Electrical burning, heavy smoke w/ 3yr old grandson sleeping in AI

[Boom23]

Magnum investigated further by looking the 2018 AI schematics and they said the following regarding disconnecting the batteries:

"I don’t see the issue – the schematic doesn’t show it is possible. Opening the inverter disconnect switch only disconnects the inverter from the battery bank (and the rest of the coach). There is no way (short of opening a fuse) to disconnect the batteries from the inverter without disconnecting them from the B+ distribution.

Please see annotated schematic."

Again, I am not saying that this is what happened in Alex's case.

[sajohnson]

Originally Posted by Boom23

Magnum investigated further by looking the 2018 AI schematics and they said the following regarding disconnecting the batteries:

"I don’t see the issue – the schematic doesn’t show it is possible. Opening the inverter disconnect switch only disconnects the inverter from the battery bank (and the rest of the coach). There is no way (short of opening a fuse) to disconnect the batteries from the inverter without disconnecting them from the B+ distribution.

Please see annotated schematic."

Again, I am not saying that this is what happened in Alex's case.

At the risk of appearing stupid (quite possible) that statement makes no sense.

1) In one breath the Magnum CSR says:

a) "Opening the inverter disconnect switch only disconnects the inverter from the battery bank..." [right, that's the problem]

and in the next says:

b) "There is no way (short of opening a fuse) to disconnect the batteries from the inverter..."

So, in short, you can disconnect the inverter from the batteries, but you cannot disconnect the batteries from the inverter(??).

Am I reading that correctly?

The attached schematic has the path traced in red -- presumably by the Magnum rep him/herself. It is:

From coach battery pos(+) / thru 150A fuse / to "ST-1" battery separator / thru 150A inverter fuse / thru inverter main disconnect switch to the inverter.

Quote from the Magnum rep:

"There is no way (short of opening a fuse) to disconnect the batteries from the inverter without disconnecting them from the B+ distribution."

Actually opening the inverter disconnect switch *does* 'disconnect the batteries from the inverter without disconnecting them from the B+ distribution.' B+ distribution is before the inverter disconnect switch -- it branches off between ST-1 and the 150A inverter fuse.

I'll say again, we own a View, not an AI, and while I'm a technician I'm not an AS tech.

The schematic seems straightforward to me, but different industries and even different mfrs within an industry use their own symbols.

I have to admit being stumped by the wires connecting the "House Main Disc Switch" and the "Inverter Main Disc Switch". I'm guessing that either switch can be operated manually, but they can also be actuated by solenoids. I read thru the owner's manual a bit but it wasn't clear to me what's going on there.

In any case, it seems clear that the Inverter Main Disc Switch will indeed disconnect the 1012 inverter from the batteries, which is the cause of the problems reported to the NHTSA.

[Boom23]

Sajohnson,
I sent you a personal message with the tech person contact info.
If you want, please discuss your observations with him directly.

[Boxster1971]

Originally Posted by Boom23

Magnum investigated further by looking the 2018 AI schematics and they said the following regarding disconnecting the batteries:



"I don’t see the issue – the schematic doesn’t show it is possible. Opening the inverter disconnect switch only disconnects the inverter from the battery bank (and the rest of the coach). There is no way (short of opening a fuse) to disconnect the batteries from the inverter without disconnecting them from the B+ distribution.



Please see annotated schematic."



Again, I am not saying that this is what happened in Alex's case.

I agree with sajohnson - this makes no sense.

[Boom23]

Assuming that Airstream has wired the AI as shown in the schematics, I believe, we came to the conclusion that if we do not disconnect the batteries from the Inverter while AC-in is present, the Inverter should be fine.

I plan to do just that, and wait until Alex has concluded his situation and can share his findings.

[Alex AVI]

BOOM23, SAJOHNSON, MIKE - different terminology used by AS in the same docs. makes for some confusion. Also, agreed that the Magnum rep. does not know how to read the AI schematics. It is very clear that the Inverter Main Disconnect Switch can be manually rotated or electronically actuated via sense line ACE . More clarification below, for a lot of other folks who may be reading this and confused by all the different terminology. Hope this clears that part up Both pics courtesy of WACHUKO !


Info below taken directly from 2018 Interstate Owner's Manual page 5-13 and Diagrams page 9-17. Prior model years may be on different pages.

