by folypers » Sun Jun 05, 2011 3:22 pm This is my very first 'adventure building'/how-the-hell-am-i-going-to-pull-this-off-project. I'm from Belgium, so sorry for any spelling or grammar mistakes. I'm around twenty years old, so I don't have enough money to buy property. And just like Jamie, I think paying rent is one of the dumbest things to do. So, I came up with an alternative!
I want to buy a coach (or a touringcar, as we call 'em in Belgium), rip out all the crap and convert it to a home. It's not a secret mountain robot laboratory, but a mobile headquarters still sounds cool, doesn't it?
It would have most modern conveniences and (obviously) an off-grid approach. That means solar panels, a wind generator, a backup generator, a motherload of batteries, big storage tanks for water, a water filterer, grey water reusal, low power, efficiency, and so on. I also want to go all-electric (besides the engine, to clarify) if is possible. Heating, cooling, and hot water will be handled with electric options and a hydronic system. A hydronic system consists of water and a heat transfer fluid. The heat transfer fluid is ran through highly absorbing tubes in the roof for warming and tubes on the bottom of the bus for cooling. Then the heat transfer fluids exchanges temperature with the water in orde to create a thermal equillibrium. The water can then be looped through tubes under the floor for warming and cooling and it can be used for showers or other hot water stuff. I've also read that a hydronic system could be used on a fridge but I'm not sure if it was water or the heat transfer fluid. I also plan thick insulation walls, reflecting paint, foil for the double pane windows or replacing the windows,... Cooking with electricity is also rough, but you could use inductive heaters, I don't know how it's called in English.
By having such a mobile headquarters I could bring power, water, maybe even construction items (?) to my future construction site AND live on site. Building a mobile headquarters would also pay off in terms of experience, which I lack at the moment
.I can't apply for a bus drivers license yet and I don't have enough money to make the conversion go fast and obviously all that I've got are ideas, no plans. So yeah, this isn't a project like the others, where there is actual progress. Only talk for the moment
I've stopped school a month ago, so I'm only working right now but I'm starting again next year. It'll be construction engineering! Hehe.Plans:
Plumbling system:
The plumbing system is going to be a part of the hydronic system from above, it's going to get it's hot water from a heat battery through a boiler and a 'solar boiler'. There will also be water reusage and water filtering to some extent.
The shower sink is going to get two (or more) drains, since the bus will not always be completely level. Kinda like this picture below, but a little bit better
Electrical system:
I'm planning a 48V battery bank. This voltage is the best choice for my all electric system. There will be less losses and heat with 2,3 kW solar power, a 4000 Ah battery bank and a 230V inverter (230V is the european voltage)
Most buses use 24V batteries for their chassis system, but it's possible to buy a switcher which will swich the way the 48V battery bank is connected and supply 24V on demand, for ignition or accesoiries.
The automotive system is made up from the ignition system, instrument panel and controls, and the headlights, taillights, turn signals, and other vehicle lights and accessories as a gps chargers, computer screens in the 'cockpit', a LED-ticker that can display text and/or destination,... The 24V automotive battery bank will start the engine. After that, the vehicle's alternator takes over. The maximum voltage of that alternator is about 29 volts, so it can only charge 24. There is also a solution to that, in the form of another switcher. I'm not sure about this yet, I'm wondering if it's possible to draw 48 volts from batteries in one configuration while at the same time charging half of those..
The 'life systems'-system will also power be powered of the battery bank, and is made up from all the stuff that can be done on 24V like pumps, vents, lighting, dc motors... But only because I don't want to constantly put loads on my inverter so it doens't have to be constantly on. Everything draws an equal amount of amps from the batteries, no matter what the voltage. Thanks to sjvs for confirming this to me.
The normal electrical system will power my appliances like a microwave, an electric cooker, a refrigerator, entertainment stuff,...
