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

[Boxster1971]

I see that sajohnson and Pahaska have also connected the problem.

[Pahaska]

Originally Posted by Boxster1971

With both SB-164 Solenoid and the manual disconnect Airstream has inadvertently created the potential condition to damage the Magnum MMS1012 inverter just as Crestline Coach discovered and reported to NHTSA that created the Part 573 Safety Recall Report 17V-704.

If any Airstream Interstate owner plugs their coach into shore power with the inverter disconnected from the batteries it can cause the same excess AC ripple current that could result in an internal failure of the inverter as reported by Crestline Coach and Magnum Energy.

I could find no caution notes in the 2015 to 2018 Interstate owners manuals that alert the user to this potential damaging condition that can easily happen. I also looked at the owner’s manual for the Magnum MMS1012 and could find no caution about leaving 120VAC power connected to the inverter when disconnecting the batteries as would be done in an inverter reset. However I did find a caution in the manual for my MM2000 inverter, it says:
"CAUTION: If AC is connected while performing an inverter reset, damage may occur."

Magnum knows their inverter can be damaged when AC is connected and the batteries are disconnected.

This is exactly what happened to my Magnum. I was plugged into the AC at the storage yard when I tried to reset the Magnum and it smoked.

I replaced my SB-164 solenoid with a HD battery switch and I have disconnected the Magnum numerous times with AC plugged in. I will not do that again.

I'll print up a big-font warning and tape it under the lid of the electrical box.

The replacement Magnum was delivered today and will be installed tomorrow.

[sajohnson]

Excellent write-up MIke!

Installed an MS2000 in our rig as well. This is the first I've heard of this issue, I'm glad to be made aware.

I don't think there is any warning in my manual regarding disconnecting the batteries when AC power is connected either.

In our case I used a class T fuse to protect the pos(+) cable, so (for better or worse) the batteries are semi-permanently connected. Still, good to know.

I wanted to mention that at least on the schematic I referenced above, the generator starter is wired directly to the coach batteries -- so it is possible to start the genset with the disconnect switch off.

If I understand correctly, the reason AS has a disconnect is because of concern about the power draw of the 1012 when it is in sleep or standby mode, is that right? In the schematic it looks as though there is a remote control. If so, can the inverter be turned off from there?

That's what we do with the MS2000 -- just shut it off when we aren't using it.

I don't know if the 1012 works that way though.

[Pahaska]

The inverter can be turned on from the remote. I leave it in the off state all of the time.

I think Airstream was trying to simplify things for the user by making the disconnect automatic, first by the terrible SB-164 fix and then by a second motorized disconnect switch. Unfortunately, this can damage the Magnum, although there is nothing in the Magnum manual that would warn someone.

[Boom23]

I am not saying that what I write below is what happened in Alex's case.

I just want to share one scenario which can damage the Magnum inverter installed in our AI.

Magnum tech support confirmed our assumptions that disconnecting the House batteries can cause inverter problems. I will include the complete email conversation here.

My original email to Magnum tech support:

"I am the owner of a new 2018 Airstream Interstate Tommy Bahama RV. It has come to my attention that the Magnum MMS1012 inverter/charger installed in my RV may overheat and start smoking or catch fire, even under normal use.

I bought my RV to travel with my family and an inverter accident or fire is the last thing I want. I would like to know what you plan to do to correct this problem so that I can enjoy my new RV."

Magnum tech support replied:

"The issue is not with our inverter but with some connections made on the dc side during installation. If proper maintenance is performed on the battery cables to and from our inverter to the dc loads there should be no problems. All battery cables should come with a fuse that will blow if there is a short or overcurrent causing thermal runaway installed from the manufactuer."

I attached the Magnum recall information and asked:

"Can you be a little more specific? What should I check or change? Can you provide a diagram?
I just want to avoid problems.