Manual Disconnect Switch (page 5-13) = House Main Disconnect Switch (page 9-17, M4d-1) = the big red knob (red arrow in pic below) = "located at the base of the driver's side rear jumper seat behind the decorative access door, is used to turn off power from the battery to the 12-volt distribution panel. Push knob in before manually rotating it to the ON/OFF position."

Multiplex System Disconnect Switch / Battery Disconnect Switch (page 5-13) = Master Disconnect Switch (page 9-17) = the red SPST toggle switch = "located on the multiplex panel at the entry door is used to separate the 12-volt distribution panel from the converter charging system. When connected to an external AC power source, the 12-volt distribution panel will receive power from the converter and the touring coach will function normally."

On 2018's, it does not matter what position the above switch is set to - with the presence of any charging source, the batts. will charge (via solar active, gen on, or plugged into shore power via Magnum converter charging ckt). How does it do this? On 2018's a new sense line ACE (AC Enabled) will sense when plugged in to shore power and automatically close the switch below (Inverter Main Disconnect Switch) which connects the converter charging ckt. to the batts. If shore power is unplugged, the same switch will open and disconnect the converter charging ckt. from batts. If the switch below is doing it's job, it is safeguarding the inverter from ever being disconnected from batts. when it is sensing shore power. VVVVVVVVV


Inverter Main Disconnect Switch (only referenced in diagram, page 9-17, M4d-2) = the other big red knob (yellow arrow in pic above) = located inside of the electrical compartment under the driver's side rear jumper seat to the left of the Magnum inverter. This can only be accessed by removing the jumper seat and the mesh grill. It can be manually rotated to the OFF position, disconnecting the inverter from the batts. and will expose the inverter to problem if plugged into shore power.

[amirm]

Originally Posted by Alex AVI

On 2018's, it does not matter what position the above switch is set to - with the presence of any charging source, the batts. will charge (via solar active, gen on, or plugged into shore power via Magnum converter charging ckt). How does it do this? On 2018's a new sense line ACE (AC Enabled) will sense when plugged in to shore power and automatically close the switch below (Inverter Main Disconnect Switch) which connects the converter charging ckt. to the batts. If shore power is unplugged, the same switch will open and disconnect the converter charging ckt. from batts. If the switch below is doing it's job, it is safeguarding the inverter from ever being disconnected from batts. when it is sensing shore power. VVVVVVVVV
Attachment 314858

Inverter Main Disconnect Switch (only referenced in diagram, page 9-17, M4d-2) = the other big red knob (yellow arrow in pic above) = located inside of the electrical compartment under the driver's side rear jumper seat to the left of the Magnum inverter. This can only be accessed by removing the jumper seat and the mesh grill. It can be manually rotated to the OFF position, disconnecting the inverter from the batts. and will expose the inverter to problem if plugged into shore power.

That is a very good analysis and write-up.

Problem is, that is a latching, motorized switch. It takes it a few seconds to engage. If the Mangum can be damaged due to AC ripple (?), there is ample time for that to happen during the time it takes for that switch to turn on.

Magnum needs to address this design problem. There are tons and tons of installations which disconnect DC connection and they can't have such a catastrophic failure as a result of it.

[sajohnson]

Originally Posted by Alex AVI

BOOM23, SAJOHNSON, MIKE - different terminology used by AS in the same docs. makes for some confusion. Also, agreed that the Magnum rep. does not know how to read the AI schematics. It is very clear that the Inverter Main Disconnect Switch can be manually rotated or electronically actuated via sense line ACE . More clarification below, for a lot of other folks who may be reading this and confused by all the different terminology. Hope this clears that part up Both pics courtesy of WACHUKO !
Attachment 314859

Info below taken directly from 2018 Interstate Owner's Manual page 5-13 and Diagrams page 9-17. Prior model years may be on different pages.

Manual Disconnect Switch (page 5-13) = House Main Disconnect Switch (page 9-17, M4d-1) = the big red knob (red arrow in pic below) = "located at the base of the driver's side rear jumper seat behind the decorative access door, is used to turn off power from the battery to the 12-volt distribution panel. Push knob in before manually rotating it to the ON/OFF position."

So far so good. My feeble brain comprehends.

Originally Posted by Alex AVI

Multiplex System Disconnect Switch / Battery Disconnect Switch (page 5-13) = Master Disconnect Switch (page 9-17) = the red SPST toggle switch = "located on the multiplex panel at the entry door is used to separate the 12-volt distribution panel from the converter charging system. When connected to an external AC power source, the 12-volt distribution panel will receive power from the converter and the touring coach will function normally."

