Inverter/Charger Misconceptions

[Gil_J]

There's no doubt that our inverter/chargers can be technically overwhelming for many. There's some misconceptions that seem to be perpetuated even though they are inaccurate.

I just confirmed that the most common inverter/chargers we have in our coaches handle these functions pretty much the same.

Myth #1, Setting the Shore or Grid Max Amps at or below the shore power connection will prevent the coach from tripping the shore breaker. This setting DOES NOT limit the appliance loads being serviced by the inverter. For example, if you set this to 15A because your coach is plugged into a 30A/120V shore connection, you can still turn on appliances that exceed the 15A. What this setting does and why you should use it is that it limits the amount of shore power current dedicated to the battery charging function. Load shedding is your responsibility if your converter didn't install some sort of intelligent load shedding system.

Myth #2, You should reduce the Maximum battery charging current when you are plugged into something less than the standard 50A/240V connection. This should ALWAYS be set to 50% of the maximum charge current rating established by your battery manufacturer for the size of the bank you have. It's set at 50% because you have 2 battery chargers and together they will not exceed the maximum charge current recommendation for your battery bank. Look at Myth #1 on why you do not need to reduce this setting. Note, depending on your inverter this setting may be stated in AC amps or a percentage of the chargers maximum charging current.

Myth #3, You should set your shore current setting to something less than what it is because shore breakers can trip below their rated current. This is a half truth in that it might be a good idea if you have an inverter that will supplement shore power, like a Trace SW series or Magnum Hybrid series, but as stated in Myth 1, this will not limit the appliance loads being serviced by the inverter.

[Mike GAy]

There's no doubt that our inverter/chargers can be technically overwhelming for many. There's some misconceptions that seem to be perpetuated even though they are inaccurate.

I just confirmed that the most common inverter/chargers we have in our coaches handle these functions pretty much the same.


Myth #1, Setting the Shore or Grid Max Amps at or below the shore power connection will prevent the coach from tripping the shore breaker. This setting DOES NOT limit the appliance loads being serviced by the inverter. For example, if you set this to 15A because your coach is plugged into a 30A/120V shore connection, you can still turn on appliances that exceed the 15A. What this setting does and why you should use it is that it limits the amount of shore power current dedicated to the battery charging function. Load shedding is your responsibility if your converter didn't install some sort of intelligent load shedding system.

Myth #2, You should reduce the Maximum battery charging current when you are plugged into something less than the standard 50A/240V connection. This should ALWAYS be set to 50% of the maximum charge current rating established by your battery manufacturer for the size of the bank you have. It's set at 50% because you have 2 battery chargers and together they will not exceed the maximum charge current recommendation for your battery bank. Look at Myth #1 on why you do not need to reduce this setting. Note, depending on your inverter this setting may be stated in AC amps or a percentage of the chargers maximum charging current.

Myth #3, You should set your shore current setting to something less than what it is because shore breakers can trip below their rated current. This is a half truth in that it might be a good idea if you have an inverter that will supplement shore power, like a Trace SW series or Magnum Hybrid series, but as stated in Myth 1, this will not limit the appliance loads being serviced by the inverter.



Gil: We are at a site using two 30A plugs, on a 2004 Liberty Elegant Lady. How do I access the controls for the Shore or Grid Max Amps? I see nothing on the Creston controls that affects that level. Also, I took a quick look at one of our two inverters and I only saw 3 little buttons, which do not appear to be such a control.

We are OK for now, but I'm obviously pulling a big load with the chargers and we just won't run other stuff until I get this figured out. Oh, and my new Generator starter battery is not working this morning, but that's a separate issue. Correct me if I'm wrong, but I'd say the worst thing that would happen is that I would trip a breaker. If I cannot adjust the amperage going to our chargers, it will not damage any circuitry, correct?

Thanks!

[Joe Camper]

There's a couple different ways that AC power is supplied to those inverters depending on the converter. The circuit protection is quite a bit different from converter to converter too.

I pulled a pair and replaced heart inverters from a mid 90s Marathon. They had the inverter remotes on 1 rectangular panel up on the dashboard. These are the old simple Style on, off, low charge. That was the only control you had with the remote for the freedom style imagine that.

Okay so follow me on this one and let's hear your opinion on what I found. I sent the motherboards and the remotes to gustdorf electronics to redo everything and I used these two inverters in two separate applications. I had to cut the two remotes down the middle to make them separate again because they were on that one panel custom panel that Marathon would use in that vintage. As I was discussing things with Dave at gustdorf before he sent me my stuff back he mentioned he found something wired wrong and he corrected it. It was the switch for the right side remote. On, and, the low charge on the right inverter was backwards. They were flipped.

Was that a mistake by heart or was that a deliberate design by Marathon. I think Marathon did that.

[Joe Camper]

I have a question about the 30 amp circuit breaker that's on the front of the Trace 4024 and 4012.The converter is Marathon. The little round white one that will pop out that you can reset by pushing in.

You're plugged in to a good 50 amp Shore power source. Let's say it's morning time and it's hot.
All the Cruisers are going including the two that are on each of the one inverters. The fridge is going you got the microwave on the coffee pots on you got toast down your wife's in the bathroom with a curling iron and a blow dryer.

