The Conversion of my 86 Crown Supercoach

[flattracker]

I have been researching the charge controller I have to find a manual for it and found a youtube video stating it is actually a PWM type controller. KeyWest is correct about the inverter being unhappy with that voltage. With the battery voltage that high it sets off the high volatege alarm and does not run.

I am also troubleshooting a problem with the 8D batteries for the bus. The RV electrical system is isolated from the bus electrical system so any problems with them aren't related. I have been seeing low battery voltages for the bus batteries. The bus will start up fine even so, but I need to see why they have been low. The day before yesterday I had the solar panels disconnected from the RV charge controller and temporarily connected all to the charge controller for the bus batteries. I came back to the bus in the later afternoon and found battery voltages at about 12.5 volts. The sun angle was down enough that the panels output was down, but I expected higher battery voltages. I had an 8D battery that has been sitting for more than a year that was extra so I brought it with me. I disconnected both 8D batteries in the bus and removed and replaced the upper one with the spare, which read 12.2 volts. Hooked up to the solar charger with just two of the panels I read 13 volts. after a few minutes, I started the bus with the one spare battery, no problems. I brought the upper battery home and will check its voltage before going back to the bus. I also assured that there is high resistance at the battery connections with no battery connected and the key off. I did find that the "map light" switch was on and this did put a load on the batteries (and turned it off). I then remembering that I had turned on the light the night before. I don't think that a single 1156 lamp would drain 2 8D batteries very fast though. Today's troubleshooting will tell.
Note: My solar power system is set up so that two panels can be switched over to a second charge controller to charge the bus batteries or connect all five to the primary charge controller for house battery charging.
The secondary charging system seems to be working OK.

 

[flattracker]

The conversion of my 86 Crown Supercoach

I finally have a picture of the terminal block all connected with the solar panels and charge controllers. The wiring looks a little like a rat's nest due to variations in wire length. I had some ambiguity when it came to wire lengths running down most of the length of the bus as well as across the bus inside so this caused some of the unkempt appearance. Maybe later I will shorten some of the wires to provide a better appearance. The terminal block is securely attached to the extruded channel mounted above the windows. It has two bus bars, one for all negative connections and one for most of the positive connection. The fifth one from the left is connected to panels 4, 5 and the secondary charge controller through a DPDT switch. This setup allows for connection of two of the panels to charge the bus starting batteries. If I want some extra boost I just stick a small jumper between the 4th and 5th terminals and all panels charge the starting batteries. I am still waiting on the replacement charge controller so the house batteries are not getting charged for the moment.
I am reasonably convinced that at least one of the 8D starting batteries for the bus is bad since it has been dropping its voltage one day to the next with no connections to it. My next trip to town I will be getting a specific gravity tester that will probably reveal any bad cells.

 

[Iceni John]

I have decided in the future that I will do the wiring re-work at night because I kept getting electrical shocks from the array. The voltage doesn't get higher than 26 volts but it is enough to let you know when you complete the circuit.

Do you have individual fuses for each panel? My Sharp 255W panels' data sheet specifies that each panel needs a 15A fuse. Each of my two arrays is four panels in parallel, and I made a simple combiner box for each array that has four AGC fuse holders in it; the combined outputs are then fed through the roof ribs by two 4AWG cables to a circuit breaker box with two 50A breakers for the arrays' inputs to the charge controllers and two 80A breakers for the outputs to the house batteries. This way I can isolate individual panels if needed, and I can isolate each array and each charge controller.

John

 

[Iceni John]

I have been researching the charge controller I have to find a manual for it and found a youtube video stating it is actually a PWM type controller. KeyWest is correct about the inverter being unhappy with that voltage. With the battery voltage that high it sets off the high volatege alarm and does not run.

If you can use true MPPT charge controllers (if you have the space for them), you will be able to harvest considerably more power from the panels. PWM CCs can only reduce the panels' voltage; they cannot increase the panels' current. MPPT CCs will convert excess voltage into extra current, thus maximizing power output to the batteries. PWM CCs are adequate for low-power systems, but for systems over several hundred watts they waste too much power.

John

 

[flattracker]

The conversion of my 86 Crown Supercoach

Today I wanted to complete some woodworking before the rain came tonight, with work on the bed. Wood working is not my strong point but simple tasks I can get done.


