Our wealth of experience allows us to provide the optimal charging solution for your application (lead acid, NiMH, Li-Ion and lithium iron phosphate). Chargers for battery packs in several cell chemistries and several sizes (1-13S) are available, and at speed.
The slogan, “Standing still is a step backwards” drives us on to constantly develop our product range and equipped with innovative and varied charging technologies stay at the top of the industry. It is the only way to provide our customers with optimal, tailored solutions. ANSMANN strives to study, meet and exceed the latest trends and standards (e.g. Induction charging).
Lead acid chargers
There are several charging techniques that can be used for lead acid chargers.
Charging according to UI characteristic curve:
Voltage and current are regulated, making “automatic” charging perfect for lead acid battery packs. Until reaching the preset end-of-charge voltage, current will be limited. After that, the charging current decreases continuously until there is only a trickle charge going into the battery. The charger can be permanently connected with no loss of power to the battery. This procedure is also referred to as parallel standby.
Charging according to IU0U characteristic curve:
This charging technique allows a battery to be charged safely and in a short period of time with current and 2-stage voltage control. The rechargeable battery is first charged to obtain a high voltage value (e.g. 14,5V at a 12V battery). If the battery achieves this value, the end-of-charge voltage will reduce to a lower and safer value (e.g. 13,8V at a 12V battery). The charger is now in the recharging phase.
Consequently, charging time is shorter but without overcharging your batteries. The charger can be permanently connected in order to keep the battery charged. In order to achieve careful charging of lead acid batteries you can set formation charging with a low charging current.
Parallel standby is also possible.
Induction charging is an alternative when a non-contact power transmission is required.
With this charging approach an electromagnetic field is used for transferring energy between two objects. Therefore, this technique can charge a device without charging contacts or cable.
Made possible by induction technology, charging current can be transmitted from the transmitter (base station) to the receiver (mobile device). The subsequent charging circuit can be customized and used for simple trickle charging for NiMH, lead acid batteries or controlled charging for Li-Ion battery packs. The integration of the complete induction charging circuit in a battery pack can also be achieved. The charging process starts by putting the equivalent device on the induction charger, compatible devices are identified automatically.
Advantages of induction charging are that it carries a far lower risk of electric shocks and there are no contact problems due to contamination or oxidation. This is interesting for applications that are used in harsh environments. In addition, applications can be easily charged in splash and explosion-proof housings.
- Non-contact charging
- No mechanical linkage
- No contact problems due to contamination
- Splash-proof housings
- Easy operation
There are three different methods of charging NiMH-batteries:
- Voltage-monitored charging
- Temperature-monitored charging
- Timer charging
Voltage-monitored charging is the most common and most intelligent method of charging. During the charging process, the voltage of NiMH batteries rises until it reaches maximum. This means that the battery is fully charged. If you continue to charge the voltage will drop by a small amount.
If you string together all measured voltage values you will receive the typical voltage curve for those rechargeable batteries.
The switch-off of the charging takes place after:
- Turning point – the battery voltage is increasing but not as quickly as at the beginning (the rise of voltage decreases)
- Maximum – the battery voltage is no longer rising
- deltaV – the battery voltage has achieved its maximum and has already begun to decline
A timer-controlled charger terminates the charging process at a pre-set time.
Timer chargers are the easiest automatic battery chargers to use. As they are not able to determine the charging condition neither before nor during the charging process it is recommendable to only charge fully discharged rechargeable batteries with this type of charger. Otherwise, batteries will be partly overcharged.
This kind of charging utilizes the thermal behavior of batteries. At the end of the charging process, when the batteries are fully charged, the temperature increases quickly. There are three different switch-off criteria.
- The charging process is usually stopped when a battery temperature of 45-50°C is detected.
- After dT/dt: This means the charging process will end if the battery temperature rises within a certain time to a certain value. A common value is for example 1°C per minute.
- Only changes in temperatures are measured. Time is not a factor.
Normally, temperature-monitored charging is paired with a voltage-monitored charging for safety reasons.
In addition to custom-tailored system solutions ANSMANN also offers a wide range of standard Li-Ion chargers.
Thanks to an intelligent modular system chargers for all types of Li-Ion technology are available without any additional development. The charging control is adapted to the appropriate battery chemistry.
Using a software-based charging algorithm, customized changes can be made easily.Country-specific primary plugs, interchangeable primary plugs and individual secondary connectors can be used when creating this kind of system solution.
CC – CV (constant current – constant voltage)
Li-Ion batteries need special chargers being equipped with the CC – CV charging process.First, the chargers limit the charging current to a permitted value of, for example, 0.5C (i.e. 1000mA for a 2000mA battery). As the voltage is constantly rising during the charging process, it is necessary to ensure that 4.2V, which is an important value for Li-Ion batteries, is not exceeded. This voltage value is also referred to as end-of-charge voltage which is held constant by the charger. If the battery voltage comes very close to the end-of-charge voltage the charging current will decrease. If the charging current falls below a preset value (e.g. 0.05C) the charging process will stop. Instead of using the falling charging current, you can use the time as a switch-off criteria as well. It can be assumed that the battery is fully charged in three hours when using a 1C charging process. In the case of Li-Ion batteries it is important that the charging process is finished completely, as there is no trickle charging. This would damage and destroy the Li-Ion battery over a period of time.