The LiPo (Lithium Polymer) smart batteries are batteries whose reaction is based on lithium not in the ionic state, but in the form of polymer: the electrolyte is in fact in gel form.
In this form, they have several advantages: they have no bearing of discharge, and thus retain all their power during use. In terms of weight: they are devoid of any metal packaging, and are therefore much lighter.
They are composed of elements that each have a nominal value of 3.7V. When loaded, they each get the value of 4.2V. When all the cells have reached this value, we say that the battery is intact. But the older the battery, the more it will lose tension.
This battery life can be checked by pressing the power button once for 5 seconds. If, for example, only one LED out of four comes on, then it means that there is only 25% of its life left. (Very useful technique if you are going to buy batteries or a drone from someone, and check if he was honest with you).
The charge of a LiPo battery
During normal use of a LiPo battery, the different cells of the battery tend to discharge at a different speed. When a battery is discharged at a dangerously low voltage, the cells can become unbalanced. It is therefore very important that your charger is specialized for LiPo batteries and that the charger has a “Balance” feature, which is now by default in most specialist chargers. This feature is essential for safety reasons and battery life, and will reduce gaps between cells.
If you have chosen the “Lipo” function of your charger, it will be set to stop when it detects a peak of 4.2V on one of the cells.
The operating voltage of a LiPo battery typically being 3 to 4.2V per cell: reaching the destruction voltage of 2.5V or charging at more than 4.2V per cell can be very dangerous, and cause irreversible damage to your battery. In addition, exceeding the upper threshold of 4.2V can make it catch fire quickly … that’s why it’s important to always watch your batteries while charging.
The discharge of a LiPo battery
A LiPo battery does not discharge: if it’s charged at 60%, 6 months later, it will still be at 60%. DJI batteries are said to be smart because they are designed to be discharged every 10 days at 50 – 65%. (You can manually adjust the time to discharge via the application, which I advise you, for example to 3 days).
If it’s not recommended to fully discharge the LiPo batteries: do it every 20 – 30 flights or every 3 months to optimize its operation.
- The ideal storage temperature is between 10 and 26 degrees. (Avoid leaving batteries in the car when it is very hot or very cold).
- It is important not to wet your batteries: after flying in fog or near the sea, it’s recommended to wipe the battery with a cloth and drying it in the open air.
- Just after a flight, it is recommended to wait at least 1 hour for the battery to cool before recharging directly. Likewise, you should avoid recharging it 100% at one time. This has a strong impact on the battery voltage. It’s better to load it at 50 – 60% maximum, then the next day to load at 100% in two times.
- Minimize shocks, if the LiPo cells are altered, there is a risk of explosion. In the same way, it will be necessary to pay attention if the battery is inflated: don’t use them if they received a big hit.
- Do not throw in the trash: if it is less than 2.5V, put in a container of salt water for a minimum of 24 hours. If the voltage is not greater than 0, recycle it to a suitable bin, such as a battery collection bin.