Weird Inverter Issues

Battling Bob
Battling Bob Registered Users Posts: 20
Early this winter, I wrote the following to a well-known Trace/Xantrex tech in Redmond, Oregon. The saga continues, with recent developments, but this is the background through late November. (For those who will immediately jump on the China Diesel/Mecc Alte combo, some of these things were occurring before with a Yamaha EF12000DE, too.)

Anyway, flashback to November...

[I have a fully off-grid setup with a Trace SW4024D Integrated Power Panel, self-installed in 2001. My current genset is a 1998 Hardy Diesel (Shanghai Tractor variety) with Mecc Alte 15Kw. Got this with less than a hundred hours on it from an unfulfilled Y2k survivalist in Northern Idaho--runs great, churns out a steady 120/240 supply on teaspoons of diesel.

My #1 inverter, though, has taken to drawing the voltage on its leg up, up, and up--until it either loses sync, or pops the 35-amp breaker out, or simply stops drawing power even though it's still showing sync on the display. While #2 shows 120 volts inverter and maybe 121 or 122 genset, and draws steadily at or near max charge amps, #1 starts that way and then drifts steadily up until inverter voltage is as high as 130, genset voltage at 133 to 135. If it doesn't pop the little breaker, it'll sit there showing sync but with 0 input amps. I've tried several different diagnostic configurations on consultation with Erick Bentsen and "Thomas" at Schneider Electric, who currently handle tech support.

With minor variations according to the scenario, this behavior from #1 occurs in all the following configurations: 1) swapped hot leads from the generator between #1 and #2--no change whatsoever; 2) Moved inputsfrom AC2 to AC1--no change; 3) Removed series stacking cable--no change in #1, but #2 now shows a corresponding DROP in inverter and genset voltage, as you might see with an unbonded neutral when the two legs vary widely but still add up to 240. Genset always shows balanced voltage at about 122 or 123 when breaker to inverters is open--nor does it seem to vary much when I bypass the inverters and apply loads to either leg.

I'm assuming that whatever is happening is on the charger side, as the inverter function still seems to be perfect on both legs of the household circuit--120 volts on the nose, with no peculiarities.

I'd appreciate any guidance you can offer. I believe my present difficulty may be a further evolution of the "hunting" problem back when--a wandering demand from the #1 inverter that surely contributed to the demise of the Yamaha. Now, though, we're rapidly approaching the point where there'll be no load on the leg to #1, which will eventually trash the generator. Thus far, the genset doesn't seem much troubled--I guess it's a big enough set that even this unbalanced draw isn't working it too hard--but that can't go on forever.]

End flashback. Update--on Dean Abney's advice, I did some tinkering with the max charge amps, max volts, and whatnot between the two inverters, and achieved a reasonable balance. At least the 35 breaker button quit tripping. THEN, however, as we've always had plenty of extra power in the summer, and because our Crystal Cold gas fridge was giving us trouble, we bought a Kenmore 21-cubic foot electric fridge for summer use. What I've discovered with this, now, is that when I'm charging the batteries, I can't turn off the generator while the fridge compressor is running--or, when I come back into the house and look at the power panel, the top inverter is buzzing and showing an error light AND AN AC INPUT LIGHT...as if the bottom inverter was somehow backfeeding through the fridge compressor motor into the top inverter, or...or...or... Hell, I don't know. Anyway, if I go in and turn off the fridge and turn it back on, the problem goes away--no error light, no AC Input light, and normal operation is back. If I wait until the compressor is not cycling to go turn of the genset, no problem.

Any ideas, folks?
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Comments

  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues

    Check to make sure you have the battery float and absorb voltage settings on the two inverters exactly the same.

    Series stacked SW's will throw current spitballs between themselves if the battery float or absorb levels are different.

    Get yourself a clip-on ampmeter with DC capability and check the DC currents on each inverter individually.

    Sounds like one is trying to raise the battery voltage while the other thinks the battery voltage is too high. This causes the one that think the battery voltage is too high to suck off battery power and push it to its ACin/ACout node.

    If they are set the same the calibration might be off on one of the units. Again, you will see one inverter pulling DC current while the other is pushing DC current at the battery.

