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+.
Votronic 3324 Battery-to-battery charger VCC 1212-30
| PRODUCT CODE: | C85065 |
|---|---|
| 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 3326 Battery-to-battery charger VCC 1212-50
| PRODUCT CODE: | C85066 |
|---|---|
| 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 |
|---|---|
| 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 |
|---|---|
| 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
CTEK D250SE Dual DC-DC Charger
| PRODUCT CODE: | C8664B |
|---|---|
| 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: | 1.100 |
C8664B
In Stock
CTEK Smartpass 120S Power Manager
| PRODUCT CODE: | C8663B |
|---|---|
| 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: | 1.100 |
NDS PSB 12V 40A Battery-to-Battery Charger
| PRODUCT CODE: | C8221 |
|---|---|
| Manufacturer's product code: | PSB 12-40 |
| MANUFACTURER: | NDS |
| 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 |
|---|---|
| Manufacturer's product code: | PSB 12-80 |
| MANUFACTURER: | NDS |
| 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 3067 D+ Simulator Pro
| PRODUCT CODE: | C85179 |
|---|---|
| Manufacturer's product code: | 3067 |
| MANUFACTURER: | VOTRONIC |
| Product Net KG: | 0.100 |
| Warranty period - Years: | 5 |
| weight: | 0.150 |
C85179
In Stock
Power Service Gold 30-M Triple Charger
| PRODUCT CODE: | C8203 |
|---|---|
| Manufacturer's product code: | GOLD 30-M |
| MANUFACTURER: | NDS |
| What's in the box: | 1 x unit;1 x User Manual;1 x pack of misc fuses;1 x Mains Euro 2 pin Lead |
| Suitable for use with smart alternators?: | Yes |
| Input Voltage - Volts: | 12 |
| Output voltage - Volts: | 12 |
| Recommended minimum output of alternator- Amps: | 90 |
| Max. charging current - Amps: | 30 |
| Input: | Alternator, solar panel and 230v mains |
| Input from alternator - V: | 11.8 - 15 |
| Input from solar panel - V: | 12 / 28v |
| Conventional alternator cut-in: | AUTOMATIC |
| Max. Charging Current from Alternator: | 30 |
| Max. charging current from solar panel - Amps: | 20 |
| Max. charging current from 230V supply - Amps: | 20 |
| Charging characteristic: | 5 stage with desulphation |
| Suitable for battery size - Ah: | 85 - 300 |
| Suitable for battery types: | All types of lead-acid battery inc. wet, AGM, Gel and Lithium LifePo4 |
| Max. power input from solar panel - Watts: | 250 |
| Dimensions (L x W x H) - mm: | 228 x 135 x 98 |
| Product Net KG: | 1.70 |
| Warranty - years: | 2 |
| weight: | 1.700 |
C8203
In Stock
Power Service Gold 40-M Triple Charger
| PRODUCT CODE: | C8202 |
|---|---|
| Manufacturer's product code: | GOLD 40-M |
| MANUFACTURER: | NDS |
| What's in the box: | 1 x unit;1 x User Manual;1 x pack of misc fuses;1 x Mains Euro 2 pin Lead |
| Suitable for use with smart alternators?: | Yes |
| Input Voltage - Volts: | 12 |
| Output voltage - Volts: | 12 |
| Recommended minimum output of alternator- Amps: | 110 |
| Max. charging current - Amps: | 40 |
| Input: | Alternator, solar panel and 230v mains |
| Input from alternator - V: | 11.8 - 15 |
| Input from solar panel - V: | 12 / 28v |
| Conventional alternator cut-in: | AUTOMATIC |
| Max. Charging Current from Alternator: | 40 |
| Max. charging current from solar panel - Amps: | 20 |
| Max. charging current from 230V supply - Amps: | 20 |
| Charging characteristic: | 5 stage with desulphation |
| Suitable for battery size - Ah: | 85 - 400 |
| Suitable for battery types: | All types of lead-acid battery inc. wet, AGM, Gel and Lithium LifePo4 |
| Max. power input from solar panel - Watts: | 250 |
| Dimensions (L x W x H) - mm: | 228 x 135 x 98 |
| Product Net KG: | 1.70 |
| Warranty - years: | 2 |
| weight: | 1.700 |
C8202
In Stock
Votronic 3305 Battery-to-battery charger VCC 2412-45 IUoU-Li
| PRODUCT CODE: | C8503 |
|---|---|
| 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 3350 Battery-to-battery charger VCC 1212-25 IUoU-Li
| PRODUCT CODE: | C85060 |
|---|---|
| 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 3321 Battery-to-Battery Charger VCC 1212-20C
| PRODUCT CODE: | C85060A |
|---|---|
| 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 3242 Battery Charger VBCS 30/20/250 Triple
| PRODUCT CODE: | C85069 |
