Charging Boosters | Chargers for a Second Battery

Charged batteries even without solar and mains power

If an inverter is used in a motorhome, service or emergency vehicle, it makes sense to install or retrofit a second battery and an inexpensive second battery charger or a high-quality charging booster with an IUoU charging characteristic to protect the starter battery: especially if you mainly make short journeys, are mainly self-sufficient or work independently or only have a small solar system and want to use the journey times effectively for charging the battery even in bad weather.

It is not possible to install a second battery charger in vehicles equipped with alternators with energy-saving charging strategies. In Euro 6 vehicles, the use of a charging booster is even mandatory, as the charging voltage of the alternator can fluctuate greatly.

12 V charging boosters for vehicle, caravan and solar


Model	IVT Chaging Booster 12 V, 30 A	Schaudt Chaging Booster WA 1208	Schaudt Chaging Booster WA 121525	Schaudt Chaging Booster WA 121545
Charging current, regular mode	max. 30 A (30 A mode)	-	25 A (max. 30 A)	45 A (max. 70 A)
Charging current, caravan mode	max. 10 A (10 A caravan mode)	8 A (max. 9 A)	-	-
Supported battery types	Lead-acid, lead-gel, AGM, lithium	Lead-acid, lead-gel	Lead-acid, lead-gel, AGM, lithium	Lead-acid, lead-gel, AGM, lithium
Battery capacity	from 35 Ah	from 35 Ah	up to 300 Ah	min. 80 Ah/max. 700 Ah
Temperature sensor	optional accessories	not available	optional accessories	included in delivery
Charging characteristic	IUoU	IU constant voltage	IUoU	IUoU
E-certificate	yes	no	yes	yes
Item no.	920033	920001	910000	–
Available set	Charging Booster car set IVT, incl. connection material for batteries	–	Charging Booster set Schaudt, incl. connection material for batteries	Charging Booster set Schaudt, incl. connection and sensor set
Item no. Set	920073	–	920006	920000

Model

IVT Charging Booster 12 V, 30 A
Charging current regular: max. 30 A
Charging current caravan mode: max. 10 A
Batteries: from 35 Ah,
lead-acid, lead-gel, AGM, lithium
Charging characteristic: IUoU
Item no: 920033

IVT Charging Booster car set 12 V, 30 A
Set incl. connection material to batteries
Item no: 920073

Schaudt Charging Booster WA 1208
Charging current caravan: 8 (max. 9 A)
Batteries: from 35 Ah,
lead-acid, lead-gel
Charging characteristic: IU
Item no: 920001

Schaudt Charging Booster WA 121525
Charging current: 25 A (max. 30 A)
Batteries: up to 300 Ah,
lead-acid, lead-gel, AGM, lithium
Charging characteristic: IUoU
Item no: 910000

Schaudt Charging Booster set WA 121525
Set incl. connection material to batteries
Item no: 920006

Schaudt Charging Booster WA 121545
Basic set, incl. connection and sensor set
Charging current: 45 A (max. 70 A)
Batteries: min. 80 Ah/max. 700 Ah,
lead-acid, lead-gel, AGM, lithium
Charging characteristic: IUoU
Item no: 920000

Advantages of IVT Charging Booster

Intelligent charging management

The charging converter essentially ensures that both the starter battery and the supply battery in a motorhome, camper van or commercial vehicle, for example, are charged safely, efficiently and completely while driving or while the engine is running.

Priority charging of starter battery

The charging booster constantly monitors the voltage of the starter battery. The second battery is only charged when the starter battery is sufficiently charged. If its voltage falls below a certain level, the charging booster reduces the charging current.

Charging different battery types

By utilising the charging booster, different battery types (starter and supply battery) can be charged simultaneously.

The IVT Charging Booster is suitable for lead-acid, lead-gel, AGM and LiFePO₄ batteries.

Compensates voltage fluctuations

The intelligent IVT Charging Booster is a clocked step-up/step-down converter that equalises the strongly fluctuating alternator voltage.

As soon as an alternator signal is applied to the charging booster (D+), it automatically goes into operation.

Optimum recharging guaranteed

The IVT Charging Booster works according to the principle of constant current charging (IUoU). The IUoU charging process ensures fast and complete charging of different on-board batteries.

In regular mode, the booster limits the charging current to max. 30 A, in caravan mode to max. 10 A. This prevents the cut-off relay and the wiring harness from being overloaded by high equalising currents.

When the nominal capacity is reached, the IVT booster switches to trickle charge mode.

No discharge of starter battery

When the engine is switched off, the connection between the two batteries is automatically separated. This prevents the starter battery from discharging. As a result, the vehicle always remains ready to start.

Extends the service life of the batteries

The optimised and gentle charging of both batteries considerably extends the service life of the starter and on-board batteries.

Standard protective functions

Deep discharge protection starter battery
Temperature management/overtemperature protection
Short-circuit protection at the output
Overvoltage protection input/output

E-certification

Both the IVT Charging Booster and the large Schaudt Charging Boosters are approved for permanent installation in all 12 V vehicles with road approval.

