Install guide / Truck camper
Every wire, every fuse, in order.
A 460Ah LiFePO4 bank, a 3000VA inverter in a detachable kitchen module, solar, and alternator charging, planned to the individual conductor before the first lug was crimped. This is the working document from the build: the reference (decisions, math, tables), the master diagrams, and the install sequence that energizes the system one fuse at a time.
- Battery
- 460Ah · 5.89 kWh
- Inverter
- 3000VA
- Charge ceiling
- 200A DVCC
- Conductors mapped
- 36
- Install phases
- 8
How to use this document: §01–06 are the reference: decisions, math, tables. Plates 01–03 are the master diagrams (the conductor map shows every individual wire with a schedule); keep them one scroll away during every phase. Everything after that is the build, in order, with sub-figures inside the phases they serve.
§01
Design decisions
Every choice locked during design, in one place, so the reasoning survives the build.
| Decision | Choice | Why |
|---|---|---|
| Inverter SKU | MultiPlus-II 12/3000/120-50 (standard) | US 120V/60Hz shore and loads. Not 230V (wrong grid, wrong loads); not 2x120V (split-phase passthrough is dead weight on a 15A inlet). |
| Cooktop | Single 1800W | Dual 3600W exceeds both the inverter and the 230A BMS. |
| Inverter DC run | Single 4/0 per polarity | No current-sharing risk vs paired 1/0; trivial routing at under 3 ft. |
| System ceiling | 230A BMS continuous | The battery, not the inverter, is the limit. One big AC appliance at a time. |
| Charge coordination | Closed-loop DVCC, 200A cap | Total 270A of stacked chargers against a 210A battery charge limit. |
| Cerbo supply | F4 post tap, 3A inline | Off load-side switching (Cerbo loss halts closed-loop charging) but downstream of the master cutoff, preserving a true kill switch. |
| Driver-side feed connector | SB50, 6 AWG contacts | Replacing the PP45 (10 AWG / 45A max). Fuse 40A until swapped, 50A after. |
| Module umbilical | SB350 · L5-15 · bulkhead RJ45 · SB50 | Tool-free dock. Precharge circuit protects SB350 contacts from capacitor inrush. |
| Comms routing | Epoch→BMS-Can 500k · MPPT→VE.Can 250k · Orion→VE.Direct · Multi→VE.Bus | The Cerbo MK2 has two independent CAN buses; running the VE.Can MPPT on its own bus frees the single VE.Direct cable for the Orion XS. |
| Chassis bond | Lynx middle ground stud, 2/0, single point | Purpose-built stud on the negative busbar; Victron’s red-lug PCB wire stays in place under the lug. |
§02
Load math
Worst case is dinner: the induction cooktop alone pulls roughly 160 amps DC at low state of charge. Everything else in the camper together adds another twenty-something, and the total has to clear the battery’s 230A continuous ceiling with margin.
| Load | Draw | DC amps @ 12.2V | Notes |
|---|---|---|---|
| Induction cooktop, 1800W AC | 1800W AC | ~160A | 1800 ÷ 0.92 inverter efficiency ÷ 12.2V. Worst case at low SOC. |
| Truma Cooler C60 | 50–70W | 4–6A | Compressor duty cycle; assume running. |
| Maxxair fan | 4–48W | 0.3–4A | 4A only at max speed. |
| Truma VarioHeat | 7–23W | 0.6–1.9A | Combustion fan; brief spike on ignition. |
| Starlink Mini | 25–60W | 2–5A | Higher when snow-melt / heavy TX. |
| LED lighting | ~30W | 2–3A | All zones on. |
| Cerbo GX + comms | ~5W | 0.4A | |
| Worst-case simultaneous | n/a | ~180–185A | vs. 230A BMS continuous: OK. |
Operating rule
The cooktop is fine, but do not stack a second large AC load (kettle, microwave, heat gun) on top of it. Full inverter output (2400W ≈ 215A DC) plus house loads exceeds the 230A BMS limit and the battery will disconnect under load. One big AC appliance at a time.
Charge-side coordination required
MPPT 150/100 (100A) + Orion XS (50A) + MultiPlus charger (120A) = 270A potential charge current against a 210A max charge rating. The Epoch talks BMS-CAN to the Cerbo, so run closed-loop DVCC and set DVCC max charge current = 200A. This is a settings task, not a hardware one (checklist in Phase 6).
