If you are into RC vehicles, helicopters, planes or any other RC machinery then you must have heard about the LiPo batteries. Lithium Polymer (LiPo) batteries are a new type of batteries that are getting popular because of their light weight, sizing and large storage capacities. That is the reason they are preferred over other batteries especially when it comes to RC machines. In fact, the use of RC items is increasing after the introduction of LiPo batteries a few years back.
Lipo Battery Advantages
LiPo batteries are light weight which makes them suitable for many machines especially for Radio Control Cars, planes, boats and rc helicopters etc. When compared to other batteries, their weight to storage capacity is very good.
LiPo batteries comes in a wide range of sizes. As a matter of fact, they can be designed in any size you want. Not only the size, they come in a comprehensive range of shapes and can be designed for any shape you want as well.
Capacity of a battery basically means the amount of charge that it can store. Of course, the higher the capacity the better and that is why LiPo batteries are preferred because they provide a very decent size to capacity ratio.
What damages your LiPo Battery?
Although LiPo batteries are very efficient but they are quite sensitive and need proper care if you don’t want them to get damaged or decrease their life span. These are the things that you should try to avoid if you want a 400-500 charge/discharge cycle (Very Good) for your battery.
- Over discharging
- Unbalanced charging
- Leaving the battery for longer periods of time (especially fully charged)
Since LiPo batteries have a very different chemistry than that of other batteries, the charging of these batteries is quite different as well. Properly charging your LiPo battery is important because it determines the life of your battery.
Cell count and Voltages
One of the main things to keep in mind for properly charging a LiPo battery is the cells and voltages. LiPo batteries have cells in them. A 1S battery means it has 1 cell in it. Similarly a 2S or a 3S battery means it has 2 or 3 cells respectively. Knowing how many cells are in your battery is quite important because each cell has a 3.7v nominal charge so if you have 2S battery that means 7.4v and so on or if you have a 3.7v battery that means it’s a 1 cell battery. The cell is considered fully charged when it reaches 4.2v and is fully discharged when it reaches 3.0v. Your duty is to keep these cell voltages between these ranges to ensure the safety of your battery.
Knowing the maximum voltages that you can charge your cell isn’t enough. You need to balance the cells as well. Balancing basically means to keep all of your cells at the same voltages during charging. When you have a single cell then you don’t have to worry about balancing. But when you have multiple cells then balancing is important.
The problem occurs during the charging. What happens if, during charging, one of your cells is charged to 4.1v but the other one charged at 4.3v? Surely the first cell is fine but the second one is overcharging. So this is what balancing is, to keep all the cells charged at the same voltages. Usually the differences isn’t that big, that was only an example, you only have to make sure that your cells have no more than 0.01 to 0.03v difference between them.
How to balance Lipo Batteries
Every LiPo battery will have a balance plug that can help you charge or discharge a cell individually. There are multiple ways with which you can make sure that your cells are charging in a balanced way.
External balancers, as their name suggests are balancers that are used externally for balancing. These are standalone balancers that can be used during the charging with the charger to balance the voltages of any cell that is being over charged or can be used after the charging is done (not recommended).
Fully computerized chargers are available in the market that have a built-in balancer in them. These are a bit expensive but provide the safest way of charging and balancing at the same time.
Storage of a LiPo battery is as important as charging and discharging because improper storage of a LiPo battery will damage it beyond any repair. LiPo batteries tend to discharge over time and if your cells discharge below 3.0v then the damage will be, most likely, irreversible. On the other hand don’t leave the battery fully charged either as it can cause damage as little as in a week. The best way to ensure the safety of the battery if you have to leave it is 3.8v. Computerized chargers nowadays have functions that will either charge up to or charge down to 3.8v for you.
Another thing worth mentioning is to keep your batteries in a cold place. Leaving a charged battery in a hot car for over a day can cause damage. So it’s better to leave them at room temperature. If you have to leave them for a longer period of time then 0 Celsius temperature is a good option. You can put your battery in a fridge (not freezer) to slow down the discharge process. Also, keep your batteries away from any fire or explosive material.
The bottom line is to keep your LiPo battery at proper storage voltage (3.8v) to ensure that it will be in working condition the next time you use it. If you are leaving it for longer periods of time then don’t forget to check the voltages every once in a while.
You have to keep a few things in mind for properly discharging a LiPo battery because of the lithium in it. The Lithium in a LiPo battery reacts with water, oxygen and is combustible. So you have to make sure that you don’t let the battery get too hot as that can cause oxygen to build up inside the battery which will build up rust. This will increase the internal resistance of the battery. You can get a charger from the market that measures internal resistance and collect the values to see how your internal resistance is increasing. If it is increasing too fast then your battery is on its way to prematurely die. Also, make sure that your battery stays away from water and doesn’t come directly in contact with oxygen as it might cause a fire.
- Since LiPo batteries are combustible, it’s a good idea to not keep them all together. Placing them separately will make sure if one gets on fire then the others are safe
- Always charge your batteries on a clear floor with no heating or combustible material around them
- Always charge LiPo batteries in safe bags
- If you are about to charge your battery after a run, let it cool for a while otherwise temperature and heat might damage your battery
Overall, LiPo batteries are very impressive when it comes to performance and size. But the downfall is that they need proper care. What people don’t realize is that there’s a lot more to LiPo battery then just charging and discharging. So if you keep all the above mentioned things in your mind and take good care of your battery then you will surely be happy with the results.