Rechargeable batteries and batteries

Accumulator? Battery? Which is correct and what are the things that make the difference?

A battery is an electrochemical storage device. In the past, there was a clear distinction between batteries and accumulators: batteries were non-rechargeable (primary cells) and accumulators were rechargeable (secondary cells). Nowadays, there are almost only rechargeable batteries. However, there are differences that we would like to explain in more detail.

Lithium batteries


  • Long service life : Lithium batteries have a long service life.
  • No memory effect : They have no memory effect.
  • Long storage life : Lithium batteries can be stored for a long time.
  • High energy density : They offer high energy density and therefore more capacity with less weight.
  • Many charging cycles : They have a significantly higher number of charging cycles compared to lead batteries.
  • BMS (Battery Management System) : This system monitors the cells and intervenes in the charging or discharging process if necessary.


  • Deep discharge : Deep discharge can irreparably damage the battery.
  • Temperature sensitivity : Very low or too high temperatures damage the battery. The optimal operating temperature is 22°C.

Lead batteries


  • Value for money : Lead batteries are inexpensive and reliable.
  • High current delivery : They can deliver high currents in a short period of time.
  • Robustness : With good maintenance and care they have a good lifespan.


  • Low energy density : Lead batteries are heavier than lithium batteries with the same capacity.
  • Position dependency : They must not be operated upside down and only to a limited extent in a side position.

Amount of energy (Wh)

The energy is given in watt hours (Wh) and is calculated using the formula capacity times voltage (Ah x V = Wh). The running time is the amount of energy divided by the power consumed by the device.


The capacity is the stored electrical energy and is given in milliampere hours (mAh) or ampere hours (Ah). A battery with a capacity of 1 Ah can deliver a current of 1 ampere for one hour. The higher the current drawn, the shorter the running time.

Measuring capacity

Capacity cannot be measured directly. It is measured through a process of charging, discharging and recharging with cooling phases under load. This takes several hours to a whole day.

Range of a battery

The range varies depending on the power consumption of the motor, distance traveled, load, tire pressure, wind conditions and route topography as well as the age, condition and charging behavior of the battery. The capacity in Wh or Ah indicates a fixed, measurable value.

Loading and unloading

Important voltages are:

  • Nominal voltage : e.g. 12 V for lead batteries.
  • Final charging voltage : Charging must not exceed this voltage (e.g. 13.8 V for lead batteries).
  • Final discharge voltage : Discharge must not be below this voltage (e.g. 10 V for lead batteries). Some batteries have a cut-off electronics to protect against deep discharge.

Wear and tear due to charging/quick charging

The higher the charging current, the greater the wear. Fast chargers reduce the charging time, but cause thermal and chemical stress, which leads to a shorter service life. Typical charging currents are 2A. Fast chargers often have higher charging currents up to 10A.

Deep discharge

Every battery cell has a final discharge voltage. If this voltage is exceeded, it is called deep discharge, which can lead to irreversible damage. Lithium batteries are particularly sensitive to deep discharge.

Facts, lifespan, care, storage

Lithium batteries

  • Losing capacity due to aging.
  • Charging cycles and the required performance influence the service life.
  • Extreme temperatures damage the battery.
  • Optimal charging range: 30-80%.
  • Operating temperature: 22°C.
  • Storage temperature: 10°C, cool and dry. Check batteries monthly and keep them at around 50% charge.

Lead batteries

  • Sulfate crystals form during discharge and are partially dissolved during charging.
  • Over time, sulfate crystals hinder the flow of energy.
  • Low voltage and long storage at low voltage promote sulfate formation.
  • Storage temperature: 15°C, cool and dry. Check batteries monthly and keep them at around 90% charge.