PowerAssist bonus
Set the AC input current limit to 12A on the 15A shore inlet. On shore power the Multi passes 12A through and the inverter tops up the difference from battery, so the cooktop runs at full tilt without tripping a campground pedestal.
§03
Usage and charging
Working capacity: 5.89 kWh nameplate, 5.3 kWh practical holding a 10% reserve. What that buys, and how fast it comes back:
| Load | Daily energy |
|---|---|
| Truma C60 (30–40% compressor duty) | ~0.55 kWh |
| Starlink Mini, 8h / 24h | ~0.30 / ~0.85 kWh |
| Cerbo GX, always on | ~0.12 kWh |
| Maxxair + LED, typical | ~0.20 kWh |
| VarioHeat fan, cold night | ~0.30 kWh |
| Cooked meal on induction | ~0.5 kWh each |
| Laptop full charge | ~0.1 kWh |
| Inverter idling 24h | ~0.5 kWh |
The silent killer: the Multi burns ~20W doing nothing: a full cooked dinner per day of standby. Search Mode (Phase 6, step 12) buys back half a day of runtime.
| Scenario | kWh/day | Runtime |
|---|---|---|
| Frugal: 1 cooked meal, no Starlink, inverter off | ~1.5 | ~3.5 days |
| Baseline camp: 2 meals + coffee, Starlink 8h, fridge, fan | ~2.5 | ~2 days |
| Heavy: 3 meals, all-day Starlink, cold morning, inverter on | ~4.3 | ~1.2 days |
| Source | Rate | Translation |
|---|---|---|
| Solar (Colorado summer) | ~0.45 kWh/day per 100W panel | Rule of thumb; derate 50–70% for shade, haze, flat mount. |
| The 800W array | ~3.6 kWh/day good sun | Baseline camp covered with ~1.1 kWh/day surplus; heavy days run ~−0.7 kWh, recovered from the bank and the next clear morning. |
| Driving (Orion XS 50A) | ~0.6 kWh per hour | 2h reposition recovers most of a baseline day. |
| Shore 15A (12A limit) | ~1.4 kW | Dead-to-full in ~4 hours. |
§03 · Continued
Cooking capacity
Per full battery: roughly 2.7 hours of continuous 1800W, 6–8 hours of real mixed-power cooking, roughly 50 one-liter boils. A cooked dinner is ~8–9% of the bank; laptop charges are rounding error (~50 per charge).
§04
Lynx Distributor slot map
The Lynx has exactly four fused positions, and this system has five branches. Solution: F4 feeds a dual-stud distribution post at the passenger/battery location, which splits to the driver-side box (existing 6 AWG run via Anderson SB50) and passenger-side box (short 8 AWG). The battery lands on the Lynx busbar end connections (M8), not a fuse slot; it is already protected by its integrated 400A Eaton Class T (JJN-400).
| Slot | Branch | MEGA fuse | Wire |
|---|---|---|---|
| F1 | MultiPlus-II 12/3000 DC input | 400A | 4/0 AWG |
| F2 | SmartSolar MPPT 150/100, battery side | 125A | 2 AWG |
| F3 | Orion XS 50A, output side | 60A | 6 AWG |
| F4 | DC house feed → distribution post → driver + passenger fuse boxes | 80A | 4 AWG to post; 6 AWG / 8 AWG feeds |
§05
Wire gauge and overcurrent
All DC wire: marine-grade tinned copper, 105°C insulation. All runs assume the under-3-ft battery–Lynx–MultiPlus placement. Support cables every 18 inches.