    If you back down the Max AC Chg Amps it will reduce the pushing and prevent the other inverter from raising the AC voltage on its side. You can also sweak the float voltage setting on one unit to attempt to equalize the units. Do it in 0.2 vdc steps and check current flow between inverters.

    The one that is pushing to the ACin/ACout should have a negative number on the meter menu for AC2in amps.
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Thanks for the suggestions--I'll follow them and post the outcomes. I suspect calibration may be the issue, as I'm pretty sure float and absorption volts have been set the same before without improvement--though when I just checked bulk volts on #2 was set lower... I think that was an earlier effort to stabilize these guys. But the DC output is an angle I haven't investigated. I have both a contact and a hall-effect ammeter, so will do some testing tomorrow. I'm assuming I need to do this while I'm charging...? Well--I'll try both genset on and genset off.

    Again, thanks--having these inverters go down would be semi-catastrophic for us just now.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues

    One other thing I forgot and that is the temp sensor. Since they modify the charger set voltage they must both be good and connected on each inverter and next to one another so they don't have a temperature differential between them.

    You can remove both of them also.

    The temp comp is done in discrete steps every 2 deg C. When one inverter sensor is just on lower side of the shift temp and the other inverter is just on the higher side there will be current pushing between units because of the different float voltage setting.

    To your question about assuming it has to be charging. Answer is no, SW always tries to regulate battery voltage when inverter is running and on ACin power. If something external to unit tries to raise battery voltage above its regulation point it will suck off power in attempt to keep battery voltage regulated. With two inverters on the battery you can have one pulling and other pushing. This sucks power off of L1-N ACin and pushes power to L2-N ACin.

    The issue only exist when there is ACin. Series stacking cable just makes sure when one unit shuts down the other does also, and provides a clock to keep 180 degree ACout shift when operating off batteries with no ACin. Other than this, the two inverters operate pretty much independently.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: Weird Inverter Issues

    I, Too, have had issues with SW+ 5548s in Stacked and at second site, a single 5548.

    It is impossible to use an inverter output genset on the AC 1 or 2 of these inverters. During Bulk, all seems OK, but at the point where the Inverter's Charger needs to regulate, the AAC in voltage from the generator gets yanked up to and above the Max AC input voltage, regardless of how high this value is set. The inverter makes a much LOUDER HUMMING when this happens, and then AC in is dropped, and this cycle begins anew.

    Have used the largest Honda inverter genset, the EU 6500 with 240 AVC out, and this happens. Have used it with all of the 6500's output at 120 VAC, on only one inverter, and this happens.

    In the second site, there are two SW+ 5548s, but only one running, and no stacking cable (at this poiint), with a lil EU 3000isa genset, it happens. Have backed off the AC input charger currrent, and it happens until some uselessly small AC IN Current is set.

    BUT, with either the stacked inverters, or the single, using a much larger genset, 25 KVA in the stacked system, and an 18 Kw in the second, this does NOT happen. So, guess that the inverter needs a very low impedance AC current source to be able to regulate the battery voltage (?). Have tried supplemental loads on the EU genset AC output, thinking that this might stabilize the AC Voltage, but no dice. In each of the above cases, the bank is a 1280 AH nominal, Flooded bank.

    Seems that the magic of Inverter gensets (at least the Hondas), cannot really be used for SW series Inverter/Chargers. Have been using an EU 3000 genset and a 60 Amp DC power supply/MX-60 to do the charging, while getting the larger PV array installed at the second site.

    Any thoughts ? Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues
    Vic wrote: »
    I, Too, have had issues with SW+ 5548s in Stacked and at second site, a single 5548.

    It is impossible to use an inverter output genset on the AC 1 or 2 of these inverters. During Bulk, all seems OK, but at the point where the Inverter's Charger needs to regulate, the AAC in voltage from the generator gets yanked up to and above the Max AC input voltage, regardless of how high this value is set. The inverter makes a much LOUDER HUMMING when this happens, and then AC in is dropped, and this cycle begins anew.

