Xantrex X-Power MSW inverter troubles

Socratic Monologue · November 2011

I have a Xantrex X-Power 1500 MSW inverter that was purchased and put into service in January of 2011. It has worked well up until about a month ago, when it began to shut down (no power, and fault indicator light lit) randomly. When the inverter is on but idle, it shuts down about once every day or two; when the unit is first started (either restarted after a fault shutdown or simply shut off then restarted) it shows a fault light about every other time (i.e., I have to turn the unit off-then-on at least twice to get it to power up, on average). The inverter exhibits these same symptoms whether anything is plugged into the AC outlets or not.

The inverter is connected to a pair of 6v golf cart batteries that read about 13v on the battery posts, and 13v at the input posts of the inverter (according to my cheap analogue multimeter). Battery bank is charged with a single 130w panel feeding a Morningstar SL-20L charge/lighting controller. The room the equipment is housed in is currently about 50 degrees F. The inverter itself never seems warm to the touch. No changes have been made to the system, either to the supply end or the consumption end, since the inverter was installed.

I'm in the process of contacting Xantrex, though (A) they have apparently disabled their customer service email address, (B) they don't respond to a query I sent them through their web contact form, and (C) I'm dreading the phone call to them after what I've read recently about their customer service/lack thereof. I would appreciate any insight anyone has as to what the malfunction might be; it might help me to solve this problem myself or at least be better prepared when I talk to Xantrex.

BB. · November 2011

Re: Xantrex X-Power MSW inverter troubles

Working from your last question:

From what I understand, Schneider/Xantrex does not work customer support questions initiated from emails (have not heard anyone get a reply from the websupport form either--but I am not in the business, so it it what I read here). Phone calls are the way to, at least start, the conversation (as always, some people are happy with the phone support, and a few not so much).

What fault light is it? I would guess two--One is the inverter fault LED and a second would be a ground fault indication (typically on the AC GFI Outlet).

You measured 13.0 volts at the inverter input terminals, and it does appear to be carrying loads OK when it is working--so it does not sound like you have poor/intermittent cables or cable connections.

And if it is not the GFI outlet faulting (which you can probably fix by purchasing a new GFI outlet at the local hardware store)--Not sure there is anything else you can do.

The next step is probably calling "Xantex"...

By the way, 13.0 volts? Is that during the middle of the day (sun up, charge controller charging)--Or is that at night, no loads and no other charging sources (battery resting)?

If during charging, it sounds like your batteries are undercharged--They should be reaching a charging voltage of ~14.5 Volts or so (assuming battery bank is ~80-90% state of charge).

If batteries have no charging/loading current, and have sat for a while (ideally, at least three hours of "rest"), then measure "resting" voltage--The voltage sounds a bit high--but more or less normal (especially if the battery bank is very cool).

-Bill

Socratic Monologue · November 2011

Re: Xantrex X-Power MSW inverter troubles

The fault light is the inverter fault LED. The GFCI function seems to have normal function (I tested it with the test button on the outlet, though I didn't think to test it with a receptacle tester).

Seems to carry loads fine. I run a garage door opener and a couple small lights once in a while, and they work as always.

So I tested the voltage again just now (a couple hours after dark) and it still reads ~13v (it had 15w12vdc of draw on it at the time). I do know that the panel is not really officially big enough to charge the battery bank; you folks here informed me of that when I set it up. Could this possibly be the problem?

BB. · November 2011

Re: Xantrex X-Power MSW inverter troubles

13.0 volts is a bit "high" for a resting battery and/or a battery with load (unless it is getting towards freezing 32F/0C).

I would begin to suspect that your meter is not entirely accurate (or able to read 12.7 volts vs 13.0 volts)... If you have a chance, take a read on your parked car... Assuming its battery is fully charged, it should read about the same as your storage battery bank.

Sounds like everything is OK--but it does not hurt to check the VOM meter on your car... We have chased our tails once or twice here with bad DMM (digital multi-meters--which, when they are not working right (or dieing battery), give strange readings that are not exactly "wrong", but don't make sense either).

-Bill

Socratic Monologue · November 2011

Re: Xantrex X-Power MSW inverter troubles

I guess the inverter is bad. I hooked it up to the truck battery and got the same symptoms. Xantrex agreed that it is likely bad and is going to replace it.