| # | Run | Gauge | Protection | Notes |
|---|---|---|---|---|
| 1 | Battery → master cutoff switch → Lynx + end; battery − → Lynx − end | 4/0 AWG | 400A Class T (in battery) | Master cutoff in the positive, after the Class T: physical air-gap kill for the whole house. ≥250–300A continuous rating required (215A inverter draw); verify on-hand switch spec. |
| 2 | Lynx F1 → MultiPlus DC terminals | 4/0 AWG | 400A MEGA | Single 4/0 per polarity beats the manual’s 2×1/0 option at this length: fewer terminations, no current-sharing risk. If you go paired 1/0, cut all four cables to identical length. |
| 3 | Lynx F2 → MPPT battery terminals | 2 AWG | 125A MEGA | Sized for 100A max output. |
| 4 | PV array → MPPT PV input | 10 AWG typ. | DC breaker/isolator, ≥150V rated | Existing; verify per string current. |
| 5 | Lynx F3 → Orion XS OUT+; Orion GND → Lynx − bus | 6 AWG each | 60A MEGA | Single GND terminal is the shared return for both legs (up to ~60A): full 6 AWG, landed on the Lynx − bus for accurate output-voltage sensing. |
| 6 | Truck start battery + → Orion XS IN+ | 6 AWG | 60A fuse at start battery | Fuse within 7 in of the source; 4 AWG if routed near exhaust heat. No IN− exists; the Orion XS is non-isolated. |
| 7 | Lynx F4 → distribution bus | 4 AWG | 80A MEGA | 4-stud Blue Sea BusBar (150A class, covered) works well; optional matching negative collector bar with a single 4 AWG return to the Lynx − bus. Chassis bond stays at the Lynx only. |
| 8a | Post → driver-side fuse box (existing run) | 6 AWG | 40A MIDI now → 50A after SB50 | Existing run currently has a PP45 in line and it is undersized: PP45 contacts max at 10 AWG / 45A. Swap to SB50 with 6 AWG contacts (or PP75); 50A then protects wire and connector. Blue Sea MIDI holder at the bus, jumpered from a bus stud; 40A fuse until swapped, then 50A. Strain-relieve both connector halves; check for heat discoloration at re-torque intervals. |
| 8b | Post → passenger-side fuse box | 8 AWG | 40A MIDI | Second MIDI holder at the bus. Short run, box sits at battery location. Future circuits fuse at the box; 40A feed covers Starlink + both aux receptacles with margin. |
| 9 | Lynx − busbar → chassis bond | 2/0 AWG | none | Single bonding point for the entire house system; no second neg–chassis path. Land it on the Lynx’s dedicated middle ground stud on the negative busbar, leaving Victron’s small red-lug PCB wire in place under the lug. |
| 10 | MultiPlus case ground lug → chassis | 6 AWG | none | Green/yellow. Required. |
| 10b | MPPT 150/100 case ground lug → chassis | 6 AWG | none | Per Victron manual; the only other case ground in the system besides the MultiPlus. |
| 11 | Shore inlet → AC-IN (L/N/PE) | 12 AWG | 15A breaker at inlet | 12 AWG even though 14 passes code, for voltage drop and heat margin. |
| 12 | AC-OUT-1 → branch breaker → GFCI receptacle | 12 AWG | 15A breaker + GFCI | Victron recommends Blue Sea 3090/3100-series GFCI breakers. Cooktop plugs in here. |
| 13 | F4 distribution post → Cerbo GX power | 16 AWG | 3A inline fuse at post | Not from a sub box: the Cerbo runs closed-loop DVCC, and losing it halts charging. Keep it off load-side switching, downstream of the main cutoff. |
Why 400A MEGA on 4/0
Victron’s manual calls for a 400A DC fuse on the 12/3000 because surge draw approaches 500A. 4/0 at 105°C carries ~445A in free air, so the fuse still protects the conductor. This is the combination Victron’s own install guidance endorses for short runs. Note MEGA is a slow fuse; catastrophic fault interruption is the job of the battery’s Class T upstream, which is exactly how this architecture is meant to layer.
Negative vs. ground, once and for all
DC negative (the SB350’s second pole) is a current-carrying conductor: the return half of the power circuit. The green 6 AWG case grounds (rows 10/10b) carry nothing in normal operation; they exist so a fault that energizes a metal case trips protection instead of waiting for a hand. The Orion’s GND terminal is neither, badly named: it is the shared power negative and carries up to 60A.
If a previous charger install left a negative conductor running start battery → camper, repurpose it as a dedicated return (≥6 AWG): stack its lug on the F3 negative stud with the Orion GND (two lugs per M8 stud is fine; largest down first, one nut over the stack), or use the free busbar end bolt if threads run short. Charge current then rides copper instead of frame. No such wire? Frame return is by design; verify the factory straps.
Lynx fuse LEDs will be dark: expected
The monitoring PCB is powered only via its RJ10 cable from a Lynx Smart BMS, which this system doesn’t have (the Epoch is the BMS). Fuses work fine regardless. Optional LED revival: 5V on RJ10 pin 1, GND on pin 4. Not reverse-protected; wrong wiring kills the board. Clean 5V source: the Cerbo’s power-only USB port (closest to HDMI); splice the included RJ10 to a spare USB-A, meter before plugging. The red-lug wire on the ground stud is the detection circuit’s reference; it stays either way.