    Any thoughts ? Thanks, Vic

    Ah, you have found the other little flaw in the SW charging. Remember the inverter is bidirectional, when the battery voltage is taken above the SW's float or absorb voltage setting (depending on what mode is active) it will suck off battery node and convert to ACout node, which is also ACin node when power relay is engage during ACin sourcing.

    When it finishes absorb charging phase and switches to float phase the battery voltage regulation on SW is immediately and suddenly changed from your absorb setting to your float setting. Well guess what, having just finished absorb, the battery is at a higher voltage then the float setting for a while. When inverter makes the hard switchover to the lower float setting it thinks the battery voltage is too high and sucks current off the batteries to reduce their voltage to the inverter's float setting. It will do this for a short while until the battery voltage drops to float setting voltage. If ACout loads cannot consume the pushed AC power output from the inverter then it goes out the ACin port. If this is a generator then you push power at the generator. Most generators don't like that.

    You can see it in the ACin current meter in menu 4, as a negative number. If you have a battery current meter you can also see a sudden discharge current right after it switches from absorb to float. Same issue if you do an equalize when it finishes and drops back to float setting.

    You can remedy the issue by have some ACout load to consume the short period of backwash, avoiding too much being pushed at the generator. I never let the charger go to float on a generator, not because of issue but because it is just bad fuel economy to run a generator all the way to float mode switchover.

    The XW inverter, with its fine resolution PWM adjustment capability does a graceful, slow transition between absorb and float voltage settings to avoid pushing AC power out.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: Weird Inverter Issues

    Interesting, Thanks RC. I have seen this when in Asorb, at least for the Stacked configuration, where one inverter seems to yank a lotta current on one side of the AC in, and the other side seems to be pushed or dragged out of regulation and this inverter drops the AC in. All of this was with the EU 6500isa Inverter genset.

    The only remedy I've found is either DC charging with an EU gen, or using a much larger generator with traditional alternator and voltage regulator.

    OK, RC, you ARE THE Xantrex Inverter/Charger guru, in my book. Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    So--an update on my initial posting at bottom. I cut back the charging amps, pulled the temp sensors--one HAD fallen to the floor between batteries--and lengthened the absorption time. As long as I turn off the generator before either inverter goes into "float," I'm fine. If the bottom inverter is in "float," AND the electric refrigerator's compressor happens to be running, I may get the pushing effect when I kill the genset--inverter still charging even with the genset off, but inverter still providing AC power. If the TOP inverter goes into "float" first, I get a tripped-off inverter with a steady error light--"Input Relay Failure." Not sure what to think about that--I'd think a physical failure, as in fused contacts, would be consistent. As for a computer failure, I think I updated way back in 2001 or so, when I notified Xantrex that my inverter kicked out when the auto-start genset I had then would spool down on shut-off--they sent me a free upgrade and instructions for installing it. It worked perfectly for eight years with that upgrade.

    How might I get a look at the relays? Don't want to start tearing things apart without some idea where I'm going and what I'm looking for.

    Thanks.

    Update 6/19--Actually, I found that you can see the relays right through the air vents in the front of the cabinet. Not that it's a good view, or helpful in terms of diagnosing the issues here, but at least I know where they are. And my software is the 4.20 version, so I believe I'm updated past the early glitches.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues
    As long as I turn off the generator before either inverter goes into "float," I'm fine. If the bottom inverter is in "float," AND the electric refrigerator's compressor happens to be running, I may get the pushing effect when I kill the genset--inverter still charging even with the genset off, but inverter still providing AC power.

    The only way I can think of that would cause the inverter to stay in charging mode with generator off is if one inverter is pushing back through generator stator winding and creating output on the other phase pushing into the inverter that is staying in charge mode. The generator is acting like a transformer.

    The pushing inverter that is not in charge mode should have opened up its AC2in relay. What do the AC2in green LED's say?

    Try cutting off the breakers between AC2in and the generator.

    There were problems with software recognizing a generator dropout causing 'welded relay" contact problems. There is a service bulletin on it.

