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Victron Buck-Boost 25A

Model Buck-Boost DC-DC 25A

Buck-boost DC-DC converter for Euro 6 smart-alternator vehicles. 25A output; programmable, supports B2B charging from 10–30V input. Common in vans where the alternator regulates down at idle.

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Victron Buck-Boost 25A
Victron Buck-Boost 25A · 4 terminals
01 — Wiring diagram

How the Buck-Boost 25 is wired

Victron Buck-Boost 25A wiring diagram WIRING DIAGRAM Victron Buck-Boost 25A wiring diagram 12 V battery bank Charged by this unit Buck-Boost 25 Victron · Buck-Boost DC-DC 25A 35 A 10 mm² (8 AWG) → OUT + 10 mm² (8 AWG) → OUT − 3 m one way IN + IN − crimp.studio 25 A · 2.2% drop · ABYC E-11
Victron Buck-Boost 25A wiring diagram, 10 mm² (8 AWG) positive feed protected by a 35 A fuse and a matching negative return between the 12 V battery bank and the unit, plus IN +, IN −.

The run drawn here is the 3 m reference run sized below. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Confirm your own run length, routing and terminations before ordering — open this part in the designer to size it against your actual system.

02 — Reference run

What size cable and fuse does the Buck-Boost 25 need?

Conductor10 mm²8 AWG
Fuse35 Apositive run
Voltage drop2.2%3 m one way
Design current25 A12 V system

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 Crimp engine applies its ordinary continuous-load headroom, voltage-drop budget, terminal clamp, and standard fuse ladder. The 3 m one-way run is a stated reference, not a universal installation prescription.

03 — Catalog specification

Victron Buck-Boost 25A specifications and terminal map

Rated output
25 A
Typical charge current
24 A

Terminal map

TerminalPolarityDirectionRating
IN +positiveinput50 A
IN −negativeinput50 A
OUT +positiveoutput25 A
OUT −negativeoutput25 A
04 — Supporting parts

What else you need to wire the Buck-Boost 25

  • 6 m total of 10 mm² (8 AWG) marine cable
  • Four 10 mm² cable lugs matched to the equipment studs
  • 35 A fuse and holder on the positive run
  • Heat-shrink, strain relief, and terminal boots sized to the cable

Start from this part

Open the canvas with the Buck-Boost 25 already placed, then wire the rest of the system around it. Nothing to install and no sign-up — the project is saved in this browser, and you can download the file whenever you want it.

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05 — Method & provenance

What is known, assumed, and computed.

Catalog profile

The manufacturer, model, ratings and terminal map are maintained as planning data in Crimp's component catalog. Confirm the current manufacturer manual, exact revision and installed nameplate before ordering or wiring.

Engine reference

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 published conductor, fuse and voltage-drop result uses the visible reference length and current basis; it is not a universal installation prescription.

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06 — Related components

Alternatives to the Buck-Boost 25

Browse all charger profiles →