§05 · Interface
The detachable kitchen module
The MultiPlus, AC branch breaker, GFCI, and cooktop live in a vented, removable module. Four tool-free connections dock it:
| Circuit | Connector | Rating | Notes |
|---|---|---|---|
| DC + / −, 4/0 AWG | Anderson SB350, 4/0 contacts | 350A cont. | 2-pole, keyed, one-push mate. 400A MEGA upstream in the Lynx protects the run to and through the connector. Panel-mount on module bulkhead; handle kit on camper half. |
| AC shore feed → AC-IN | L5-15 flanged twist-lock inlet | 15A | PE pin carries the AC fault path. Cooktop circuit stays internal on AC-OUT-1. |
| VE.Bus → Cerbo | Bulkhead RJ45 coupler | n/a | The Cerbo simply reports the Multi offline when the module is off the truck. Neutrik etherCON NE8FDP recommended; any straight-through all-8-pin coupler works. |
| Case / chassis ground, 6 AWG | Anderson SB50 | 50A | Maintains the DC case bond when docked. |
Precharge or pit the contacts
The Multi’s capacitor bank draws a violent inrush at connection. Fit a battery switch in the module’s 4/0 positive plus a momentary pushbutton through a 15Ω/25W wirewound resistor bridging that switch. Dock procedure: mate SB350 → hold precharge ~5s → close switch. Never separate under load: cooktop off, switch off, then unplug.
§06
What you still need
The buy list, checked against on-hand stock, and just as deliberately, the skip list.
- MEGA fuses: 400A, 125A, 80A, 60A (32V or 58V rated; both fine at 12V). Check against existing MEGA stock first.
- Spare Eaton JJN-400 Class T for the battery. You do not want to source one from a trailhead.
- 4/0 AWG tinned cable (~6–8 ft total red + black) and 4/0 M8 lugs ×8 if not in stock.
- Distribution: 4-stud Blue Sea bus bar(s) + 2× MIDI/AMI fuse holders with 40A/50A fuses (on hand) for the branch feeds.
- Comms (inventory-checked): on-hand Victron cables cover it: 3× RJ45 UTP (Epoch→BMS-Can, MPPT→VE.Can, one VE.Bus leg) and 1× VE.Direct (Orion XS). Still to buy: one generic RJ45 patch (second VE.Bus leg) and the bulkhead coupler (Neutrik etherCON NE8FDP). The VE.Can-to-CAN-bus-BMS Type B cable stays on the shelf as the troubleshooting spare. Terminators: 2 with the Cerbo + 2 with the VE.Can MPPT.
- AC hardware: 15A branch breaker (DIN or Blue Sea), GFCI duplex receptacle, 12 AWG stranded (marine or SOOW), cable glands/strain reliefs for the MultiPlus AC knockouts.
- Inline 3A fuse holder (ATC/ATO) for the Cerbo tap at the distribution post.
- Module interface: Anderson SB350 housing pair + 4× 4/0 contacts (hydraulic hex crimp), SB350 panel-mount + handle kit, L5-15 flanged inlet + cord body, bulkhead RJ45 coupler, SB50 pair + 6 AWG contacts for case ground.
- Precharge circuit: 15Ω 25W wirewound resistor + momentary pushbutton (module battery switch from existing stock).
- Cable clamps, adhesive-lined heat shrink, anti-oxidant paste.
Skip (not needed in this architecture):
- MK3-USB: VE.Bus configuration now runs through the Cerbo via VictronConnect/VRM.
- SmartShunt / BMV: SOC comes from the Epoch BMS over CAN. A shunt would be redundant.
- Temp / voltage sense leads: DVCC shared sensing (SVS/STS) sources both from the BMS.
Plate 01
System single-line
The whole system on one page: AC row across the top, DC spine below it, comms converging on the Cerbo. Negative conductors mirror every positive run shown; fuses live on the positive side only.
Plate 02
Point-to-point detail
The same system drawn the way it lands: + rail left, − rail right (both are the Lynx busbars). Every branch takes its fuse on the positive side, every negative comes home to the Lynx − bus, and the whole house bonds to chassis exactly once.
