FAQ about Lipo Batteries By Genstattu
This entry was posted on January 11, 2016.
LiPo batteries are normally safer and more environmentally friendly than other batteries like NiCd and NiMH. LiPo batteries have become the most common high performance R/C battery and are used in R/C cars, boats, planes, helis, multirotors and more. However, if charged, discharged, stored, maintained, or handled improperly, they can become extremely dangerous. Here we collect some frequently asked questions about Lipo batteries from RC hobbist and our customers.
Q: What is battery cycling? How important is it? How often do I have to do it?
A: Battery cycling is the use of some type of loading device (ideally a calibrated charger with a discharge function) to drain the current from a battery pack until it approaches the lowest safe voltage for the pack, then recharging the pack back up to its peak capacity again. Often 3 complete cycles are done to help 'condition' a battery, ensure that it is capable of holding a complete charge, and to help maintain/increase the life and reliability of the battery pack. Cycling does not need to be done frequently.
Q: Can I use a higher cell count battery than the one that came with my airplane?
A: It depends on your speed controller and motor. If the battery does not exceed their rated limitations for voltage, then you can use a higher cell count battery which will give you more power and/or longer flight times.
Q: Can I use a higher mAh battery than what is recommended?
A: Yes, so long as it's only the mAh that's higher than specified, it'll simply give you longer flight times. As an added bonus, the battery should also last longer because it'll be less stressed, since higher mAh also means it's capable of delivering more amps.
Q: How safe are lithium polymer batteries?
A: Lithium Polymer batteries are safe if you take the time and learn to use them properly. You always need to insure they are being charged at the correct rate and not discharged past their rated capacity. People get into trouble when they over-discharge the batteries or charge them incorrectly. Before using a Lithium Polymer battery, you should understand your charger and the amp draw of your system.
Q: How to charge my batteries?
A: The optimal charge rate for your Li-Po battery 1C (because most chargers can charge at that rate without overloading the charger). Translated, this means that for every 1000 mAh of battery capacity, you set your charger at 1 amp. (eg. You should charge your 2000mAh battery at 2 amps, 3000mAh battery at 3 amps, etc). Also insure that the cell count setting on your charger is correct. Most chargers automatically detect the number of cells in the battery but you should always double check the detected cell count. Incorrect cell counts on the chargers are how most Li-Po fires occur. A battery charged at 1C should take about an hour to charge. You can charge at rates less than 1C but it will take longer for the battery to charge. Perfect Balance batteries can handle up to a 2C charge rate (if your charger can charge at that rate) without affecting capacity or battery life.
Q. How fast can I charge a Lipo battery?
A: Most Lipos are designed to be charged at a 1C maximum rate. This means that the charge rate (milliamps) must not exceed the capacity (mah) of the Lipo. So a 500 mah Lipo should not be charged at a rate greater than 500 milliamps (0.5 amps), and an 1800 mah Lipo should not be charged at a rate greater than 1800 mah (1.8 amps). THIS IS VERY IMPORTANT! BE CERTAIN OF YOUR CHARGE RATE!!! You might consider charging at a lower rate than 1C if you're not in a hurry, as this may help extend the life of your Lipos.
Q: How should I store my batteries?
A: If you plan on long term storage (1 month or more), you should charge your battery to 70% of it's capacity (about 3.8 volts per cell) and check the voltage every few months. You should also store them in a temperature controlled environment. For normal short term storage, you should never leave your batteries in a discharged state. Always charge your batteries after you use them. If you leave them in a discharge state, they will slowly lose voltage and be damaged.
Q: Should I discharge my battery like I do with Ni-Cads?
A: No. Li-Po batteries do not have a memory and should not be manually discharged unless you are very familiar with their operation and safety. Even if you only fly for a minute, all you need to do is put the battery on the charger and charge it at the 1C or 2C rate.
Q: Battery should be removed after finished using it?
A: Yes, you are recommended to remove or detach the battery.
Q: How many cycles can I expect from my battery?
A: Normally, Gens Ace & Tattu Li-Po batteries are good for about 200 cycles at full capacity. After that, the capacity will be reduced until about 400 cycles. Of course, this depends on how the battery was treated during its life. If you discharge it at full capacity or never balance the pack, your battery will usually only last 30-50 cycles. Always measure your amp draw and choose a battery that is rated for discharge at least 25% more than your recorded discharge amps. (If you are pulling 20 amps - you should use a 25 amp continuous battery)
Q: My battery gets warm during discharge. Is this normal?
A: As your battery discharges, it will generate heat. The amount of heat will vary depending on your amp draw. A 75 amp continuous draw battery that is used in an aircraft drawing only 35 amps will stay relatively cool. That same battery discharged at 70 amps will usually heat to about 135 degrees. For long term life, it is best not to let your battery get to over 120 degrees. The amount of airflow also affect the battery temperature. The more airflow you have over the battery, the better it will perform.
Q: Can I use two batteries in my plane?
A:You can use two batteries hooked to a single receiver with no problem as long as both batteries are the same voltage. First you will plug one into your battery slot either alone or into a Y-harness with a servo. The second battery can also be "Y-ed" with a servo into any other servo slot that you like. Both batteries will supply power in unison with each other unless you have a dual battery switch, which stops the second battery from operating until the first pack has reached a certain voltage.
Q: Can I use Li-ion polymer batteries mixing with other battery types?
If different types of batteries are used together, or new batteries are used with old ones, the difference in characteristics of voltage, capacity, etc., may cause over-discharge of the battery which is exhausted first, leading to swelling, bursting or fire.
At last, we hope these answers can really help you. If you have any more questions about these batteries feel free to contact us at firstname.lastname@example.org.