The Conversion of my 86 Crown Supercoach

[DeMac]

Start Capacitor

I believe I now have an answer as to why the 400 Watt and 500 Watt inverters could not power my referigerator.
Using an extension cord with the wires separated to allow the use of a clip-on ammeter I powered the fridge up using the 3000 Watt inverter and measured the current flow using the ability of the meter to show peak current flow.
I measured 9. Amps in a surge of current flow. 9.2 amps at 115 volts AC = 1058 watts.
The 400 Watt inverter is rated for an 800 Watt surge, so a nogo is expected there.
The 500 Watt inverter is rated for a 1000 Watt surge, so that one cannot handle the load either.
I did not expect a surge that large for a referigerator the the manufacturer says uses 1.4 Amps running.
I now think a 600 Watt inverter would probably work, but that leaves a small margin for error. Probably 800 to a 1000 watts is a reasonable starting point but the law of diminishing returns is starting to come into play.



Is the efficiency of running a 1000 Watt sine wave inverter running a device that has asurge current of 9 Amps and a running load of 1.4 Amps enough to justify the extra wiring and hardware over just running the 3000 watt inverter?


I may use the 400 Watt inverter for my CPAP, or just use the DC to DC converter made to run the CPAP. The DC to DC converter that plugs into a 12 volt socket (cig lighter) may be the most efficient way to address this.


Of course the 400 Watt inverter will be useful to charge phones, run a laptop in the bedroom, etc.

A $10-$15 start capacitor may provide the startup torque required for the fridge compressor.

Amazon Motor-Start-Capacitor 1000-1200 110v

 

[Iceni John]

I believe I now have an answer as to why the 400 Watt and 500 Watt inverters could not power my referigerator.
Using an extension cord with the wires separated to allow the use of a clip-on ammeter I powered the fridge up using the 3000 Watt inverter and measured the current flow using the ability of the meter to show peak current flow.
I measured 9. Amps in a surge of current flow. 9.2 amps at 115 volts AC = 1058 watts.
The 400 Watt inverter is rated for an 800 Watt surge, so a nogo is expected there.
The 500 Watt inverter is rated for a 1000 Watt surge, so that one cannot handle the load either.
I did not expect a surge that large for a referigerator the the manufacturer says uses 1.4 Amps running.
I now think a 600 Watt inverter would probably work, but that leaves a small margin for error. Probably 800 to a 1000 watts is a reasonable starting point but the law of diminishing returns is starting to come into play.



Is the efficiency of running a 1000 Watt sine wave inverter running a device that has asurge current of 9 Amps and a running load of 1.4 Amps enough to justify the extra wiring and hardware over just running the 3000 watt inverter?


I may use the 400 Watt inverter for my CPAP, or just use the DC to DC converter made to run the CPAP. The DC to DC converter that plugs into a 12 volt socket (cig lighter) may be the most efficient way to address this.


Of course the 400 Watt inverter will be useful to charge phones, run a laptop in the bedroom, etc.

I plan on having two small (maybe 5 cu.ft. each) chest freezers in my bus, one used as a freezer and the other used as a fridge. I was surprised to find out that they have instantaneous starting surges up to nine times their running current! For this reason I'll need a reasonably-large TSW inverter for each freezer; I was hoping to use the excellent Morningstar inverters, but they don't have sufficient surge output for small freezers. I may need to use the 1500W Samlex/Cotek TSW inverters instead, or maybe even the 2000W ones. I've heard of folk using extra-large start capacitors to lessen the surge on start-up, but I know very little about doing this.

John

 

[Rwnielsen]

I'm completely intimidated by my black tank installation. I need the dump valve to be accessible but not vulnerable. I plan on a simple water fill fitting on the outside, above it, that's plumbed directly into the top rear of the tank for flushing it out. I'm guessing I'll need a vent line running up through the interior wall through the roof. I've been avoiding this for months. Your brackets look very professional

 

[flattracker]

Thank you for the compliment. One does not need to go through the roof for plumbing vents these days. A local plumber showed me how to do another way. You can purchase a form of check valve that opens to let air flow into the drain pipes when draining water, but doesn't stay open and let stinky air into a room with a drain. They need to be high enough so that water cannot reach the opening when present in the pipes. I used two in the "new Crown", one for the washing machine plumbing and one for the sinks. RV toilets don't use a trap but a valve that closes off the smell when not flushing, so no need for one there.


