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Updated Jun 14, 2026Fact-checked on Jun 14, 2026
VANPOWERCALC.COMYOUR ENERGY PROFILE
YOUR ENERGY PROFILE.
This document contains the sizing of your future electrical installation, calculated based on your appliances.
Minimum Daily Consumption
0 WH / DAY
Inventory:
SYSTEM SIZINGPage 2
Battery
To guarantee 0WH without damaging your bank (80% max discharge):
0 AH
LiFePO4 12V
Solar
Minimum power required to recharge your consumption:
0 W
via MPPT
220V AC
Maximum power (with 25% safety margin).
0 W
No Need
Safety & CablingPage 3
12V Cable Sizing Guide
Use this professional reference table to select the correct gauge (mm²) for your cables. For 12V in a van, the maximum tolerated voltage drop is 3%. Always use multi-stranded flexible automotive wire.
| Current (A) | Round trip < 2m | Round trip 4m | Round trip 6m |
|---|---|---|---|
| 5A (LEDs, USB) | 1.5 mm² | 2.5 mm² | 4 mm² |
| 10A (Fridge, Pump) | 2.5 mm² | 4 mm² | 6 mm² |
| 20A (Heater) | 4 mm² | 10 mm² | 10 mm² |
| 50A (DC/DC Booster) | 10 mm² | 16 mm² | 25 mm² |
| 100A (Inverter) | 25 mm² | 35 mm² | 50 mm² |
Fuse Sizing
The fuse protects the wire, not the appliance. Always place it as close to the power source as possible (battery or busbar).
- Wire 1.5 mm² → Max fuse 10A
- Wire 2.5 mm² → Max fuse 20A
- Wire 4 mm² → Max fuse 30A
- Wire 6 mm² → Max fuse 40A
- Wire 10 mm² → Max fuse 60A
SCHÉMA ÉLECTRIQUE
PANNEAUX SOLAIRES
0W
RÉGULATEUR MPPT
BATTERIE AUXILIAIRE
0 Ah
Lithium LiFePO4
FUSIBLE
FUSIBLE
BOÎTE À FUSIBLES 12V
Pompe, Leds, Frigo...
CONVERTISSEUR 220V
NON REQUI
PRO GEARPage 4
SHOPPING LIST
Where to find this equipment? Here is the community-approved selection.
12V 6-way Fuse Box
Mandatory protection
Digital Multimeter
Test your connections
Heavy Duty Crimping Tool
For perfect lugs
Heat Shrink Tubing
Insulation and safety
GENERATED BY VANPOWERCALC.COM
The Ducato is the most converted van in Europe for good reason — tall ceiling, flat floor, massive cargo area. But its electrical system has quirks you need to know before drilling holes and running cables. The Euro 6 engine's smart alternator is the biggest one.
Ground points on the Ducato are located on the chassis rail behind the driver seat and under the passenger footwell carpet. Don't drill your own ground holes in the body — the Ducato's body panels are thinner than you'd expect and rust quickly at drill points. Use the factory-provided M6 bolts on the chassis. For cable routing from engine bay to living area, the factory grommet behind the battery (left side of engine bay) is your best friend.
Expert tip
The Ducato's factory battery is under the driver seat on newer models. If you're installing a leisure battery, put it on the same side — shorter cable run to the DC-DC charger means thicker cables aren't needed. I mount mine directly behind the driver seat on a marine battery tray bolted to the chassis rail.
Example calculation for your setup
Results based on a typical use case
| Appliance | Power | Usage/day | Wh/day |
|---|---|---|---|
| Compression fridge | 45W | 24h | 1080 |
| LED lighting | 20W | 4h | 80 |
| Water pump | 30W | 0.5h | 15 |
| Phone charging | 15W | 2h | 30 |
| Daily consumption | 1205 Wh | ||
Recommended LiFePO4 battery
151 Ah
(80% depth of discharge)
Recommended AGM battery
241 Ah
(50% depth of discharge)
Recommended solar panels
402 Wc
Comparison table
| Spec | Ducato 2014-2019 (Euro 5) | Ducato 2019+ (Euro 6d) |
|---|---|---|
| Engine | 2.3 Multijet | 2.3 Multijet Euro 6 |
| Alternator Type | Conventional | Smart (variable voltage) |
| Alternator Output | 14.4V steady | 12.4-14.8V variable |
| VSR Relay Works | Yes | No |
| DC-DC Charger Needed | Optional | Required |
| Battery Location | Under driver seat | Under driver seat |
| Starter Battery | 70-95Ah AGM | 70-95Ah EFB/AGM |
| CAN Bus Interference | Minimal | Possible with cheap chargers |
| Recommended DC-DC | Any compatible |
About this tool
The 2.3 Multijet Euro 6 alternator is a smart unit that varies voltage between 12.4V and 14.8V depending on battery state and engine load. This means a traditional VSR relay won't reliably charge your leisure battery — the voltage drops too often for the relay to engage. You absolutely need a DC-DC charger (Victron Orion, Renogy DCC50S) with the Ducato. I learned this the hard way: spent 3 weeks wondering why my AGM was never above 60% despite driving 2 hours daily. The relay was clicking on and off every few seconds as the smart alternator cycled. Swapped to a Victron Orion-Tr 30A and the problem disappeared overnight. One more Ducato-specific thing: the OEM fuse box under the dashboard has several spare slots. You can tap into these for small loads (LED lights, USB chargers) using add-a-fuse adapters, avoiding the need to run new wires from the leisure battery for everything.
Frequently asked questions
Does the Fiat Ducato have a smart alternator?▼
Yes, all Euro 6 Ducatos (2016+) have a variable-voltage alternator that fluctuates between 12.4-14.8V. A traditional split charge relay won't work reliably. You need a DC-DC charger like the Victron Orion-Tr Smart or Renogy DCC50S.
Where are the best ground points on a Ducato?▼
Factory M6 bolts on the chassis rail behind the driver seat, and under the passenger footwell carpet. Always sand the paint off around the bolt for clean metal contact. Don't drill new holes in body panels — they'll rust.
How do I route cables from engine bay to living area?▼
Use the factory grommet behind the engine bay battery (left side). It's pre-sealed and large enough for 2-3 cables. Drill a new hole only as a last resort, and always use a waterproof cable gland if you do.
Can I tap the OEM fuse box for accessories?▼
Yes, for small loads under 10A. Use add-a-fuse adapters in the spare slots under the dashboard. Good for LED strips, USB outlets, or a dashcam. Don't run high-current loads (fridge, inverter) from the OEM fuse box — those need dedicated wiring from the leisure battery.
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