The '13v' reading was taken with a cheapie analogue meter. I purchased a DMM, and got a reading (charging, no load) of 13.52v. (At least I think it was charging; the Morningstar controller always seems to have the 'charging' light on when the sun is shining.) I'd like to know how to use this meter to figure out if I could improve life for my battery bank. I hunted the NAWS battery articles but didn't find exactly that. I understand the general procedures of testing resting voltage and testing voltage after loading the bank, and BB's comments above are helpful to me; what I'm not clear on is how to test to determine whether the charging system is ever able to equalize the batteries, whether it is charging them at the correct rate, etc. Could someone direct me to (or give me a short) primer on "how to use a DMM to determine how well your charging system and batteries are performing"?

richard · September 2012

Re: Xantrex X-Power MSW inverter troubles

I have a question about a Xantrex Freedom 458 series 1500w inverter/charger installed in my motorhome. Recently, whenever I plug into shore power (GFCI outlet) the GF trips. I've narrowed down the fault to the inverter/converter. It also trips with the two output circuits on the inv/conv turned off. How do I go about testing it to verify the inv/conv is the problem and if so what could be the cause? I have a digital multimeter.

Cariboocoot · September 2012

Re: Xantrex X-Power MSW inverter troubles

Welcome to the forum.

This is a common problem. It's cause is that the shore power feed has neutral-ground bond, so does the inverter's GFCI outlet (inside the inverter), and the AC out (at least the neutral and/or ground) of the inverter is being inadvertently connected to to the AC distribution system when shore power is in use. It shouldn't. If you are on shore power the AC out of the inverter needs to be bypassed completely. If you are using the inverter to pass-through AC to other loads there's the trouble.

Frankly the most sure-fire way to eliminate the problem is to remove the GFCI from the inverter. These were really only meant to have generators as AC IN, which have no N-G bond.

richard · September 2012

Re: Xantrex X-Power MSW inverter troubles

Cariboocoot wrote: »

Welcome to the forum.

This is a common problem. It's cause is that the shore power feed has neutral-ground bond, so does the inverter's GFCI outlet (inside the inverter), and the AC out (at least the neutral and/or ground) of the inverter is being inadvertently connected to to the AC distribution system when shore power is in use. It shouldn't. If you are on shore power the AC out of the inverter needs to be bypassed completely. If you are using the inverter to pass-through AC to other loads there's the trouble.

Frankly the most sure-fire way to eliminate the problem is to remove the GFCI from the inverter. These were really only meant to have generators as AC IN, which have no N-G bond.

Cariboocoot: Thank you for the quick reply. I am not an electrician but know a little about the topic. What I failed to mention is that I have a 7.5kw diesel generator on-board and the transfer switch automatically switches between shore power, if available, and the generator. If I remove the internal GFCI will that be a problem when I am running on the generator? The strange thing is that the factory installed system and components have worked properly for 9 years with no trouble. Now all of a sudden I have this problem when plugged into the GFCI at the storage facility where I store my motor home. Could the interanl GF be the problem and would replacing it fix my situation?

I also failed to mention that this problem devleoped after we returned from a recent trip. On that trip one night we experienced two very close lightning strikes which tripped the GFCI in the coach's bath area. The surge protector on the 50amp shore power cord did not display any error codes and the campground did not lose power. Nothing even blinked. That GF in the bath protects several duplex outlets in the coach including the ones that the TV's plug into. So both TV's went off. I reset the GF and everything was fine. About an hour later another huge bolt of lightning struck very close to us and the same thing happened. I reset the GF and everything worked fine again. I wonder if the lightning damaged the internal GF in the inv/conv?

Cariboocoot · September 2012

Re: Xantrex X-Power MSW inverter troubles

GFCI's are greatly overrated in terms of the safety they afford. Mostly they add trouble. For instance your case where the shore power is coming from a GFCI and then going through another GFCI before reaching the loads. This is not a recommended wiring procedure. No doubt your storage facility has this GFCI outlet protection because it is outdoors. This is normally where you'd use them; wet areas (outside, bathrooms, kitchens).

Remember that we lived for years without these things. Now it seems they've gone crazy and are stuffing them in every circuit everywhere. This is by no means necessary, nor is it viable (as you've found out). In operation they're a kind of magnetic circuit breaker which 'measures' current going through both sides of the power feed. If it detects an imbalance (more current 'going out' that 'coming back') it trips the breaker to shut off power. The reasoning being that the most likely cause of this is the current finding a different path to ground - like through someone's body. Trouble is when you hook them in series (or have certain other wiring anomalies) they will 'false trip' because of current fluctuations caused by the magnetic windings (becomes a reactive load) or actual other paths to ground (the notorious 'ground loop').

Next question: does the thing trip on its own, or only when supplied from the GFCI protected source? If it has taken to tripping regardless of power source (inverter, generator, or shore power) then the lightning could well have frazzled the internal components. Either way the solution is to ditch the GFCI on the inverter. You can add GFCI outlets to locations in the RV to protect against ground faults, providing there are no loads on them when running shore power (they will trip). Even so you will have eliminated the problem of all the power going down everywhere due to the tripped protection.

