Tool Battery FAQs
As a result of our work with batteries and rechargeable batteries, we got many questions. You can find a selection of these questions and answers on this website!
Can rechargeable batteries really manage 1000 times?
Yes. But mostly only under laboratory conditions that often cannot be achieved under normal conditions.
How long should I leave my rechargeable batteries in the charger?
With modern, electronically controlled chargers there is no danger if you leave the batteries in the device for several days, for example. They switch off when the battery is fully charged or switch over to a lower current maintenance rating. Rechargeable batteries can be damaged or destroyed if they are not taken out in time from a charger that does not have reliable switching off. The maximum charging duration can be calculated as follows, given that there had previously been a full discharge:
(capacity of the battery x 1.4) : Charging current of the charger
(capacity of the battery x 1.5) : Charging current of the charger
In what charging state are rechargeable batteries supplied?
Rechargeable batteries are in principle charged during production to be able to check if they are functioning properly. The battery loses its charge, depending on how much time elapses from the production of a cell until it is sold at the shop. The rechargeable battery must be charged before it is used for the first time. NiCd rechargeable batteries must first be discharged so that a memory effect does not arise.
How should I look after a rechargeable battery?
This depends on the system. For example, a NiCd rechargeable battery must always have been completely discharged each time before it is recharged. This is best done by using a charger with a discharge function. All rechargeable batteries benefit from occasional "cycling": The rechargeable batteries are discharged and recharged several times in succession. This restores the full capacity that had been lost as a result of the memory effect.
What is cycling?
Cycling is a sort of "cure" for the rechargeable battery: It is discharged and recharged again 2 or 3 times in a row. This restores its original capacity. We recommend regular cycling for the rechargeable batteries of all systems, and also for new rechargeable batteries whose storage time and state of charge is not known, cycling 2 or 3 times can be a good idea.
Should the cells get hot when charging?
No. They may become warm, but not really hot. If they do get hot, they have either been overcharged or are defective. A good charger detects the sudden rise in temperature and switches itself off. A good charger for a mobile phone battery has a thermoswitch that turns off the charging function at around 70°C and thus prevents overcharging and overheating.
Does quick-charging damage my rechargeable battery?
No. Charging takes around 1-2 hours with a quick-charger, as opposed to more than 10 hours charging time for normal chargers. The relatively high current of the quick-charger requires an especially reliable form of switching off once the battery has been fully charged.
Does a new rechargeable battery have its full capacity available at once?
No. A new rechargeable battery only develops its full capacity after a few charge/discharge cycles.
How quickly can a battery be recharged?
That depends on the type of charger used: The greater the charging current of the charger, the more quickly will the battery be fully recharged. Normal charging takes around 10 to 16 hours (typical "overnight charging"). Quck0charging can be done in around 2 to 3 hours, ultra-fast chargers can even recharge a battery within around 30 minutes. The exact details can be found in the instructions for use of the relevant chargers.
What is intelligent charger switching?
Intelligent charger switching determines the exact end of the charging process and switches over to maintenance charging.
Should you take the batteries out of the device if it is not going to be used for a longer period?
Yes. There can still be a small current flowing in devices that have been switched off, and this can cause a deep discharge over a longer period of time that damages the battery and, in extreme cases, destroys it.
How should a rechargeable battery be stored?
The recommended temperature range for long-term storage is between +10°C and +30°C at a relative humidity of 50%. A normal refrigerator at +8°C can be used for extended periods of storage since that minimizes the degree of self-discharge.
In what state should rechargeable batteries be stored?
Since rechargeable batteries lose their charge within a few months, in principle it makes no difference with NiCd batteries and NiMH batteries as to what state they are stored in. However, in the event of long periods of storage (more than six months) a NiMH battery should be stored in a fully charged condition. In addition, it should be recharged at least once every 12 months. By contrast, Li-ion batteries have active electronics that fully discharge the battery over the course of time. For that reason lithium-ion batteries must in general be stored fully charged and recharged again within no more than 12 months, otherwise, the battery can be destroyed.