Welcome to Manins' truck camper project

DC Power Wiring

Overview

To use the power of the 360 Ah LiFe battery, new wiring was required.

The diagram shows the OEM situation and the modifications for the battery and inverter:

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Battery box, existing wiring and new wiring.

Battery Wiring

With a design maximum current of 300 A from the the two 6 V LiFe packs joined in series, we use 95 mm² cable for that task and for connections to the BEP monitoring shunt and the inverter.

The winch supply front and back of vehicle is made in 70 mm² cable. The negative cable from the battery goes nearby onto the chassis rail to a common point, an insulated block with 1/2" UNC bolt and nut, with cables going to the front and back. The positive cable from the battery first goes to an isolating switch on the outside of the battery box and then crosses over to the other chassis rail to another common point, with cables going to front and back.

A 50 mm² positive cable goes directly to the cab, where it enters a BEP switch group for the starter battery and the house battery, providing power in the cab and in the camper. The 95 mm² negative cable goes to the 450 A/50 mV shunt for the BEP Systems Monitor. Since it is a major consumer it is important that the inverter's power consumption be measured by the BEP Systems Monitor. So the cabling for the inverter had to include the main 450 A shunt under the truck. There are four cables leaving the shunt:

  • One 50 mm² goes to the power distribution module in the camper.
  • One 50 mm² goes to the power distribution module in the cab.
  • One 50 mm² goes to the chassis ground bolt on the rail behind the fuel tank.
  • One 95 mm² cable goes to the negative terminal on the Victron Inverter.

Wiring for the Inverter

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95 mm² BOC Superflex welding cable.

The 3000 VA Victron Phoenix inverter uses 95 mm² cables for the DC supply. A first cables, lugs, 32 mm dia. Nylon glands, black and red heatshrink, and an overnight loan of a large hydraulic crimping machine, were obtained from BDL Cable & Electrical Co. Pty. Ltd.. However, although flexible, the cable still proved to be too stiff and the route I chose for cables entering the camper body did not allow for the significant movement between camper and chassis. The cables tore the glands from the wall.

A fellow recommended welding cable for this job. Enquiries showed that short lengths of Transarc Superflex welding cable are available from BOC. A local agent was able to supply 3 m of 95 mm² cable as well as 2 m of 50 mm².

The end result is thus a mix of cables:

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Lug crimped to the 95 mm² BDL cable.

  • A new 95 mm² BDL negative cable replaces the 50 mm² cable going from the battery to the shunt (lugs with M8 at battery, M10 at shunt).
  • A 95 mm² BOC negative cable is added to the group at the shunt and goes via a vertical loop into the camper and to the negative plate in the inverter (lugs with M10 at shunt, M8 at inverter). The flexibility of the cable and the loop assures good behaviour with camper movement.
  • A new 95 mm² BOC positive cable goes from the battery via a vertical loop into the camper to an isolation switch (lugs with M8 at inverter, M10 at switch). Camper movement is accommodated.
  • A twin 50 mm² BOC cable goes from the isolation switch in the camper to the positive plate in the inverter (lugs with M10 at switch and M8 at inverter).
  • A short length of 95 mm² BDL cable makes a bridging link between the 6 V groups of LiFe batteries when they are installed (lugs with M8 at both ends).

The twin cable was made up so as to give the necessary extra flexibility required in the camper and to allow a good connection to the pair of +12 V bolts in the Inverter.

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DC connections to the Inverter.

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Prepared 2 x 50 mm² BOC cables – isolation switch to inverter.

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Prepared 95 mm² BOC cable – battery to isolation switch.


Assembly

All connector surfaces were deburred, scrubbed with steel wool and smeared with silver-based thermal paste from Jaycar.

Access to the shunt was a challenge. I had to obtain a longer M10 brass bolt for the load side of the shunt because of the extra lug for the 95 mm² cable to the inverter. This bolt had a 15 mm AF head, not 14 mm AF like the original, so I filed it down but not very carefully and it suffered in the installation. A 14 mm AF very fine ratchet spanner was necessary to tighten the bolt after much struggle to get it to line up with all four lugs on. The connection to the battery side of the shunt was relatively easy.

The isolating switch is a NARVA 61082BL Battery Master Switch rated at 300 A continuous load.

The main 450 A shunt is bolted to the passenger-side chassis rail. Access to the load-side connector is very restricted.

Peter attempting to assemble the load-side bolt onto the shunt.

A view of the main 450 A shunt with new 95 mm² cables connected.

Cables entering the camper.
32 mm dia. glands are used.

Cables leaving the battery box (cover off). The cables are UV stabilised.

Orange DC cables to Isolation Switch and Inverter under the passenger-side seat.


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