BB. · September 2012

Re: Xantrex X-Power MSW inverter troubles

GFI's do go bad too... Replacing with a new GFI may fix the problem.

-Bill

richard · September 2012

Re: Xantrex X-Power MSW inverter troubles

I replaced the GFCI at the shore power outlet and it still trips. How do I replace or remove the internal GFCI in the Xantrex as Cariboocoot suggested and will that cause any problems?

Cariboocoot · September 2012

Re: Xantrex X-Power MSW inverter troubles

richard wrote: »

I replaced the GFCI at the shore power outlet and it still trips. How do I replace or remove the internal GFCI in the Xantrex as Cariboocoot suggested and will that cause any problems?

You have to take the inverter apart. You may not feel comfortable doing this.

BB. · September 2012

Re: Xantrex X-Power MSW inverter troubles

You need to find the point in your RV's wiring that the green wire/frame/chassis ground is (or may be) attached to the AC white/neutral wire.

Given that you are using a MSW inverter--The inverter and/or the external AC wiring (to the inverter output) cannot be (safely) grounded (neutral to green wire/chassis) bond. It creates a short through the MSW inverter back to the battery bank and through the battery's (typically) negative to frame ground connection (not all battery banks are grounded--but most are--common to vehicles to have negative ground to chassis).

You have an inverter/charger--so it should have its own AC input power transfer switch (shore power to AC wiring vs inverter AC output to AC wiring... So, if everything is working/connected correctly, there should be no AC Neutral/green wire to earth ground connection.

So, to test things, start "lifting" (disconnecting) various major AC sub-systems... For example, try disconnecting (or turning of a breaker) the Inverter's AC output and try shore power. If the shore power GFI does not trip, then the problem may be somewhere in the AC wiring/attached equipment. Again, now disconnect each AC wiring "branch" until shore power does not trip--Then look for AC neutral to green wire connections (could be a short circuit, or even a small appliance/light/night light/etc. that connects from Neutral to ground--or even hot to ground).

If the shore power GFI still trips (from disconnecting inverter's AC output), then disconnect the inverter's AC input. If the GFI does not trip, it is probably the Inverter/Charger that is causing the "problem".

That may be because there are enough capacitors inside the inverter/charger to "leak" current from AC line/hot/neutral to earth ground. And that can be a problem. There is no way of you "fixing" the problem without going inside (and possibly creating other problems).

In general, the internal GFI on the Xantrex output should not cause the shore power one to trip.

And--here is where things get tricky--Assuming that all is working (no shorts anywhere), you can try plugging the RV shore power plug into a non-GFI outlet. Hopefully everything works.

In theory, that should be "good enough" to leave the RV's inverter power protected by the GFI on the Xantrex (assuming all AC wiring in the RV goes through the inverter). Any outlets in the RV that connect directly to the shore power (not through inverter), such as a coffee maker outlet near the sink, should have their own GFI outlet.

This is where we "get into trouble"... GFI protection should be at the "point of use"/last branch circuit. If there is a problem and a GFI trips--in will only turn off the failed appliance and nothing else (i.e., a GFI for a "whole cabin" would trip if there was a blender in the sink--but it would also turn off power to the rest of the cabin too--Leaving the whole space in "darkness"--Hazardous in itself.

So--the GFI outlet on the shore power is great for when you plug in an electric drill to work outside in the rain... However, when plugged into an RV, you have a "single" point of turning off power to the whole RV--which is not what GFI is really intended for.

I am hesitent to tell you to simply remove the GFI outlet and use a standard outlet for the trailer--and use GFI where needed in the RV... Because there may be other wiring "issues" that removing the GFI on the shore power may simply "hide" (it is fairly common to find black/white/green wirings "mixed up" in an installation). So, if you where to to that--I would only do it after you are sure everything else is fine.

You can check wiring to an AC outlet by using a AC Outlet Tester (or even use a DMM once you get the hang of it):

Note, the outlet tester will read "OK" when connected to shore power, and probably with an "open ground" when running the MSW inverter or show both Black and White hot to ground--depending on how the battery negative ground is configured (floating or grounded).

Anyway--use the tester to verify shore power connected wiring first--Then you can figure out the off-grid behavior next.

-Bill

BB. · September 2012

Re: Xantrex X-Power MSW inverter troubles

Forgot to add--There are lots of websites on how to use a DMM--such as this one:

http://www.sparkfun.com/tutorials/202

-Bill

Xantrex X-Power MSW inverter troubles

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