I posted pictures of the washing machine plumbing a while back but can re-post one if you need.
See post 106 of my thread

 

[DeMac]

Adding... a Cap is No Bueno

A $10-$15 start capacitor may provide the startup torque required for the fridge compressor.

Only when replacing the internal start capacitor if it's bad or too small. Still won't change the start load.

Adding a capacitor before or after the inverter will not help either. Probably worsen things.

 

[flattracker]

I have a battery question regarding the use of AGM batteries with flooded deep cycle batteries.


I about a month ago I purchased a couple of the Interstate flooded cell deep cycle batteries as I needed them right away. I connected one of them up the the main DC bus for testing and performed charging tests using the RV charger and also the second alternator.


The RV charger brought the bus voltage to 13.6 VDC, and the alternator brought the voltage to 14.6 VDC.


Today I purchased an AGM version of the battery (all group 31 batteries).


My brother tells me that I cannot use both types on the (main DC) bus at the same time. What little I found on the net speaks to using starting batteries with AGM batteries (they say NO).


My brother has been using the AGM batteries in his camper using the same brand of RV charger but lower charging current OK.


Will the alternator's voltage cook my batteries? It has a current capability of 250 amps.
I am planning of 4 group 31 batteries in parallel.

 

[flattracker]

The conversion of my 86 Crown Supercoach

Some more progress on the "new Crown".
The battery tray has been fabricated and ready to be mounted in the trunk of the Crown.
Currently I have only three group 31 batteries and am waiting for a fourth one. I designed the battery tray for four total, with an expected capacity of 400 amp/hours.


Included in this post is a picture of the tray with three batteries and a 1000 watt sine wave inverter. The batteries are secured in the tray with ratcheting tie down straps from Harbor Freight. I used most of the remaining battery cable wire saved from the Crown I parted out years ago to produce the interconnect cables for the batteries.



The batteries got a test of sorts the other day, providing power for my stereo used on a float during the July 4th parade in Klamath Falls. The stereo can pull over 900 watts turned up loud (and it was) and ran for about one hour.
All worked well though.


I placed the battery tray into the trunk of the Crown and set the batteries in the tray, connected all them up and performed another test of the system. This test gave me a rough idea of how much battery was left after the hour of high current usage.
I started up the generator and powered on the RV charger and using the battery monitor observed 13.5 volts present on the main DC bus. I then started up the Crown's engine and checked the battery voltage again and observed 14.2 volts on the bus and the batteries taking a charge rate about 40 amps. I let the Crown's engine stay running for about 20 monites to observe what change in charging current i would find. After about 20 minutes the battery voltage was about the same, but the charging current had dripped to less than 20 amps. With each battery then taking about 6 amps (when the current got down to about 18 amps total) at 14,2 volts, it seemed to me that the batteries were then well charged and based on the starting charge current weren't very low at the start of the test.


Today I removed the dead 300 watt inverter from the mounts and connected the 1000 watt inverter in its place. I plugged the refrigerator in to it and monitored the results.
Initial power-up of the fridge upset the inverter, and a second try came up with better results. The inverter seemed to power the fridge OK. The inverter has a display (with a weak backlight) that showed power consumption in watts but it had inconsistent readings. The battery monitor showed about 114 watts being used from the battery, and about 9 amps of current flow from the batteries. I left the fridge running for the night to see how much battery will be left in the morning. Once I have recovered the batterioes state of charge I will repeat the test but run the fridge from the 3000 watt inverter to see what difference in power consumption I will see.
It will be interesting to see how long battery recovery takes running the Crown's engine (charging the batteries from the second alternator).