Plate 03
Every wire, individually
Every physical conductor, drawn individually and keyed to the schedule below. Wire numbers sit at the Lynx-stud end of each run; gauges live in the schedule. Dashed gray = optional; dashed blue = data.
| # | From | To | Gauge | Protection |
|---|---|---|---|---|
| W1/W2 | Battery + via master cutoff (≥300A cont.) / battery − | Lynx busbar ends | 4/0 | 400A Class T (internal) |
| W3/W4 | Lynx F1+ / N1− | SB350 camper half | 4/0 | 400A MEGA |
| W5/W6 | SB350 module + → switch → Multi DC+ | 4/0 | same | |
| W7 | SB350 module − | Multi DC− | 4/0 | same |
| W8/W9 | Precharge: button + 15Ω/25W bridging the switch | 16 AWG | n/a | |
| W10/W11 | Lynx F2+ / N2− | MPPT BAT+ / BAT− | 2 AWG | 125A MEGA |
| W12/W13 | PV array (+ via breaker) | MPPT PV+ / PV− | 10 AWG typ | DC brkr ≥150V |
| W14 | Start battery + | Orion IN+ | 6 AWG | 60A ≤7 in of post |
| W15 | Lynx F3+ | Orion OUT+ | 6 AWG | 60A MEGA |
| W16 | Orion GND | Lynx N3− | 6 AWG | none (shared return) |
| W16b | Start battery − (optional, if old run exists) | stack @ N3 stud | ≥6 AWG | n/a |
| W17 | Lynx F4+ | Dist bus + | 4 AWG | 80A MEGA |
| W18/W20 | Dist bus + / driver neg | Driver box via PP45→SB50 | 6 AWG | 40A now / 50A after swap |
| W19/W21 | Dist bus + / passenger neg | Passenger box / neg collector | 8 AWG | 40A |
| W22 | Neg collector | Lynx N4− | 4 AWG | n/a |
| W23/W24 | Dist bus + via 3A / Cerbo − | Cerbo power / stack @ N4 | 16 AWG | 3A ATC |
| W25 | Lynx middle GND stud | Chassis (only bond) | 2/0 | n/a |
| W26 | Multi case lug via SB50 | Chassis | 6 AWG | n/a |
| W27 | MPPT case lug | Chassis | 6 AWG | n/a |
| AC1–3 | Inlet → 15A brkr → L5-15 | L/N/PE | 12 AWG | 15A |
| AC4–6 | L5-15 → Multi AC-IN | L/N/PE | 12 AWG | 15A upstream |
| AC7–9 | AC-OUT-1 → 15A brkr → GFCI → cooktop | L/N/PE | 12 AWG | 15A + GFCI |
| C1–C6 | Comms per the Phase 4 map | RJ45 ×4, VE.Direct, Touch | n/a | n/a |
Prime directive
No Lynx MEGA fuses get installed until Phase 5. Every branch is built dead, checked with a meter, and energized one fuse at a time in a specific order. If you remember one thing, remember that.
Phase 0
Prep and safety
Goal: nothing can bite you, everything is staged
Battery arrived: charge it or not?
Check shipped SOC with the included monitor cable or Epoch app (typically 30–60%). No pre-charge is required at any SOC. Even 30% is ~1.7 kWh, plenty for every commissioning test, and the first full charge happens through the finished system under DVCC, which doubles as a commissioning check. If install is weeks out, the shipped partial SOC is the correct LiFePO4 storage state; leave it. Bench-charging anyway: lithium-profile charger only (14.4V class, battery switch ON), never a lead-acid unit with pulse/desulfation modes. The battery’s own switch is the BMS internal disconnect: OFF for storage, transport, and all of Phase 2 cabling (even with the Class T pulled); ON at the top of Phase 5 before the Class T goes back in; stays on in service. Heated model in a cold garage: first charge current feeds the internal heater before the cells; expect a delay before amps show.
Disconnect hierarchy: when to throw what
Wiring work: BMS switch OFF + master cutoff OFF + Class T pulled (layers, not alternatives). Storage/transport: both switches OFF, Class T stays in. Daily use: everything ON. Branch service: masters stay ON, pull only that branch’s MEGA/MIDI. Emergency: the master cutoff. One throw kills the house. Energize order: BMS switch → master → branches (Phase 5); de-energize in reverse. Either master OFF blinds the Cerbo (fed from F4). Expected, not a fault.
- 01De-energize everything. Battery switch OFF, master cutoff OFF, then pull the Epoch’s user-serviceable Class T fuse (front access panel on the battery). Open the PV breaker. Pull the Orion input fuse at the start battery if the holder exists; if not, disconnect that lead entirely. Why: the Class T out means the 4/0 lugs you’re about to handle are dead metal, not a 460Ah arc welder.