I am concerned because another 2018 Airstream Interstate, same year as mine and with presumably the same wiring, had inverter problems…"

Magnum tech support replied:

"Crestline coach and Airstream do not wire the systems the same. Make sure the batteries are always connected when ac is applied to the coach. (shore or generator) You would not want to have shore power to coach with an open dc circuit that could cause ac ripple inside the inverter. No one should ever be plugged into shore with the battery cables off the inverter or have a battery switch open between house bank with shore power applied to input of inverter. If you need to work on batteries do not have the coach plugged into shore until batteries are connected to inverter. The battery B+ cable will have a fuse inline so that if there is a short on the battery side it will trip before the cables get too hot and cause thermal runaway. We have been making these units for 12+ years and never had any fire related problems because of overlapping protection inside unit and installation protection on the dc and ac side with proper breaker or fuse sizing."

Finally, I asked:

"If I understand correctly, on the Airstream Interstate, the problem can happen when one connects to Shore Power, Charger is ON and the House Battery, and possibly the Engine battery, is disconnected (switch is OFF). It is very easy to have the House Battery disconnected as the disconnect switch is by the side door with the light switches. Also, people may disconnect the battery, by habit, when they have the RV stored, even if connected to Shore Power.

This can cause the problem you are describing. Correct?"

And the Magnum tech support reply was:

"Yes this is only on the Airstream applications that they found a way to damage our unit during some testing. If you follow all our instructions for installation and operation it will work fine with no fire issue at all."

The solution to this problem is to NEVER disconnect the House batteries, when connected to Shore Power or running the Generator.

[Boxster1971]

Originally Posted by sajohnson

Excellent write-up MIke!



Installed an MS2000 in our rig as well. This is the first I've heard of this issue, I'm glad to be made aware.



I don't think there is any warning in my manual regarding disconnecting the batteries when AC power is connected either.



In our case I used a class T fuse to protect the pos(+) cable, so (for better or worse) the batteries are semi-permanently connected. Still, good to know.



I wanted to mention that at least on the schematic I referenced above, the generator starter is wired directly to the coach batteries -- so it is possible to start the genset with the disconnect switch off.



If I understand correctly, the reason AS has a disconnect is because of concern about the power draw of the 1012 when it is in sleep or standby mode, is that right? In the schematic it looks as though there is a remote control. If so, can the inverter be turned off from there?



That's what we do with the MS2000 -- just shut it off when we aren't using it.



I don't know if the 1012 works that way though.

Thanks SA - in my rush to get the info out I forgot that the generator power comes directly from the batteries and it is possible to start the generator with battery disconnect OFF.

The caution about disconnecting the AC power when resetting the inverter is in the MS2000 manual in section on RESET. A soft reset is done with button on inverter. A hard reset is done by disconnecting the batteries from inverter.

You are reading the schematics correctly the two disconnect switches are motorized and can be turned off remotely. However the disconnect switches we are discussing should not be confused with turning off the inverter or charger from the Magnum remote control panel.

I too keep my inverter turned off when not using it.

Just to be complete I just looked at a wiring diagram for 2018 Airstream trailer. Good news is they don't have a battery disconnect switch between batteries and inverter. But some owners may have installed one for convenience.

[Pahaska]

When I was at Alumapalooza, I had my disconnect switch off for quite a while while connected to the very chancy AC that was daisy chained along the row of rigs. I had turned it off before I had AC to the AI which took a while. Then, after AC was hooked up, I didn't turn the disconnect back on until we came back to the rig after eating.

If there was ever a situation with wonky AC, that was it.

[Boxster1971]

Originally Posted by Pahaska

The inverter can be turned on from the remote. I leave it in the off state all of the time.



I think Airstream was trying to simplify things for the user by making the disconnect automatic, first by the terrible SB-164 fix and then by a second motorized disconnect switch. Unfortunately, this can damage the Magnum, although there is nothing in the Magnum manual that would warn someone.

