Trace SW4024 refusing to remain in charge mode when on new generator

Hi folks,

I'm new to this forum, but I've been living with alternative energy since 1996. My home has a hybrid solar/wind charged 24V system with a Trace SW4024 at the heart of it. I also now have grid power available, after laying over a mile of concentric-neutral 7200VAC cable under my pasture and throwing a couple 30:1 transformers at each end of it. Once I got the grid power online, my system basically became a "whole-house UPS" for all loads powered through the inverter. I put the inverter into SILENT mode so I wasn't spinning my meter charging batteries, and just let the PV panels float the battery.

For years, I had a small/portable 4.5kW Onan gasoline generator that I used to charge the batteries, run my well pump, small MIG welder, air compressor, lathe, etc... The 4024 had no problems charging the battery bank on that generator (tho' I would have to reduce the inverter's max grid charge amps setting when using it, or it would quickly trip the generator's 20A breaker).

I've just permanently installed a new genset - a Yanmar diesel spinning a Mecc Alte 5kW head - to replace the aging Onan that I've used for tons of OTHER stuff around the ranch for years. Like the old Onan, it connects to my system through a 200A manual Grid/Gen transfer switch. (GEN AC input is unused on my inverter.)

Everything seems to work fine, EXCEPT the inverter's charge function. When AC is present from the generator, the inverter will only enter charge mode for 20 seconds, then go back to inverting for about a minute before endlessly repeating the cycle. Naturally, my first thought was that the battery charger was too large a load and the voltage was dropping, so I went into the setting menu (even before I grabbed a DMM) to check things out. I made the following changes...

- BATTERY/MAX CHARGE AMPS AC: 12 Amps. This had been at 35 Amps. Was really SURE that was it! (The SW4024's grid input is fed from a 50A single-pole breaker.)

- AC INPUTS/SET GRID SIZE AMPS AC: 20 Amps. This had been at 45 Amps for years with no issues.

- AC INPUTS/SET GRID LOWER LIMIT: 105 Volts. This had been at 108 Volts. (Upper limit remains at 129VAC.)

After making those changes, I still have the charge/invert problem exactly as before. Using a cheap Tenma DMM, my new Yanmar is putting out ~126.5VAC under NO load. With the SW4024's AC Input breaker OFF (so all of its loads are supplied from the battery bank and it can't try to charge), system voltage throughout my home is ~123.4VAC. Running a 1HP 240VAC well pump drops the system voltage to 122.1VAC. All that seems fine.

As soon as I throw the inverter's AC Supply breaker ON, the "AC In Good" LED comes on, and after about a minute, it goes into charging mode, which lasts 20 seconds and then the cycling starts again. Not trusting the Trace's internal voltmeter, I checked an outlet below it and when it's inverting, I have 119.8VAC and when it goes into charge mode, I have about 122.2VAC. That's nowhere near the 105VAC limit I set for the GRID LOWER LIMIT, so I have NO CLUE what is causing the inverter to drop out of Charge Mode when it's being supplied by this little Yanmar. Again, it never had a problem with the Onan.

There's something I must be missing, or some sort of noise coming from the Yanmar that the Trace doesn't like.

Anybody have any ideas? Thanks in advance for your consideration!

Darrin in Wyoming

Comments

  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    Welcome to the forum Darrin,

    There is one thing that people have done to "stabilize" an AC genset for some off grid inverter-charger issues... Basically put a 100 Watt lamp or, in you case (because this is a larger genset and 100 Watt lamps are getting hard to get), a small electric heater on the genset AC output and see if it changes the behaviour of the genset.

    Usually, this is done for inverter-chargers that don't ever "connect" for charging. I am not sure if it would do anything on an I-C that is connecting for 20 seconds the dropping. Some gensets do not have very stable AC output when unloaded and/or with small AC loads.

    For some inverter-chargers/UPS type units, if the frequency of the genset swings/hunts--That sometimes causes the charging section to interpret this as an impending AC line failure.

    Making sure the engine's RPM governor is well adjusted/lubricated/working correctly may help.

    Those are my first guesses.

    Good luck!
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Posts: 2,906Solar Expert ✭✭✭✭
    Hi Darrin,

    Just a couple of things;

    You might set the AC Charger amps to a very low value -- perhaps 5 A, and see how that works, if that is OK, then ramp up that value slowly, over time.