I did some finish work on the solar panels on the roof of the Crown today. All the masking tape is now removed as well as the thin plastic film from the panels (shipping protection film). I will get some pictures of the solar panels tomorrow.


Tonight I started extracting the circuit breakers from an electrical panel from a C2 aircraft (I believe). Some nice things about using electrical panels from aircraft is good breakers fro DC operation and the use of small "bus bars" that were used to provide power to as many as six breakers in a row. Short interconnect wires that go from one place to another in the panel are real handy also. I got more than enough 5 amp mil-spec breakers, a 1 amp breaker, and a couple real nice double throw double pole 20 amp switches also.
See the pictures for that also.

 

[flattracker]

Today some pictures of the solar panels:
There is a total of five, with one forward of the front air conditioner, and the other four between the air conditioners. They cannot be seen from the ground, which I like. The black wires will have white heatshrink surrounding them. I am using pass-through covers with gland nuts to seal out the weather where they go through the roof of the Crown.


Results from my overnight test running the fridge using a 1000 watt inverter running on the batteries:


The run-time of the test was about 15 hours.
Starting battery voltage was about 12.7 -12.9 volts DC?
Ending battery voltage was 12.3 volts DC. The fridge was not already cold at the start of the test.


With the fridge and inverter still running, I started up the bus and within 45 seconds of engine start, the battery monitor showed the batteries taking about 95 amps of charging current. The battery voltage at 95 amps charging, was about 13.2 volts.


After about 15 minutes the charging current got below 70 amps and the battery voltage while charging was 14.1 volts DC



After some additional charging time later to bring the batteries up to full charge, I will switch to the 3000 watt inverter and monitor the load current from the batteries to see how much difference there is.


With the 1000 watt inverter the current flow was about 9 amps at the start of the test. when I checked the current flow at the end of the test it was about 7 amps.


The current measurements aren't more precise as the current flow changed when reading the battery monitor.


In each case the only load to the batteries was the 1000 watt inverter,which in turn had the load of the fridge.


One thing I have noticed about the fridge is the first time it is powered up in a warm state, there is a current surge about 900 watts or more. Even the 1000 watt inverter did not like this.


The 3000 watt inverter was not bothered by the startup surge of the fridge though.

 

[flattracker]

The conversion of my 86 Crown Supercoach

Time for another update:
Progress on the electrical panels - some pictures of the construction of the upper and lower panels. The upper panel is the DC power distribution panel and inverter remote controls. The lower panel includes the generator remote control/monitor panel, AC voltage/current/power monitors and the battery monitor system.
The first picture is of the DC distribution panel after drilling holes for the circuit breakers, switches, main inverter remote control and holes for push button and two LEDs for secondary inverter remote control.


The second picture is of the rear of the assembled DC distribution panel (minus the remote control for the secondary inverter). The red part is a connector normally used for jumper cable connectors. Using this connector provides safety when working on the electrical system. Unscrewing the panel and disconnecting the red connector prevents unfused high current 12 VDC being shorted to ground during removal of the panel. The large connector was needed as current passing through the panel can be 70 Amps. Two switches are used as each switch is rated for 50 amps and I didn't want to have a situation with more current flow through a switch than it is rated for.


The third picture is of the hole cutting process I used for making rectangular holes for the voltage/current monitoring modules and the battery monitor module display.


The fourth picture shows the AC panel under construction. At one end is the generator remote control. Since the picture was taken additional modules were added.


The fifth picture shows the panels temporarily installed for testing. In this picture the battery monitor is on, as well as two voltage/current/power monitor running. The left monitor is not reading correctly as the inductive current sensors are not yet connected.


The main inverter is now wired to the electrical panel. Four wires connect the inverter to the electrical panel. Since the inverter has to provide power to both the L1 and L2 buses, I ran two wires connected to the L terminal, one wire from the N terminal and one wire from the ground terminal. The two wires connected at the L terminal go to both connections on a mechanically ganged dual breaker. This allows following the rules about not connecting more than on wire on each circuit breaker.


