Charger
See the ProMariner ProNautic 1220P connection points and wiring example. Open the diagram in Crimp to add your equipment and plan the cables between them.
Open this example as a new project. Use your own parts and cable lengths to make the plan yours.
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.
1.5 m one way
12 V system
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.
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.
Single-bank example uses 20 A shared charger output. Manual PDF 12 gives output+10 A =>30 A fuse on EACH connected bank. 6 mm² rounds up 10 AWG; the two 1.5 m runs plus 0.3 m disconnect lead total 3.3 m, within the manual's 15 ft round-trip entry. Additional banks share one profile and total 20 A; unused positives stay open. AC PE/chassis bonding and AC breaker are separate installation requirements. Manufacturer installation manual
Wiring diagram
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Single-bank example uses 20 A shared charger output. Manual PDF 12 gives output+10 A =>30 A fuse on EACH connected bank. 6 mm² rounds up 10 AWG; the two 1.5 m runs plus 0.3 m disconnect lead total 3.3 m, within the manual's 15 ft round-trip entry. Additional banks share one profile and total 20 A; unused positives stay open. AC PE/chassis bonding and AC breaker are separate installation requirements. Manufacturer installation manual
Edit this wiring exampleInstallation notes
Guidance for this model, with sources linked beside the relevant advice.
Verified against the manufacturer's documentation (rev. ProNauticP instruction manual M131803; manufacturer-authored yacht-association mirror), checked 2026-10-01. Manufacturer documentation →
ProNautic 1220P is the 12 V, 20 A member of the ProNauticP family. It has three positive bank outputs and a common negative return. The banks share 20 A total and the selected charging profile; three connections do not provide three independent 20 A chargers. Unused outputs remain open. Match every connected bank to the selected profile, including a lithium bank's own BMS requirements. See model table, PDF p. 1 and DC connections, PDF p. 12.
The universal AC input uses line, neutral and protective earth. The DC outputs feed each bank through separate positive conductors; connect the common negative as shown. The chassis-earth stud is a protective bonding connection, not a substitute for the DC return cable. Connect the temperature sensor to the specified negative battery terminal and keep its lead separate from the large charging conductors.
The manual specifies a fuse 10 A above charger output, giving 30 A on each positive battery lead for this model. The 20 A cable-table row permits 10 AWG for 10 or 15 feet total positive-plus-negative length, then increases conductor size for longer runs. The example uses 6 mm², rounding up from 10 AWG. Its two 1.5 m runs and 0.3 m disconnect lead total 3.3 m, within the 15-foot entry; retain the 30 A protection on the battery-side lead. The AC table gives a 10 A breaker at 110–120 V or 5 A at 220–250 V; those are protection choices, not continuous current ratings of the AC terminals. See AC protection, PDF p. 10 and DC cable table, PDF p. 11.
Secure the unit in the documented ventilated location, check polarity and verify protective earth before energizing AC. Select the battery type, confirm the displayed program, and measure voltage at each connected bank during charging. Check the shared total current and inspect the cable connections for heating. A bank that remains low while another charges warrants checking its fuse, polarity and cable drop before changing the common profile.
Build it out
Add ProNautic 1220P to your diagram, then connect your batteries, chargers and loads. Crimp calculates cable sizes and checks the connections as you draw.
Every cable you draw there is sized against ABYC E-11, from the same tables as the reference on this page.
Technical reference
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
AC LINE
ac-in-l
neutral · input
AC NEUTRAL
ac-in-n
neutral · input
AC EARTH
ac-in-pe
ground · input
DC CHASSIS EARTH
chassis
ground · bidi
BANK 1 +
out-pos
positive · output
BANK 2 +
bank2-pos
positive · output
BANK 3 +
bank3-pos
positive · output
DC COMMON −
out-neg
negative · bidi
BATTERY TEMP
temp
signal · bidi
REMOTE
remote
signal · bidi
A dash means a current rating is not specified here.
Method & provenance
Manufacturer specifications describe the equipment. Crimp calculates cable results from the circuit and assumptions you enter.
From the maker
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
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.
Next step
Open this example as a new project. Add your equipment and cable lengths, then review the sizing and checks for your setup.