12V / 24V Power & Distribution > Battery to Battery DC-DC battery chargers

“Intelligent” battery chargers are great when you have access to mains hook-up but how do you keep your batteries properly charged when on the move?
Most motorhomes, boats and other vehicle with living accommodation use a simple split-charge relay or something similar. But, these operate just like an old-fashioned battery charger, measuring voltage alone and with no reference to what the leisure batteries actually need to perform at their best.
The answer: install a battery-to-battery charger, a remarkable device which - when the vehicle’s engine is running - constantly monitors both starter and auxiliary batteries.
It then takes spare energy (supplied by the alternator) from the starter battery and uses it to charge the auxiliary battery or batteries in the same way that a 230V “intelligent” charger would. This not only ensures that batteries are as fully charged as possible but also prolongs their working life.
We have a choice of models from different manufacturers to enable you to get exactly the right one for your vehicle or boat.
NOTE: All Votronic battery-to-battery chargers will trickle charge the starter battery at 2 Amps when the leisure battery is close to fully charged and there is a charge going in from solar panels or 240V hook-up. For this feature to work, the battery-to-battery charger must be connected to D+.

CTEK D250SE Dual DC-DC Charger
PRODUCT CODE: | C8664B |
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Manufacturer's product code: | 40-315 |
MANUFACTURER: | CTEK |
What's in the box: | 1 x Unit with wired temperature sensor |
Suitable for use with smart alternators?: | Yes |
Input Voltage - Volts: | 11.5 / 23 |
Output voltage - Volts: | Max 14.4V (14.7V in AGM mode) |
Max. charging current - Amps: | 20 |
BACK CURRENT DRAIN: | Less than 1Ah/month |
Battery Temperature Sensor: | YES |
Charging Ports: | 1 |
Input from alternator - V: | 11.5v TO 23v |
Input from solar panel - V: | 11.5V to 23V |
Conventional alternator cut-in: | >13.1V, for 5 sec. (engine running, alternator charging) |
Conventional alternator cut-out: | <12.8V, for 10 sec. (engine running, alternator not charging) or service battery voltage > starter battery voltage |
Smart alternator cut-in V: | >11.8V, for 5 sec. (engine running, alternator charging) |
Smart alternator cut-out V: | <11.4V, for 10 sec. (engine running, alternator not charging) or service battery voltage > starter battery voltage |
Suitable for battery types: | All 12V lead-acid batteries including: Wet, A.G.M, gel, calcium and maintenance free + LiFePO4 lithium batteries |
Max. power input from solar panel - Watts: | 300 |
Solar regulator type: | MPPT |
Cooling method: | Convection cooled |
Operating temperature range - °C: | minus 20 degrees C to plus 50 degrees C Automatic reduction of power at high ambient temperature. |
Power reduction: | 30 degrees C 16A, 50 degrees C 13A |
Enclosure class: | IP65 (splash and dust proof) |
Notes: | This charger can only be used with solar panels that have a peak voltage maximum of upto 23V. Please ensure that your panel is compatible before purchasing. |
Protections: | Temperature compensated charging, Reverse Polarity protection |
Certification: | Fully certified for use in vehicles |
Dimensions (L x W x H) - mm: | 192 x 110 x 65mm |
Product Net KG: | 1.047 |
Warranty - years: | 2 |
weight: | 2.100 |
C8664B
In Stock


CTEK Smartpass 120S Power Manager
PRODUCT CODE: | C8663B |
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Manufacturer's product code: | 40-289 |
MANUFACTURER: | CTEK |
What's in the box: | 1 x unit;2 x connection plates to connect to D250SE |
Suitable for use with smart alternators?: | Yes |
Input Voltage - Volts: | 11.5 to 23V, Max 120A (350A temporarily for 10 seconds.) |
Max. charging current - Amps: | 120 |
Charging Ports: | 1 |
Battery guard cut-in: | 11.5V |
Battery guard cut-out: | 12.0V |
Temperature protection cut-in: | 60 degrees C (140 degrees F) |
Start assistance activation: | Starter battery 6V |
Trickle charge starter battery: | Starter battery 11.5V to12.6V. |
Suitable for battery types: | All 12V lead-acid batteries including: Wet, A.G.M, gel, calcium and maintenance free + LiFePO4 lithium batteries |
Operating temperature range - °C: | minus 20 degrees C to plus 50 degrees C Automatic reduction of power at high ambient temperature. |
Enclosure class: | IP65 (splash and dust proof) |
Protections: | Temperature compensated charging, Reverse Polarity protection |
Certification: | Fully certified for use in vehicles |
Dimensions (L x W x H) - mm: | 192 x 110 x 65mm |
Product Net KG: | 1.047 |
Warranty - years: | 2 |
weight: | 2.100 |
C8663B
In Stock


Votronic 3324 Battery-to-battery charger VCC 1212-30
PRODUCT CODE: | C85065 |
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Manufacturer's product code: | 3324 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 0.385 |
Warranty - years: | 5 |
weight: | 0.500 |
C85065
In Stock


Votronic 3321 Battery-to-Battery Charger VCC 1212-20C
PRODUCT CODE: | C85060A |
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Manufacturer's product code: | 3321 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.350 |
Warranty - years: | 5 |
weight: | 1.600 |
C85060A
In Stock


