Rechargeable batteries-FAQs

FAQ – Frequently asked questions

STIHL Cordless Power Systems

Ποια είναι η διάρκεια ζωής μιας επαναφορτιζόμενης μπαταρίας;

The service life of rechargeable batteries cannot be generalized because it depends on:

  • proper use of the battery
  • care and storage of the battery
  • the number of charge cycles (a charge cycle is a full charge from 0% to 100%)
  • natural aging of the lithium-ion cells over time

For example, STIHL batteries in the PRO cordless system can be fully recharged up to 1200 times.

 

PRO cordless system usage scenario

Professional Private User
Charge cycles
per year

2 charge cycles per work day
= 440 charge cycles per year*

10 charge cycles per month
= 120 charge cycles per year 

Time required for
1200 charge cycles:


about 2.5 years**


about 10 years**

* assuming 220 work days
** assuming the battery is always used, maintained and stored correctly

What are the benefits of the 36V technology?

The quoted voltage alone says nothing about the power of the batteries or the cordless products.

Power is defined as the product of voltage and current:
Power = Voltage x Amperage --> W = V x A

The interaction between voltage and current and the technical implementation of the overall system are the points that determine the performance of a cordless product.

In the case of hand-held cordless battery products, a compact build and weight are crucial for operator convenience. From a technical point of view there are certain restrictions when it comes to making products compact:

  • One goes for a high voltage (e.g. 80V) and can technically use only low electrical currents because the number of components and the weight would otherwise increase.
  • On the other hand, one confines oneself to a still meaningful high voltage (36V), which allows high electrical currents technically and can limit the number of components and the weight.

STIHL, like many other established manufacturers of cordless battery products, decided in favor of a system with a maximum voltage of 36V. This high voltage, which is still technically meaningful and allows high electrical currents to be used, guarantees high performance and future sustainability of the cordless products.
Cordless products are compact, lightweight and more robust due to the use of fewer electrical components.

Furthermore, STIHL offers an efficient, high-performance overall system of matched components:

  • The intelligent motor control guarantees constant high power over the entire running time.
  • The energy supply to the electric motor is actively controlled in response to the type of application. Full power is always made available for extreme applications. However, power is automatically reduced if it is not necessary for the current application. In this way the energy in the battery is used optimally and the runtime on a single charge extended.
  • Efficient batteries in compact design and available in different versions (with high energy content or low weight) ensure a long runtime and operator convenience.
  • Cutting attachments designed to match the cordless product, e.g. the ¼" P saw chain, guarantee optimum performance in every application.

Ultimately, it is always the energy content of the battery and the efficiency and implementation of the overall system that define the runtime and performance. For this reason systems with 56V or 80V have no advantages over the STIHL cordless system with 36V.

How high is the power of cordless battery products compared to gasoline products?

STIHL offers products with different types of drive. Corded and cordless electric products as well as classic gasoline products.

Performance specifications and the methods of determining power differ between the types of drive:

  • Gasoline: The mechanical output power is quoted
  • Electric: The electrical power consumption (nominal value) is quoted

These power specifications have become established for the two types of drive, but as they differ they cannot be compared directly with each other. That means therefore: A comparison of performance, e.g. between a gasoline chainsaw and an electric chainsaw, is not possible, nor is it meaningful.

The comparison is even more difficult with cordless battery products. In this case manufacturers have not yet established a standard way of specifying power.
The situation is further complicated if one wants to compare cordless battery products with gasoline products because of the differences in behavior during operation. For example, the cordless product’s electric motor produces high torque even at low RPM. In difficult situations, e.g. when the cutting attachment becomes slightly pinched, the cordless product feels more powerful than a comparable gasoline product and does not jam as quickly. A comparison would therefore have little meaning and cannot reflect the perceived power available in different working situations.

How are batteries protected against thermal and energy-related influences?

Current and voltage monitoring

  • Reducing motor RPM if the cutting attachment is blocked

Temperature monitoring

  • Signal and automatic shutdown in case of too high a temperature

Voltage monitoring of individual cells

  • No overcharging possible during charging
  • No exhaustive discharge possible during operation

Charge

How long does it take to recharge batteries?

For the charge times of STIHL batteries and STIHL cordless products with built-in batteries visit www.stihl.com/charging-times.

What do the 80% and 100% charge times mean?

The specifications 80% and 100% refer to the battery’s state of charge. The corresponding charge time indicates how many minutes it takes for a flat battery to reach that state of charge.

About one third of the charge time is required for the last 20%. The reason for this is that the battery cannot be recharged up to 100% at a constant high charging current.
The charging current drops continuously towards the end in order to protect the cells and retain their performance over many charge cycles. Therefore, a relatively long period is required to charge the last percentage of capacity.

It is possible to work with STIHL cordless products and use full power even if the battery is not fully charged.

What points have to be observed during the battery charge process?

Does the use of a quick charger harm the battery in the long term?

The use of a quick charger has no detrimental effect on the useful life of the battery.

The battery and charger are intelligently connected during the entire charge process. Both components jointly determine the optimum charge process and are monitored by the battery management system. This avoids the cells in the battery being damaged by excessively high charge currents and temperatures.

Purchase

Why are the prices of cordless products so high?

STIHL offers a broad range of cordless products in different price categories – from the attractively priced STIHL lithium-ion cordless system for use in small gardens and around the house to the STIHL PRO cordless system for professional users.

In principle, all STIHL batteries and STIHL cordless products are manufactured to a high quality and ideally rated for the respective usage scenarios and target groups.

After the initial purchase, the purchase of further products in the same cordless system becomes even more attractive. The modular concept allows batteries that have already been purchased, and the charger, to be used for all other products in the same cordless system. Compared to gasoline products, there are no costs for fuel or spark plugs.

What points must be observed when disposing of the batteries?

Information on disposal is available from STIHL servicing dealers.

  • Dispose of batteries in accordance with local regulations and environmental requirements.