Description of the electrical system

The house battery is 220ah deep cycle lead acid.

They are charged by 3 sources - engine, solar of hook up charger.

Engine. There are 2 alternators. The original Mitsubishi 24v alternator, which charges the engine 24v starter battery, and an additional 12v Bosch alternator on its own separate pulley. The cable from this goes via a beaker switch in the engine compartment, to the bus bars in the cupboard, and then via the common cable to the house battery. This will charge the house batteries while driving, and the power delivered should be visible on the display. It's all automatic.

Solar. There are 4 panels on the roof. 2 240w panels in series at the back, and a 150w and a 120w in parallel in front down the side. The two big panels are fed into the larger of the 2 Epever controllers, and the two smaller panels into the smaller one. The output of these is in parallel and fed to the busbars in the cupboard, and then down the to the battery. It's all automatic. You will see the power delivered on the display.

Hook up charger. When plugged in, the blue Victron 30a smart charger in the cupboard is also live, and this will charge the house batteries in the same manner. 

Display. The display is a battery monitor, it is fed by a sensor on the negative of the house battery. This is the small white box on top of the battery. On top of the small white box is a switch. The switch enables you to reset the box. Switch it off, count to 5, then back on again. There is no wiring between the sensor and the display - it's wireless. Occasionally it gets its knickers in a twist and needs resetting - that's why the switch is there. It's a cheap chinese unit that I installed to experiment with. It's not as perfect as the more expensive ones - Victron etc, but it does the job. If it ever needs replacing, suggest the Victron BM, or the Nasa BM1, around $200.

It is important to remember that the display is a guide, not an absolutely accurate device. The percentage display and the bar graph display, are approximate not absolute. But the voltage display is accurate. Also you need to remember that the display will only display the number of amps that are going into the battery, minus what is going out. If the house battery is fully charged, it will often display zero. So don't be worried if in bright sunshine, the display says 0 amps - this is normal - it means the battery is fully charged. A full battery will not take any more charge.

The battery voltage will always be higher if any charge source is running. But at night, when there is no charge source - ie it's dark so no solar, no engine and not plugged in, the battery voltage is an accurate indication of battery state of charge. This is known as the resting voltage. A good habit to get into is to check the battery voltage last thing at night before bed. 12.8v represents a fully charged battery, 12.4v is 50% and 12.0v is almost fully discharged. If the voltage at night starts to approach 12.0v, then you should think about reducing usage, and also think about where tomorrows charge is going to come from - either sunshine, driving or plugging in.

Solar power is entirely dependent on the weather and the time of year - the amount of power you get from solar can vary from almost nothing in cloudy midwinter, to more power than you need in summer.

In summer, you can stay off grid almost indefinitely - the panels are big enough to fully recharge the batteries within a few hours, no matter how much power you used the night before. But in mid winter it's different. Off grid, you might get very little charge from solar, so you have to plan accordingly. A fully charged house battery should last you between 2 and 4 days, if no solar is available. This depends entirely on how much power you use. So your best friend is the battery monitor display.

You should avoid running the battery below 12v, although down to 11.5v is ok, as long as you don't make a habit of it.

However there is one additional system you can use for emergency power.

This involves taking some house power from the engine battery. This is a huge 200ah 24v battery that does nothing except start the engine, It has lots of power that you can tap into. But of course this is generally regarded as bad practice, because careless use means if you run the engine battery down too much the bus won't start. 

When I first bought the bus, it had quite an old low power solar system - the original owners did not use the bus much in winter, and used camp sites a lot where they would plug in. But we prefer freedom camping. But as autumn went into winter, it soon became obvious that the solar needed upgrading - we use a lot of power, laptops and TV etc. But at that time we did not know how long we were going to be in NZ, so not sure if we could justify the cost of a big solar upgrade. So as a temporary fix, I decided to tap into the engine battery. To do this I installed 2 small Victron devices. One is a 10amp 24 to 12v converter, and the other is a battery protect device. The battery protect will cut in if the engine battery falls below a certain level. This is to solve the problem of using too much engine battery power, or forgetting to switch it off. So when switched on, a small amount of engine battery power gets fed into the house system. This does not recharge the house battery, all it does it power the house, which stops the house battery discharging any more. 

It actually works very well - the engine battery is equivalent to 200 amp hours of 12v power. With the TV and lights on at night, the house uses around 5a. So in theory, the engine battery can provide many hours of house power. In practice, we have only ever used it for a few hours at a time. If we are freedom camping in winter, and watching TV, and we notice the voltage going down towards 12.2v, then we just switch it on for a few hours before bed. Then the next day we see how much solar we get, check the weather, and then decide what to do. 

But then after a few weeks we got more visa time, so I went ahead and upgraded the solar panels anyway. So now, in practice, this emergency backup isn't needed any more. But I have left it installed - to uninstall it would be a waste of the two devices, and it's a useful thing to have in emergency.

To use it, there is a switch i the cupboard marked 24 - 12 Boost. It should not be switched on unless the voltage is well below 12.5v. 12.2v is probably the best figure. When switched on - there is a bright red light which comes on under the display - this is a good reminder that the system is on - you can't miss it! When switched on, the display will settle to 12.5v, and the amps should go to zero. This is because the display measures the house battery, not the engine battery. So zero means that the house battery is no longer discharging.

We have only ever used it for a few hours at a time - even a full evenings TV, say 6 hours, would only use around 15% of the engine battery.

