Inverter By-Pass

[Joe Cannarozzi]

Jon IMO this thread is a perfect example of the beauty of POG.

Let me rephrase my question from my previous post.

Why would they design that system so all circuits that are powered by the inverters could not be powered by gen. or shore when available, without needing the inverters?

If our switch fails in a manner that takes those circuits offline I simply remove the inverter from the loop. Its behind the wall behind the freezer, 10 min. max.

If you remember ours was not working when we bought the bus. All circuits continued to function and we left it in cause the battery charger end of it was still good.

Once I did remove it for repair I could plug the recepticals leading to and from it into each other to complete those circuits. On a side note that switch was one of the things that failed. A contact was burnt keeping the inverter function down but could have just as easily burnt the other side restricting shore/gen.

Seems like what your trying to achieve is exactly the set up we have and it was designed 10 years prior to yours.

Unnecessarily overcomplicated, a relatively common occurrence on many features on these campers

Jon If I were in the market for another bus and it's style was EXACTLY what we wanted but had inverters set up like yours, I'd pass, I would not be willing to risk that inconvenience unnecessarily.

It will be reassuring and informative to hear from new coach owners, and who their converters are, who do not have to deal with this.

Jon here is Daves# at Gusdorf electronics 505-983-4095. He knows inverters as well as you know norgrin valves. I'm sure he is aware of your set-up and can be of some assistance.

[Jon Wehrenberg]

Joe,

I cannot defend the design except to say that was the way things were done, and yours and mine being at least 10 years apart show that the way they were installed was not a one time thing, but was common practice. I know for certain that several converters built a lot of coaches that way, and I also know of at least one Prevost owner that lost the contents of his refrigerator because he could not get power to it after his inverter failed. I also know of a coach built in 1995 for a former PP president that was specifically equipped with an outlet for the refrigerator powered by shore or generator power to be used as a backup in the event of an inverter failure. This problem is not new or unheard of.

In our coaches we have many failure modes that are capable of messing up a trip. The fact that with 10 minutes worth of rewiring gets you going says more about how your inverters are placed than the whole concept of being able to by-pass a failed device with a simple switch.

I am addressing potential failure modes in my coach one at a time. I dealt with a plumbing issue previously. I have made access to engine fuel priming much easier. I am going to deal with an inverter failure via a by-pass switch, and I am adding a second water pump solely to be used as a standby. Each time I find something whose failure will force me to repair it immediately, or which will disable us making life less than pleasant I am going to incorporate some means of dealing with it.

In the end I will still have some items whose failure will require a repair, but I am adding parts to my inventory of spares to minimize the grief. I already have a replacement control for the Webasto, a backup Watchdog generator control, miscellaneous circuit breakers, relays, air hoses, lights, etc. And those things that are not practical to replace, or to have back-up, or to repair I am going to replace based on time in service or miles such as I am contemplating for my engine air compressor or my big alternator.

If we never left the immediate area we live in I would never consider doing what I am doing. But that is not the case, so I will do the next best thing and that is try to never have a failure while on the road that will curtail a trip. At least that is the plan.

[Joe Cannarozzi]

How does Thompson do it?

[Jon Wehrenberg]

I cannot specifically describe how he does it, nor how the current versions of CC do it.

There may be others out there that also by-pass. My guess is that a system of relays or switches open the circuits to and from the inverters when there is shore or generator power automatically doing what I am going to do manually.

A by-pass is not anything sophisticated or expensive relative to the cost of a coach. I just think that the designers did not necessarily think about failure modes when the coaches were designed. As people became aware of the issue some converters responded by creating systems to accomplish a by-pass.

[Jim_Scoggins]

My coach is not here for a look see.
However, I will certainly be in the running to put an inverter by-pass in mine.

In the event of a failure of the inverter that powers the refrigerator my interim plan would be join the wires as mentioned by another or to switch positions of the inverters in order to restore refrigerator power. Or, depending how easy, or not, if I can get to the back of the refrigerator by removing a panel, I would run an extension cord.

So, an inverter/charger thinky: The combination inverter chargers just aggravate me a lot more than they should. In an 86 bird I lost (it failed) a Heart inverter charger and it's replacement, a Trace. In the case of this older bird there was only one. Hence, for repairs (yes, I really believed one could get them fixed) one was without the inverter, in the event of a charger failure or vice versa. Inverter failure was not a big deal as it had a propane refrigerator.

Anyway, I thought I could do better. I wanted redundancy, and easy componet, replaceability. I bought two True Charge 40s (40 amps each) and an 80 amp PDI and wired them up together. One of the True Charge 40s acted as the brains of the outfit and would bring everything, or portions thereof, on line when needed.

I then bought an inexpensive 1000W inverter and installed it separately. Granted, 1000W isn't much but it would run, individually, the curtains, TV, ice maker, refrigerator, coffee maker, or the crock pot. Obviously, in our current coaches a larger inverter would be necessary.

Wouldn't you know it. After I set it up like that, I never had another failure but I did have a system with easily replaceable componets while on the road.

Accordingly, while I will pursue Jon's fix with a by pass switch, I will also start researching building up a system with an independent 24 volt charger and independent inverter.

Also, I think if there is an inverter failure, the charger portion will be OK. Accordingly, a simple inverter of approx 1500W should keep the refrigerator going till permanent repairs can be made.

[Joe Cannarozzi]

There is no doubt that Liberty and whoever else does this is aware of the compromise for doing it this way but has good reason why and I would love to find out.

[bill&jody]

jon-
i still think the right way to do this is to put a transfer sw after the inverter, with the two inputs to the switch being the output of the inverter and the output of your shore/gen power, with the switch having a preference for the inverter. the xfer sw can't be expensive (its just two relays in a metal box) and it would be completely automatic. and very easy to install.

thoughts?

wmm

[Jon Wehrenberg]

WM, I agree with your solution, however while your solution on the surface seems simple, it involves running wires to my inverter location that are not already there. Additionally this is only a switch to be used in the event of a failure. My coach like yours will often have shore power or generator power on one of the lines you mention so the relay will be working each time it sees those sources of power, and as an electro-mechanical device it is something else besides the inverter that can fail. I want my fix for my coach to be cheap and simple and not prone to fail.

[win42]

Jon: You don't have to debate what your doing with any of us. Please continue with your project so those of us needing it can copy it for our buses.
Thanks for another heads up change for the better.

[truk4u]

Jon,

Unlike my Marathon, I had to check this out and I gotta give an atta boy to CC, nothing runs through the inverters as long as shore/gen power is available.