    I love their software configuration management, from the bulletin, [ The original software read “Revision 4.20”, the revised software now reads “SW Series Revision 4.20”. ] :(
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Thanks for your response, RC. The genset is a China Diesel, 2-pot, with a 15 KW Mecc Alte generator head. It's not set up for auto-start with the 4024's, so my routine is to make sure the breaker is open; fire the genset and wait for adequate warm-up; then trip the breaker closed. Shut down is just the opposite--trip the breaker open; allow a couple of minutes cool-down; kill the genset. It's when I trip the breaker open--completely cut all power to the inverters--that this latest phenomenon occurs and I get the "Input Relay Failure" error reading.

    BUT--perhaps you mean the onboard breakers on the Power Panel's connection box...the uppermost cabinet in the IPP assembly.

    I guess I should put out a sort of Event Log here. Maybe it will tell you something.

    1. Prehistory: had a Yamaha 13000DE genset that always started "hunting" a few minutes after syncing up with the 4024D Power Panel--WAAAooooWAAAoooWAAA, and so on. Blew a lot of voltage regulators over the years--ultimately turned out to be an improperly set valve on the #1 cylinder.

    2. Got the China Diesel genset and new batteries--12 Surrette 460's. Things are fine for several months. No "hunting." No problems. At normal charge levels for the 4024's, this genset is hardly working at all.

    3. Began to observe occasional spiking of the input voltage on the #2 inverter; up and up it crept until sometimes it tripped the 35-amp onboard breaker. Played with Charge Amps and other adjustments and achieved a working balance that stopped tripping the breaker.

    4. Installed electric fridge for the summer months, and observed that when the compressor was running, and if either of the inverters had gone into "float" mode when I tripped the input breaker, I was likely to come back in and find the top inverter still showing AC in good, but flashing an error light and buzzing loudly. (Still providing house power, by the way.) Bottom inverter normal. Reaching into the fridge and turning it off stopped the problem--inverter returned to normal.

    5. Determined not to let "float" mode occur, I only run the genset a half hour at a time. But now, if that fridge is running when I shut down the genset while still getting 8 or 10 charge amps, I'm liable to come back in to find the inverter shutdown and the "Input Relay Failure" lamp burning steadily on the bottom inverter. But...not always.

    I'm stumped.

    Update--sorry to be redundant here. In the "Reply" window, I couldn't see that I'd gone through most of these details in my first posting. This does lay out the progression a little more succinctly, though.
  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
    Re: Weird Inverter Issues

    I've never been completely satisfiedwith the generator charging through my SW4048. It would drop to float before the absorb time had elapsed. To work around this (I'm always there when generator runs) I put the float voltage point the same as the absorb point. Checking the SOC with hydrometer determines the generator charge stop (Mk 1 eyeball).

    If you're always around when charging why not try "outsmarting" the inverter by changing the float setpoint?

    Ralph

    ps I had "hunting" issues too. The inverter would ramp up to the charge amps setpoint then drop to zero, then repeat ad nauseum. 35 amp breaker at fault...complete failure of charge and invert...repaired and fine for the last 5 years.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues

    The backwash problem on a series stack SW arrangement doesn't happen until the SW goes into battery voltage regulation, either at bulk voltage setting or float voltage setting. Problem is made worse because one unit will always go to voltage regulation before the other. It really gets bad when one flips to float mode while the other is still in absorb mode.

    For manual operation I set the bulk (absorb) voltage setting a bit high so I can be sure I have more time to manually shut off the generator before SW start voltage regulation at bulk voltage setting. It also gets the battery to a higher state of charge.

    For automatic generator control there might be a way to use the relays on a voltage sense setting to shut the generator off at a battery voltage lower then the bulk voltage settting thereby avoiding the back push of power into the generator.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues
    Ralph Day wrote: »
    I've never been completely satisfiedwith the generator charging through my SW4048. It would drop to float before the absorb time had elapsed. To work around this (I'm always there when generator runs) I put the float voltage point the same as the absorb point. Checking the SOC with hydrometer determines the generator charge stop (Mk 1 eyeball).

    If you're always around when charging why not try "outsmarting" the inverter by changing the float setpoint?

    Ralph

    ps I had "hunting" issues too. The inverter would ramp up to the charge amps setpoint then drop to zero, then repeat ad nauseum. 35 amp breaker at fault...complete failure of charge and invert...repaired and fine for the last 5 years.