- 02Verify dead. Multimeter across the battery cable ends: 0V. Do not trust the switch position; trust the meter.
- 03Stage tools: hydraulic crimper with dies through 4/0, torque wrench with hex sockets for M8, heat gun, wire strippers, multimeter with continuity beeper, AC outlet tester, label maker or flag tape, paint pen for torque marks.
- 04Stage parts against the §06 BOM. Lay out all MEGA fuses (400/125/80/60A) in a tray, labeled, away from the Lynx. Confirm SB350 4/0 contacts, SB50 6 AWG contacts, L5-15 hardware, precharge resistor and button, 3A ATC holder.
- 05Remove jewelry, watch, rings. 12V won’t shock you; a wrench across 460Ah will remove a finger via molten metal.
Phase 1
Mechanical mounting
Goal: every box bolted where it lives, nothing wired
- 01Mount the Lynx Distributor at the passenger/battery location, as close to the battery as the 4/0 allows (under 3 ft target). Solid substrate, fasteners into structure, cover accessible.
- 02Mount the distribution post adjacent to the Lynx with clear cable paths to both sub-box feed directions and the Cerbo.
- 03Mount the Cerbo GX in a cool, dry, accessible spot near the Lynx. Vertical orientation with connectors reachable; leave slack for the comms loom.
- 04Build the kitchen module shell: MultiPlus mounted vertically, DC terminals down, on a heat-resistant surface, with ≥10 cm clearance around it. Vent path: intake low and cool, exhaust high; duct so cooktop heat cannot recirculate into the inverter intake. Why: the Multi derates from 2400W to 2200W at 40°C ambient. A heat-soaked box costs cooking headroom.
- 05Install module bulkhead hardware: SB350 panel mount, L5-15 flanged inlet, bulkhead RJ45, SB50 pass-through. Rigid mounting on the SB350; insertion force is real, and the panel takes it, not the cable.
- 06Mount the module battery switch and precharge button inside the module, reachable with the module docked.
Phase 2
DC cabling, dead system
Goal: every DC conductor landed and torqued; zero volts anywhere
Build cables first, land second: crimp, adhesive heat-shrink, and label both ends of every cable on the bench before anything touches a terminal. A labeled loom is a debuggable loom. Lynx torque: M8 fuse/cable connections 106 in-lb, M10 interconnects 17 ft-lb (Wiring Unlimited); other devices per their printed specs.
- 01Battery → Lynx busbar ends: 4/0 pair to the Lynx M8 end connections. The Class T is still out, so these are dead. Torque to the spec printed at each terminal; paint-mark every nut.
- 02Lynx F1 stud → SB350 camper half: 4/0 pair. Route with strain relief so the connector floats free for mating.
- 03Inside the module: SB350 module half → 4/0 positive → module battery switch → MultiPlus DC+. Negative 4/0 direct to MultiPlus DC−. Wire the precharge button + 15Ω/25W resistor across the switch terminals. Why the resistor: it fills the Multi’s capacitor bank gently over ~5s instead of letting the SB350 contacts do it in one spark.
- 04Lynx F2 stud → MPPT battery terminals: 2 AWG pair. PV breaker stays open; do not land PV wires yet.
- 05Lynx F3 stud → Orion XS output: 6 AWG pair. Then IN+: 6 AWG from the start battery + through the (empty) 60A fuse holder, within 7 in of the post. GND: one 6 AWG to the Lynx − bus. The Orion XS is non-isolated, so this single terminal is the shared return for both input and output (Sub-fig E). There is no IN−.
- 06Lynx F4 stud → distribution post: 4 AWG. Post → passenger box: 8 AWG. Post → driver box: existing 6 AWG. Swap the PP45 for the SB50 with 6 AWG contacts now, while everything is dead.
- 07Cerbo power: 16 AWG from the post through the 3A ATC holder (holder within inches of the stud, fuse OUT for now) to Cerbo Power In +. Cerbo − runs to the Lynx negative bus, not a sub-box neg bar.
- 08Grounds: 2/0 from the Lynx negative bus to the single chassis bond point, landed on the Lynx’s dedicated middle ground stud; leave Victron’s small red-lug PCB wire in place under the lug. 6 AWG from the MultiPlus case lug through the SB50 to chassis. Verify there is no second negative-to-chassis path anywhere.
- 09Meter checks, every branch: ohms from each F-stud to the negative bus with loads’ switches on. You should see load resistance or open, never a dead short. Ohms from positive bus to chassis: open. Fix anything suspicious now, while it can’t cost a fuse or a fire.
