For some time I have been populating the electrical locker in Jim, with all the equipment I need to provide low voltage and main voltage power while on the move. I had largely finished the mains components and just had to connect each of the circuits to the consumer unit (fuse board) to finish the install. Below is how the install looked.
The red unit at the top is a Sterling Power automatic changeover unit. It automatically selects from the three available power sources (mains, generator and inverter) so that when you plug the truck in to the mains, the power is automatically shifts off of the inverter (saving battery power) or the generator (saving diesel).
Power is then passed down to the consumer unit below, where it is split into two separate load banks each covered by its own RCD earth leakage device. The first load bank was a direct connection from the sterling changeover unit, whilst the second passed through a contactor which disconnected the loads when operated from the inverter. The second load bank was primarily to prevent the battery charger from being operated off the inverter, which would just create a an infinite loop of decreasing battery power. Below is how the consumer unit looks without a cover on it.
The big green unit below the consumer unit is a Mastervolt Chargemaster, 60a, 3-way, 24v battery charger. The charger takes mains or generator power and uses it to charge the leisure battery and starter battery banks. After careful consideration, I decided that I couldn't live with the colour of the Mastervolt casing, and didn't like the aesthetic of the layout. I therefore ripped out the entire installation, stepping backwards many hours of work and significant expenditure. And leaving me with a blank canvas on which to waste more money and time.
Another issue, of lesser significance than my insurmountable objection to Mastervolt's choice of green, but also important, was that my previous mains install took no account of the fact that I might visit places with a different voltage. When I designed and installed the previous system, I had planned to drive east across Europe and Asia, where all mains is at a nominal 230v, or thereabouts. Now that we are planning to drive across America, the previous layout would have caused me some problems. I could of course, have just fitted a big transformer to convert incoming mains from 110v to 240v (the actual voltage we receive in the UK), but this is a bit of a bodge, and the Mastervolt charger (the most expensive component of the previous install) had failed at an opportune time.
To make the mains system more versatile I completely changed the layout; below is the basic schematic before my redecorating
An below is how the system looks now:
With an output of 50a at full power, the new charger is capable of keeping the battery fully charged, even when the inverter is running at full capacity. I can therefore always be guaranteed a stable 230v, 50hz supply on the three general use circuits for up to 1200w, when plugged in anywhere in the world. If I need more than 1200w at 230v, I can simply turn on the generator and switch the manual changeover to the generator supply, even when using an 100v mains supply to run the battery charger.
The observant may notice that despite having listed three circuits on the consumer unit fed from the manual changeover switch, the unit has only been fitted with one MCB overcurrent device. This is because I have a Victron ESP 4-way AC panel on the outside of the electrical cupboard to provide individual overcurrent protection to each circuit and to make it easier for me to switch each circuit on and off. The design of the Victron ESP panels is perfectly adequate for DC use, but falls short for use on AC; one of the issues is that it has no neutral or earth bus bar; this is not problem as I can split each 3-way cable as it enters the cupboard, sending the neutral and earth cables to the consumer unit bus bars, and the live to the overcurrent devices in the Victron panel.
Another issue with the Victron ESP AC panel is that the rear of the panel is entirely exposed. Touching a live positive terminal on a 24v DC supply doesn't give any shock unless your hands are sweaty (electrical wiring can be pretty exciting) and you're also touching the negative, even then it's more of an uncomfortable tingle. Touching the live terminal on an AC supply is not so forgiving. Not wishing to repeat the experience of getting a 240v powered slap in the face, I fabricated a cover to go on the rear of the panel.
I fabricated the box from 3mm PVC, which as well as being extremely cheap, is also easy to glue using commonly available solvent weld, normally used for bonding pipes together in waste water systems. I fitted a grommet to the bottom of the box and glues the enclosure in place using double sided foam tape.
The small recesses in each corner are to ensure that the screws holding the panel in place are outside of the enclosure, reducing the risk of the live cables chafing on the screw end and turning the body of the truck live (for a split second until the RCDs does its job.
Given that it took me less than an hour, and about £5 in materials to make the box, it seems strange that Victron do not offer something equivalent.
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