The charging converters fulfil the legal requirements of the ECE regulation and therefore have E-certification.

Development & production in the EU

Charging boosters are often exposed to high loads and must function absolutely reliably even under difficult conditions.

That is why we only use quality components in all IVT devices, place the highest demands on the manufacturing process and put every product through its paces before it is delivered.

Accessories: Temperature sensor

Temperature-controlled charging protects the battery from damage, as the charging voltage always adapts optimally to the ambient conditions: it is reduced at high temperatures and increased slightly at low temperatures.

If batteries are charged without a protective circuit (BMS), we recommend connecting a temperature sensor to the battery terminal.

Recommended use IVT Charging Booster

For a complete and safe charging of the vehicle battery and supply battery via the alternator, we recommend the installation of a charging booster in both commercially and privately used vehicles. For vehicles with the Euro 6 emissions standard, the installation of a booster is mandatory from a technical point of view.

Charging boosters for delivery vans, service and emergency vehicles

Work has to be done quickly: Repairs have to be carried out urgently, often without a fixed power connection, in the middle of the road, off-road or in an open field.

In cases like these, it makes sense to equip the van with a powerful supply battery, an intelligent charging booster and a digital sine wave inverter. This investment ensures that you can operate powerful tools, pumps or chargers anytime and anywhere.

Do you need support in selecting the individual components? Talk to us. We will be happy to help you.

Charging boosters in fully integrated & semi-integrated motorhomes, campers and caravans

Many small devices that make your life easier require a 230 V AC power supply (coffee machine, electric toothbrush, air conditioner, charger/mains adapter for e-bike batteries, lap top and mobile phone, etc.).

Don't want to miss out on the comfort you are used to at home when travelling?

Then we recommend (retrofitting) an additional living area battery, a charging booster and an IVT inverter with a genuine 230 V sine wave for reliable power supply.

How to install the IVT Charging Booster

If a charging booster is to be retrofitted in a vehicle or boat, the following questions arise:
Where is the best place to install the charging booster? How do you connect a charging booster correctly? What accessories do you need for this?

The charging booster is preferably installed near the on-board battery. The booster can be mounted on the wall or on the floor. Cables are laid from the charging booster to the starter battery to the second battery and to the ignition signal. If no ignition signal can be tapped, a D+ simulator is also installed. During installation, care must always be taken to ensure that the battery supply cables are sufficiently dimensioned and fused. Detailed information on the various installation situations can be found in the IVT Charging Booster operating instructions. Our tip: In addition to the individual devices, we offer IVT and Schaudt charge booster car sets, including connection material for the batteries.

IVT charging boosters are used reliably in craftsmen's vehicles, delivery vans, BOS service, special or emergency vehicles, vans, small vans or panel vans, motorhomes, camper vans, tractors and coaches.

The 12 V boosters are suitable for the following vehicle models: Mercedes Sprinter, Fiat Ducato, Ford Transit, Ford Nugget, PSA, VW T4, T5, T6, VW Crafter, VW Caddy Cargo, MAN TGE, Opel Como Cargo, Nissan Townstar, Citroen Berlingo, Citroen Jumper, Peugeot Boxer and many more.

Useful information on charging boosters | FAQ

Why is the installation of a charging booster mandatory for vehicles with the Euro 6 emissions standard?

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In modern vehicles with intelligent alternators, charging the on-board battery while driving is no longer possible without further ado.

In Euro 6 vehicles, "intelligent" alternators with energy-saving charging strategies are installed. With these alternators, the charging voltage fluctuates greatly depending on the driving conditions (e.g. between 12.6 V and 15.0 V in the Mercedes Sprinter). In addition, after a driving time of 30 to 40 minutes, the alternator significantly reduces the final charging voltage or stops charging completely. Without the use of a charge booster, optimum charging of the secondary living area battery is prevented.

If the second battery is fully charged (e.g. via the 230 V mains), there is even a risk of discharge. For this reason, the installation of a charge booster is mandatory in vehicles with Euro 6 emission standards.

What is the difference between charging boosters with constant voltage (UI) and IUoU charging methods?

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A distinction is essentially made between the simple charging boosters with constant voltage (IU characteristic curve) and the high-quality charging boosters with IUoU charging method.

Charging boosters with constant current voltage

Simple charging boosters with constant voltage work with a fixed voltage that constantly charges the secondary battery. As this type of charging booster does not switch off automatically, even during long cross-country journeys, there is a risk of overcharging the second battery.

Charging boosters with IUoU charging method

The IUoU charge boosters guarantee a charge that is optimally matched to the on-board battery during the journey. Even in vehicles with battery management (intelligent alternator), continuous charging and complete charging of the on-board battery is guaranteed. High-quality charging boosters with IUoU charging process switch to trickle charging once the final charging voltage has been reached: The battery is kept full and self-discharge is counteracted. There is no overcharging.

