Find out everything you need to know about Li-ion battery charging and what you need to be aware of.
09.10.2024
Charge STIHL lithium-ion batteries to 80-100% before using them for the first time
Safety technologies prevent lithium-ion batteries from overheating
Worry-free overnight charging
Protect lithium-ion batteries from moisture, heat and cold
The assumption that batteries need to be fully charged after purchase no longer applies to advanced lithium-ion batteries. However, there are a few things you should keep in mind to ensure that your batteries have a long service life.
You can charge STIHL batteries within a temperature range from +5 to +40 degrees Celsius without any problems. Storage between -20 and +50 degrees is possible – though there will be functional losses at the top and bottom of this range.
STIHL chargers offer you additional safety: If your battery is too warm after a long period of use, the charging process will only start once the battery has cooled to a certain temperature.
To protect lithium-ion batteries and charge them correctly, they should not be placed on heaters. That’s because temperatures which are too high or too low can be harmful to the batteries – so you should always observe the approved temperature range.
It is best to charge batteries at normal room temperature or at moderate outdoor temperatures.
Advanced lithium-ion batteries only require 80% charge before their first use – this takes between half an hour and four and a half hours, depending on the battery.
One myth suggests that a battery should be placed on a heater during charging. This theory is based on the idea that electrical activity will increase because of the heat input, which should protect the battery during charging and extend its service life. Some claim it should even be possible to briefly reactivate a fully flat battery by heating it, on the grounds that only a warm battery can access its entire energy reserve. Now we know that this theory is incorrect and harmful to the battery.
During charging and discharging, the ions essentially migrate from one electrode to another – depending on the direction of current. If the battery is heated too much, the particles accelerate and the material decomposes – and service life is reduced as a result. In the worst-case scenario, easily combustible gases may be produced if the battery is strongly overheated. The battery will become unusable. In general, we recommend that you always observe the battery’s approved temperature range.
Good to know
All STIHL batteries are delivered from the factory to retailers with a charge level of 30%. Even if a STIHL battery has been stored at a retailer for a long time, it is effectively protected against self-discharge.
It is normal for a battery to warm up during charging, and there is no need to worry when this happens. STIHL high-quality batteries are protected against overheating and are basically risk-free. The charging process ends automatically once the battery is charged, meaning you don’t have to worry about charging a battery for too long. Imitations and non-OEM parts are more likely to pose a hazard, because these batteries can burst as a result of excessive heat formation.
If a battery exceeds its approved temperature range by a very large amount, this can cause a self-reinforcing exothermic chemical reaction called a “thermal runaway”. The heat generation within the battery becomes self-reinforcing, sparking a circular chain reaction which quickly melts the battery core.
It is true that the risk of battery fire continues to be a matter of concern for many users. However, advanced STIHL batteries keep you on the safe side.
The high-quality battery products from STIHL have many advantages, including low risk of fire from lithium-ion batteries, optimal protection against deep discharge, and temperature monitoring by means of an efficient battery management system.
To prevent overcharging and excessive heat development, only lithium-ion cells that meet the highest safety requirements are installed in STIHL batteries.
Both batteries and chargers from STIHL are fitted with protective mechanisms that prevent overcharging and excessive heat generation.
Each individual cell installed in a battery is monitored by a battery management system. This involves an integrated sensor which measures the temperature at the warmest point inside the battery – if the temperature is too high, the charging process is interrupted.
With advanced lithium-ion batteries, the risk of fire is very low. This is ensured through various measures, one of which is the built-in battery management system that prevents overcharging and the associated high heat generation.
The electronics in lithium-ion batteries automatically put batteries into an idle state if they are not used for a long period of time. This protects against damaging deep discharge.
For all its battery products, STIHL uses advanced lithium-ion cells which do not need to be fully charged before first use and are ready for use within just a few hours. The reason for this is that self-discharge rates of STIHL batteries are vanishingly low – capacity loss is just one to three percent per year.
There is no memory effect with lithium-ion batteries. The memory effect refers to the permanent loss of capacity arising from partial discharge, which affects nickel-cadmium batteries (NiCd). The battery remembers the consumed energy requirement and over time only provides the previously used capacity instead of the original full amount.
If a battery runs hot
Electrical precautions in the battery, charger and work tool prevent overheating and automatically switch off functions at critical points. To counter the unlikely event of overheating, all battery cells are housed in a robust and flame-retardant housing.
For optimum storage of our lithium-ion batteries, we recommend an ambient temperature of around 20 degrees. In principle you can store the batteries between -20 and +50 degrees – however, there may be a loss of function and service life at the top and bottom of this range. That’s why we recommend storing lithium-ion batteries correctly.
Chargers such as the AL 300 quick charger actively help to cool the battery with the aid of a built-in air cooling system. Get to know our battery chargers:
The four LEDs on the battery indicate the charge level, but can also indicate malfunctions in the power tool or battery. Just press the button on the battery to activate them. The LEDs will turn green for approximately five seconds and then show the charge level. If only one LED flashes green, this indicates low charge.
When the battery is plugged into the charger, the green LEDs also indicate the charge level (if no LEDs light up, the charging process is complete). If the LEDs light up or flash red instead, there is a fault:
LED display | Meaning |
|---|---|
 | The battery should be charged. |
 | The battery is 20-40% charged. |
 | The battery is 40-60% charged. |
 | The battery is 60-80% charged. |
 | The battery is 80-100% charged. |
 | The battery is too hot or cold. |
 | The power tool is too hot. |
 | There is a fault in the power tool. |
 | The battery has a fault. |
The LED display of the battery provides information about the charge level or faults.
If you would like to find out more about how a lithium-ion battery works and how STIHL makes the most of these functions, for example with intelligent systems, you can find out more in the Basic battery knowledge article.
How long a battery needs to charge depends on its capacity. In most cases, charging to 80% takes between half an hour and four and a half hours. The battery can be used without any problems at this charge level, even the first time it is used. Charging to 100% takes a little longer, with the exact time depending on the type of battery.
Whether lithium-ion batteries can be charged with a standard charger depends on the battery. Specific connections are often needed to charge a lithium-ion battery. This is generally related to the products in which the batteries are used. So a suitable charger is required for charging.
Three points count for ensuring correct charging of a lithium-ion battery. First, the temperature should be between +5 and +40 degrees Celsius. Make sure that the battery is protected from moisture. Connect it to the appropriate charger. Advanced safety technologies in STIHL lithium-ion batteries protect against overheating and automatically regulate the flow of current. Before using the battery for the first time, you should charge it to 80-100%.
It is often assumed that the battery temperature has an impact on the amount of energy it provides. According to this theory, electrical activity should increase due to heat input. Some claim it should even be possible to reactivate a fully discharged battery by heating it up. Today this theory is known to be incorrect, and heating a battery – on a radiator for example – actually damages the battery.
When charging a lithium-ion battery, temperatures should be between +5 and +40 degrees Celsius.
Charging a battery for too long is potentially dangerous if using imitations and non-OEM parts. Quality batteries are generally protected against overheating, though defects can never be entirely ruled out.