Just for clarity, there is no conventional 'converter', correct? The system uses the battery charger in the Magnum 1012 to power 12 loads, as well as charge the coach batteries.

Originally Posted by Alex AVI

On 2018's, it does not matter what position the above switch is set to - with the presence of any charging source, the batts. will charge (via solar active, gen on, or plugged into shore power via Magnum converter charging ckt). How does it do this? On 2018's a new sense line ACE (AC Enabled) will sense when plugged in to shore power and automatically close the switch below (Inverter Main Disconnect Switch) which connects the converter charging ckt. to the batts. If shore power is unplugged, the same switch will open and disconnect the converter charging ckt. from batts. If the switch below is doing it's job, it is safeguarding the inverter from ever being disconnected from batts. when it is sensing shore power. VVVVVVVVV
Attachment 314858

I searched for "ACE" in the manual but found no mention of it. If it works as described, and there is very little delay (like the ATS in the inverter) it should be OK.

I feel like Columbo -- "Just one more thing..."

I may be thinking about this wrong, but if, "...shore power is unplugged, the same switch will open and disconnect the converter charging ckt. from batts", wouldn't that prevent the inverter from working when it should -- when shore/genset power is absent?

I'm assuming "converter" = Magnum inverter/charger. Not trying to be smarta**, just clarifying.

Originally Posted by Alex AVI

Inverter Main Disconnect Switch (only referenced in diagram, page 9-17, M4d-2) = the other big red knob (yellow arrow in pic above) = located inside of the electrical compartment under the driver's side rear jumper seat to the left of the Magnum inverter. This can only be accessed by removing the jumper seat and the mesh grill. It can be manually rotated to the OFF position, disconnecting the inverter from the batts. and will expose the inverter to problem if plugged into shore power.

That sounds correct.

This same switch (Inverter Main Disconnect Switch, M4d-2) can also be actuated by the ACE sense line, correct?

[Boxster1971]

Originally Posted by amirm

That is a very good analysis and write-up.

Problem is, that is a latching, motorized switch. It takes it a few seconds to engage. If the Mangum can be damaged due to AC ripple (?), there is ample time for that to happen during the time it takes for that switch to turn on.

Magnum needs to address this design problem. There are tons and tons of installations which disconnect DC connection and they can't have such a catastrophic failure as a result of it.

Amrim - I agree that Alex's write-up is very informative. I also agree that this problem is largely the fault of Magnum for not identifying this vulnerability with significant CAUTION notes in their owner/installation manuals. I've attached a PDF document with the installation diagrams from 2010 and 2017 versions of the Magnum MMS inverter manuals. Neither manual has a hint to this risk and both clearly show a DC disconnect as part of installation diagram.

Airstream must have know of this vulnerability and is likely the reason they added the ACE circuit on the 2018 Interstates. Just glad no one was hurt by this and the incident at Crestline Coach.

[sajohnson]

Originally Posted by Boxster1971

Amrim - I agree that Alex's write-up is very informative. I also agree that this problem is largely the fault of Magnum for not identifying this vulnerability with significant CAUTION notes in their owner/installation manuals. I've attached a PDF document with the installation diagrams from 2010 and 2017 versions of the Magnum MMS inverter manuals. Neither manual has a hint to this risk and both clearly show a DC disconnect as part of installation diagram.

Airstream must have know of this vulnerability and is likely the reason they added the ACE circuit on the 2018 Interstates. Just glad no one was hurt by this and the incident at Crestline Coach.

Good point about Magnum showing a battery disconnect switch in their manual.

FWIW, our MS2000 manual is the same -- battery disconnect shown.

I can find no mention of the AC ripple issue.

Magnum clearly needs to address this issue, and there is also the AS installation that should be improved.

[Boxster1971]

Originally Posted by sajohnson

Good point about Magnum showing a battery disconnect switch in their manual.



FWIW, our MS2000 manual is the same -- battery disconnect shown.



I can find no mention of the AC ripple issue.



Magnum clearly needs to address this issue, and there is also the AS installation that should be improved.

The MS2000 manual I have does have a CAUTION note about have the inverter/charger connected to AC power when disconnecting the DC side. It is in the section on Resting the unit.

[sajohnson]

Originally Posted by Boxster1971

The MS2000 manual I have does have a CAUTION note about have the inverter/charger connected to AC power when disconnecting the DC side. It is in the section on Resting the unit.

Well, either we have different manuals or I'm overlooking that warning.