    Am sure that the genset is on AC2, which has a fairly wide range of genset frequency, but it still the generator's AC could disqualified if the frequency if out of the frequency window.

    It is possible that if the generator is cold, that it cannot make good power, and its output falls out of qualification.

    Have you watched the gen AC output voltage at the time that the gen AC input is dropped?

    If the Diesel is cold, it will blow smoke, and perhaps run rough for a few minutes. Does the Yanmar engine have a Glow Plug?

    Believe that these Trace SWs do not have a Frequency input "meter". Still wonder if the generator cannot deliver much power when cold, and the engine speed slowly sags under .load.

    Personally, manually start AC Charge amps at about 3 A, allow a few minutes for genset to warm, then step up the charge amps slowly over a few more minutes.

    FWIW. Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 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.
  • RCinFLARCinFLA Posts: 1,280Solar Expert ✭✭✭
    The SW4024 has a phase / voltage tracking adjustment that has a limit on the rate of change it can follow. My guess is the frequency or voltage when the gen is first loaded is changing faster then the SW4024 can track so it releases from the gen. First thing to check is if you are running out of range on the voltage or frequency. Second is the rate of change. As mentioned loading the generator with a load first may stabilize it enough so it does not change after inverter engages.

    Try a heavy load on the gen first, like a hair drier on max. If inverter stays attached then back down the other load on the gen to find the minimum load on gen to keep it stable enough for the inverter to stay attached.

    Many inexpensive DVM's now have frequency readings. Check to make sure the freq is not going out of tracking range. You can also use the reading to adjust the RPM speed of the gen to get it closer to center of tracking range. If you start on low side of rpm when unloaded then is will likely fall out side of range when loaded.
  • ki7xhki7xh Posts: 6Registered Users
    Thanks for all of your suggestions. I did drop the AC charge amps limit to just a few amps during testing, and the problem remained.

    I was afraid that it might be a frequency issue, but I don't currently have a meter with a counter in it. I'm finishing welding up exhaust bits for my main generator today - a 10kW Kubota diesel with another Mecc Alte head on it. It'll be interesting to see how the SW4024 handles that one. Will certainly report, and then spend more time playing with the little guy.

    Just had a thought! I doubt they're terribly accurate, but I have a few of those Kill-A-Watt meters around, and they have a frequency function. Just for kicks, I'll see what they report. Right now, the one between my freezer and the outlet thinks it's 59.9 Hz. I always wanted a solid excuse to buy a decent Fluke, tho'. ;-) I also think I'll install some meters in my transfer switch cover, so I can monitor the grid and gen power as it hits the service entrance.

    Again, MANY thanks for your thoughts. I'll get some more data and report back, one way or another. If anyone's curious, here's my house/system on my not-updated-in-years website... www.ki7xh.com/house.htm ...and knock on wood, it's been a great system for almost two decades. (definitely time for new cells, and fresh PV panels)

  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    Wow--You have a nice place! You have done well.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ki7xhki7xh Posts: 6Registered Users
    I think I'm onto the problem here, and you guys hit the nail on the head. I did a little more measuring and testing last night, now that I remembered those cheap Kill-A-Watt (KAW) meters have a Freq. function.

    My grid power measures a solid, unchanging 59.9 Hz, according to the KAW display. When the SW4024 is inverting, the KAW meter shows 59.9/60.0 Hz. I plugged the KAW meter into an inverter-capable circuit, plugged my DMM into that meter, and tried some different modes...
    - INVERTING, AC (GRID) INPUT to inverter OFF (inverter not trying to sync with anything): 59.9-60.0Hz, 121.5VAC under normal house load

    - CHARGING, AC (GRID) INPUT to inverter connected to GRID POWER: 59.9Hz, 124.5VAC (our grid is a little hot here in winter when the irrigation pumps aren't running all around our area)

    Happy with that, I fired up the generator and here's what I found, as soon as I let the generator connect to the SW4024's AC (GRID) Input...
    - INVERTING, AC (GRID) INPUT to inverter connected to GENERATOR POWER (before it tries to enter CHARGE MODE): 63.8Hz, 119.3VAC

    - CHARGING, AC (GRID) INPUT to inverter connected to GENERATOR POWER: 63.4Hz, 118.5VAC

    So, I'm thinking that freq is too high and the Trace SW4024 can't sync with it. It sure sounds unhappy, as the inverter starts making all sorts of unhappy pulsing noises as soon as it enters CHARGE mode. Hate onomatopoeia, but it goes, "ZZZZZZZzzzzzzzzzZZZZZZZZzzzzzzzzzzzzzzzZZZZZZZZZZzzzzzzzzzzz" until it drops out and tries it again later.

