Charger
Schaudt LR 1218 wiring diagram
12 V PWM solar regulator for lead-acid / gel banks of at least 55 Ah. House priority, shared 18 A output; module Voc must remain within 25 V.
- Compatible systems
- 12 V
- Rated output
- 18 A
- PV open-circuit limit
- 25 V
Wiring diagram
How the LR 1218 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.
Direct-bank example: 20 A fuse, 2.5 mm² for <=4 m positive-plus-negative total; two 1 m conductors fit. Second bank needs its own fuse and shares total 18 A. EBL harness installations use exact connector drawing and 15/20 A fuse according to EBL marking instead. Cold module Voc <=25 V. 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.
3.3 ft one way
12 V system
- Wire
- 13 AWG · 2.5 mm²
- Example fuse
- 20 A
- Design current
- 18 A
- Voltage drop
- 2.1%
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.
Direct-bank example: 20 A fuse, 2.5 mm² for <=4 m positive-plus-negative total; two 1 m conductors fit. Second bank needs its own fuse and shares total 18 A. EBL harness installations use exact connector drawing and 15/20 A fuse according to EBL marking instead. Cold module Voc <=25 V. Manufacturer installation manual
Supporting parts
- 6.6 ft total of 13 AWG (2.5 mm²) marine cable
- Terminations for 13 AWG cable, matched to the equipment's screw terminals, leads or studs
- 20 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. 22 September 2009; combined operating/installation manuals, manufacturer-authored retailer mirror), checked 2026-10-01. Manufacturer documentation →
Match an older PWM system
LR 1218 is a 12 V PWM regulator for lead-acid or gel batteries of at least 55 Ah. It prioritizes the leisure bank and can maintain a starter bank within an 18 A total charging budget. It is not the later LRM MPPT model. The maximum module open-circuit voltage is only 25 V, with 19 A maximum module short-circuit current; many modern high-voltage roof panels exceed that envelope. See technical data, PDF p. 17.
Direct battery wiring or EBL harness
The solar connector has its own positive and negative pair. Battery wiring includes leisure positive, starter positive and a common negative. Optional display connections report charging information rather than supplying loads. For a direct connection, route each positive to its correct bank and connect the common return before applying solar.
An Elektroblock installation instead uses the harness and connector positions for the exact EBL model. The manual shows different arrangements, including one three-way connector and a split adapter. Connector position, not wire colour alone, determines the destination. See EBL connection drawing, PDF p. 13.
Protect both battery feeds
The direct-battery diagram uses 20 A fuses in the positive leads. An EBL installation may require a 15 A or 20 A solar fuse according to its front-panel marking; do not replace it automatically with the direct-wiring value. Cable lengths are out and back combined: up to 4 m uses 2.5 mm², up to 8 m uses 4 mm², and up to 12 m uses 6 mm². See cable table, PDF p. 11 and direct-bank protection, PDF p. 12.
Connect and check in order
Connect the battery side before the solar module; disconnect solar first when removing the regulator. Under useful sun, confirm charging at the leisure bank, then verify starter maintenance as the priority bank fills. An unlit optional display or low solar current needs voltage and polarity checks before assuming a failed regulator. A correctly sized fuse does not make an over-voltage PV module compatible.
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 PWM solar regulator for lead-acid / gel banks of at least 55 Ah. House priority, shared 18 A output; module Voc must remain within 25 V.
- Compatible systems
- 12 V
- Rated output
- 18 A
- PV open-circuit limit
- 25 V
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
SOLAR +
positive · input
SOLAR −
negative · input
HOUSE +
positive · output
BATTERY COMMON −
negative · bidi
STARTER +
positive · output
OPTIONAL DISPLAY
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 LR 1218.
Open this example as a new project, or add this component to your existing diagram. Use your equipment and cable lengths to review the sizing.
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