Here's the question don't these Trace inverters supplement power or at least have the ability to do that and make up the difference you don't get at the pole.

I think they can but I'm not sure if it's something automatic or it's something that's got to be programmed into that remote that's the question.

And if my assumption is correct can we then also assume that the only time that, that 30 amp breaker on a trace 4024 is going to kick out is when there's actually a short but it'll never kick it out by overloading. it is this correct? Do you have to program something into that remote to get it to do it or does it just do it on its own?

[Mike GAy]

There's a couple different ways that AC power is supplied to those inverters depending on the converter. The circuit protection is quite a bit different from converter to converter too.

I pulled a pair and replaced heart inverters from a mid 90s Marathon. They had the inverter remotes on 1 rectangular panel up on the dashboard. These are the old simple Style on, off, low charge. That was the only control you had with the remote for the freedom style imagine that.

Okay so follow me on this one and let's hear your opinion on what I found. I sent the motherboards and the remotes to gustdorf electronics to redo everything and I used these two inverters in two separate applications. I had to cut the two remotes down the middle to make them separate again because they were on that one panel custom panel that Marathon would use in that vintage. As I was discussing things with Dave at gustdorf before he sent me my stuff back he mentioned he found something wired wrong and he corrected it. It was the switch for the right side remote. On, and, the low charge on the right inverter was backwards. They were flipped.

Was that a mistake by heart or was that a deliberate design by Marathon. I think Marathon did that.

I guess that one if for Gil, since it's over my head!

[Mike GAy]

I have a question about the 30 amp circuit breaker that's on the front of the Trace 4024 and 4012.The converter is Marathon. The little round white one that will pop out that you can reset by pushing in.

You're plugged in to a good 50 amp Shore power source. Let's say it's morning time and it's hot.
All the Cruisers are going including the two that are on each of the one inverters. The fridge is going you got the microwave on the coffee pots on you got toast down your wife's in the bathroom with a curling iron and a blow dryer.

Here's the question don't these Trace inverters supplement power or at least have the ability to do that and make up the difference you don't get at the pole.

I think they can but I'm not sure if it's something automatic or it's something that's got to be programmed into that remote that's the question.

And if my assumption is correct can we then also assume that the only time that, that 30 amp breaker on a trace 4024 is going to kick out is when there's actually a short but it'll never kick it out by overloading. it is this correct? Do you have to program something into that remote to get it to do it or does it just do it on its own?

Now, I like that question, and I anxiously await the answer. I had a similar question.

[Gil_J]

Mike

What make/model inverters do you have?

[Gil_J]

Joe, the 35A, not 30A, CB in a Trace 4024 only supports the inverter and charger functions. It's not likely to ever trip in charger mode. In inverter mode the most probable cause would be excess 120V current load while in inverter mode. This can be due to a few things. Some converters run everything through the inverters with no automatic load shedding when on inverter power. FYI, they can support 60A in bypass mode. This is obviously problematic. This was how my Hoffman WAS wired. Another cause is an automatic load shedding system that reacts too slow to shedding loads when switching to inverter mode. Finally, there's the hair dryer problem or other high loads the owner plugs in.

BTW, the Trace units have 2 methods of augmenting input power. They will use inverter power to plus up shore voltage. This is a great feature for fighting brown outs. It also has a generator support function that we would not really use. It pluses up generator power when the generator load reaches a configurable current load.

[Mike GAy]

Mike

What make/model inverters do you have?

Gil, if I remember correctly, we have two 2500W Heart inverters. I'm still slowly figuring things out, but I'm making good progress. We had several things going on this weekend at our site.

-The site had no 50A receptacles, but they set up up on Fridaywith two 30A and we used our cheater box.
-Found out Saturday that one of the 2 30A receptacles was dead. The moved us to another site with two good plugs.
-Also found out that the new generator battery that Olympia installed last week appeared to be bad. Although it cranked the Generator from Wed to Friday, it wouldn't turn the engine over. I put a trickle charger on it until it was up to 13 V, but it still wouldn't start. After trying to start, my tester showed 1.6 V.
-Took the coach to Olympia Monday for installation of some parts we were waiting for, and they are checking out teh generator problem.

Things had started to gel in my mind about the path that power takes as in enters and goes through the coach. I decided to review that with Austin on the coach, and he confirmed that my new understanding was correct. it's building my confidence, and I think things will flow better in the future!

Essentially, what I've learned it that power from the generator or the 50A:
-Enters the coach and goes to (1) the direct AC breakers or (2) to the battery chargers.
-Items that are not powered by the inverters must have AC from the Generator or the 50A plug
-Items powered by the inverters only get power that come from charged batteries, goes though the inverters, and then through the respective "inverter" breakers on our panel.

It's not that complicated, but it was cloudy to me before that.
For load monitoring, al I need to remember is:
-The Generator will power everything!
-On 50A power, I need to watch to be sure my total load on each leg is 50A or less. Otherwise, we will trip a 50A breaker.
-on two 30A/cheaterbox circuits, we have to watch our load meters closely. If I'm charging the batteries with both chargers, I don't have much headroom at all and will need to turn off a charger if I need to use an AC.