The sixth picture is a view of the inside of the electrical panel. Close examination of the inside of the panel reveals the inductive current couplers placed around the outside power L1 and L2 wires, the generator L1 and L2 wires, and both L wires from the inverter. NONE of these couplers have an electrical connection inside the panel.
To provide access to the AC voltages in the panel three wires are connected to the bus bars in the panel. Even though the modules take vary little power, to assure safety, each connection to the bus bars has an inline fuse/fuse holder with 1 amp fuses rated for 125 volts. The third voltage monitoring connection is for the inverter.


NOTE: because the inverter connections apply power to both L1 and L2, the dual circuit breaker is mechanically ganged with the dual breakers that connect the lower half of the panel to the upper half of the panel. With this implementation, the lower half of the panel has three power source options, all exclusive of each other - outside (shore) power, generator power, or inverter power. The upper half of the panel has two options, outside power or generator power. This is intentional, as some items either take too much power from the batteries or they would not be operated from the inverter, such as the RV charger.


I will be connecting the air conditioners to the lower half of the panel where they can run from inverter power, but the intent is to be able to run air conditioning while going down the road. My expectations are that an air conditioner will draw about 150 amps from the main DC bus, but the second alternator will be producing most of that and since it can produce 250 amps I think that will be workable. During the daylight hours, the solar array will also contribute power also.

 

[Iceni John]

Wow, that's a lot of work! I'm lazy - I bought two Paneltronics breaker panels instead of faffing about making my own. Home-made ones probably wouldn't have worked as well and definitely wouldn't look as good as the Paneltronics ones. I still need to make a cabinet for them and for the various other meters and control panels that will also be mounted there, and my plan is to have the entire cabinet pivot away from the wall so I can easily access the back of it.

John

 

[flattracker]

The conversion of my 86 Crown Supercoach

Some more progress on the "new Crown":


I have now run the wiring for the solar panels. I installed pass-through covers on the roof and run the wiring to connect them to the charge controller. This involved cutting 1 1/8" holes through the roof but only the outer surface, and the installation of rivnuts into the roof. This surfaced a problem though. I went to change the mandrel in the rivnut tool and found that I had a mandrel for 10-24 rivnuts but not one for 10-32 rivnuts, which I had purchased a couple years ago for fastening the pass-through covers. A trip to the hardware store got me almost enough rivnuts in 10-24 and some 10-24 button head screws. I quickly found out that the rivnut tool was stronger than the aluminum rivnuts and pulled the threads out of the rivnuts. The steel ones worked better. Another trip to Klamath falls got me more steel rivnuts and screws though. Researching the correct drill size to use to make holes to install the rivnuts found the closest size drill to be ideal is actually 7mm, but no place in Klamath County carries metric drills. Finally I found that a 19/64 " drill did work.



One frustration with living in the sticks like I do is that any trip to a hardware store is time consuming and expensive as the closest hardware store is 45 miles away.


All six feed-through connections are installed and wiring run through the extrusions installed most the length of the bus above the windows. Because the feed-through connections are on both sides of the bus the wiring has to go across the bus inside so that all wiring ends up at a common point to be connected to a terminal block, and then connected to the solar charge controller.


I had been considering various means to provide charging to the bus batteries from the solar array and still maintain isolation from the house battery bank. While planning out the design of the terminal block I realized that with the addition of some additional wiring, a switch, and second charge controller, I could isolate one panel to charge the bus batteries or have it combined with the other four panels to provide all available power to the house batteries.


Since I haven't found any terminal blocks that met my needs, I designed and built my own. Images of the terminal block as well as the feed-through covers and installations are attached in this post.


As a preliminary test I temporarily connected three of the panels up to the primary charge controller and observed the house battery bank voltage went to 14.6 volts in good sunlight.


The terminal block is not yet permanently installed.


I selected panel four (fourth from the front) to use for the select-able panel as either that one or the fifth one would end up with the shortest wire length charging the bus batteries.