How powerful should the charging booster be?

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The 30 A charging booster can generally be installed in all standard motorhomes, panel vans etc. without any conversion work. If you have a battery capacity of around 100 Ah, this version is sufficient for charging the second battery.

As a guideline, the charging current of the charging booster should be max. 30 % of the battery capacity for lead batteries and max. 50 % of the battery capacity for lithium batteries. However, care must be taken to ensure that the supply cables are adequately dimensioned and fused.

Which charging booster is suitable for a caravan or trailer?

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IVT Charging Booster 10 A caravan mode	Schaudt Charging Booster WA 1208

The 12 V charging booster from IVT is suitable for charging the supply battery in a caravan, motorhome or trailer. The maximum charging current of this battery to battery charger can also be set to 10 A. The Schaudt WA 1208 charging booster can also be installed in the trailer. The charging current of the WA 1208 is limited to a maximum of 9 A.

The following diagram shows the connection of the IVT charging booster in the carava

Connection diagram: IVT charging booster in the caravan

For detailed information on installing the booster in the caravan, please refer to the IVT Charging Booster operating instructions.

Can a charging booster be installed in a 12 V solar system?

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The IVT Charging Booster can also be installed in stand-alone solar systems with separate 12 V systems. In this case, the D+ signal only needs to be routed to the device via a switch.

The following diagram shows the connection of the IVT charge booster with separate 12 V systems (different priorities), including solar module(s), solar charge controller (e.g. mppt) and additional on/off switch.

Graphic IVT charging booster connection diagram solar stand-alone system

The use of two 12 V systems is recommended for systems in which, for example, consumers with high priority are operated. All important loads (e.g. alarm system or surveillance cameras) should be connected to the primary battery. The primary battery is charged via the solar modules. Consumers with a lower priority can be connected to the secondary battery system (e.g. lighting, electrical appliances, etc.).

In addition, thanks to the IVT charge booster, batteries with different end-of-charge voltages can be charged in an off-grid system (e.g. primary battery = lead-acid; secondary battery = LiFePO₄). The intelligent IVT charge booster is equally suitable for lead-acid, lead-gel, AGM and lithium solar batteries from 35 Ah.

The charging booster can be put into operation via the switch (S1) and the secondary battery can also be charged. If the voltage on the primary battery falls below 11.8 V, the charging current is automatically reduced. If the voltage reaches 11.0 V, the charge to the secondary battery is cancelled completely to prevent deep discharge of the primary battery.

Connect the charging booster with the correct polarity according to the wiring diagram above. For further important information on the installation, setting and operation of the IVT Charging Booster, please refer to the IVT Charging Booster operating instructions.

Does it make sense to install an additional temperature sensor?

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When using a charge booster, we consider it sensible to also install a temperature sensor that measures the temperature at the battery terminal.
Advantage: Charging of the secondary battery is temperature-controlled, i.e. lead-gel, AGM and LiFePO₄ batteries are charged with an optimised charging characteristic.

For batteries without a protective circuit (BMS), it is advisable to connect a temperature sensor, as the charging voltage should be reduced at high ambient temperatures to prevent damage to the battery cells. Similarly, the charging voltage should be increased at lower (colder) temperatures.

Without temperature compensation, the battery cells may be damaged.

Can I fit or install a charging booster myself?

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In principle, installations on 12 V (safety extra-low voltage) may also be carried out by a layperson. The installation instructions for the various charging booster connection options must be observed.

If you need help with the installation, we recommend that you consult an installation partner in your area. If you do not know a specialist dealer in your area, click here to search for a retailer or give us a call. We will be happy to help.

Secondary Battery Charger – Use in vehicles and solar

The IVT Second Battery Charger, also known as a cut-off relay, is a cost-effective way of simultaneously charging another 12 V lead-acid battery in a camper van, service or delivery van as well as in a solar island system.

The charge management of the Second Battery Charger ensures that the starter battery is charged first when the engine is running. When the car battery reaches a voltage of 13.6 V, the integrated voltage monitoring system automatically switches on the second battery. Both lead batteries are now charged by the alternator. If the voltage of the starter battery falls below 12.8 V, the batteries are disconnected. The IVT Second Battery Charger is particularly easy to install as it does not require a D+ signal.

Second Battery Charger in the vehicle or boat

The IVT Second Battery Charger is suitable for vehicles without an intelligent alternator. It is not suitable for battery charging in vehicles with emission standard 6; the installation of a charging booster is mandatory for Euro 6 vehicles.

Please note that inverters or 12 V consumers are only connected to the second battery. If the second battery is exhausted, the engine can still be started using the starter battery.

Second Battery Charger as part of a solar island system

The Second Battery Charger allows the solar energy produced at peak times to be stored easily and effectively in two solar batteries.

Please note that only important consumers that must always function are connected to the primary lead-acid battery. The second solar battery is used to supply less important consumers, such as TVs or radios.

12 V charging boosters & accessories | Secondary Battery Charger