The problem Airstream was trying to fix with SB-164 and later the disconnect switch is parasitic drain on batteries. Even with the Magnum in fully off state it draws about 0.5A constantly. The only way to stop this parasitic drain is to disconnect the batteries from the inverter/charger.

I mostly blame Magnum for this whole mess because they do not make it clear in their manuals that you must not disconnect batteries when AC power is applied to their units. Reading the NHTSA Safety Recall Report closely I'd bet money that Crestline Coach was using a similar battery disconnect in their ambulances to preserve battery power when they didn't need the inverter function. Then during maintenance the users were plugging into AC power with the batteries disconnected - smoking the inverter.

This situation could end up with Airstream eliminating the inverter/charger disconnect switch. At the least they need to notify owners of the caution regarding use of the disconnect.

Dropping the disconnect in the new 2019 Interstates would not be a problem since they are now installing four batteries that could deal with the Magnum's parasitic drain much better.

I found one tidbit in my research today in the MM1012 owner manual that the inverter should be connected to at least 200AH batteries for optimal performance. Interesting because the Interstates have only had two 12V batteries with total capacity of only 160AH. Not an optimal design.

[Titus]

Thanks Boxster,
I want to be clear on the different situation for the different vintages:

For those of us that are pre ~2015 the coach as delivered by AI cannot have the problem unless we have physically disconnected the battery cable and then plugged into AC power - correct?

But if we added a battery cut-off switch (to eliminate the minor power draw of the Magnum) we can get into trouble if we have our installed switch in the 'disconnect' mode and we then plug into AC power - correct?

In reading the NHTSA post I get the sense that only some types of AC loads cause ripple currents when the batteries are not connected. But I guess it is safest to never plug into AC (or run the generator) with the battery disconnected from the Magnum.

Stating the obvious, the AI electrical system is not very robust. You can cause problems in at least two ways (NHTSA issue and Magnum reset) if you don't know all the ins and outs.

[sajohnson]

Another notice regarding the Magnum 1012 in Crestline vehicles:

"Inverter Can Overheat Causing Possible Fire – 2016-2017 Crestline Icon 2.0 Ambulances":

https://oemdtc.com/860/inverter-can-...2-0-ambulances

Looks like mostly the same info as in the NHTSA report, but there may be something useful.

[Alex AVI]

Originally Posted by Titus

But I guess it is safest to never plug into AC (or run the generator) with the battery disconnected from the Magnum.

TITUS - I think what you said ^^^ above is THE safest approach.

In case you haven't seen yet, will just paste what I said on WACHUKO's thread when I replied to MIKE - AS seemed to have learned a lesson from prior years or was prompted by Magnum to do so:

On 2018's there is an ACE line (AC ENABLE - red circle) and diode that keeps the Magnum inverter connected to batts. in the presence of shore power. The ACE and diode was non-existent prior to 2018. ACE & diode essentially renders the Battery Disconnect a non-factor in charging operation, regardless of Battery Disconnect switch position. The only thing Battery Disconnect does is disconnect it from the DC Distribution Panel. I can confirm this by behaviour of charging activity even whilest Battery Disconnect is set to OFF (again 2018's only, so the NEW practice still should hold true for units without ACE line & diode).

So given the different MY iterations of how Battery Disconnect switches were wired with different solenoids and user mods, the only safe bet is to check your particular MY wiring diagrams (or user mods) to see if Battery Disconnect switch disconnects Magnum from (+) side of batts. even in presence of shore power.

[Titus]

Alex
Appears that the newest AI with the firefly may have the battery disconnect as an electronic switch. If so, I can see how some interlock logic or a diode may keep it connected. But aren't there model years for which the battery disconnect is a mechanical switch? If so, the diode cannot KEEP the battery connected. Most it can do is check to see IF the battery is connected, and to only allow AC to pass through if that is the case. There is no good reason to have the battery disconnect switch on if you have AC power (and thus charging capability) but it is scary to think that it is possible to inadvertently have things in a state that can cause the problem.