My hard copy manual is the same as this PDF:
http://www.magnum-dimensions.com/sit...Series_Web.pdf

I thought you might have meant the section on performing a *reset*. That is on manual page 54 (the PDF page is different -- p.63). There is no 'caution' there. It may be somewhere else.

In any case, it's good that Magnum does have a warning in some of their manuals.

My concern remains the same though. A piece of equipment like an inverter should be as fool-proof as possible.

Of course people should read the manual, but we know they don't always do so. Or maybe they skim it. Or maybe they do read it thoroughly but they cannot remember everything.

It seems to me that since it is potentially catastrophic if 120Vac is connected while the batteries are disconnected, there should be (just for example) a relay with a 12V coil that is picked (contacts closed) when the batteries are connected. As soon as the batteries are disconnected the relay would drop and cut off the incoming 120Vac.

Generally though, the batteries should always be connected -- in most installations I'm familiar with. Either the inverter is acting as a 'smart' battery charger as well as passing 120V thru the ATS contacts and on to the loads, or it is acting as an inverter. Needless to say, in both cases the batteries must be connected.

In this case though, the Magnum 1012 apparently cannot be turned completely OFF, which is why some owners disconnect the batteries. That's a perfectly reasonable reaction that should have been anticipated.

I did find this in the Magnum 1012 manual, p.26:

4. a) If a remote switch is connected, press the ON/OFF switch to
turn the inverter on.

b) If there is no remote switch connected, lightly press and release
the inverter’s ON/OFF power switch—located on the top of the
inverter—to turn the inverter on.

Also, on p.35:

4.2 RV/Marine Off-Season Storage

When placing your coach or boat into seasonal storage, it is recommended
that you perform the following to ensure the system is
properly shut down (or properly configured for seasonal storage).

This is especially important for maintaining the batteries.

• Perform the recommended maintenance steps noted above.
• Fully charge the batteries.
• Connect shorepower (if available) and verify that the breaker to
the battery charger is switched ON.
• Verify the inverter is switched OFF.
• Switch OFF all unnecessary AC and DC loads.

The above suggests that the 1012 *can* be turned completely off (drawing no power). If so, that is clearly better than disconnecting the batteries.

The potential problem still remains.

[pdavitt]

I found this on the web concerning DC ripple. It's a Victron slide presentation on the subject. The thing I liked is that you don't have to be an EE to understand it.


Pat

[sajohnson]

Originally Posted by pdavitt

I found this on the web concerning DC ripple. It's a Victron slide presentation on the subject. The thing I liked is that you don't have to be an EE to understand it.


Pat

Thank you for sharing that Pat.

What I saw made sense to me.

I think the ripple that is harming some Magnum 1012 inverters is different, because it happens while the batteries are disconnected.

Regardless, this is interesting as well, and important to be aware of.

The following advice from Victron is solid:

In practice:

• The capacity of the battery bank must be high
enough
• Use as little cable length as possible
• Use the correct size (*)
• Use quality main switches
• Avoid to much fuses
• Avoid more then one shunt in a system
(*) Rule of thumb ; Amps/3 = size mm2 up to 5 metre ( every 5 mtr one step size up )

[Boxster1971]

Originally Posted by sajohnson

Well, either we have different manuals or I'm overlooking that warning...



.... It seems to me that since it is potentially catastrophic if 120Vac is connected while the batteries are disconnected, there should be (just for example) a relay with a 12V coil that is picked (contacts closed) when the batteries are connected. As soon as the batteries are disconnected the relay would drop and cut off the incoming 120Vac. .....



....Perform the recommended maintenance steps noted above.

• Fully charge the batteries.

• Connect shorepower (if available) and verify that the breaker to

the battery charger is switched ON.

• Verify the inverter is switched OFF.

• Switch OFF all unnecessary AC and DC loads.



The above suggests that the 1012 *can* be turned completely off (drawing no power). If so, that is clearly better than disconnecting the batteries.



The potential problem still remains.

My bad. It is not a CAUTION, just the first step in the Reset procedure on page 54.

"4.5 Performing a Power Reset
To perform a power reset (also known as a hard reset):
1. Remove all AC power(utility or generator power) to the inverter.
2. Open all the inverter DC disconnects (or disconnect the positive battery cable to the inverter).
3. Ensure the inverter(s) and the remote are disconnected from all AC and DC power (the remote display will be blank).
4. After the inverter(s) has been disconnected from all power for 30 seconds, reconnect the inverter DC disconnects (or reconnect the positive battery cable) and resume operation."

