Enerdrive / Dometic · EN3DC40+
Enerdrive Dometic DC2DC 40+ wiring diagram
Charger for a 12 V house battery, with separate 12/24 V vehicle and MPPT solar inputs. Output is adjustable to 50 A (40 A factory setting); PV limit is 45 V open circuit. Crimp uses the maximum output for design and does not simulate input selection, voltage conversion or ignition control.
- Rated output
- 50 A
- PV open-circuit limit
- 45 V
Wiring diagram
How the DC2DC 40+ is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
The example connects a 12 V starter bank to a 250 Ah placeholder house bank. It plans for the maximum 50 A output, with 25 mm² battery cables over 3.048 m each way, a 70 A input fuse and a 60 A output fuse. These are pinned choices from manual rev 2.05 pp16–17; review them after edits and locate protection at both batteries. The engine does not simulate source selection, voltage conversion or charging profiles. Optional solar and ignition control are disconnected. Manufacturer installation manual
Edit this wiring exampleCable sizing for this example
Use the diagram as a starting point for your installation. Replace the example equipment and cable lengths with your own, and check the connections against your exact model's instructions.
3 m one way
12 V system
- Wire
- 25 mm² · 4 AWG
- Example fuse
- 60 A
- Design current
- 50 A
- Voltage drop
- 1.8%
Sized against ABYC E-11. The design current is the unit's rated output. The length is one way; voltage drop includes an equal-length return.
Run-length and manufacturer assumptions
The editable example uses 3.048 m (10 ft) runs unless a shorter run is stated. Metric overviews round these to 3 m. Adapt the parts and lengths to your installation before choosing cable and protection.
The example connects a 12 V starter bank to a 250 Ah placeholder house bank. It plans for the maximum 50 A output, with 25 mm² battery cables over 3.048 m each way, a 70 A input fuse and a 60 A output fuse. These are pinned choices from manual rev 2.05 pp16–17; review them after edits and locate protection at both batteries. The engine does not simulate source selection, voltage conversion or charging profiles. Optional solar and ignition control are disconnected. Manufacturer installation manual
Supporting parts
- 6.1 m total of 25 mm² (4 AWG) marine cable
- Terminations for 25 mm² cable, matched to the equipment's screw terminals, leads or studs
- 60 A fuse and holder on the positive run
- Heat-shrink, strain relief and terminal boots sized to the cable
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. 2.05 — January 2026), checked 2026-09-16. Manufacturer documentation →
Which Enerdrive DC2DC 40+ is this?
This is the Enerdrive / Dometic DC2DC 40+, model EN3DC40+. The manufacturer specifies a 12 V battery output, adjustable up to 50 A with a 40 A factory setting, and separate vehicle and solar inputs. See the current product and its linked manual before matching an older unit.
Crimp uses 50 A for output-circuit design and records 40 A as the typical charging allowance. These values describe different assumptions; neither predicts the current available from your alternator or panels.
How is the Enerdrive DC2DC 40+ wired?
The editable example connects CH3 START +/− to a 12 V starter bank and CH1 BATT +/− to a 250 Ah placeholder house bank. CH2 is the separate solar input. These are physical terminal pairs, unlike chargers with one common negative connection.
The example chooses 25 mm² conductors for 3.048 m one-way battery runs, with 70 A input protection and 60 A output protection from manual pages 16–17. Both battery-positive paths need protection at their source. The catalog-specific fuse check can flag a changed rating; it does not verify a particular fuse, holder or its location. Replace the placeholder batteries and review the pinned choices after editing.
What should I bear in mind with the Enerdrive DC2DC 40+?
The manual gives a 45 V PV open-circuit ceiling, 30 A maximum PV input and 50 A maximum vehicle input. PV array voltage in cold conditions still needs checking. Vehicle input can be 12 V or 24 V; the house output remains 12 V.
Solar, ignition sense, the temperature sensor and chassis bonding are outside this starter. Crimp does not validate each input's voltage range, source-selection behavior or the vehicle's ignition wiring. Use the manual's connection and mounting instructions for those details.
What do owners and installers say about the Enerdrive DC2DC 40+?
- In a Caravaners Forum upgrade discussion, an owner considers Enerdrive while planning an AGM-to-lithium conversion. Another reports satisfactory operation but flags the unit's size and mounting needs; alternatives include a separate Orion charger and solar controller. This is an individual installation discussion, not a reliability comparison.
What belongs around the Enerdrive DC2DC 40+?
The dual-battery examples put the charger between the vehicle and house systems. The charger sizing tool helps examine vehicle headroom; the methodology explains the ABYC-based calculations without claiming AS/NZS compliance.
Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Charger for a 12 V house battery, with separate 12/24 V vehicle and MPPT solar inputs. Output is adjustable to 50 A (40 A factory setting); PV limit is 45 V open circuit. Crimp uses the maximum output for design and does not simulate input selection, voltage conversion or ignition control.
- Rated output
- 50 A
- Planning charge current
- 40 A
- PV open-circuit limit
- 45 V
Terminal map
CH3 is the vehicle input, CH2 the solar input and CH1 the 12 V battery output; each has its own physical positive and negative terminal. The listed input limits are 50 A vehicle and 30 A PV, with a 45 V PV open-circuit ceiling. Ignition sense, temperature sensor and chassis grounding are outside this power-path drawing. Follow the manual for those connections and installation location.
CH3 START +
positive · input
CH3 START −
negative · input
CH2 SOLAR +
positive · input
CH2 SOLAR −
negative · input
CH1 BATT +
positive · output
CH1 BATT −
negative · output
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Results use the example current and run length shown above. Set your actual equipment, lengths and installation conditions in Crimp before choosing hardware.
Read how the sizing worksNext step
Plan your installation with DC2DC 40+.
Open this example as a new project, or add this component to your existing diagram. Use your equipment and cable lengths to review the sizing.
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