Disclaimer: Use of our Lithium Polymer batteries is done COMPLETELY AT YOUR OWN RISK. Due to the potential hazards of these cells we are not responsible for accidents caused by the use, proper or otherwise, of Lithium Polymer batteries.
Use of these batteries constitutes an agreement with these terms.
Lithium Polymer (LIPO) batteries can be very dangerous if not treated properly! Please carefully read and make sure you completely understand the following information before using any Lithium Polymer battery!
When summer arrives we always see more complaints of Lipo packs "swelling" There are several causes for pack swelling which are listed below but overheating is usually the most common cause.
1. The packs are subjected to extended temperatures over 100 degrees F.
2. The packs are overcharged
3. The packs are overdischarged
4. The packs are subjected to loads too high for the pack to handle.
If you want your packs not to swell you MUST follow ALL of the instructions below.
Charging: You MUST utilize a charger specifically designed to charge Lithium Polymer batteries with a balancing circuit.
1. Set the cell count selector:
If your charger has one, you must correctly set the cell count for the battery being charged. If your charger has an automatic cell count selector move on to step 2. For example a 2S Pack has 2 cells or 7.4 Volts. A 3S has 3 cells or 11.1 Volts etc. Make certain that the balance ports on your charger are the same type as the balance plug on your Lipo Pack. If not an adaptor will be required. Plug the balance tap into the proper port on your charger.
2. Set the charge rate:
Although some Lithium Polymer Batteries are rated at a 2C or higher charge rate we recommend you charge at a rate of 1C (1 x (C)apacity). For example, to charge a 5000mAh pack the charge rate would be 5 Amps. 1000mah = 1 amp.
Always monitor the progress of packs while charging. Never exceed the recommended voltage of 4.2 volts per cell (8.4 volts for a 2S pack).
3. Make sure the balance feature is turned on. Even though some manufacturers may say balancing is not required every time, we highly recommend you balance charge every time for maximum pack life.
Use of a Lipo sack while charging is also highly recommended and is required by many race tracks and by ROAR for their sanctioned events.
Discharging: Lipo batteries DO NOT FORM A MEMORY so discharging them is not necessary and wastes cycle life!
Never ever allow a Lithium Polymer batteries voltage to drop below 3 volts per cell. The low voltage threshold for discharge (under a load) is 3.4 volts per cell. Allowing any cell in the pack to drop below this voltage will irreversibly damage its internal chemistry and ruin the pack.
Storage: DON'T LEAVE A LIPO PACK FULLY CHARGED FOR MORE THAN A FEW HOURS. When you do not plan on using your Lipo pack(s) for more than a few weeks it is necessary to put a "storage charge" into them. A storage charge is about 50% of the rated capacity of the pack. Some chargers may even have a "storage charge mode". This is about 3.8 volts per cell or 7.6 volts for a 2S pack. If your pack is above this voltage then you will need to discharge the pack to this voltage level and if the voltage is lower you will need to charge the pack up to this voltage level. Putting the packs in a refrigerator will help to extend pack life! Put the pack(s) in a sealed plastic storage bag and put them in a safe spot away from food. DO NOT LEAVE YOUR PACKS OUT OR LEAVE THEM INSIDE A PARKED CAR ON A HOT DAY! They will "puff up" and cause permanent damage to them. HEAT is the #1 enemy of Lipo packs!
General Rules: - If for any reason, a Lithium Polymer battery appears deformed or is unusually warm to the touch, or after any unusual circumstances (such as a crash), use caution. Lithium Polymer battery packs with internal chemical leaks have been known to burst minutes, even hours, after being damaged.
Always disconnect your battery after every use. Even though the switch on your speed controller is off, there is still a small amount of current being drained from the battery!
If your speed controller has adjustable cuttoff voltage set it to 3.4 volts per cell. This will vastly reduce the chance of overdischarging one or more of the cells in the pack. Do not use Lipo packs in vehicles without Lipo cutoff circuitry!