If all this sounds a bit complicated, I'm sorry, but my speciality is 12v electrics, and I know what I am doing. The system should be fool proof. But as I said - it is now mainly redundant because there is now 600w of solar on the roof, which should provide enough charge, even in winter. But occasionally, circumstances might mean you want to stay off grid for a couple of extra days, and want to keep the TV on, and in this case, if the house battery voltage is running low - ie 12.2v or below, then it's a useful thing to have. And of course, you don't even have to use it - it's up to you.

Miscellaneous notes on the electrics.

The house batteries need topping up with water every 2 or 3 months. Undo one cap, use a small mirror and a torch, if you can see the plates, add about 100ml to each cell.

Inverter. The inverter is in the cupboard under the radio at the front. It powers the twin sockets under the table. It is a 300w inverter and is powerful enough for laptop chargers - which is why it is there. It is not powerful enough for anything high powered. That means anything that produces heat - kettles, fan heaters, hairdryers etc - do not try and use these. If you do, the unit will bleep and cut out. The switch to the left of the radio switches the inverter on and off, which also resets it. These sockets are for your laptop, and any small device charger - phones, pads, the rechargeable vacuum cleaner, electric tooth brush charger etc. It will also power the desk top fan. In hot weather we set this up on the front dash for a cool breeze. The fan uses very little power.

When you are plugged in, then the two sockets above the drawer unit become live - you can plug anything into these, when plugged in, that you would use in a house. This includes fan heaters if you so desire. There is another set of sockets in the bottom cupboard under the kitchen drawers next to the fridge.

The switch panel. This is the switch panel for all the 12v house equipment - lights pumps etc. To the right there is a breaker - this cuts 12v power to the van, and is for emergency use only. Most of the time you will hardly touch the switches. the only ones you will need to use regularly, are fridge fan 2, which is an extra cooling fan for the fridge for use in very hot weather. Fridge fan 1 stays on all the time, and is inaudible. The other switch you will use is Awning light - this switches the outside awning light,a nd also the porch light inside. The porch light also has its own switch.

All the other switches should be on. They are only ever needed if you want to isolate one circuit for work or maintenance. Each switch is fused - fuse failures are rare, but there are spare fuses in the cupboard.

The switch with red tape is important. It feeds power to the side of the van - which is the TV and internet router etc. It also powers the diesel heater. The red tape is there as a reminder. You should NEVER switch this switch off if the diesel heater is running. The diesel heater has to run through its cool down cycle when it is switched off at the control unit, or by the remote. If you remove power to the heater while it is running, then it will overheat and fry the circuit board. That's why the red tape is there.

The electric cupboard has a cooling fan. It is automatic. If the temperature in the cupboard rises above 30 degrees, the fan starts. It draws cool air from the bottom cupboard louvres, and up and out through the top cupboard louvres - very clever. So if you hear a fan noise from the cupboard in hot weather, that's why. The blue charger also has a fan. If this fan annoys you, it has a night mode, which cuts the fan - see the Victron manual.

Above the kitchen are the controls for the water heater and the water pump and gauges. Also the original gas heater which is under the bench below, This is a Propex 2kw gas heater. It works fine, but is noisy, and just not powerful enough to heat the van quickly. That's why we installed the diesel heater under the opposite bench. It is 5kw and much more powerful. It is noisy on startup, but soon settles down, In all but the coldest weather it keeps the van warm on its lowest and quietest setting. You can increase the setting with the remote. 1.0 is lowest 5.0 is highest. The most we have ever used is 3, and then only for 20 minutes! 

If you ever get an error on the display, that is usually because the heater air intake, at the back, has become clogged with dust. It's a 1 minute job to remove and clean, needs doing once a year.

The diesel heater draws air in though the bottom vent, heats it, and blows out through the top vent. 

In very cold weather it is fine to leave it on all night.

Because the bus is rear engined, it doesn't have a cab heater for driving. The controls and fans are just for ventilation. The diesel heater works great while driving in cold weather.

Lights

The bus has good lighting - there are led spot lights and strip lights everywhere, all individually controlled.

I have also installed led strips along the curtains. These are controlled by the remote. It is a 4 zone remote, but only 1 zone is used. To get white light, you press and hold the on button, and no matter what colour it was set to, that will switch it back to white. You can select colours modes and intensity with the other controls - play with it for a while and you soon get the hang of it. The controller for the led strips, if you ever need to get at it, is hidden behind the front left speaker.

TV

The TV is brand new. It does normal TV, satellite, and DVD, it is also a smart TV, but I have never used that feature. The satellite dish is a standard manual one, the same as most Kiwi caravans and campers. It's getting a bit stiff. We don't use it very often because we used an Amazon Stick for TV, and I'm taking that back to UK with me.  The dish had a brand new LNB 2 years ago.

Basically you wind the dish up fully, then back 2 turns, set the TV satellite channel so you can see the signal strength meter on the screen, then rotate it slowly until you get a signal. It's a bit awkward at first, but I can't tell yo much more than that, other than the fact that it works. Probably best to get somebody who has a similar system to help and show you. But I can set it up and will show you it working.

Radio. The radio is pretty standard. The manual is in the documents. It has a useful feature in that if you plug a phone into it, you can play music from the phone.

Fridge

Very reliable. we run it on gas all the time, even when driving. If on a camp site for a long time, you can switch it to 220v - see the manual. The fridge does not run on 12v while driving. It does have the feature, but it hasn't been connected.

Gas

There are 2 gas compartments. Front and back. The front one contains 2 small bottles which are refillable. he rear contains a standard 9kg which is refillable or swappable. There is an isolation tap in the rear, but not in the front.

We use the 9kg as our main bottle. When it runs out we switch to the front. When that runs out we switch to the other front bottle. Then we have 2 bottles to refill. When we refill, we switch back to the back bottle. Then repeat. If we can't refill, we just swap the back bottle.