Otherwise, I'll be making trips out to the breaker box and hoping it's not locked!! (it was at our first site)

I'm a long was from being on top of it, but this was a big step up from our Thor/Mandalay coach!

[Gil_J]

Mike,

The Heart Interface 2500 inverters have two ways of being wired. They could have 2 AC inputs. If so, there should be 2 input 30A breakers dedicated to each inverter. One will be for charging and the other for pass through. Turning off the circuit breaker for the charger function, turns off the charger. The other wiring method has a single AC input for both charging and pass through. This method supports power sharing. Through the manipulation of remote panel dip switches you can limit charger AC current draw to as little as 5 amps. Here's the documentation (CLICK HERE) (http://www.xantrex.com/documents/discontinued-products/freedom_combie_owner_manual.pdf).

Liberty's circuit breaker panel labeling could have use some more thought. The upper right and left breaker areas are labelled Line 1 and Line 2. These are labeled as expected and are the AC feeds from the generator or shore power. These will also have breakers labeled for the Shore/Generator supply to the inverters. This can be one or 2 per Line, as I described earlier. The lower section of the circuit breaker panel is the part that makes no sense. The left side is labeled Inverter 1 and the right side Line 2. This lower area also has some breakers that have a red center. The red center breakers are the output circuits from the inverters. The best thing you can do is turn off supply breaker in the upper section of the circuit breaker panel for one of the inverters and see which red centered breakers still work. This will tell you which inverter supplies power to which breakers.

I'm not a big fan of the 30A cheater boxes. If the 2 30A feeds are in the same phase then any 240V appliances in your coach won't work. For some, this will be the cooktop and clothes dryer. Also realize 2 in-phase 30A circuits subject you coach's nuetral to up to 60A. Your normal 50A/240V feed will generally have far less than 50A on it's neutral conductor given 180 degree out of phase power cancels one another. This generally should not be a big deal, but I would be concerned with some commercially available transfer switches. BTW, your coach has a Liberty fabricated transfer switch.

[Mike GAy]

Mike,

The Heart Interface 2500 inverters have two ways of being wired. They could have 2 AC inputs. If so, there should be 2 input 30A breakers dedicated to each inverter. One will be for charging and the other for pass through. Turning off the circuit breaker for the charger function, turns off the charger. The other wiring method has a single AC input for both charging and pass through. This method supports power sharing. Through the manipulation of remote panel dip switches you can limit charger AC current draw to as little as 5 amps. Here's the documentation (CLICK HERE) (http://www.xantrex.com/documents/discontinued-products/freedom_combie_owner_manual.pdf).

Liberty's circuit breaker panel labeling could have use some more thought. The upper right and left breaker areas are labelled Line 1 and Line 2. These are labeled as expected and are the AC feeds from the generator or shore power. These will also have breakers labeled for the Shore/Generator supply to the inverters. This can be one or 2 per Line, as I described earlier. The lower section of the circuit breaker panel is the part that makes no sense. The left side is labeled Inverter 1 and the right side Line 2. This lower area also has some breakers that have a red center. The red center breakers are the output circuits from the inverters. The best thing you can do is turn off supply breaker in the upper section of the circuit breaker panel for one of the inverters and see which red centered breakers still work. This will tell you which inverter supplies power to which breakers.

I'm not a big fan of the 30A cheater boxes. If the 2 30A feeds are in the same phase then any 240V appliances in your coach won't work. For some, this will be the cooktop and clothes dryer. Also realize 2 in-phase 30A circuits subject you coach's nuetral to up to 60A. Your normal 50A/240V feed will generally have far less than 50A on it's neutral conductor given 180 degree out of phase power cancels one another. This generally should not be a big deal, but I would be concerned with some commercially available transfer switches. BTW, your coach has a Liberty fabricated transfer switch.

Gil: Many thanks for the info. We head out in the AM for a 12-day trip, and I will dig into the documentation and your post while on the trip.

I'm leaving to pick up our coach from Olympia in a bit. It turned out that the new generator cranking battery that Olympia installed had a bad cell cell. They also installed a few parts that had some in for other things, so we should be set.

The complexity of a Prevost means that it takes a while for a newbie to grasp how things work together, but we are getting there. We've owned a houseboat for 20 years, and we are accustomed to having stuff go wrong. There is always something to fix on a boat!

[GoneCrazy]

Gil: Many thanks for the info. We head out in the AM for a 12-day trip, and I will dig into the documentation and your post while on the trip.

I'm leaving to pick up our coach from Olympia in a bit. It turned out that the new generator cranking battery that Olympia installed had a bad cell cell. They also installed a few parts that had some in for other things, so we should be set.

The complexity of a Prevost means that it takes a while for a newbie to grasp how things work together, but we are getting there. We've owned a houseboat for 20 years, and we are accustomed to having stuff go wrong. There is always something to fix on a boat!

You now own a land yacht , gotta love em !