Charger
ProMariner ProNautic 1220P wiring diagram
12 V shore charger with three positive bank outputs sharing 20 A total and one common charge profile. Leave unused outputs open; output fuse recommendation is 30 A per bank.
- Compatible systems
- 12 V
- Rated output
- 20 A
Wiring diagram
How the ProNautic 1220P 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.
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 exampleCable 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.
4.9 ft one way
12 V system
- Wire
- 10 AWG · 6 mm²
- Example fuse
- 30 A
- Design current
- 20 A
- Voltage drop
- 1.5%
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.
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.
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
Supporting parts
- 9.8 ft total of 10 AWG (6 mm²) marine cable
- Terminations for 10 AWG cable, matched to the equipment's screw terminals, leads or studs
- 30 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.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. ProNauticP instruction manual M131803; manufacturer-authored yacht-association mirror), checked 2026-10-01. Manufacturer documentation →
Three outputs share 20 A
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.
AC and DC terminals have separate jobs
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.
Protect every connected bank
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.
Commission the selected battery profile
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.
Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
12 V shore charger with three positive bank outputs sharing 20 A total and one common charge profile. Leave unused outputs open; output fuse recommendation is 30 A per bank.
- Compatible systems
- 12 V
- Rated output
- 20 A
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
AC LINE
neutral · input
AC NEUTRAL
neutral · input
AC EARTH
ground · input
DC CHASSIS EARTH
ground · bidi
BANK 1 +
positive · output
BANK 2 +
positive · output
BANK 3 +
positive · output
DC COMMON −
negative · bidi
BATTERY TEMP
signal · bidi
REMOTE
signal · bidi
A dash means a current rating is not specified here.
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 — the US reference, and what Transport Canada accepts as an alternative to TP 1332 for pleasure craft under 24 m. 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 ProNautic 1220P.
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