BUBB 1990 Thomas, 72 passenger

[BUBB]

roof rack before and after side angle pieces were attached

[BUBB]

It is all installed and charging.

six 12v (18.1v) panels at 158 watts each, mounted on the roof.

four Trojan 12v batteries at 150ah each,

The 6 solar panes are hooked up in pairs on 8ga wire for 24v output, it allows me to use thinner wires without loosing efficiency.

When the panels wires enter the bus they go into a house QO panel through a 15amp breaker, (3 pairs to 3 breakers) after the breakers they leave the box in 4ga wire into a 70amp switch/breaker (not visible in the picture , extra safety and a convenient way to turn on/off the panels output. After this breaker the wire runs into the morningstar 60amp mppt charge controller.

6 panels in 12v equals 54amps output.

6 panels hooked in pairs for 24v equals 27amps output.

I used a 70amp breaker so I can use the max input of the 60 amp charge controller in 12v if I needed to.

The four golfcart wet lead-acid batteries are hooked up to bus bars at 12v so they can be charged very efficiently as one big battery. In systems without a bus bar and using more than about 4 batteries the batteries on the ends take most of the work load and end up aging faster, this is important if you use the batteries a lot but not so important if you just keep them charged and dont really tax their capacity often.

The mppt charge controller can take 24v/48v input from the solar panels and change it into 12v output to charge the batteries.

I used 2/0 cable to connect the batteries to the bus bars, each positive wire coming off the battery has a 100amp ANL fuse, the bus bar is 1.5in wide, 0.35in thick and 8 inches l long.

Between the bus bars and the charge controller hooked up through the negative wire you see a small black rectangular block with 2 big brass bolts sticking out, it is a 500amp shunt (it's the one they recommended) which allows the tristar meter to measure the amp's flowing through the system.

The gray cable you see twisted and hanging is the battery temperature sensor, the charge controller will adjust how it charges the batteries depending upon the batteries actual temperature.

The device you see with the 14.6 on the display is the tristar meter, it is not yet mounted in its box, it gives much more information then the 3 blinking lights on the charge controller.

[BUBB]

see image

[BUBB]

The solar stuff has been working well, it powers my 5000 btu window AC unit in full sun,
My six 158 watt panels regularly put out about 50-55 amps as measured at the bus bar in full sun, around 25-40 amps in cloudy weather, the AC unit on full pulls 40 amps,

I need to move the inverter closer to the batteries, it was already installed on the other side of the bus with the smaller battery bank, it looks like the 6ft long 2/0 cables which attach the bus bar to the inverter are too long and I am loosing too much voltage, the bus bar voltage will show 12.5amps while the inverter is showing 11 to 12 volts depending upon the amps being provided by the charge controller,

I had once incident of the mppt giving me an overheating error message and it started to dump most of the power, in the bright sun it should have been giving over 50 amps but was only providing about 10, I put a small Dc powered fan near the mppt and it cooled it off quickly, I could only touch the heatsink for a second when it was overheating, withing 2 minutes it was much cooler, probably down to 90 degrees or so and its power output went up to max again, the overheating happened when the I had just opened up the bus and it was probably still 120 degrees inside the bus,


I have ordered a small 12v temperature controlled switch so I can attach it to the mppt heatsink and the fan, it can then turn the fan on and off as needed.

[BUBB]

5000 btu AC unit with 7in diameter vent installed,

[BUBB]

Panels from beneath, you can see the small metal angle piece that I put under the black j-boxes to keep them from flopping around, I still need to finish covering the wires to protect from the weather.
You can also see (barely) the box with a compression fitting that the wires go through to get inside the bus.

[BUBB]

full length roof rack seen from ground,

[bansil]

I like the solar install and how good it works...Why are the posts missing between updates?

anyways...good job

[claydbal]

great to hear the system can run the A/C! can you give more detail? how many hours per day do you think you can run A/C off this current system and still have battery power for the night?

[BUBB]

The AC unit pulls about 45 amps dc, my solar panels provide up to 55 amps measured at the batteries, I have four 150ah batteries, I can run the AC unit during daylight only, the panels must be providing at least 30amps for the inverter to provide the amps and to keep the volts above 11 or the inverter shuts off. The AC unit is only large enough (5000 btu) to keep the cab cool, about 7ft by 7ft, I have tinted the windows and installed roll down shades, without the blackout roll down shades it would not cool the cab, the panels cover about 5ft by 12ft, I imagine I would need to triple the panels and batteries to run the AC 3 hrs during the day and 2hrs at night while keeping the batteries charged daily, assuming a Texas summer
600 ah divided by 45 amps equals 13.3%
So the AC unit pulls 13% of the full batt capacity but 26% of the available batt capacity, which means the 600 ah batt bank only has 300ah available to be used without damaging the battery, this bank is all I can afford now and it is barely large enough to run the AC unit.

[claydbal]

thanks for the reply bubb. the holy grail seems to be able to support A/C on solar. 3 hrs may be enough (if started after sundown) to cool the bus so one could sleep.

