[Archived]

Tom,

I could be wrong but I am pretty sure I was told my Leon or someone at Marathon that they also have the inverters setup up to aid during peak usage on shore power as well. Say your running a couple of ACs cooking and doing something else. As I recall the inverters are in play here adding additonal output when you need.

I could be mistaken but I think I have seen it on techlink as well

Bi;;

[Andy]

I have no knowledge of the specific set up on a Marathon, or for that matter the way the inverters function relative to lack or availability of incoming power but I suspect that when a coach is set up to run devices via inverters those devices are on electrical panel bus bars that are isolated from the other devices that only receive power from sources other than the inverters.

So when power is availble, such as running the generator, the inverters are functioning as pass through devices.

Tom, do the same analysis on shore power and see if you draw the same conclusions. I suspect you will see the same thing.

[Archived]

Nope, when on shore power they all pass through and show on the Trace remotes as well as the Techlink inverter/shore power screen. All of this changes with the engine running and shore power unhooked. Turn on the gen and the two A/C’s on the inverter leg do not get pass through power.

[Jonathan]

Strange. I would like to know the logic on that decision because of all the power sources the generator is the best.

[Tim]

Tom,

You stated anytime you’re “driving” but I think it’s anytime you turn on the generator, even when dry camping and the Bus is not turned on, only my Aux & Galley A/C’s pass thru the Inverters. At least that’s what I noticed when monitoring my Inverters … which confused me at first why all four weren’t running thru the Inverters like when connected to shore power.

Thanks for explaining …

[Archived]

I think Marathon has a flaw/feature on how they handle inverter-driven large loads. One of my three Cruiseairs is run off battery but whether it is run by the inverter or pass through depends on the charge state of the battery.

Example: If the batteries are still in bulk charge mode (because I just pulled into a campground), one inverter will pull 50+ amps out of battery, the other inverter will put 60+ amps into the battery bank. This works the inverters pretty hard and they will get very warm. Now, if the battery bank was in float mode, the inverter driven AC will simply run on pass through (allmost no amps from batteries).

Same thing happens when I plug in the block heater. The outlet in the engine compartment is run off the inverter. If in float mode, the block heater will be run as pass-through; if in bulk mode, one inverter will pull 50A out of the battery while the other inverter puts the same amount back into the battery. In this situation one inverter will never enter float mode. I notice this situation when the inverter fans spool up to high after a while. Then simply disconnecting the large load until both inverters have gone to float fixes the problem.

So, at least on my bus vintage, you can get into an inverter/charger loop where one inverter pulls out amps while the other inverter puts back the amps at the same time. I guess this is a side effect of having two inverters feed a single battery bank without any communication between the inverters.

Gerald

[Andy]

Hey Jon,

What do you mean by “because of all the power sources the generator is the best.”?

Sorry, I’m sure it’s obvious to everyone else but is lost on me? Yah Yah Yah, I hear you saying, “typical”!

Harry

[Andy]

On my 2014 Marathon, while the Salon and Bedroom are the defaults for the inverter, there’s an AC Select button tht switches the defaults to the Galley and mid section…in my floor plan, that’s the bunk/bath area.

Harry, I won’t speak for Jon, but I’m to understand while shore power delivers 50amps, the generator delivers 70amps, making it the most powerful power source on the bus. I’m like Harry and a newbie and welcome corrections from the more seasoned members.

[Archived]

Generally speaking, later model coaches with 17.5 and 20KW generators, they put out more power than is availble from shore power.

Harry, I have no clue how the previous owner screwed up your battery system and inverters, but I think your is unique in that until you get some experience using the coach you will not know if you are stuck dealing with power management issues when on shore or generator power. I think your generator may be a 12.5 in which case the output is equal to the available shore power so your generator may not be your best source. And in your case the question is how did the previous owner set up the invewrter(s) and how did he balance loads which needs to be answered so you know your best source and how to deal with power managment.

[tom]

Andy,

Shore power is 50 amps on each of two legs for a total of 100 Amps. A 20kW generator gives you about 167 Amps (20,000W/120V= 167A).

[Per]

Tom,

Before applying generator power, can you turn off the dedicated/respective inverter(s) for those ACs then turn the generator on to pick up the load? Our Foretravel is wired that way and that is what we do (it wont automatically switch to gen power).