Enerdrive / Dometic · EN3DC40+

Enerdrive Dometic DC2DC 40+

Name: Enerdrive Dometic DC2DC 40+
Brand: Enerdrive / Dometic

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.

Use this component in Crimp Show sizes in AWG

The reference run on this page is 3 m one way, sized against ABYC E-11. Your own run will differ, and the canvas sizes that one.

Wiring diagram

How the DC2DC 40+ is wired.

The drawing shows where the feed, the return and the fuse land on this part. The starter uses the same reference circuit and sizing assumptions. Read the installation notes for manufacturer requirements before adapting the runs.

Starter bank +
positive connection
25 mm² (4 AWG) · 70 A fuse
3 m one way · 50 A design
To DC2DC 40+ CH3 START +
DC2DC 40+ CH1 BATT +
positive connection
25 mm² (4 AWG) · 60 A fuse
3 m one way · 50 A design
To House bank +
Starter bank −
negative connection
25 mm² (4 AWG) · unfused return
3 m one way · 50 A design
To DC2DC 40+ CH3 START −
DC2DC 40+ CH1 BATT −
negative connection
25 mm² (4 AWG) · unfused return
3 m one way · 50 A design
To House bank −

Example allowances · ABYC E-11 sizing · verify actual protection

Enerdrive Dometic DC2DC 40+: 4 DC connections from the same editable starter, with individual feed, return and supply-lead assumptions. Read the installation notes before adapting this example.Example allowances · ABYC E-11 sizing · verify actual 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

Open starter in Crimp

Build it out

Build the system it goes in.

Open the canvas with EN3DC40+ already placed, then add your batteries, charging, distribution and loads around it.

Every cable you draw there is sized against ABYC E-11, from the same tables as the reference on this page.

Technical reference

Specs, terminals and the parts around them.

The catalog facts for this part, which terminal takes what, and the hardware you'll want around it. Check the nameplate on your own unit before you order.

Catalog specification

Rated output: 50 A
Planning charge current: 40 A
PV open-circuit limit: 45 V

3 m reference run

12 V system

Wire: 25 mm² · 4 AWG
Fuse: 60 A
Design current: 50 A
Voltage drop: 1.8%

Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. The design current is the unit's rated output. The length is one way; voltage drop includes an equal-length return. The shared starter uses 3.048 m (10 ft) runs unless a shorter run is stated. These are example assumptions for you to adapt to your own installation.

Supporting parts

6 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.

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.

TerminalPolarityRoleLimit

CH3 START +

in-pos

positive · input

positiveinput50 A

CH3 START −

in-neg

negative · input

negativeinput50 A

CH2 SOLAR +

pv-pos

positive · input

positiveinput30 A

CH2 SOLAR −

pv-neg

negative · input

negativeinput30 A

CH1 BATT +

out-pos

positive · output

positiveoutput50 A

CH1 BATT −

out-neg

negative · output

negativeoutput50 A

Field notes

How it actually goes in.

What we've read and heard about installing this exact part. These are notes, kept apart from the numbers Crimp works out.

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.

Verified against the manufacturer's documentation (rev. 2.05 — January 2026), checked 2026-09-16. Manufacturer documentation →

Method & provenance

What is known, assumed and computed.

The manufacturer publishes some of these numbers and Crimp works out the rest. It's worth knowing which is which.

From the maker

What the catalog says

Manufacturer, model, ratings and which terminal does what come from the catalog. A newer revision, or the nameplate on the unit in your hand, can say something different — when it does, the nameplate wins.

ABYC E-11

What Crimp worked out

Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. The run length and the current above are what drive the result. Crimp doesn't know how warm your space gets; draw the cable inside an engine-bay zone on the canvas and it sizes for the heat.

Read how the sizing works

Next step

Draw the DC2DC 40+ into your own system.

It lands on the canvas already placed. Add what it connects to, and every run gets its wire and fuse as you draw.

Use this component in Crimp