The MMS1012 will always draw about 0.5A from the batteries when connected. That's the reason for a disconnect to be used when your storing without external power.

[sajohnson]

Originally Posted by Boxster1971

My bad. It is not a CAUTION, just the first step in the Reset procedure on page 54.

"4.5 Performing a Power Reset
To perform a power reset (also known as a hard reset):
1. Remove all AC power(utility or generator power) to the inverter.
2. Open all the inverter DC disconnects (or disconnect the positive battery cable to the inverter).
3. Ensure the inverter(s) and the remote are disconnected from all AC and DC power (the remote display will be blank).
4. After the inverter(s) has been disconnected from all power for 30 seconds, reconnect the inverter DC disconnects (or reconnect the positive battery cable) and resume operation."

The MMS1012 will always draw about 0.5A from the batteries when connected. That's the reason for a disconnect to be used when your storing without external power.

No problem, I see what you mean.

Of course, these are instructions for performing a Power Reset-- something that most people will never have to do, so very few people will read them.

The instructions do say to disconnect AC power first, followed by DC, but there is no indication that power must be removed in that order.

There is no warning or advisory about leaving the AC source connected with the batteries disconnected.

I saw in the specs for the MMS1012 that it uses about 5W (~0.5A) in 'search mode'.

The MS2000 manual says searching uses "<8W", but the MS2000 can be turned off -- either using the small pushbutton switch on the inverter case, or by using the remote. Then (as far as I know -- and I've been fooled before) it is truly 'off' with no power being consumed.

I'm kinda flying blind here because I do not have a MMS1012 or an AI, but from what I've been able to tell, it is possible to turn the 1012 completely off (see my post above). It seems to have an on/off switch just like our MS2000.

Of course, it's possible that there is some power consumption even when the 1012 is turned off that I'm not aware of, but in my limited experience 'off' = no power usage.

Now which one of these rabbit holes did I originally enter...?

[sajohnson]

BTW -- the instructions in the MMS1012 manual are even worse.

http://www.magnum-dimensions.com/sit...Series_Web.pdf

Page 38:

~~~

Internal fault
(the status indicator
blinks x5 every 4 secs)

This fault occurs when an internal
fault is detected.

To clear this fault, an inverter reset
is required. Remove DC power to the
inverter or press and hold down the
power switch on the inverter for 15
seconds (until the green Status LED
comes on). If this fault does not clear, the
unit will need to be serviced.

~~~

No mention of removing AC power first.

It may not cause any harm, but I wouldn't chance it.

The bottom line though (IMHO) is that even if the Magnum manuals had prominent cautions/warnings about disconnecting the batteries when the 120Vac source is connected, it is simply too easy to do (with most installations). Whether it's children playing, absent-minded owners, or simply people that do not know any better, it is easy to imagine a battery disconnect being opened up.

Magnum really should have a 12V relay that drops out and cuts AC power when the batteries are disconnected (or something similar).

[Boxster1971]

Originally Posted by sajohnson

No problem, I see what you mean. ...

I saw in the specs for the MMS1012 that it uses about 5W (~0.5A) in 'search mode'.

The MS2000 manual says searching uses "<8W", but the MS2000 can be turned off -- either using the small pushbutton switch on the inverter case, or by using the remote. Then (as far as I know -- and I've been fooled before) it is truly 'off' with no power being consumed.

I'm kinda flying blind here because I do not have a MMS1012 or an AI, but from what I've been able to tell, it is possible to turn the 1012 completely off (see my post above). It seems to have an on/off switch just like our MS2000.

Of course, it's possible that there is some power consumption even when the 1012 is turned off that I'm not aware of, but in my limited experience 'off' = no power usage.

Now which one of these rabbit holes did I originally enter...?

Unfortunately with either Magnum model OFF there is still a drain on the batteries. It is less than the search mode. I just checked my notes and past posts and this totally OFF drain is 0.3-0.4A as measured on my van since I have a shunt current meter for both the Magnum and Blue Sky solar controller. The power to keep the comm line between inverter and remote has to come from somewhere.

This parasitic drain is what drove both Airstream and Crestline Coach to add a 12VDC disconnect on the Magnum Inverter.

This issue is not limited to Interstates, but is aggravated because the Interstates only have a 160AH's of coach batteries and another parasitic drain from the entertainment system. That is less battery capacity than recommended by Magnum. The new 2019 Interstates will now have double that with four batteries and 320AH capacity. Progress.