I am now regretting installing the battery disconnect switch on my 2013 and it seems that I have introduced an easy way of causing a problem. I installed it in case there were instances of long term inside storage (ie no solar) for which I wanted to totally remove all loads but not disconnect the batteries. But I have never used it. In the summer it is outside and in the winter it is inside but I always remove the coach batteries and pull the Sprinter plug at the accelerator.

Here is how I have things figured out on my 2013:
Three large cables coming from coach batteries:
1) To Magnum (a small electrical load that I can remove with the disconnect switch that I have installed)
2) to generator (via generator starting solenoid)
3) to + buss bar of thermal breakers

Digging a bit deeper into 3), there are 5 thermal breakers fed from the buss bar
a) 50 A breaker feeding the AI battery cutoff switch then to the fuse panels feeding ALL 12V circuits in the AI (Note: step and awning power comes from the Sprinter battery via panel under driver seat)
b) 15A breaker to (from) solar controller
c) 15A breaker to Kenwood radio/GPS
d) 20A breaker to tank heat pad switches
e) 30 A breaker to lounge seat recline switch.

So by using the AI disconnect, my disconnect switch, and the Sprinter plug by the accelerator I can totally remove all power drains from the coach and chassis batteries.

[InterBlog]

Originally Posted by Alex AVI

.... Surprising as Sears normally back their products very well in all the years we have bought durable-type goods from them. ....

I'm pursuing both prongs of the resolution simultaneously, hoping that one or the other will bear fruit - litigation track plus continuing repair iteration track.

This is the latest piece to get replaced in our fridge. I asked the repair guy why something like this would spontaneously develop a hole, given that it's buried deep in the fridge where nothing can impact it. He said, "Because they are making them out of insufficient aluminum. The lines are just too thin and so they develop leaks. Years ago, the tubing was much thicker and this didn't happen as much."

You can see that it appears to be a sizeable piece of equipment (my feet for scale). But I put it on our scale, and it weighs less than two pounds. It's flimsy.

Moral of this part of the story: Don't give up your old fridge for as long as it continues to work. Its old guts are probably better quality than what's for sale right now.

[Alex AVI]

Originally Posted by InterBlog

This is the latest piece to get replaced in our fridge. I asked the repair guy why something like this would spontaneously develop a hole, given that it's buried deep in the fridge where nothing can impact it. He said, "Because they are making them out of insufficient aluminum. The lines are just too thin and so they develop leaks. Years ago, the tubing was much thicker and this didn't happen as much."

INTERBLOG - yeah, that is the evaporator, the same part that cost me $1,200 to get replaced along with complete sealed-system evacuation that only licensed HVAC techs can do (and other smaller minor items). My Sub-Zero evaporator lasted 18 yrs. because as your tech said, they used to make them much thicker and thus last longer. But in the world of refrigeration, no matter how thick, they will eventually fail. So extrapolating $9,000 Sub-Zero lasts <18 yrs. and new model $3,000 Kenmore lasts <6 yrs.

[Alex AVI]

Originally Posted by Titus

But aren't there model years for which the battery disconnect is a mechanical switch? If so, the diode cannot KEEP the battery connected. Most it can do is check to see IF the battery is connected, and to only allow AC to pass through if that is the case. There is no good reason to have the battery disconnect switch on if you have AC power (and thus charging capability) but it is scary to think that it is possible to inadvertently have things in a state that can cause the problem.

TITUS - From pics I have seen of pre-2018 non-Firefly units, they have discrete switches but do not know for sure if they are mechanical (hope others here can chime in & confirm).

The diode is not what keeps the batteries connected to inverter. It's function is to isolate the Battery Disconnect switch (near slider door) from having any effect on the inverter disconnect switch (see previous diagram & orientation of diode). It is the ACE (AC Enabled line) that pulls inverter disconnect switch to keep the inverter connected to battery (+) . If ACE goes low (i.e. no shore power) then inverter disconnect switch opens disconnecting inverter from batteries & eliminates inverter drain.

