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Tales of the travels, trials and triumphs as we explore Australia in a converted bus

Motorhome Tour - The motorhome electrics


The electrics of Hobohome are quite complex - I enjoy making the electrical systems in the motorhome as functional and as automated as possible. I am an electrician (from many years ago) and have a keen interest in microprocessor based electronics. Much of the motorhome's electrical systems reflect this interest.



The roof of the motorhome - [Click for a Larger Image]
The roof of the

The vast majority of our electricity needs are met by the solar panels mounted on the roof of the motorhome. I think we have panels from almost every manufacturer - not by choice, but simply because they were purchased at different times and from different suppliers. There are two 80 watt BP solar panels (the orignals), four 64 watt Unisolar panels, two 85 watt Kyocera panels and four 64 watt Sharp panels (total 842 watts at 24v). These charge the two 12 volts deep cycle 'House Batteries' via a Plasmatronics PL40 solar regulator.

The solar regulator also serves as a status display showing the current discharge or charge rate, the current battery voltage and the number of amp-hours in and out since midnight.

We have also added a Xantrex battery monitor - this is a wonderful device that provides all the information regarding battery status and condition you could ever want. You can read more about this device here.


There are three separate banks of batteries. One bank (the "Crank" batteries) is reserved for starting the motorhome engine. The second bank of batteries are known as the "House Batteries". These are 2 X 240 amp-hour 12-volt Gel batteries connected in series to provide 24-volts. These batteries replaced the old flooded cells in 2008. These batteries provide power for all of the motorhome equipment (like lights, computers, fridge, the inverter etc). The third battery system is for the winch (to get the Moke in and out of the back). This is 12 volt system and is trickle charged whenever the engine is running, or by turning on a switch on the dash. The same trickle charger provides a tiny current to the battery in the Moke. This keeps this battery topped up even if we do not use the car for months at a time.

When the engine is running, I am able to charge either the house or the crank or both banks from the massive 140 amp 24v alternator. The alternator regulator can be adjusted to raise the charge voltage by up to 1.2 volts for quick charging the deep cycle house battery bank.




High output LED spot light - [Click for a Larger Image]
High output LED spot

All of the lighting in the motorhome is 24-volt and most of it is fluorescent - there are a few LED spot lamps and the outside lights have also been converted to LED. I must say that I have had some trouble with the LED lighting. Some of the M16 lamps do not like a regulated power-supply. As almost all of these lamps available commercially are designed to run from 12 volts, I have installed a tiny voltage regulator into the base of the light. This regulator convertes the 24 volt power supply to 12 volts for the lamps. I feel that further smoothing is required to stop the high instantanious voltages from damaging the LED lamps.


240v Inverter/charger

The inverter (the device that takes 24-volt battery power and converts it into 240-volt mains power) is a "Trace-DR Series" 1500 watt unit. This unit also incorporates a microprocessor controlled three stage smart charger. When the motorhome has external 240-volt power attached (either mains supply or generator) the inverter starts charging the battery bank. While the inverter is a modified square wave inverter (as opposed to the favoured "True sine-wave" type) I feel that it is a very good unit for this type of application. Trace now also make a true sine-wave version that is slightly more efficient and a bit easier on high-tech gear (and of course more expensive).



Honda 210i Inverter Generator - the motorhome backup power supply
The 2Kva Honda backup generator

For when the sun won't shine! We have a small Honda 2kva inverter generator as a back-up. These units are great, they are whisper quiet and are very easy on petrol. When connected it is able to charge our house batteries at about 30 amps via the inverter/charger. A transfer relay detects 240v power either from the generator or external power and switches the inverter to that source automatically.






Hobohome Tour


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The Mechanics

The Engine Bay The Engine Bay
Driving Area Driving
Living Area Living Area
Kitchen Kitchen
Bedroom Bedroom
The Electrical System Motorhome Electrics
Changes made Changes
Fuel Economny Changes




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