Battery to battery charger 12V to 12V with 25A for lead, GEL, AGM, and lithium batteries, galvanically isolated

The VCC series charge converters (boosters) have been developed in accordance with the latest requirements for charging supply batteries (leisure battery) on the move from the alternator (starter battery).
In contrast to conventional cut-off relays, the charging voltage is lowered or raised according to the charging program specifications, making it particularly suitable for EURO 6, 6 + plus vehicles.
For leisure batteries in classic lead-acid, lead-gel or lead-AGM, as well as modern lithium LiFePO4 technology, the 4 selectable charging programs ensure unsupervised, rapid and gentle full charging from any state of charge, followed by full maintenance and care of the battery.
Even on short journeys, the battery is charged with full charging current. Connected 12 V consumers are automatically supplied, even if the on-board electrical system is heavily loaded. Automatic power control ensures the necessary safety and starting capability of the vehicle.

Product advantages:

• The powerful charge converter ensures high charging performance even on short journeys.
• Full charge on longer journeys.
• It increases/decreases the voltage to the necessary level to precisely charge the leisure battery with its optimal charging curve.
• It fully compensates for line losses and voltage fluctuations of the alternator, as they constantly occur to a significant extent in Euro 6 vehicles (intelligent alternators), for example.
• It is characterized by a compact design, low weight (high-frequency switch mode technology) and robustly dimensioned power components for safe operation.
• Significantly better energy balance of the leisure battery, no intervention in the starter circuit
• The supplied 12 V consumers are protected against overvoltage and voltage fluctuations.

Further device features:

• The charging voltage is free of peaks and regulated in such a way that overcharging of the batteries is impossible.
• Fully automatic operation via switching input (ignition, engine running) and voltage control.
• There is no intervention in the vehicle's electrical system; the charge converter behaves like a consumer on the alternator.
• Automatic, adjustable power control enables the starter battery to be charged preferentially by the alternator in the event of an overloaded vehicle network, thus ensuring the immediate starting capability of the vehicle.
• No discharge (current 0.000A) of the batteries in standby or when the charge converter is switched off.
• Parallel and buffer operation: If consumers are switched on simultaneously, the battery continues to be charged or maintained at full capacity. The charge converter automatically calculates and monitors the adjustment of the charging times.
• Unsupervised charging: Multiple protection against overload, overheating, overvoltage, short circuit, reverse polarity at the output, malfunction and battery back-discharge by electronic regulation up to complete separation of charge converter and battery by built-in safety switches.
• Galvanic isolation between input and output ensures excellent interference suppression through absolute separation of the battery circuits, clean ground conditions on both sides even with long cables, safety in case of fault (no breakthrough 12V/24V or 24V/12V possible) and reliably prevents unwanted back-discharge of the battery circuits.
• Charging aid for deeply discharged lead or switched-off LiFePO4 batteries: Gentle pre-charging of the (lead-acid, -gel, -AGM) battery or automatic reactivation of the Li battery if consumers are still switched on.

The charge converters of the IUoU-Li series are characterized by a compact design, low weight (high-frequency switch mode technology), robustly dimensioned power components and thus full charging power even with long charging cables and strong voltage fluctuations at the alternator/starter battery (EURO norm 6, 6 + plus vehicles), for information see page 9, table 2, switch position D of the operating manual.

6 LEDs indicate the operating status of the device at all times.

Adjustable battery types: There are 4 charging programs stored in the device for the different battery types, selectable via 2 slide switches on the device.

a) Lead Acid/AGM1: Sealed and open acid/wet lead-acid batteries and AGM 14.4 V (factory setting)
b) AGM 2: Sealed, gas-tight AGM batteries (Absorbent Glass Mat, lead-fleece technology)
c) Gel: Sealed, gas-tight gel batteries (dryfit, fixed electrolyte)
d) LiFePO4: Charging voltage 14.4 V for lithium LiFePO4 batteries with fully integrated electronics and protective circuitry (BMS).

Function of power control for starter battery and alternator:
The charge converter is activated via the control input Kl.15 / D+ and automatically deactivated when the ignition is OFF / engine is OFF. It starts with 10% of its possible charging power.

The setting of the two slide switches "Input Type" on the back of the device (see table 2 of the operating manual) now influences the further load on the starter battery circuit from which the charge converter draws its current. After the engine has started, the starter battery should also be recharged immediately and remain ready to start. Therefore, the charge converter only gradually increases the charging power for the leisure battery when the voltage value "Increase charging power" is reached at the starter battery.

If the starter circuit is heavily loaded by many large consumers and the starter battery voltage drops again below the "Reduce charging power" value, e.g. when the engine is idling, the charging power for the leisure battery is reduced to relieve the starter circuit. However, the minimum charging power is always at least 10% of the possible charging power.

If the voltage drops below the "Charge converter switch-off threshold" for 30 seconds, the charge converter switches itself off. If the voltage rises above the "Increase charging power" threshold, the converter switches on again and gradually increases the power until the required (maximum) charging power is reached.
A reduction in charging power of more than 30% due to insufficient input voltage from the alternator is indicated by the "Battery II" LED flashing. The LED goes out when either sufficient input voltage is present again or when the power requirement has decreased anyway due to a well-charged leisure battery I.

Option: Parallel connection of two charge converters: To increase the charging power for large battery banks or high loads (e.g. air conditioning operation with less powerful devices), two identical devices can also be connected in parallel.

Scope of delivery:

• B2B25Vo1212V3 Battery-to-battery charger / charge booster galvanically isolated, Votronic 3306
• Battery temperature sensor 825