    Man, you guys nailed it. That generator frequency must be outside the capability of the Inverter to track. At the generator, no load, I measure 63.9 Hz. I'm guessing that's too far out of sync for it to lock onto. Before I tweak anything, I'll call the builder and make sure I understand the manual correctly for making any frequency changes.

    Thanks again! Will report when I make the change and run some more tests. Whether this fixes the situation or not, I learned a crucial lesson... CHECK YOUR GENERATOR's OUTPUT, and don't assume it's right because it's new! (I'm going to install a digital gauge in my transfer switch, so I can always watch it from now on.)
  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    +/- 5 Hz is not unusual for a genset... Hopefully, your's does better.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    aside from the frequency being off a bit...
    ZZZZZZZzzzzzzzzzZZZZZZZZzzzzzzzzzzzzzzzZZZZZZZZZZzzzzzzzzzz
    Could it be that you L1 & L2 legs are not well balanced ? the buzzing sounds like it may be trying in vain to resolve an imbalanced load.
    My new diesel genset is still in the warranty shop for being 68Hz. Started at 63, I lost sync at 50 hours break in at 67Hz 280V !! yow!
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • techntrektechntrek Posts: 1,366Solar Expert ✭✭✭
    My APC UPS won't sync at all with my Generac when set to +/- 0.1 slew, and will drop out frequently when set to +/- 3.0. I have no doubt most non-inverter gensets have a +/- 5 Hz slew.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • RCinFLARCinFLA Posts: 1,280Solar Expert ✭✭✭
    The SW does not actually measure input AC freq. It is measuring the inverter frequency. If you have a valid AC that sync'd and remains connected then the inverter freq will be the same as AC input freq..

    Sound like you should tweak the engine's RPM's down a bit to lower frequency. Remember the rate of change issue also. Even if you stay within freq range of inverter if a sudden AC load change causes a fast change in voltage or frequency the phase lock tracking of the inverter may not be able to keep up with the change and release from the generator.
  • ki7xhki7xh Posts: 6Registered Users
    mike95490 wrote: »
    aside from the frequency being off a bit... Could it be that you L1 & L2 legs are not well balanced ? the buzzing sounds like it may be trying in vain to resolve an imbalanced load.
    My new diesel genset is still in the warranty shop for being 68Hz. Started at 63, I lost sync at 50 hours break in at 67Hz 280V !! yow!

    First of all, thanks again to all of you. I'm curious about the potential balance problem, and it's something I've always wondered about since I wired my home 19 years ago. This may show my lack of understanding of electricity and generators in general.

    The SW4024 is 120VAC, both IN and OUT, right? There are AC inputs for GRID and GEN. They are both 120VAC inputs. I have nothing connected to my inverter's GEN input, because my whole home is on a 200A Cutler-Hammer double-throw manual transfer switch, and my generators connect through that. That transfer switch feeds my home's main 120/240 distribution panel, as I need generator capability with some 240VAC loads.

    I feed my SW4024 with a 50A breaker in that panel, and my inverter then feeds a secondary AC load center configured for 120VAC only (L1 and L2 bars tied together) for all of my inverter-capable AC loads. (I actually installed another 60A transfer switch between them, so that I can transfer my inverter-capable load center to grid-only power when I need to service the inverter without killing all my inverter-capable loads. I have never had to do that, in 19 years, and that breaker stays off, BUT should the need arise, the inverter die, or whatever, I can just throw a lever and be totally grid/gen-only, without having to run a jumper.)

    In this configuration, only one half of my generator's output, either L1 or L2 (depending on which tab in that breaker box the 50A single-pole "Inverter Input" breaker snaps onto), will connect to that GRID AC input. That means that all of my inverter loads are only getting powered by half the generator. And, truth be told, I live daily on those inverter loads - the largest of them being a 1/3HP jet-pump for house water pressure, my chest freezer, and my kitchen's fridge. Thus, ALL those loads are on one half the generator, AND when the charger comes online, it TOO is on that half, along with those other loads.

    So, how can you balance a 120/240 generator which has a L1 and L2 output with a neutral between them? You're only going to be able to connect either L1-N, or L2-N. The only way I can think to "balance" a generator with L1-N-L2 coming out of it would be to supply a 2:1 transformer from L1-L2, and dump that output into the inverter's GEN input. (But then I'd be hosed for running other 240VAC loads, without another strategic transfer switch, so I could feed one, OR the other.)