The terminal block is made from machinable plastic and flattened copper tubing made into the copper bus bars.


The solar array is rated to output 1000 watts in good sunlight. being able to switch one panel to charge the bus batteries during storage time still leaves 800 watts to maintain the house batteries. The switched panel will provide a 200 watt battery maintainer system for the bus battery.


I also now have four 100 amp/hour house batteries installed in the trunk. When that installation is completed that will be posted.

 

[Iceni John]

Another way to keep the start batteries healthy if you already have solar is to use LSL Products' Ultra Trik-L-Start battery maintainers. I have two of them, one for each Group 31 start battery, and they're powered by the house batteries. Essentially they're just DC-DC chargers, but they work well: my start batteries are always good to go, regardless how long since they were last used. And if I need extra power to help start the engine in cold weather or at high elevations, I can switch my house batteries directly to the starter for an infusion of amps. So far, so good.

John

 

[flattracker]

Thanks for the suggestion. I have considered the cross connection approach for the Crown. Both alternators are next to each other so a connection between them using a Cole Hersey battery switch is feasible. This also allows for isolation between the house and bus batteries except when I need the extra power.

 

[flattracker]

The conversion of my 86 Crown Supercoach

A step forward and a step backwards:


The step forward:


I now have completed the installation of the wiring of my solar array. The feed through covers are all sealed up. The wiring has been run to the terminal block although it ended up looking like a rat's nest so I will do some cleanup work on that. 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.



I also installed and wired up the second charge controller that through a DPDT switch connects two of the panels to the secondary charge controller and charges the bus batteries. That seems to work OK.



My step back:


The next day I came back to check on the bus and found a battery voltage of 16 volts DC on the house batteries. I troubleshot the problem and have decided the charge controller does not regulate the battery voltage. I disconnected the negative lead from the terminal block to the charge controller.


The charge controller I used is rated for 80 amps and 12 or 24 volt batteries, and an array voltage up to 48 volts. Since the panels don't exceed about 26 volts unloaded and the array will never put out as much as 80 amps, I consider the controller to be defective. I have considered purchasing a replacement one of the same make/model as that would be a direct plug and play, but figure if this one failed the next one may also fail. I have been looking at a more expensive replacement controller that will probably fit the mounting location. The more expensive controller is rated for 100 amps and handles even more voltage than the defective one.

 

[cadillackid]

is it possible that the charge controller expects a certain minimum battery load? or perhaps that brand of charge controller works off of the principle that a heavier charge load reduces the voltage.. if so that would be a brand i wouldnt want.. ive seen consumer car battery chargers that you put a meter on them with no batteries connected and they are at 17 or 18 volts.. connect a good set of batteries and they never go above 13-8 to 14.2 or so.

 

[flattracker]

The same controller Is on eBay and doesn't state whether it needs a specific type of battery. I just bought another controller on eBay that is rated for 100 amps. The failed one does everything but regulate its output voltage. The one I would like to use won't fit in the mounting location I have in the bus. It has to be less than 8 3/4 " tall with wiring.

 

[KeyWestPirate]

"The next day I came back to check on the bus and found a battery voltage of 16 volts DC on the house batteries. I troubleshot the problem and have decided the charge controller does not regulate the battery voltage. I disconnected the negative lead from the terminal block to the charge controller."



Is this a PWS controller ?

I couldn't see either PWS or MPPT on the front of the box

If it's PWS then what you saw with the 16 V is normal.

 

[KeyWestPirate]

PWM,, sorry

 

[flattracker]

It is stated to be MPPT in current offers on eBay. Taking the batteries up to 16 volts is too high.

 

[KeyWestPirate]

The PWM controllers don't modulate the voltage, but apply the full voltage from the solar panel, for an increasing shorter period as the battery comes up to full charge. So, depending on the internal resistance of the battery and the voltage of the solar panel, we will see voltages like this.



This voltage doesn't hurt a LA battery, but may shut your inverter down due to a sensed over voltage.