DO NOT PULL ON ANY OF THE WIRES EXITING THE PACK! THE WIRES ARE NOT "HANDLES" TO LIFT THE BATTERY OUT OF THE CAR. I CAN'T TELL YOU HOW MANY TIMES I HAVE SEEN LOCAL RACERS AT OUR TRACK LITERALLY YANK THE WIRES RIGHT OUT OF THE PACK WHILE BEING IN A HURRY TO CHANGE OUT THEIR PACKS!
The harder you work the battery the shorter the cycle life will be. Do not expect to drain a 5000 mah pack in 5 minutes and get very many cycles out of the pack! For this reason you should always buy the highest "C" rated battery you can afford if cycle life is important to you. Make sure you do not exceed the "C" rating at any time during the discharge of the pack. One way to tell if you are overworking the battery is to check the temperature of the battery pack with an IR temp meter before and then again immediately after a race/run. If the temperature difference of the battery is more than 15 degrees hotter than when you started it is likely you are overstressing the pack!
Why You Should Balance Your Packs: Standard lithium battery chargers and battery cut-off circuitry, such as that found on electronic speed controls, must rely upon the average voltage of the entire pack to determine when charging and/or discharging is complete. This is because the cells in the pack are effectively wired in a series configuration . Unfortunately, this has a negative drawback. If for some reason one of the cell's voltages becomes higher or lower than the other cells in the pack, the charger or battery cut-off circuit may improperly sense the voltage of the cells in the pack (because of voltage averaging). When this happens, the averaged voltage of the pack will no longer properly reflect the voltage of each cell in the pack. This improper information may lead to the over-charging or over-discharging of one or more of the cells in the pack. Lithium Polymer chemistry is such that over-charging or over-discharging will substantially reduce the life of the pack and in extreme cases, POSE A SERIOUS FIRE HAZARD.
Taps - Lithium Polymer batteries are equipped with special plugs called "Taps." Tap plugs provide access to each cell in the pack individually. Individual access to each cell provides reliable voltage readings, allowing one to correct an imbalance should one develop. Taps allow each cell to be charged individually. However, Taps must be shown a great deal of respect. Depending upon the equipment used, it may be very easy for one to accidentally short one or more of the cells by simply allowing testing gear or exposed testing leads to come into contact with one another or a conducting surface. The balance tap wires are small and somewhat fragile so take great care when handling them.
TAKE EXTREME CAUTION WHEN USING TAPS. Take every precaution to prevent short-circuiting Lithium Polymer cells, not just because this will almost instantly ruin the cell, but because it may pose a fire hazard. PAY CAREFUL ATTENTION TO THE BALANCE WIRES COMING OUT OF THE PACK. DO NOT ALLOW THEM TO GET CRUSHED OR EXPOSE THE BARE WIRES. DO NOT ATTEMPT TO CUT TAP CONNECTORS OFF OF A LITHIUM BATTERY PACK - THE CUTTING INSTRUMENT IS CONDUCTIVE AND MAY SHORT-CIRCUIT THE CELLS!
A number of products are on the market to facilitate cell balancing for packs with Tap plugs. A properly configured adapter and use of a pack balancer will greatly reduce the risk of mistakenly short-circuiting a cell. Taps, when used properly, are a great feature, and should significantly improve the life and performance of your Lithium Polymer batteries.
Do Not short circuit Lipo batteries! Do Not open battery or dispose of in a fire!
Fire: In the rare case of a fire where lithium batteries are present, apply a smothering agent such as METL-X, sand, dry-ground dolomite, soda ash, or flood the area with water.
A smothering agent will help extinguish burning lithium batteries. Water may not extinguish burning batteries but will help to cool any adjacent batteries and control the spread of fire. When water is used, however, hydrogen gas may evolve. In a confined space, hydrogen gas can form an explosive mixture. In such a circumstances, smothering agents are recommended.
Disposal: To properly dispose of a Lithium Polymer Pack cover the pack with sand or dirt and discharge the pack to less than 1 volt per cell then drop the pack into a bucket of salt water (1/2 cup salt to 1 gallon of water) for 2 weeks. Wrap in newspaper and toss into the trash. The packs are landfill safe at this point.