Phase 3
AC wiring
Goal: shore path and cooktop circuit complete, still dead
- 01Shore path: existing 15A inlet → 15A breaker at the inlet → 12 AWG (L·N·PE) → L5-15 cord body that mates the module’s flanged inlet.
- 02Module AC-IN: from the L5-15 flanged inlet, 12 AWG through a strain-relief gland into the MultiPlus AC-IN [L | N | PE] terminals. The Multi’s terminal block is labeled; match letters, not wire colors you assume.
- 03Module AC-OUT: AC-OUT-1 → 12 AWG → 15A branch breaker → GFCI receptacle where the cooktop plugs in. AC-OUT-2: cap, tape, label unused.
- 04Continuity audit: with everything dead, beep out L to L, N to N, PE to PE end-to-end through the whole chain, and confirm no L–N, L–PE, N–PE shorts. Five minutes here prevents the worst category of first-power surprise.
Phase 4
Comms loom
Goal: every device has a data path to the Cerbo before anything powers up
- 01Epoch → Cerbo (BMS-CAN): per the Epoch harness card: waterproof bung in the battery’s blue master port, RJ45 out of the black master port → Cerbo CAN socket. Into the Cerbo MK2’s dedicated BMS-Can port at 500 kbit/s. Terminator in the Cerbo’s unused BMS-Can socket; battery end per the Epoch harness card. Terminators go in CAN sockets only, never in VE.Bus ports. If the battery never appears at 500 kbit/s on the straight cable, swap in the Type B CAN-bus BMS cable; that is its job as the shelf spare.
- 02MultiPlus → Cerbo (VE.Bus): RJ45 from either Multi socket, through the module’s bulkhead RJ45, to a Cerbo VE.Bus port. Standard straight-through network cable is fine.
- 03MPPT → Cerbo (VE.Can): the 150/100-Tr VE.Can connects by plain RJ45 to the Cerbo MK2’s VE.Can port, a separate bus from BMS-Can, profile 250 kbit/s. Terminators (included with the MPPT) go in the MPPT’s empty second socket and the Cerbo’s empty VE.Can socket. Rotary address switch stays at 0.
- 04Orion XS → Cerbo: the VE.Direct cable to any Cerbo VE.Direct port.
- 05GX Touch (if fitted): the MK2’s dedicated Touch connector. Route the display cable to its dash/galley cutout now while the loom is open.
- 06Dress the loom: comms separated from the 4/0 runs where practical, no cable tie cinched over an RJ45 boot, service loops at every device.
Phase 5
Energize, one fuse at a time
Goal: system live, verified at each layer before the next layer gets power
Sequence is the safety system: house first (so the Cerbo is watching), then solar, then alternator, then the inverter last. Do not skip ahead because a step seems boring.
- 01Battery switch ON → reinstall Class T → master cutoff ON. Meter the Lynx busbars: you should read battery voltage, ~13.2V at 50% SOC. No MEGA fuses in yet, so every branch is still dead.
- 02Install F4 (80A) + the Cerbo’s 3A ATC. Sub boxes and Cerbo go live. The Cerbo boots to the console (or GX Touch). Verify each driver/passenger circuit works: fan, fridge, lights, USB.
- 03Cerbo first-boot basics (full walkthrough in Phase 6): set the CAN profile to CAN-bus BMS (500 kbit/s) and confirm the Epoch appears in the device list with live SOC, voltage, and temperature. Do not proceed until it does. The BMS link is what supervises everything else you’re about to energize.
- 04Enable DVCC: it may already be forced on by the CAN BMS. Set max charge current = 200A; confirm SVS and STS show the battery as source.
- 05Install F2 (125A). The MPPT wakes on battery power. In VictronConnect over Bluetooth (the VE.Can model configures via BT): firmware update if offered, confirm DVCC/network shows it under GX control. Then close the PV breaker and watch it start charging. Verify charge current appears on the Cerbo.
- 06Install F3 (60A), then the 60A fuse at the start battery. Configure the Orion XS in VictronConnect: lithium charge profile, engine-shutdown detection on. Start the truck; confirm ~50A into the bank, then confirm it stops after shutdown.
- 07Install F1 (400A). Dock the module: mate the SB350 → hold precharge ~5s → close the module switch. The Multi’s LEDs wake. Connect L5-15 and the bulkhead RJ45 if not already.
