Note: This pertains to the 3.6 volt Lithium batteries
The more I read here the more I find the a-lot of people don't understand how to safely use Lithium batteries. I fly electric RC airplanes and heli's and the R/C crowd has been using the very similar Lithium polymer for for over 5 years. Seemed like every day someone one the forum was reporting a battery fire, but most can be prevented with a little understanding of the batteries.
Lithium batteries can become unstable if:
Using unprotected lithium batteries in a device that does not have a built in low voltage cutoff will damage the battery unless you have a way to monitor the voltage of each cell and stop using it before the cells start dropping below 3 volts under a load. A battery that has been damaged in any way can catch fire during recharging or normal use. (Li-poly batteries have been reported to swell and catch fire just sitting after being damaged)
Proper chargers for lithium batteries will stop charging at or below the 4.2 volts to prevent overcharging as long as you are charging each cell individually.
If you have 2 or more unprotected cells in a device the cells can get out of balance. One cell may be 3.3 volts and the other might be 2.7 when the device cuts off at 6 volts possibly damaging the lower voltage battery.(If the device even has a low voltage cutoff) If the same 2 cells are charged in in the device then the higher voltage battery most likely will get overcharged.
The protected cells are new to me and in theory should prevent most of these issues as the 3 main causes of battery failure are undercharging, overcharging and shorting out. If your amp draw is a little high for the battery you will notice the battery getting warm when using it.
We can't use protected cells or fuses in RC aircraft due to the battery also powering the receiver and servos, but we have a cutoff that will reduce or kill power to the motor without killing our means of controlling the aircraft.
You can visit RCgroups.com Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports for more info.
Charles
The more I read here the more I find the a-lot of people don't understand how to safely use Lithium batteries. I fly electric RC airplanes and heli's and the R/C crowd has been using the very similar Lithium polymer for for over 5 years. Seemed like every day someone one the forum was reporting a battery fire, but most can be prevented with a little understanding of the batteries.
Lithium batteries can become unstable if:
- Their voltage drops below 3 volts.
- They are charged above 4.2 volts.
- The amp draw of the device exceeds the battery rating.
- If they are dropped or damaged.
Using unprotected lithium batteries in a device that does not have a built in low voltage cutoff will damage the battery unless you have a way to monitor the voltage of each cell and stop using it before the cells start dropping below 3 volts under a load. A battery that has been damaged in any way can catch fire during recharging or normal use. (Li-poly batteries have been reported to swell and catch fire just sitting after being damaged)
Proper chargers for lithium batteries will stop charging at or below the 4.2 volts to prevent overcharging as long as you are charging each cell individually.
If you have 2 or more unprotected cells in a device the cells can get out of balance. One cell may be 3.3 volts and the other might be 2.7 when the device cuts off at 6 volts possibly damaging the lower voltage battery.(If the device even has a low voltage cutoff) If the same 2 cells are charged in in the device then the higher voltage battery most likely will get overcharged.
The protected cells are new to me and in theory should prevent most of these issues as the 3 main causes of battery failure are undercharging, overcharging and shorting out. If your amp draw is a little high for the battery you will notice the battery getting warm when using it.
We can't use protected cells or fuses in RC aircraft due to the battery also powering the receiver and servos, but we have a cutoff that will reduce or kill power to the motor without killing our means of controlling the aircraft.
You can visit RCgroups.com Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports for more info.
Charles
