Engine
Engine 20HP — Bukh DV20 wiring diagram
Bukh DV20 family with generation-dependent starter, alternator and panel equipment. The modeled 55 A charging output, 110 A cranking and 220 A surge are unverified planning defaults; read the installed labels and the matching ME/SME manual before sizing wiring.
- Continuous draw
- 110 A
- Rated output
- 55 A
- Surge current
- 220 A
Wiring diagram
How the DV20 20HP 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.
Cable 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
- 120 mm² · 4/0 AWG
- Example fuse
- 250 A
- Cranking current
- 110 A
- Voltage drop
- 0.8%
Sized against ABYC E-11. The cranking current is what the starter draws. ABYC E-11 doesn't require a fuse on a cranking-motor conductor, so the fuse shown is the usual cranking-rated (Class T) choice, sized to hold the crank without nuisance tripping — it isn't there to protect the wire. 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.
Supporting parts
- 6.1 m total of 120 mm² (4/0 AWG) marine cable
- Terminations for 120 mm² cable, matched to the equipment's screw terminals, leads or studs
- 250 A cranking-rated (Class T) fuse at the battery
- 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.
Reviewed against manufacturer family documentation (rev. Undated manufacturer document; printed revision not established), checked 2026-10-01. Exact variant details still require confirmation. Manufacturer documentation →
Engine and edition
BUKH’s archived handbook covers DV10 and DV20 M/ME/SME versions. The electrical discussion applies to ME equipment. It does not support the previous claim that every DV20 has a 1.0 kW Bosch starter and 55 A Bosch alternator: its specification table lists alternative starter makes, 2 hp starting power and a Paris-Rhône alternator rated 700 W.
What the terminals mean
`Starter` represents the high-current starter supply, `Alt B+` the alternator charging output, and `Block GND` the intended negative return on an earth-return installation. They are functional drawing ports, not three interchangeable physical studs. Trace any factory link between alternator B+ and the starter battery stud before changing it; do not duplicate or remove that link without accounting for the original harness.
Controls and protection
Figure 20 identifies the battery switch, starter, alternator B+/61+/D− connections, stop magnet, engine warning senders and panel fuse assembly. These are separate power, excitation and control functions. Match the fitted panel and harness before rewiring. The catalog exposes only the full-current starter feed, charging output and engine return; it omits the stop-magnet and warning circuits.
Checks and model limits
The handbook’s prose also mentions approximately 30 A maximum charging current, which does not cleanly reconcile with its 700 W table. Accordingly, neither value is silently converted into a new universal alternator rating. The catalog 55 A output, 110 A cranking and 220 A surge remain unverified planning defaults that must be replaced with fitted-equipment information. Do not use a battery-disconnect switch as the normal stop control, or disconnect a running alternator from its battery. Control-fuse and cable values must be confirmed on the installed ME/SME arrangement.
Source: manufacturer document — electrical diagram printed p. 17 (PDF 19), electrical-system discussion p. 19 (PDF 21), electrical ratings p. 31 (PDF 33). Legacy copies hosted outside the manufacturer site are manufacturer-authored archive documents; the review date does not make them current installation instructions.
Fit check
Connect it to the rest of your system.
Describe your setup to draft a system with DV20 connected. Review the selected parts and cable lengths, then edit the diagram in Crimp.
The model only picks parts and draws the connections. Every wire size and fuse rating still comes from Crimp's own sizing, never from the model.
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Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Bukh DV20 family with generation-dependent starter, alternator and panel equipment. The modeled 55 A charging output, 110 A cranking and 220 A surge are unverified planning defaults; read the installed labels and the matching ME/SME manual before sizing wiring.
- Continuous draw
- 110 A
- Rated output
- 55 A
- Surge current
- 220 A
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
Starter
positive · input
Alt B+
positive · output
Block GND
ground · bidi
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 DV20 20HP.
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