Wiring diagramsfor boats, vansand off-grid.
Draw your setup from a catalog of real parts — Crimp sizes every cable and fuse against ABYC E-11 as you wire it.
Free · no account needed
works in the browser
“…it would eventually smoke my small 75-amp alternator. I downsized to an 18-amp charger.”
Fig. 1Example: “A 100 Ah lithium battery, 175 W of solar through an MPPT, a fridge and cabin lights.”
Live canvas — hover any cable for its wire size and fuse.
All 10 cables come back sized — 4 mm² and a 40 A fuse on the battery feeder, down to 1.5 mm² and 3 A for the lights.
Drop in the parts you actually bought.
300+ components in the palette, 229 of them real branded parts. Each has its own terminals: a busbar has studs, an MPPT has a PV side and a battery side, a fuse block has slots. Missing something? Customise a part or build your own — it's saved to your library for the next project.
Victron Blue Sea Systems Renogy Battle Born Epever Balmar Volvo Penta Yanmar Sterling Power Morningstar CTEK Redarc Wakespeed Trojan Lifeline Pylontech Garmin Dometic Webasto Bluetti and 40+ more.
The numbers come from the tables, not from a guess.
Connect two terminals and Crimp works out the current that run will carry. It sizes the wire off the ABYC E-11 ampacity tables, picks the fuse off the standard rating ladder, and checks voltage drop against the allowance E-11.14.2.6 sets for that kind of circuit. Switch the loads on and it runs the bank down, so you can see how long a night at anchor really lasts.
Your tool identified I selected a larger amperage DC-DC charger and it would eventually smoke my small 75-amp alternator. I downsized to an 18-amp charger and all I can say is “Thank you — Thank you!”
That check has a name — Crimp compares what a DC-DC charger will pull against what the alternator behind it can actually give, and says so before the cable goes in.
…as someone who has struggled with 12V wiring in the past this is simplifying it so much (and teaching me along the way). Obvs will get it all double checked by someone qualified.
Hand it to someone who has to read it.
With Crimp Pro, print the device list, export a PNG of the schematic, or take the project file with you. Or publish a link: readers see the live diagram with the sizing on it, and can pin a question to one specific cable instead of arguing in a thread about which run they meant.
What people ask first.
This is a planning aid, not a certified design tool. Wire sizes, fuse ratings, and connections must be verified by a qualified person before you build. Mistakes can cause fire, injury, or equipment damage. You are responsible for the final installation.
01Which standards does the sizing follow?
02Do I need an account?
03Is it only for boats?
04What if my exact part isn't in the catalog?
05What does Crimp Pro unlock?
06Can I print it, or get the numbers out?
07Who makes this?
Check the part before you place it.
Browse 229 branded component profiles, each with catalog specifications, a terminal map and a stated reference run sized by the same engine as the canvas.
Start with one battery and one load.
The first cable you draw comes back sized. Nothing to install, nothing to sign up for.