    Setting float and absorb voltages the same will not prevent the units from going into voltage regulation where the backwash begins. You have got to avoid hitting the bulk (absorb) voltage level regulation point.

    The hunting issue is likely the interaction with generator and how generator is reacting to a reverse current on one of the 120 vac legs.

    Aside comment: I have a 15kW Generac with direct split phase connect that I have the problem with. I also have a Yamaha EF3000i inverter generator with 120vac output that I feed into an isolating 120vac to split phase 240 vac transformer which I feed into two SW4048's set to 11 amps max AC input each. I don't have the problem allowing the inverters to go to float on the Yamaha setup. It seems to be because the isolation transformer is passing the push through to other inverter without the generator seeing any backwards current.

    The Yamaha setup is my quiet 'trickle charger'. I pull the 15kW Generac out when I need a quick charge.
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Question--is there any record of modern inverter-driven appliances being incompatible with older Xantrex inverter/chargers? I've read some posts from folks who have trouble with inverter gensets and their inverter/chargers--that made me wonder if the odd issues I've been having with the refrigerator and/or freezer compressors running when I shut down the genset could possibly be a compatibility problem. If so, are there any workarounds?

    Thanks for any help anyone can offer.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Weird Inverter Issues

    My rule of thumb for electronic supplies:

    Power Factor > 0.95 then MSW or TSW inverters are probably OK. PF corrected power supplies typically have a input switching power supply that attempts to mimic a "resistor" (Current = Voltage/Resistance). Typically "wide range" power supplies with an input voltage range of 100 TO 264 VAC have a PFC front end which limits inrush current.

    Power Factor < 0.85 or so then MSW is probably going to be "hard" on the device. Most switching power supplies have a Diode feeding a high voltage capacitor. The MSW almost instant change from 0 to 150 vdc causes high current flow through that diode. TSW has a slower rise time and limits current naturally. Remember that heating is P=I^2*R -- So that if the peak current is 2 or 4x higher, then the waste heat in that diode/capacitor is 4-16x higher. Typically non-PF power supplies have 120 OR 230 VAC input voltage... And either a manual 120/230-240 switch or an "auto-switch".

    Today, larger power supplies are supposed to be Power Factor Corrected and smaller supples (net book computers, wall transformers, etc.) are not.

    I would look at measuring the current and power into a device and see if:
    1. If power/current/VA is about the same between MSW and PSW power--then you may be OK.
    2. If power/current/VA is higher for MSW (upwards of 20% or more)--then I would suspect that there will be problems.
    Note that voltage may be different between MSW and PSW power sources (inverter vs grid)--so you may have to account for the different in voltage (10% lower voltage may use 10% higher current).

    Also--the wave forms for electronics / MSW inverters are actually quite complex. And simple DMM (digital multi meters) and Kill-a-Watt meters are not really designed to properly measure/report current/voltage/power/etc. correctly.

    Meters that are listed as True RMS (Root Mean Square) are designed to properly display non-sine wave voltage/current/etc. readings (even then, there are details that push the costs way up for "good" True RMS reading meters).

    Unfortunately, it is a very complex subject. And there is very little out there from manufacturers that can give a consumer/end user good guidance.

    That leaves it to the end user to perform their own "smoke tests"... Not a good thing either.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Thanks for your response. My inverters are series-stacked SW 4024's in an integrated power panel. True Sine all the way. We're completely off grid, so it's a) fairly critical that I figure this out sometime before winter, and b) not possible for me to test against grid power. I'm getting "Input Relay Failure" error readings when I trip off the genset (240) breaker with either or both fridge and freezer compressors running; if neither is running, no problem at all. Of course, come winter, we'll be back into our propane fridge and freezer, so maybe it's just a passing inconvenience--but somehow, I smell inverter failure on the breeze...
    Rob C
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    As for smelling inverter failure in the breeze, I didn't have to sniff too long or too hard. This evening, fired the genset to pick up a little charge for the night--had run the washing machine a lot today--and began to hear popping noises from the back of Inverter #1. Weird surges in the inverter fans...funny smells...wild fluctuation outside at the generator...inverter shutdown--managed to get out and get the genset shut down. Inverter is running the house just fine on AC--but I'm going to have to look in the back of that thing, and I'm going to find something burnt. Guess I'll see if I can charge batteries with the lower inverter and cut the upper out until I can figure out what's going on in there.
  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
    Re: Weird Inverter Issues