|---|---|
| Manufacturer's product code: | 3242 |
| MANUFACTURER: | Votronic |
| Suitable for use with smart alternators?: | Yes |
| Product Net KG: | 2.700 |
| Warranty - years: | 5 |
| weight: | 2.800 |
C85069
In Stock
Votronic 3244 Battery Charger VBCS 45/30/350 Triple
| PRODUCT CODE: | C85070 |
|---|---|
| Manufacturer's product code: | 3244 |
| MANUFACTURER: | Votronic |
| Suitable for use with smart alternators?: | Yes |
| Product Net KG: | 2.850 |
| Warranty - years: | 5 |
| weight: | 3.000 |
C85070
In Stock
Votronic 3246 Battery Charger VBCS 60/40/430 Triple
| PRODUCT CODE: | C85071 |
|---|---|
| Manufacturer's product code: | 3245 |
| MANUFACTURER: | Votronic |
| Suitable for use with smart alternators?: | Yes |
| Product Net KG: | 2.900 |
| Warranty - years: | 5 |
| weight: | 3.000 |
C85071
In Stock
Votronic 1247 LCD Charge Control S for VBCS Chargers)
| PRODUCT CODE: | C85092 |
|---|---|
| MANUFACTURER: | VOTRONIC |
| Manufacturer's product code: | 1247 |
| Product Net KG: | 0.055 |
| Warranty period - Years: | 5 |
| weight: | 0.155 |
C85092
In Stock
Votronic 1248 LCD Charge Control S (only for Charging Conver
| PRODUCT CODE: | C85093 |
|---|---|
| MANUFACTURER: | VOTRONIC |
| Manufacturer's product code: | 1248 |
| Product Net KG: | 0.055 |
| Warranty period - Years: | 5 |
| weight: | 0.270 |
C85093
In Stock
Votronic 3351 Battery-to-battery charger VCC 1212-45 IUoU-Li
| PRODUCT CODE: | C85061 |
|---|---|
| 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 3343 Battery-to-battery charger VCC 1224-25 IUoU
| PRODUCT CODE: | C85062 |
|---|---|
| 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 |
|---|---|
| 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 |
|---|---|
| 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 0664 Battery Charger VAC 45-10/25 Triple
| PRODUCT CODE: | C85072 |
|---|---|
| Manufacturer's product code: | 0664 |
| MANUFACTURER: | Votronic |
| Suitable for use with smart alternators?: | Yes |
| Product Net KG: | 2.850 |
| Warranty - years: | 5 |
| weight: | 3.000 |
Votronic 3352 Battery-to-battery charger VCC 1212-45 Li
| PRODUCT CODE: | C85061A |
|---|---|
| Manufacturer's product code: | 3352 |
| MANUFACTURER: | Votronic |
| Suitable for use with smart alternators?: | Yes |
| Product Net KG: | 1.7 |
| Warranty - years: | 5 |
| weight: | 1.900 |
Recent Reviews
Quality
Value
Ease of Use
I fitted the NDS Gold Service 40 to my custom-built campervan in 2017 and have been using it ever since. The key benefit to me is the 40A battery to battery charger which enables me to rapidly recharge my two 100AH Banner leisure batteries between campsites, or photo and video shoot locations if I’m working. As my vehicle also uses a compressor fridge, as well as a diesel hob/heater and a 1500W NDS inverter powering a Nespresso coffee machine it can be quite demanding on power – especially on winter shoots with the heating on - so I wanted something that could recharge the batteries rapidly and would be a fit and forget item. It can also charge from a hook-up at up to 20A and has a built-in solar regulator allowing for panels of up to 250W (I use a 150W panel and it has been fine over winter).
Even over lockdown, it managed the charge from the solar panel to keep both leisure batteries fully charged. It looks after the batteries with no intervention from me – which is perfect for a forgetful journalist! The other point to make is that including the solar regulator/charger/B2B in one compact box makes for an easy and neat install – important in a campervan where every mm of space counts. The unit itself is easy to wire, too. It also works fine with the smart alternators fitted to modern vehicles, sending far more charge to the leisure batteries than any split charge or VSR system would do. In the four years I’ve had it, it’s performed exactly as it said on the box and has proved reliable.
Peter Rosenthal (specialist technical writer for campervan and motorhome magazines)
- Ray Thomson, 01/07/2016
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- Marco Deveria-Bishop, 16/04/2018
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- Mike Biggs, 09/07/2016
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