I also wanted to run wiring for a small inverter to be mounted in the bedroom wall for a backup means of running my CPAP machine. I ran a second 10 gauge wire along the main DC bus cabling as my calculations found a 500 watt inverter could pull as much as 45 amps at 12 VDC. Since 10 gauge wire is rated for 30 amps I figured two runs would safely handle that without too much voltage loss or heat. Where the main DC bus goes through the floor to the trunk, these wires go up to the rear of the bus, back of the bed.


One of my changes to the bed is to provide storage underneath it in the pedestal. To make that work I added 5 1/2 inches of height to it and cut openings in the front for access underneath. To accomplish this I added a layer of 2 x 6 boards fastened to the first layer of the framework of the pedestal with steel brackets fasted with wood screws.


The upper half of the bed is fastened to the pedestal with wood screws also.
The bed was partially dismantled to allow access for running the main DC bus wiring to the trunk.


The right picture is of the bed as initially installed (the day after).

The left picture shows the pedestal as it is now. The bed was being held up with straps attached to the end of the extrusions above the windows.

The wiring to power a small inverter at the rear of the bus is visible at the left in the picture.
The pedestal will be painted black and the bed frame will be finished in clear urethane.

 

[flattracker]

The conversion of my 86 Crown Supercoach

Today, some more progress in the bus:


The bed is now assembled, secured to the floor and ready for sanding, painting and urethane finish.
The pedestal will have two large drawers that will be useful for storing bedding and maybe towels and such. I figure there is no such thing as too much storage in a skoolie.
The pedestal will be painted gloss black and the upper portion will be finished with clear urethane.

 

[KeyWestPirate]

If you can use true MPPT charge controllers (if you have the space for them), you will be able to harvest considerably more power from the panels. PWM CCs can only reduce the panels' voltage; they cannot increase the panels' current. MPPT CCs will convert excess voltage into extra current, thus maximizing power output to the batteries. PWM CCs are adequate for low-power systems, but for systems over several hundred watts they waste too much power.

John



True,, and another thing: The MPPT controller will start charging earlier in the morning, and continue later into the afternoon.


They can be fine tuned to the needs of your system.

 

[Iceni John]

Today, some more progress in the bus:


The bed is now assembled, secured to the floor and ready for sanding, painting and urethane finish.
The pedestal will have two large drawers that will be useful for storing bedding and maybe towels and such. I figure there is no such thing as too much storage in a skoolie.
The pedestal will be painted gloss black and the upper portion will be finished with clear urethane.

Are you still going to keep the rear heater where it is now next to the E-door? Won't it be blocked by the driver-side drawer under the bed?

When I constructed my bed I also made lots of under-bed storage there, but I moved my heater so it's now on the centerline of the bed. This way, when it's working the heat blasts down the full length of the bus, and I still have a useful amount of storage space around it. I actually had to slightly shorten the heater's coolant hoses, and it wasn't too hard to relocate it.

John

 

[flattracker]

The heater that was present in the image from when the bed was first installed has been removed and a replacement non duct-ed heater will be installed. I still have the heater but it would only be useful when the engine is running. The replacement heater runs on propane and will be mounted inside one of the closets within a compartment that meets the clearance requirements of the heater. This location is actually over one of the wheel wells.

I have already run the gas plumbing for it. Crown placed the original heater right in the way of the emergency door at the rear. The bed is partly in the way but the door is more accessible now.

 

[flattracker]

The conversion of my 86 Crown Supercoach

More progress on the "new Crown" today.
I put urethane on the upper part of the bed the other day and now it is cured. I fixed up the right rear corner of the bed to be properly aligned and put the mattress back on. Before re-installing the mattress, a much needed cleaning was done on the floor of the bus. bringing the mattress from the front room to the bedroom was done by putting a tarp under the mattress on the floor, attaching some wire to the eyelets of the tarp and dragging it back. Even after cleaning and vacuuming the floor would have added a lot more dirt on the mattress so this approach worked well. A picture of the bed as it is now is included with this post



I added a length of uni-strut between two of the installed vertical strut in the kitchen to provide a channel for wiring for the left side of the bus. Another length will be added in the right side of the kitchen for the same purpose. I will get pictures of that later.