    Bob
    Sorry to hear about your smokey failure. Repair/parts for an SW inverter might be really expensive or just about impossible. Don't forget to factor in the cost of freight/shipping with the repair costs when deciding whether to pop for a new 120/240 split phase XW6048 or Magnum. You can tell I like to spend other people's money!:-)

    Ralph
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Weird Inverter Issues

    Those Relays seem to have a number of life cycle's. The way your charging is the same way we use them in the Marine world. At our Inverter service center they will file or sand the cont actor points off, but they won't last to long, it's worth a try though if you don't want to spend $$$. You might be able to resource a couple replacements, if they don't have a weird coil voltage.

    Experience says if you let them chatter like they are doing the will heat up and melt the solder off the board and create a bigger issue..
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues

    There are relays available. It is Deltrol 375P series 3PST with 12 vdc coil. I have seen them for $15 to $25. If you have trouble finding a 12 vdc coil you may have to switch out your old coil in the new relay. They run the three 30 amp contacts in parallel for the 60 amp max current spec. Not exactly great way to do a 60 amp relay but they got it past UL approval.

    If you are off grid you can switch the generator over to AC1in which will then run on the other power relay. I would do that first just to make sure nothing is wrong with inverter electronics. My next suspect after relay would be power MOSFET's.

    Arcing relay contacts may throw off the inverter syncronization lock which will make things worse. That would start stressing the MOSFET's.
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Not sure what "let them chatter" means--the popping in the back of the inverter was a one-time event that only lasted as long as it took me to sprint to the genset, though I did cause it to happen again, briefly, in doing some diagnosis. Perhaps you're referring to something else in the thread history, though.

    In any case, this inverter is definitely down and out as a charger, and may have taken out the genset as well--flipping the breaker causes the diesel to bear down as if heavily overloaded, even with the bad inverter switched out of the circuit at the power panel. I'll be disconnecting my main cable and applying direct loads to the genset this morning in the desperate hope that I just shorted something in the buried line from genset to inverter--I have several splices under there. At least under no load, it was putting out a steady 122 per leg, so there may be hope. Wild noises, though--wish I'd reacted by cutting the breakers on the power panel's distribution center as soon as I heard the popping, rather than racing a hundred feet out to the shop to kill the genset. I swore I saw a wisp of blue smoke as I approached, too. Hope it's just a short--or at worst, a voltage regulator.

    The popping noise appeared to come from the area of the FET board in the back of the inverter. I've seen a couple of those for sale on ebay, new in their boxes; the relays are readily available from the original manufacturer, and not terribly expensive, though their being soldered onto the boards is an issue. But I'll bet that even if I couldn't safely unsolder the old ones and resolder the new ones using a heat sink, I could cut those little legs off close to the relay body and make little spade-terminal couplers to connect the new ones.

    Anyway, if I can get the system to charge with my little backup gasoline generator using 120 on the lower inverter, I'll have the leisure to pull the upper one apart and see what's what. If it just won't work, then I'll be rather urgently shopping for a new inverter.

    From the general "word" out there, it seems a no-brainer to go with Magnum Energy MS--I can't seem to find any bad stuff on them except complaints about the noise, which isn't really an issue for me, and they're about half the price. People rave about the charger side. I'm a little concerned that they're less than half the weight of my old SW's--maybe technology has advanced enough in the last decade to explain that, though. Anyone got any reviews on the Magnum Energy MS series?
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Just a follow-up. If I ended up getting a Magnum inverter to replace this one, is there any reason it couldn't be on the same panel and charging the same batteries with the one Trace inverter that's still good? I don't actually use my 240-volt capacity at all, so there's no need to maintain my series stacked configuration--but would there be some incompatibility issues as a result of the common ground in AC, or being hooked up to the same battery bank in DC? I see that the Magnums are available with a 240 outlet, and I probably only need 4000 watts overall--but it would be nice to disrupt my present setup as little as possible. Thanks for any advice you may have--I'm pretty good at Tab A to Slot B operations, and detecting large scorched areas, but electrical theory is out of my depth, I'm afraid.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues

    Picture of one of my SW+5548's MOSFET board after a snap, crackle, and pop.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Weird Inverter Issues

    You need to read the Magnum manual for that inverter regarding DC and AC grounding closely.