[aaronsb]

Have you looked at these DC split units? They seem really efficient.

http://www.geinnovations.net/HSAC_Productline.html

Originally Posted by BUBB

The solar stuff has been working well, it powers my 5000 btu window AC unit in full sun,
My six 158 watt panels regularly put out about 50-55 amps as measured at the bus bar in full sun, around 25-40 amps in cloudy weather, the AC unit on full pulls 40 amps,

I need to move the inverter closer to the batteries, it was already installed on the other side of the bus with the smaller battery bank, it looks like the 6ft long 2/0 cables which attach the bus bar to the inverter are too long and I am loosing too much voltage, the bus bar voltage will show 12.5amps while the inverter is showing 11 to 12 volts depending upon the amps being provided by the charge controller,

I had once incident of the mppt giving me an overheating error message and it started to dump most of the power, in the bright sun it should have been giving over 50 amps but was only providing about 10, I put a small Dc powered fan near the mppt and it cooled it off quickly, I could only touch the heatsink for a second when it was overheating, withing 2 minutes it was much cooler, probably down to 90 degrees or so and its power output went up to max again, the overheating happened when the I had just opened up the bus and it was probably still 120 degrees inside the bus,


I have ordered a small 12v temperature controlled switch so I can attach it to the mppt heatsink and the fan, it can then turn the fan on and off as needed.

[BUBB]

I have a dozen hours of searching for dc units because they are at least 20% more efficient depending upon the particular unit, the problem is their prices start at about $2000,

[BUBB]

I am adding a second fuel tank, will have pictures tomorrow,
Comments and suggestions are welcome,
It is a 75 gallon tank, is 13in tall, 20in wide, 66in long,
I will hang it on the drivers side frame, the main tank is on the passenger side, I wanted to spread the weight around.
I will bolt a total of 4 vertical supports to the frame,
The main tank is about the same size, it has 3 L-shaped supports, the 12 bolts holding this other tank onto the frame are good for about 27tons so I am doing the same for the auxiliary tank.
The two end vertical supports will be 3in angle, I will then add a 22in long vertical support of 2in angle for the tank to sit on, I will then add a 45 degree piece of angle so the shelf holds up the weight,
Between the two end vertical supports will be two 2in angle vertical supports but these will be on the inside of the frame opposite of the tank, I will still add a 2in angle horizontal support to the bottom of these supports to support the tank but then I will put a 3in metal strap over the tank to attach/tighten the tank, the 3in strap is 3/16th thick and will have two 3/8th inch grade 8 bolts on each end of the strap.
I then plan on adding another piece of 2in angle to the end of all the horizontal shelf pieces to keep then from swaying,
It will be an auxiliary tank that needs an external pump to put fuel into the main tank, at least for now.
I added a few pieces of 1x5 boards between the tank and frame to keep it away from the bolts, I added a few pieces of 2x4's above the tank to fill the void that will occur when it is mounted.
So far I have almost completed bolting the 4 verticals to the bus frame.

[BUBB]

I attached a picture of the beginnings of the fuel tank mount,
You can see at the far end of the picture the 3in angle piece bolted in place,
You can see the 3 red pieces of wood that will act as bumpers to keep the tank from grinding on all the bolts sticking out of of the frame,
Between the red pieces and on the inside of the frame you can see two brown pieces of 2in angle,
You can see black marks drawn on the angle beams, these are how far down the tank will hang,
All these vertical frame pieces will have a horizontal piece bolted to the bottom to act as a shelf to set the tank in,
At the top of the picture you can also see the two brown 2x4's I bolted to the "floor" of the bus to fill the void that will be above the tank.

[BUBB]

added extra fuel tank, ~70 gallons,

[bubb, the real one]

I don't know what happened for sure but the email and password on this acct got changed, this thread is dead, if anyone posts as "bubb" it is not me, my new thead will be "bubb, the real one".

[M1031A1]

Originally Posted by bubb, the real one

I don't know what happened for sure but the email and password on this acct got changed, this thread is dead, if anyone posts as "bubb" it is not me, my new thead will be "bubb, the real one".

I know the feeling, I had to do the same, just made my new acct. with the standard military modification......

[bubb, the real one]

I have already posted pictures of each end of the fuel tank mount, the tank is held on with 4 vertical pieces bolted to the frame, this is one of the two verticals that are bolted to the inside of the frame, 2in square tube at 11ga, it has 2 bolts that are 3/8in and 4 bolts that are 1/4in connecting it to the frame, and two 3/8 bolts connecting the horizontal to the vertical piece, all are grade 8 bolts.
Each of the 4 verticals have over 10 tons of bolt strength, which is similar to my calculations for how much bolt strength is on the original fuel tanks 3 hangers,
You can see 2 chains in this picture, the top chain has a 1/2in bolt holding it to the frame, it is the one that goes over the tank to the other end of the horizontal piece, the lower chain connects the frame to the vertical piece so the vertical piece can not slide down the frame piece.

[iBiskuit]

Originally Posted by BUBB

5000 btu AC unit with 7in diameter vent installed,

Where did you get your clear lights that replaced the flashers?


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