I punched a couple holes in the electrical box for conduit to carry the wiring to the above window extruded channel on the right side. There is bunches of room in there to add some more wiring. The front room will get a couple outlets added in that channel also.

 

[flattracker]

I have a small request for recommends for an MPPT charge controller. I replaced the main charge controller in the Crown and the replacement isn't working well either. I am looking for a reliable MPPT charge controller with a 100 amp capacity, in a 12 volt system. The open circuit voltage of my panels as about 26 volts. With two of the panels connected to the secondary charge controller that charges the bus batteries the battery voltage is staying about 15.5 volts DC, but bringing them on-line so that all five are connected to the main controller, the voltage will get to 16 volts, and the inverter goes into over-voltage condition.


The expected maximum current from the panels would be less than 80 amps.



I am willing to spend maybe $300 if I have to. Any suggestions?

 

[Iceni John]

People who use fan-cooled charge controllers report having more failures than folk with convection-cooled (i.e. no cooling fan needed) charge controllers, especially in dusty deserty conditions (Burning Man, I'm looking at you!). The fans draw in dusty air that can coat the electronics and lead to greater heat buildup due to the dust insulating them. This was one (of several) reasons that I chose Morningstar's charge controllers: they have a huge heatsink that easily dissipates whatever slight heat they produce. So far, so good.

John

 

[flattracker]

Last night I found a copy of an older Crown Bus manual in one of my book cases. Would there be any interest in copies of this? For those who have not seen a Crown bus manual, they were produced for individual buses. Some parts were common the all the Crowns of the time but other parts had factory manuals supplied by various component manufacturers who supplied the various parts for the bus. I am not sure of the vintage of the manual but I thinks maybe 60s maybe.

 

[Iceni John]

Last night I found a copy of an older Crown Bus manual in one of my book cases. Would there be any interest in copies of this? For those who have not seen a Crown bus manual, they were produced for individual buses. Some parts were common the all the Crowns of the time but other parts had factory manuals supplied by various component manufacturers who supplied the various parts for the bus. I am not sure of the vintage of the manual but I thinks maybe 60s maybe.

If you're a member of the CCJ forum on Facebook, you could mention it there. I have the Service Manual and Parts Catalog for my bus, and they're indispensable when working on it and doing a conversion.

John

 

[flattracker]

The conversion of my 86 Crown Supercoach

An update on my solar power system:
A picture of the "dead soldiers", all of the charge controllers that failed while charging the batteries in the Crown. The other day I was checking the photovoltaic panel voltages and found they had reached 30 Volts DC. I think that the panel voltage was just too high for the controllers. I never reached the current limits for any of the controllers.
The smallest cheapest controller lasted the longest.
The top controller was rated for 80 Amps, but my array isn't capable of generating that much current flow even with all five panels in parallel.
The second controller was rated for 100 Amps and failed within a day or so.
The third controller failed the first time it saw a good sunny day of charging.


The top two controllers were connected to take power from either three of the panels or all five panels through a toggle switch, and charge the batteries in the trunk (house batteries). The bottom controller was connected to two panels through the toggle switch to charge the bus batteries. The two panels collectively would provide about 400 watts at maybe 24 Amps of current flow.


The bus battery charging system connecting to 2 panels now has a PowMr 60 Amp 12V/24/36/48V DC MPPT Solar Charge Controller. This controller is rated for 60 amps of current flow, more than twice the expected current from the panels. The maximum photovoltaic panels voltage rating for the controller is 48 Volts DC connected to 12 volt batteries.



The main solar charging system now uses a PowMr 100A MPPT Solar Charge Controller 12V 24V Solar Panel Regulator. This controller is rated at maximum 48 Volts DC from the photovoltaic panels with 12 Volt batteries, and 100 amps of current flow.


So far both systems are working well. The house batteries are staying at 14 Volts and the bus batteries are now 13 volts.


Since I was at the bus last we got about a foot of snow so I haven't been back to the bus.

 

[flattracker]

I haven't updated my thread for a long time so I thought I would provide some current info about the project. I have gone through three winters with 1000 watts of solar on the roof and my batteries seem to be holding up fine. I start the bus every now and then and drive it around the block. It is still OK.

 

[Rucker]

Good to hear from you!