By Press January 05, 2018

Guides

In other publications we have already talked about LiPo type batteries, which are the best alternative for your racing drones. However, these same batteries turn out to be somewhat fragile in terms of charging, maintenance and storage methods, since it is not a common battery that has a single power supply cell; on the contrary, LiPo batteries are formed by highly volatile 3.7V cells connected in series or in parallel and sometimes even in a mixed way, that is, both in series and in parallel. This means that a LiPo has as many batteries as there are cells in it.

The fact that actually a battery of this type represents several batteries integrated with each other provides a series of advantages and disadvantages that must be taken into account. For example, LiPo are much lighter and more powerful than a conventional battery. But this same power can lead to overheating or worse, a failure between the charges of the cell that will end up damaging the battery and in the worst case, also to the device connected to it, such as the charger or the drone. To prevent this type of accident from happening, it is necessary to charge each of the cells equally, and for this you will need a LiPo battery charger with balancer.

Why is a charger with balancer important?

A charger with balancer is one that lets you know when each cell of your battery is charged to the same voltage level as the rest. This way of calibrating the charge is considered by many as a fine adjustment that helps to extend the life of your LiPo, but it is also a very important safety measure that prevents your battery from exploding or causing great damage.

The first thing to consider is that the charging cycle of a LiPo battery consists of two phases:

• In this first phase the charger will circulate all the current that it can, within the technical parameters of It as voltage output among others, and will keep monitoring the tension of the battery when it is charging and when it is at rest, this to avoid overheating or voltage overcharge. After a certain time, the battery still without its full charge will reach a level that will notify the charger that it is already very close to the maximum limit, signal that will start the second phase.

• The charger will decrease the intensity of current that it sends to the battery, this is because none of the cells must exceed its maximum capacity, which is usually 4.2V, because it is when this amount exceeds that the battery tends to explode. During this second phase the balancer will continue to monitor the battery when it is charged and when it is at rest, when this last data also indicates a charge of 4.2V, your battery will be charged at its maximum capacity.

Now, the only way that the charger has to know in each phase which is the individual charge of each cell and that these are exactly the same, is with the balancing cable. Because it is not the same to have a 2S or 2 cell battery and that each of them is charged with 4.2V for a total of 8.4V, to have another identical one whose cells are charged with 4.1V and 4.3V respectively, because although their total charges are equal, the excess charge in the cell of the second battery could make it explode. And it is a slight difference that the balancer cable detects in advance, allowing us to abort the recharging of our LiPo.

How to balance the cells of our LiPo battery?

There are two ways to balance a LiPo battery, one more complicated than the other. Here we will talk about the simplest and safest, which is where the balanced LiPo chargers intervene. There are many of these devices in the market but one of the most popular is the iMax B6 model, which also turns out to be one of the cheapest with an approximate cost of $ 22.

The iMax B6 is designed for batteries of up to 6 cells and can supply a direct current of 11 to 18V. Its most basic model does not have a transformer but it does have the necessary cables for the charging process. To use it safely you should only follow these few steps:

• Connect the charger to the outlet.

• Then connect the two cables, both the balancing one and charging one to the LiPo battery, once you have done that, press the button that says BATT.TYPE until the charger screen shows you the following message:

• Once you read the previous text, you must press the START button and then you must press the status controls that are the ones that say DESC. or INC. until the screen shows the data of the last recharge that was made to the battery. These data are shown as follows:

• Then we press START again and the charge intensity will begin to blink, which in this example is the equivalent of 0.6 Amperes.

• To set the desired charge intensity for your battery you must press the DESC. or INC. buttons taking as a reference half of the indicated amount of mAh, for example for a battery of 1800 mAh the intensity would be 0.9 A and for one of 1600 mAh the appropriate intensity is 0.8 A.

• We press the START button again to indicate this time the number of cells that our battery has, here will begin to blink the data of the screen that shows the 8.4V, which is equivalent to 2 batteries.

• We press DESC. or INC. once more to establish the appropriate number of cells of our LiPo, for example if it is a three-cell battery (3S) the appropriate amount would be 4.2V * 3 = 12.6V

• We press START and wait until the charger beeps showing the following message on the screen:

To immediately change the text to the following:

This last message means that the device detected 3 cells (R) and that we effectively indicated that they were 3 cells (S), as the message is correct, press once more START and ready, our battery will start charging in a balanced way . Otherwise, in which the R and the S are not equal you must cancel the whole process by pressing the BATT.TYPE button.

It is important that you bear in mind that the charger will never start the process if the number of cells does not match the ones we have indicated.