteries. Even charging at 1C, batteries may become unstable--especially if they are older--and may start on fire. Charging bags will help to contain the fire. Better to be safe than sorry.
-- Always charge batteries on a fireproof surface. This cannot be overstated: lipo batteries are FLAMMABLE. Use a granite, marble, or cement surface for your charging station, NOT your wooden workbench.
-- Use storage charge for batteries that will not be used within a week. We send new batteries at a storage charge of 3.7-3.8v because we don't want to set our warehouse on fire. We recommend you do the same. If you have charged up a battery and will not be using soon, discharge the battery to storage charge levels.
-- Store your batteries in a cool, dry place. When batteries get hot, their cells may become unbalanced and/or the battery may start a conflagration.
-- Allow your batteries to drop below the minimum voltage. On any lipo battery, the minimum voltage is 3.0v per cell. A battery that drops below its minimum voltage will lose its ability to recharge and will thus be rendered useless. Note: The ESC in your aircraft has a low voltage cut-off (LVC) which will cut battery power to the motor when the cell voltage reaches a set minimum. The LVC is programmable, and should be set to a cell voltage level higher than the bare minimum (3.1v or 3.2v per cell are good settings). Also note that some ESCs have a default LVC below the minimum voltage; we strongly suggest reprogramming the LVC to a higher setting prior to use of the ESC. Another good way to ensure that a battery does not drop below minimum voltage is to end your flight before the LVC kicks in. Also, remember to keep your battery at a storage charge of 3.7v. Storing a battery near minimum charge will result in unbalanced cells and possibly ruin the battery for further use.
-- Leave your batteries unattended while they are charging. Say you followed our advice and are charging your batteries at no more than 1C on a non-flammable surface and the batteries are in a lipo safe charging bag. Surely, you think, it's safe to leave. NO. You will still need to be on hand in case something happens, so you can shut down the charger and/or use a fire extinguisher or smother the fire with a bucket of sand. We recommend keeping the latter two resources nearby. Installing a smoke alarm above your charging station adds another layer of safety, in case you get too wrapped up in another project to see the smoke.
-- Charge your batteries beyond the maximum voltage of 4.2v per cell. Most battery chargers have an automatic shut-off, but anything can happen. Be watchful. An overcharged battery can start on fire.
REMEMBER: Only YOU can prevent lipo battery fires.