Without the ACE & diode, the Battery Disconnect switch (near slider door) controls BOTH the inverter disconnect AND Main House Disconnect at same time. Meaning when you disconnect house batteries, you also disconnect inverter. And since there is no ACE sense line, when you plug in to shore power, there is nothing to pull inverter disconnect to close and connect batteries to inverter.

[Tobbun]

My wife and I have talked about this a lot. Our fridge was a present from my dad when we got an apartment together. Our washer/dryer were purchased when we got our first house. All three are over 20 years old. We have replaced some belts and minor things and every tech says the same thing. Keep these as long as they keep working. We wanted to upgrade to stainless in the kitchen but ours is still going strong.

[Alex AVI]

Originally Posted by Tobbun

My wife and I have talked about this a lot. Our fridge was a present from my dad when we got an apartment together. Our washer/dryer were purchased when we got our first house. All three are over 20 years old. We have replaced some belts and minor things and every tech says the same thing. Keep these as long as they keep working. We wanted to upgrade to stainless in the kitchen but ours is still going strong.

TOBBUN - My Maytag Neptune W/D is also 18 yrs. old, same age as house and Sub-Zero. I have rebuilt the washer with new bearings, seals, etc. etc. (big pain to do, but having bearing puller tools from extensive cycling toolset helped, still took entire weekend). IMHO Do not upgrade just for looks. If you do, then just accept the fact that they will be throw-away appliances good for 3-5 yrs. I won't even buy a new model Sub-Zero unless my old one becomes un-repairable.

[Pahaska]

I just finished installing and testing my new Magnum.

I had a bit of a scare when the first time I turned the inverter on at the remote, it gave me a red light and the remote indicated "Bridge" error. A quick look at the remote manual told me to reset the Magnum. Sure enough, the error went away and I was able to turn on the inverter and play the TV from the batteries.

I then hooked up to shore AC and the AC pass-through worked fine. The charger is happily bringing my batteries back up in "Absorb" and the Blue-Sky BIM clacked happily after a minute or so when it connected the charger through to the chassis battery. That is a good indication that the charger is working.

Now to do a little woodwork to account for moving the Magnum and to figure out a cover for the disconnect switch so it doesn't get bumped again.

We really have almost never used the inverter function in nearly a year and a half of owning the AI. If I were to do it again, I would install a high-quality charger in place of the Magnum and simply splice the Magnum in and out AC wires together to provide direct power to the TV circuits. That would save a couple of hundred dollars and simplify things quite a bit.

[Alex AVI]

Originally Posted by Pahaska

I just finished installing and testing my new Magnum.

JOHN - GREAT to hear all is good. I do not have your carpentry or metal fabrication tools/skills to effect my electrical compartment changes. Luckily, I have friends that have skills to help me. So I hope to have a better enclosure than what Airstream provides.

[Boxster1971]

Originally Posted by Pahaska

I just finished installing and testing my new Magnum.



I had a bit of a scare when the first time I turned the inverter on at the remote, it gave me a red light and the remote indicated "Bridge" error. A quick look at the remote manual told me to reset the Magnum. Sure enough, the error went away and I was able to turn on the inverter and play the TV from the batteries.



I then hooked up to shore AC and the AC pass-through worked fine. The charger is happily bringing my batteries back up in "Absorb" and the Blue-Sky BIM clacked happily after a minute or so when it connected the charger through to the chassis battery. That is a good indication that the charger is working.



Now to do a little woodwork to account for moving the Magnum and to figure out a cover for the disconnect switch so it doesn't get bumped again.



We really have almost never used the inverter function in nearly a year and a half of owning the AI. If I were to do it again, I would install a high-quality charger in place of the Magnum and simply splice the Magnum in and out AC wires together to provide direct power to the TV circuits. That would save a couple of hundred dollars and simplify things quite a bit.

John - the Magnum is a top quality battery charger, you won’t find one much better.