    In general, TSW inverters can have one AC output neutral (or the split phase 120/240 VAC with grounded neutral).

    And, usually MSW inverters cannot have any output grounded.

    But, again, need the manual for your specific product.

    You can run multiple inverters from one AC battery bank--I would suggest that you home run the DC cable from the inverter to the battery buss common point (do not run one cable from battery to inverter A then to inverter B--they could affect each other with electrical noise).

    Regarding AC output--you will need a completely separate AC distribution box/breakers/etc. between the two different inverters. Since they are not frequency sync'ed--you do not want mix AC output connections between the inverters.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Weird Inverter Issues

    i have a 1kva model and it is doing a good job for me. i use a gen start remote for it so i can customize my charging parameters for my agm batteries and that includes my charge amps. i thought i had an issue with it slipping out of inverter standby, but it's ok now and i'm attributing it to my error even though i'm not too sure what that error exactly was even though i have a theory as to what it was. even though i thought i had a problem the folks at magnum energy were there for me and i appreciate that.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Weird Inverter Issues
    Not sure what "let them chatter" means--the popping in the back of the inverter was a one-time event that only lasted as long as it took me to sprint to the genset, though I did cause it to happen again, briefly, in doing some diagnosis. Perhaps you're referring to something else in the thread history, though.

    In any case, this inverter is definitely down and out as a charger, and may have taken out the genset as well--flipping the breaker causes the diesel to bear down as if heavily overloaded, even with the bad inverter switched out of the circuit at the power panel. I'll be disconnecting my main cable and applying direct loads to the genset this morning in the desperate hope that I just shorted something in the buried line from genset to inverter--I have several splices under there. At least under no load, it was putting out a steady 122 per leg, so there may be hope. Wild noises, though--wish I'd reacted by cutting the breakers on the power panel's distribution center as soon as I heard the popping, rather than racing a hundred feet out to the shop to kill the genset. I swore I saw a wisp of blue smoke as I approached, too. Hope it's just a short--or at worst, a voltage regulator.

    The popping noise appeared to come from the area of the FET board in the back of the inverter. I've seen a couple of those for sale on ebay, new in their boxes; the relays are readily available from the original manufacturer, and not terribly expensive, though their being soldered onto the boards is an issue. But I'll bet that even if I couldn't safely unsolder the old ones and resolder the new ones using a heat sink, I could cut those little legs off close to the relay body and make little spade-terminal couplers to connect the new ones.

    Anyway, if I can get the system to charge with my little backup gasoline generator using 120 on the lower inverter, I'll have the leisure to pull the upper one apart and see what's what. If it just won't work, then I'll be rather urgently shopping for a new inverter.

    From the general "word" out there, it seems a no-brainer to go with Magnum Energy MS--I can't seem to find any bad stuff on them except complaints about the noise, which isn't really an issue for me, and they're about half the price. People rave about the charger side. I'm a little concerned that they're less than half the weight of my old SW's--maybe technology has advanced enough in the last decade to explain that, though. Anyone got any reviews on the Magnum Energy MS series?
    Well " Let them Chatter " means to me that they were not making a reliable contact based on your " I'm getting "Input Relay Failure" error readings " on transfer. Now the MOSFET failures could be the Chicken or the Egg. I have no idea what came first. All the boards with the MOSFETS popped open and burnt are like yours, have no AC output. I have learned at the first time they won't transfer, to take them in to the service center.

