Folks,

I PM'd Ben Cummings with the following questions regarding Vantare inverter configuration. With his permission, I'm posting his reply to the forum:

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Quote Originally Posted by Travelite
Hi Ben,

I understand that Vantare inverters are set up differently than most in that all house circuits go through the inverters? Apparently this means that the owner has to manage the power dispensed by the inverters so as to not overload the them when off shore or genny power.

I'm trying to understand the difference in how the Vantare is set up compared to my LXi. My LXi uses 2 3000W Trace inverters and a 15KW generator. The 110V load center has 2 input and 2 output breakers per inverter. Certain loads are not connected to the inverters: engine heater, toe space heaters, etc, but 2 roof top A/C's are wired so I can easily draw more power than the inverters can source; in other words, I have to manage power. Furthermore, the LXi has an external automatic transfer switch that switches between shore and generator power. There's no inverter bypass, but I don't need one - if my inverters are pulled, the load center still connects outside shore/genny power to the circuit breakers. If an inverter detects an outside source of 110V it switches to converter mode.

What are the striking differences between my LXi behavior and the behavior I would get from the Vantare in terms of power management, inverter bypass, and shore/generator transfer switching?
What follows is Ben's reply:

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Hi David,

Thank you for the excellent question regarding inverters. I am actually co-hosting a seminar in Kerrville with Jon regarding inverters and their differences.

In short, however, yes you are correct. Vantare coaches do run all power through this series of inverters. Load management is the customer responsibility, however a down-stream load management system, similar to what I designed into the Parliament Coaches can be added to limit/reduce/unload certain items when shore or gen is not available. I had tried to work with the Sanford engineers when I was still employeed by them to incorporate this valuable idea into the Vantare coaches, but to no avail.

Let me say that the inverters in the coach you are looking at were designed for the alternative energy market, and are actually capable (in the non-RV software) of selling power back to the utility company. In order to do this, they do something that no other RV inverter can do. These inverters actually synchronize up with and are perfectly in phase with the AC input source. They either transfer current to their transformer to charge batteries by lowering their output voltage setting, or augment power of the AC source by raising their output voltage above the source. This allows them to either use power to charge the batteries or augment the AC input if the shore cord limit set on the inverter is exceeded. The advantages to how the Vantare and Parliament coaches are set up is that since all the power going through the coach is seem by them, you can actually set the AC1 input (shore cord) so that you don't trip a shore power breaker while living in the coach, without having to constantly be aware of what the load on the cord is for everything you use. This allows temporary loads such as microwave, hair dryer, etc to temporarily run (by the inverters actually taking energy out of the batteries to run these) without tripping a shore breaker.

Another advantage to the SW-series being "in synch" is that power transfers are virtually seemless. If the generator were to be started, the inverters first disconnect from the shore cord input and then proceed to slowly phase shift their output to synchronize up with the generator source and then "lock in" the contactor that parallels the inverter with the generator. There is normally no abrupt transfer of power which can make clocks reset to zero, etc.

One more advantage to these inverters is that since their output is EXACTLY like generator or shore power, and not a modified block square wave, motors run cooler and clocks run precisely on time, and ceiling fans don't hum like they would when running on the inverters like are installed in your LXI.

While most other inverters have a "shore cord size" input setting, since they do not actually synchronize up with the shore cord, they only attempt to keep you from tripping the shore breaker by cutting back the battery charging. They are incapable of making up the difference/augmenting the shore cord power since they are not actually synchronized with their AC source. The inverter circuitry is dormant until the AC source is removed.

The only disadvantages to the Vantare is that:

1) You will have to perform the "unloading" before unplugging the shore cord, or transfering to generator, or just running down the road on inverter.
2) You will have to be a bit more interactive...i.e. you will have to set the proper "Shore Cord size" on each inverter to get all the benefits and prevent a shore breaker trip.

In summary, if you don't mind being more interactive with your coach power system, at least in the initial setup, then you will see much more capability than you have experienced with the LXI. It can be a bit confusing if you are the type of person who does not want to have this level of understand or interaction. There are those people who simply want and ON/OFF button for inverters, televisions, etc. If that is your personality, then the Vantare is not for you. If you don't mind understanding, and want to be able to no only know what is going on, but also to be able to have the flexibility to really use what the capabilities of these inverters offer, then this IS the coach for you.

As I said, we can add a load managing system to what Vantare already has done if that is something you budget in from the beginning. I'll have to work up a quote for this addition, which would take out of the equation the possibility of inverter overload, which is really the major drawback to the Vantare setup/use of these inverters.

I hope you are going to attend the Kerrville rally, as I would love to be able to thoroughly go over with you what I have put here in brief.

Sincerely,

Ben Cummings
Coach Worx LLC