Votronic 3326 Battery-to-battery charger VCC 1212-50
PRODUCT CODE: | C85066 |
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Manufacturer's product code: | 3326 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.040 |
Warranty - years: | 5 |
weight: | 1.200 |
C85066
In Stock


Votronic 3328 Battery-to-battery charger VCC 1212-70
PRODUCT CODE: | C85067 |
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Manufacturer's product code: | 3328 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.300 |
Warranty - years: | 5 |
weight: | 1.500 |
C85067
In Stock


Votronic 3329 Battery-to-battery charger VCC 1212-90
PRODUCT CODE: | C85068 |
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Manufacturer's product code: | 3329 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.480 |
Warranty - years: | 5 |
weight: | 1.600 |
C85068
In Stock


NDS PSB 12V 40A Battery-to-Battery Charger
PRODUCT CODE: | C8221 |
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Manufacturer's product code: | PSB 12-40 |
MANUFACTURER: | NDS |
Barcode: | 8058093761089 |
What's in the box: | 1 x Unit |
Suitable for use with smart alternators?: | Yes |
Input Voltage - Volts: | 12 |
Output voltage - Volts: | 12 |
Max. charging current - Amps: | 40 |
Minimum Altenator rating: | 90 |
Suitable for battery types: | All types of lead-acid battery inc. wet, AGM, Gel and Lithium LifePo4 |
Charging Programs: | Upto 8 Step charging based on battery type installed |
Notes: | Buck Booster for super stable charging, Aux Bypass for direct coonection of extra loads to the alternator, Opticharge firmware, N-Bus communication Protocol, Optional Bus dsiplay available, |
Protections: | Alternator and starter battery protection from Overload, unexpected stress and undervoltage |
Certification: | E24 & CE marked |
Dimensions (L x W x H) - mm: | 225 x 195 x 90 Boxed |
Product Net KG: | 1.475 |
Warranty - years: | 2 |
C8221
In Stock


NDS PSB 12V 40A/60A/80A Battery-to-Battery Charger
PRODUCT CODE: | C8222 |
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Manufacturer's product code: | PSB 12-80 |
MANUFACTURER: | NDS |
Barcode: | 8058093761096 |
What's in the box: | 1 x Unit |
Suitable for use with smart alternators?: | Yes |
Input Voltage - Volts: | 12 |
Output voltage - Volts: | 12 |
Max. charging current - Amps: | 3 Programs, 40a, 60a, 80a |
Minimum Altenator rating: | 140 |
Suitable for battery types: | All types of lead-acid battery inc. wet, AGM, Gel and Lithium LifePo4 |
Charging Programs: | Upto 8 Step charging based on battery type installed |
Notes: | Buck Booster for super stable charging, Aux Bypass for direct coonection of extra loads to the alternator, Opticharge firmware, N-Bus communication Protocol, Optional Bus dsiplay available, |
Protections: | Alternator and starter battery protection from Overload, unexpected stress and undervoltage |
Certification: | E24 & CE marked |
Dimensions (L x W x H) - mm: | 230 x 200 x 90 boxed |
Product Net KG: | 1.480 |
Warranty - years: | 2 |
C8222
In Stock


Votronic 3305 Battery-to-battery charger VCC 2412-45 IUoU-Li
PRODUCT CODE: | C8503 |
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Manufacturer's product code: | 3305 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | y |
Product Net KG: | 1.8 |
Warranty - years: | 5 |
weight: | 1.900 |

Votronic 3351 Battery-to-battery charger VCC 1212-45 IUoU-Li
PRODUCT CODE: | C85061 |
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Manufacturer's product code: | 3351 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.7 |
Warranty - years: | 5 |
weight: | 1.900 |

Votronic 3067 D+ Simulator Pro
PRODUCT CODE: | C85179 |
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Manufacturer's product code: | 3067 |
MANUFACTURER: | VOTRONIC |
Product Net KG: | 0.100 |
Warranty period - Years: | 5 |
weight: | 0.150 |
C85179
In Stock


Votronic 3350 Battery-to-battery charger VCC 1212-25 IUoU-Li
PRODUCT CODE: | C85060 |
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Manufacturer's product code: | 3350 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.350 |
Warranty - years: | 5 |
weight: | 1.500 |

Votronic 3343 Battery-to-battery charger VCC 1224-25 IUoU
PRODUCT CODE: | C85062 |
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Manufacturer's product code: | 3343 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.700 |
Warranty - years: | 5 |
weight: | 1.900 |

Votronic 3303 Battery-to-battery charger VCC 2424-25 IUoU
PRODUCT CODE: | C85063 |
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Manufacturer's product code: | 3303 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.700 |
Warranty - years: | 5 |
weight: | 2.000 |

Votronic 3304 Battery-to-battery charger VCC 2412-25 IUoU-Li
PRODUCT CODE: | C85064 |
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Manufacturer's product code: | 3304 |
MANUFACTURER: | Votronic |
Suitable for use with smart alternators?: | Yes |
Product Net KG: | 1.350 |
Warranty - years: | 5 |
weight: | 1.500 |

Votronic 1247 LCD Charge Control S for VBCS Chargers)
PRODUCT CODE: | C8565 |
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