[Alex AVI]

Good evening folks. Sorry to be MIA since early a.m. yesterday. Pls. bear with me as I try to catch up on some posts that I need to reply to. Was busy after I picked up AI from dealer, getting her ready for trip to So Cal and Malibu for 4th of July.

BOOM23 - not sure if I can make time to stay in Huntington Beach. Will see

Quick update:
1. New Magnum inverter, smoke detector, new CO detector. Unit has been "burning in" (hate that phrase but an industry norm that I have used before) at dealer's service bay & outside for over a week under load & stresses of Las Vegas heatwave.

2. Jackson Center ok'ed the pickup Friday afternoon.

3. Jackson Center assured me there will be a thorough investigation starting this week. Magnum tech people are supposedly to meet with them early this week. My inverter was overnighted to Jackson Center.

4. As for my strategy:
- keeping the cushion off the top of electrical compartment.
- keeping an exhaust fan over the protective grill to remove as much heat.
- designing a separate active exhaust enclosure that will be imbedded in the seat cushion.
- enclosure will contain multiple exhaust fans, goal is >59 CFM airflow.
- will enlarge the grill opening to be as large as possible.

Just to give an idea of how hot it can get here, when I picked up unit around 3pm, AI was only sitting in sun for couple hours. Outside temp 114 degF, inside was 117 degF, parking lot ashphalt was 152 degF. Top of new Magnum is the same 117 degF using Snap-On multi-laser infrared thermometer at 1" reading (remember, the seat cushion is not installed yet). May test with seat cushion on top, but debating if I even want to take that risk? Maybe after my trip.

[Alex AVI]

Originally Posted by amirm

That is a very good analysis and write-up.

Problem is, that is a latching, motorized switch. It takes it a few seconds to engage. If the Mangum can be damaged due to AC ripple (?), there is ample time for that to happen during the time it takes for that switch to turn on.

AMIRM - Thanks. Yeah, not sure what the delay on a latching switch is and what amount of time Magnum's ripple current exposure is considered to be catastrophic to it (when batts are disconnected). And even in the case where the latching switch is the insurance policy, the few seconds you talk about maybe cumulative in weakening components that are being affected by ripple current vs. immediate melt-down of those components in cases where no latching switch exists.

Originally Posted by sajohnson

Just for clarity, there is no conventional 'converter', correct? The system uses the battery charger in the Magnum 1012 to power 12 loads, as well as charge the coach batteries.

I searched for "ACE" in the manual but found no mention of it. If it works as described, and there is very little delay (like the ATS in the inverter) it should be OK.

I feel like Columbo -- "Just one more thing..."

I may be thinking about this wrong, but if, "...shore power is unplugged, the same switch will open and disconnect the converter charging ckt. from batts", wouldn't that prevent the inverter from working when it should -- when shore/genset power is absent?

This same switch (Inverter Main Disconnect Switch, M4d-2) can also be actuated by the ACE sense line, correct?

SAJOHNSON - As I have yet to find any diagrams for Magnum 1012, I can not say for sure that all functions go through the same circuitry all the time. But a good assumption would be yes, being an all-in-one inverter/converter/charger.

ACE (AC Enabled sense line) is not mentioned anywhere except in page 9-17 of 2018 diagrams. Although if you read section 5 over&over&over (maybe about 100x as I think I did ) you begin to realize there is "something happening" behind the walls (ACE in this case) that allow the batts to charge regardless of Battery Disconnect Switch position wenever plugged into shore power. It was what led me to chase this "something" and found it when I compared 2017 vs. 2018 diagrams.

COLUMBO - yes, if shore power is unplugged, the Inverter Disconnect Switch will disconnect the converter charging ckt. from batts. This is where the Multiplex System Disconnect Switch / Battery Disconnect Switch = the red SPST toggle switch comes into play. If it is OFF, obviously, no shore power, no batts. But if it is ON, the batts connect to inverter and you can invert away. I have and did confirm this functionality many times over.

Taken earlier today, intentionally unplugged from shore power (specifically to double-check new Magnum behaviour & to give you accurate answer), gen off, Battery Disconnect Switch set to ON, press Invert, green led turns on, entertainment system components turn on, front Samsung tv turns on, drawing down -3A from batts.




The Inverter Main Disconnect Switch, M4d-2 is actuated by ACE (again, we are all assuming 2018 AI diagrams are accurate.