    On a boat , it's very easy to have many transfers a day when the inverter is in use and charging with a generator. I try to unload the inverter as much as I can before I switch. 10-30 amps is a big load to transfer and the contact points get pitted and burnt pretty easy.
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Well, it's stranger and stranger--attempted this morning to cut the top inverter out of the circuit by disconnecting its lead from the genset, and charge through the bottom inverter. No sooner had I tripped the breaker on than my wife stepped out on the porch hollering about an explosion--so off goes the genset, and into the house I sprint. Sure enough, the flexible metal conduit that carries the generator leads into the house had arced through, about two feet from the power panel's distribution box, having been in that exact position for close to eleven years now. Pulled the cable, twisted off the shielding, and found better than two feet of #6 cable--black, red, and white--fused to the metal, with regular little burns right through to copper about every quarter inch. Found it had been arcing a little bit at the conduit's strain relief at an outside junction box--but under the nut, so it was invisible from the outside.

    It's POSSIBLE all the popping I heard was coming from inside that conduit, issuing right out the end of the tube where it connects with the distribution box. Completely rewired the outfit today--still just hoping to be able to charge on one leg, through the "good" inverter. Cut off both breakers at the distribution box, fired up the genset, then gingerly tripped on the lower inverter...waited...sync! Charging! Let it go for a half hour or so (I know, not a good imbalance for the genset, but it's a big guy), then tripped the lower inverter off and REALLY gingerly tried the upper--the one I KNEW had fried the night before.

    To make a long story just a tad less long than it COULD be--both inverters are charging normally even as I write. Don't know how much influence a little developing short might have had in all the weird inverter issues that preceded this incident--no breaker ever tripped, which makes me think I'm a little underprotected by them. But I knew a guy once whose camp trailer shocked everyone who grabbed the front door for two years. It also never tripped a breaker, never arced and burnt--but had a little nick in one side of a 240 lead that I happened to find for him when I accidentally moved that cable close enough to metal to get an actual spark.

    So--for the moment, things are just aces here on the ranch. We'll see...
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Weird Inverter Issues

    Great you found it. I was thinking that, on a boat you have a shore power cord 30-50 amp. A bad M/F plug connection or cord on one leg will give you the same thing. As the boat moves up and down and rocks the inverter will keep transferring on and off 24/7. A transfer Relay failure is not far behind in that condition.
  • Battling Bob
    Battling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Yeah--the Great Miracle of 2011, in my book, is that this inverter appears not only to be working normally now, but better than it has in years. There was simply no doubt in my mind, given the dimming lights, flashing error signal, sudden spooling down of the genset--a full-blown crash, to all appearances--that this sucker was just gone. After charging for an hour last night, I shut down without issue, even though the refrigerator and freezer were both cycling at the time.

    If there was any chance I could understand it all, I'd love to hear a technical discussion of how a slowly developing short could cause all those issues without ever starting a fire, tripping a breaker, or shocking someone, until it suddenly blew a hole in a piece of armored cable... It also never showed a short in cold testing--a bad cable connection somewhere was one of the first things I suspected, long before the behaviors got really bizarre--and never showed any voltage loss or other odd reading with the genset running.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: Weird Inverter Issues

    Am curious, you mention Black, Red, and White. What forms the safety ground ? The "conduit" itself? Was there a separate ground (Green wire for example)? Was the cable MC ?

    Am no hotshot on this, just curious.

    The SW and SW+ inverters seem very tough ... knock knock, have four of them in service and so far they have been real troopers.

    Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Weird Inverter Issues
    Vic wrote: »
    Am curious, you mention Black, Red, and White. What forms the safety ground ? The "conduit" itself? Was there a separate ground (Green wire for example)? Was the cable MC ?

    Am no hotshot on this, just curious.

    The SW and SW+ inverters seem very tough ... knock knock, have four of them in service and so far they have been real troopers.

    Good Luck, Vic

    Black is L1, Red is L2, White is neutral, Green is ground. Ground green wire is to grounding lug on SW case. You should never use conduit as ground return. If you put an aux box you run a green wire from main box case to aux box case through conduit between boxes. Only main breaker box has ground connection to outside ground rod.

    For the generator feed you need a four wire connection. Green is chassis of generator to ground on breaker panel. The NEC says AC source should be ground reference but I prefer not to connect a ground rod directly to a portable generator, instead I use the green interconnect ground to breaker box. If it was a permanent, fixed generator hard install then maybe I would use ground rod on generator as grounding reference.

    Sounds like you need to replace the generator wires with some good THHN #6 or #4 wire.