- 08Configure the MultiPlus from VictronConnect via the Cerbo (no MK3 needed; enable two-way VRM comms if configuring remotely): firmware update first if prompted, then charger 14.4V absorption / 13.6V float / 120A (DVCC and the BMS override targets in operation), AC input current limit 12A, PowerAssist on, grounding relay enabled.
- 09Inverter-only AC test: no shore cord. Verify 120V at the GFCI, press its TEST button, outlet tester shows correct wiring. Run the cooktop at 50% for 10 minutes; feel every lug in the DC path for heat. Then a full 1800W boil test.
- 10Shore test: plug in the 15A cord. Verify the Multi accepts input (charging begins), then run the cooktop at full and watch PowerAssist blend battery on top of the 12A shore limit without tripping the pedestal.
- 11Close-out: re-torque every M8 after the first full heat cycle, refresh paint marks, thermal-scan or hand-check lugs one more time under load.
Phase 6
Cerbo GX and display setup, in full
Goal: monitoring on the wall, on your phone, and on the web
| Path | How | Use it for |
|---|---|---|
| GX Touch on the wall | Plugs into the Cerbo MK2’s dedicated Touch port; shows the console directly | Daily glance: SOC, solar, loads |
| Remote Console on phone/laptop | Join the Cerbo’s own WiFi AP (SSID + key on the Cerbo sticker) → browse to 172.24.24.1; or same LAN → venus.local | Setup, settings, anything the Touch does |
| VRM portal + app | vrm.victronenergy.com after registration | History, alerts, remote access from anywhere with signal |
- 01Firmware first. Settings → Firmware → Online updates → check and install. Do this before touching any other setting; menus move between versions.
- 02Network: Settings → WiFi → join the camper network (Starlink Mini’s WiFi works fine as the uplink). Leave the Cerbo’s own access point enabled as the fallback door when boondocked.
- 03Date & time: set timezone; auto time comes with the network.
- 04Verify the device list. You should see: Epoch (CAN BMS) with SOC/temp, MultiPlus, SmartSolar 150/100, Orion XS. Anything missing is a cable or CAN-terminator problem; fix before proceeding.
- 05Name the devices. Each device → Device menu → Name. “Module Inverter,” “Roof Solar,” “Alternator DC-DC.” Future-you troubleshooting on a phone in the rain will be grateful.
- 06Battery monitor source: Settings → System setup → Battery monitor → the Epoch BMS (usually auto-selected). This is the SOC everything displays.
- 07DVCC review: Settings → DVCC → confirm on, limit charge current 200A, SVS on, STS on.
- 08VRM registration: Settings → VRM online portal → note the Portal ID. Create an account at vrm.victronenergy.com, Add installation, enter the ID. Install the VRM app; add the dashboard widget. Enable Settings → VRM → two-way communication for remote adjustment of the Multi and MPPT.
- 09Alarms: Settings → System setup: low SOC alarm at 20% (the reserve line). In VRM, enable push alerts for low battery and VE.Bus error.
- 10Display polish (GX Touch): Settings → Display & language → adaptive brightness on, night mode if you want the galley dark. On the console home, pick the overview page that shows AC loads + solar + SOC in one screen and set it default. Screen-off timer to taste; tap wakes it.
- 11Set the Multi’s self-consumption behavior: in the console, Multi → Advanced (or VictronConnect) → enable Search Mode/AES so the inverter sips instead of burning ~20W idle around the clock. Verify the cooktop still wakes it promptly; if a small load doesn’t, nudge the search threshold down.
When the module is off the truck: the Cerbo shows the MultiPlus as disconnected and raises a VE.Bus alarm once. Acknowledge it; everything else keeps logging normally. It reappears on the next dock with settings intact.
Phase 7
Operating drills
Goal: the habits that keep it boring
- 01Dock: SB350 → precharge 5s → module switch on → L5-15 → RJ45 → SB50 ground.
- 02Undock: cooktop off → Multi off (switch or console) → module switch off → unplug in reverse order. Never separate the SB350 under load.
- 03Daily: one glance at the Touch: SOC, solar yield, no alarms. Inverter in search mode unless cooking.
- 04Cooking on battery: one big AC appliance at a time; the 230A BMS ceiling from §02.
- 05Seasonal: re-torque M8s, inspect the SB350 and driver-side SB50 contacts for heat discoloration, test the GFCI, confirm the spare JJN-400 is still in the truck.