Charge two batteries at the dock
Use separate charger outputs to replenish two batteries without joining their positive terminals.
Follow the circuit
01
Separate positive outputs
Each charger output reaches one battery through its own fused lead. The batteries share a negative bus, but the charger keeps the positive outputs isolated.
02
One shared current limit
The charger can supply 15 A in total, not 15 A to each battery at once. Current sharing depends on the batteries; Crimp's split is a planning estimate.
03
Use a compatible charge profile
The outputs share one charging algorithm. Both batteries must accept that profile; separate outputs do not provide independent settings for different battery chemistries.
The source and this example
Victron's IP22 multiple-output installation drawing uses separate fused positive leads and a common negative bus.
We model two of the 15 A charger's three outputs with matching AGM batteries. This is the DC side only; the AC shore-power installation is outside the drawing.
- Victron: IP22 installation schematics ↗
Section 5.3.1: multiple-output hard-wired installation.
- Victron: how the isolated outputs share current ↗
Section 4.7.
Before you build
- Place each charging-lead fuse close to its battery.
- Check both batteries' allowed charge voltage and current.
- Plan the complete AC supply separately with appropriate marine protection.
This is a planning example. Cable sizing uses Crimp’s ABYC-based method; the drawing does not certify an installation.
Cable sizes and connections · 5 conductors
Lengths are one way. Sizes and currents come from the same Crimp model as the drawing. Each drop value covers one drawn conductor; the full circuit includes its supply and return. AWG values are approximate counterparts to the metric areas.
| Connection | Length | Wire | Design current | Fuse | Drop |
|---|---|---|---|---|---|
| C1 · House battery + → Shore charger · DC side BATT 1 + | 1 m | 4 mm²AWG 11 | 15 A | 20 A | 0.55% |
| C2 · Reserve battery + → Shore charger · DC side BATT 2 + | 1 m | 4 mm²AWG 11 | 15 A | 20 A | 1.09% |
| C3 · Shore charger · DC side BATT 1 − → Negative Bus Bar − | 80 cm | 4 mm²AWG 11 | 15 A | — | 0.44% |
| C4 · House battery − → Negative Bus Bar 2 − | 60 cm | 4 mm²AWG 11 | 7.5 A | — | 0.16% |
| C5 · Reserve battery − → Negative Bus Bar 1 − | 60 cm | 4 mm²AWG 11 | 7.5 A | — | 0.33% |
A dash means no fuse is assigned to that conductor; upstream protection may apply. Recheck the exact device, holder and placement after edits.
Equipment · 4 components
- Shore charger · DC side
15 A rated / planning output
DC side only. A suitable AC supply, shore inlet, protective earth and AC protection are outside this example. Output 3 is unused. The three negative symbols represent the charger's common negative connection.
- House battery
12 V · 110 Ah
12 V, 110 Ah AGM Deep Cycle (BAT412101084), rated at C20. Victron prefers charging at 0.2C (22 A); this is a recommendation, not an absolute maximum. Flat terminals have 8 mm through-holes.
- Reserve battery
12 V · 110 Ah
12 V, 110 Ah AGM Deep Cycle (BAT412101084), rated at C20. Victron prefers charging at 0.2C (22 A); this is a recommendation, not an absolute maximum. Flat terminals have 8 mm through-holes.
- Negative Bus Bar
Negative bus bar — common return with multiple output studs.
Crimp checks · 4 findings to review
These are the current engine findings for the saved example. They remain visible when you open it in Crimp.
- warning: Grounding path missing: Shore charger · DC side
- warning: Check fuse suitability: House battery
- warning: Check fuse suitability: Reserve battery
- warning: Cable sizing needs checking
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