The 230V electrical system's power will come from a pure sine wave inverter/battery charger (230V) that's hooked to the 48V battery bank. This is to avoid heat loss: the higher the voltage, the less of it. My battery banks will be charged by solar panels and a back up generator, when I get enough batteries to have a 48V system I will include a 48 wind generator for a boat and a regulator/rectifier. The generator can also charge batteries or run DC systems through a converter or directly power the 230V system and finally, there will also be an exterior power (shore power) connection, that would be treated the same as the generator. There will also be sockets on the outside of the bus. A circuit panel will be connected to the 'exterior power' with a disconnect so that the panel either takes power from the shore supply, OR the genny, but NOT both at the same time...don't want any polarity or backfeeding problems that will turn my wiring or batteries to smoke! I'm also wondering if it would be feasible to attach all my batteries to the alternator on the bus...? The battery bank will eventually be composed of exclusively gel batteries or absorbed glass mat batteries.
I want to have a lot of safety, independance and automation. Examples:
- ground the interior and exterior so nobody gets zapped from leaning against the bus. Circuits that will be protected by breakers will include, but are not limited to, the kitchen area, the bath area, and any exterior outlets.
- a computer controlled generator will detect when battery levels are too low and charge them
- the genny will be a diesel, since I want to connect her to my fuel tanks, since the bus is probably going to be a diesel.
- the converters and inverters would have to be real smart so they recognize incoming power and where it's coming from so it can detect where it can deliver power where needed. If I'm on the grid, I would like run everything that's 230V directly from it and also invert the electricity to charge my batteries
- also fuses and isolators for when the automation fails, of course
List of electrical components I will need:
- solar panels (check)
- charge controller
- backup generator
- battery bank (semi check)
- a battery charger (converter)/true sine wave inverter combo!
- extension cord wiring
- breaker box
- automation stuff
- a 3 amp switching regulator, thanks corrado33!
Mechanical, structural, safety, insurance stuff and bus selection:
Here I will spend most of my money, I'm going to inform myself with local bus dealers, parts dealers, an electrical engineer and maybe an structural engineer? I really want a solid 'platform' that will last long, is safe and insulated and will be able do a lot of miles. It also has to be roadworthy and insurance-able. Since I don't have the money for it, I'm not spending my time on that right now. There will be a vault and improved locks, anyhow. And if the windows need to be replaced, I'm getting some kind of Gorrila Glass
Things I eventually want:
- - Gel batteries or Absorbed Glass Matt (AGM) batteries:
longest lifetime of all batteries, most efficient, least self-discharging, it is probably the most ideal for construction of a mobile battery bank, they can be mounted in any direction, resist vibrations, do not require maintenance, can't explode, do not vent toxic gasses and don't spill acid. And oh, they cost sh*tloads
- Maximum Point Power Tracker (MPPT) charge controller:
It is essentially an electronic DC to DC converter that optimizes the match between the solar array (PV panels), and the battery bank or utility grid.
Solar cells are neat things. Unfortunately, they are not very smart. Neither are batteries - in fact batteries are downright stupid..
OK, so now we have this neat 130 watt solar panel. The catch is that it is rated at 130 watts at a particular voltage and current. The Kyocera KC-130 is rated at 7.39 amps at 17.6 volts. (7.39 amps times 17.6 volts = 130 watts).
So what happens when you hook up this 130 watt panel to your battery through a regular charge controller? Unfortunately, what happens is not 130 watts. Your panel puts out 7.4 amps. Your battery is setting at 12 volts under charge: 7.4 amps times 12 volts = 88.8 watts. You lost over 41 watts - but you paid for 130. That 41 watts is not going anywhere, it just is not being produced because there is a poor match between the panel and the battery. With a very low battery, say 10.5 volts, it's even worse - you could be losing as much as 35% (11 volts x 7.4 amps = 81.4 watts. You lost about 48 watts.
Maximum Power Point Tracking isn't panel tracking, where the panels are on a mount that follows the sun. These optimize output by following the sun across the sky for maximum sunlight. These typically give you about a 15% increase in winter and up to a 35% increase in summer. Instead MPPT is electronic tracking - usually digital. The charge controller looks at the output of the panels, and compares it to the battery voltage. It then figures out what is the best power that the panel can put out to charge the battery. It takes this and converts it to best voltage to get maximum AMPS into the battery. (Remember, it is Amps into the battery that counts). Most modern MPPT's are around 93-97% efficient in the conversion. You typically get a 20 to 45% power gain in winter and 10-15% in summer. Actual gain can vary widely depending weather, temperature, battery state of charge, and other factors.
All recent models of digital MPPT controllers available are microprocessor controlled. They know when to adjust the output that it is being sent to the battery, and they actually shut down for a few microseconds and "look" at the solar panel and battery and make any needed adjustments. Although not really new (the Australian company AERL had some as early as 1985), it has been only recently that electronic microprocessors have become cheap enough to be cost effective in smaller systems (less than 1 KW of panel).- Cold weather
Solar panels work better at cold temperatures, but without a MPPT you are losing most of that. Cold weather is most likely in winter - the time when sun hours are low and you need the power to recharge batteries the most.
- Low battery charge
The lower the state of charge in your battery, the more current a MPPT puts into them - another time when the extra power is needed the most. You can have both of these conditions at the same time.
- Long wire runs
If you are charging a 12 volt battery, and your panels are 100 feet away, the voltage drop and power loss can be considerable unless you use very large wire. That can be very expensive. But if you have four 12 volt panels wired in series for 48 volts, the power loss is much less, and the controller will convert that high voltage to 12 volts at the battery. That also means that if you have a high voltage panel setup feeding the controller, you can use much smaller wire.
Crazy list:
- - build a tracker on my roof that tracks the sun based on data such as: latitude (gps), orientation (digital compass) and time (date and hour of the day).
- install regenerative braking!
- as much automation as possible! things like magnetic locks for remote locking/opening, automatic shutdown if batteries are in risk of deep discharges, a computer-controlled generator
- have the maximum feasible number of meter displays together with the automation controls on the dashboard, I don't want that stuff in the living area
- maybe even an 'artifical intelligence agent' running the bus with sensors and relais and stuff? I have a friend that does software stuff and he says he'll look into it
Bus conversion information:
ADVANTAGES include: body, chassis, engine, and transmission are designed and built to last a lifetime. Many call the MCI's, Prevosts, and Eagles "million mile coaches" and they are. Hollywood movie stars, rock stars, politicians, and wealthy travelers call these coaches home for much of the year so they offer the most prestigious of choices.
Bus conversions are nearly indestructible, exterior maintenance is minuscule due to solid stainless steel, aluminum or fiberglass skins. Conversions are solid, the safest of ALL vehicles on the highway for the occupants, quiet, offer a smooth comfortable ride due to air ride or torsimatic suspension, do not get blown around in bad weather, and are the best cold-weather vehicles to live in (due to the occupants distance from the ground with storage bays and additional insulation underneath).
Parts for the major brands are available for even 30 to 40 year old buses from licensed dealers. More obscure brands, those made in foreign countries and imported, and models only produced one year, present problems however.
DISADVANTAGES include: most expensive option for full time liveaboard comfort. It is easy to underestimate the total costs for enjoying this finest of motor home options. They are also huge, heavy, scary for some to drive, steer and backup.
Parts & service can usually only be obtained from big bus & truck repair shops which may be difficult to locate. Parts for less known brands may be impossible to find at any price.
Size - When it comes to buses which are going to get nothing but heavier as you modify them, longer and wider (like the 102" wide models) is NOT always better. Sure the bigger bus gives you more room, but remember the bus might have been already maxed out before you added 20,000 pounds of modifications.
Weight - Weight issues for your new coach should not be ignored, or underestimated. Build it too heavy and it won't steer right, will destroy the engine and transmission, will eat up the tires, smoke the brakes, flatten the suspension, burn extra fuel, and be slower in traffic. Make sure the company or individual had a plan for weight distribution and that they followed it. You MUST conduct a thorough test drive to get a handle on acceleration, fuel mileage, steering, braking, etc.
Useful links:
- gypsyjournal.com
- Von Slatt's bus conversion
- The Lindy Bus
- a guide covering RV fulltiming, living fulltime in a mobile home
- a Google Sketchup model of a typical bus conversion
- the Skoolie.net wiki
- lots of articles
Folypers,
Belgium