    Have I set this whole thing up with a fatal flaw? (And again, the 4024 never had a problem holding charge-mode with the little 4.5kW Onan.)

    I have yet to get my Yanmar running at a solid 60Hz instead of 64Hz, but I'm off to attempt that as soon as I post this. I just seriously needed to ask this question after mike95490 brought up an imbalance issue.
  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    You can put your 240 VAC loads in parallel with the input of a 2:1 transformer for your 120 VAC loads--As long as the total currentVA does not excess the generator's capacity.

    But--Yes--This the problem with US 120/240 VAC split phase world with split phase output gensets. A few gensets can be rewired to 120 VAC at 2x current output. You have to check the documentation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    Outback PSX 240 balancing transformer. Or any other 2-4KVA 240V, CT transformer would work. (too small and it overheats, too large and you have a excess core loss) So the McAlte genhead @ 5Kw, should be pretty good, I'd have expected at least as good as your old genset. Bummer.. Does your genset have a "full power" switch ? That puts both windings in parallel for more 120V power, but gives no 240V anymore. My XW has a GenSupport Plus mode, where the big output toroid becomes the balance transformer, which is good, because the cheapo ST-5 head I have really groans if there is much imbalance at all.
    Just got a note from fleabay a day ago transformer for sale http://rover.ebay.com/rover/0/e11021..._trksid%3Dm194 It's a pretty decent price, and decent shipping - if you think you need it, grab it.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • ki7xhki7xh Posts: 6Registered Users
    Okay Bill, Mike, et.al....

    Success! I'm charging! Since the generator guy didn't get back to me today and I was looking at a weekend of wonder, I decided to try putting a load on the other half of the generator, that was pretty much just powering some LED lamps around the house.

    I plugged a little ceramic heater into an outlet in the generator room and set it to low power - prolly 800W or so. Came to the house, kicked on the SW4024's AC Input break, and in half a minute, it went into charge mode and locked on! I'll be darned, IT WORKS!

    I do not understand why that old cheap Onan WOULD work, nor do I understand why putting a load on the other half of the Yanmar / Mecc Alte makes such a difference to the inverter. I am all ears if any one of you would like to explain it to me in layman's terms (without calculus, perhaps). Inquiring minds, and all that stuff.

    Also verified was my inverter's amp meter, and my overcurrent protection. As I raised the BATTERY/MAX AC CHARGE AMPS setting from 6 A up to 12 A, my fridge or something kicked on and increased the AC coming out of the inverter from 8 to 10 amps. Sure enough, tripped the 20A two-pole breaker on the generator's service disconnect.

    Now I'm wondering how much load I need on that other circuit to make it work, and what useful stuff I can do with it. I have a water still, so I could probably draw a couple gallons out of it and let it kick it on, so the energy wasn't going to total waste, OR dumping heat where I do NOT want it. I could always go with the transformer system instead, and I'll look at that. Clearly, I want whatever is the least loss. Diesel is precious!

    Thank you guys SO MUCH for the help! I can't tell how much I appreciate it.
  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    This thread has pictures of voltage and current wave forms. And a scope of a "cheap generator" waveform running unloaded...

    http://forum.solar-electric.com/forum/solar-electric-power-wind-power-balance-of-system/off-grid-solar-battery-systems/19120-generator-hz-issues

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Posts: 2,906Solar Expert ✭✭✭✭
    ki7xh wrote: »

    ... I have nothing connected to my inverter's GEN input, because my whole home is on a 200A Cutler-Hammer double-throw manual transfer switch, and my generators connect through that. That transfer switch feeds my home's main 120/240 distribution panel, as I need generator capability with some 240VAC loads.

    OH, AC2 is for the Generator AC input. It has considerably wider Frequency range tolerance than does the AC1 -- Grid Input. AC2 probably is also more tolerant of AC voltage variations, as well.

    FWIW, Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 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.
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    Different styles of generators, create their power differently. I don't know what style Mecc Alte has in your model, my ST5 is a "Harmonic Excited" head. Has an extra winding that creates the field voltage and it's output vary's according to the load on the generator. If the load is imbalanced, it may goof up the control voltage, and the generator falls out of spec. Or maybe the 120V leg you are using, is the one without the voltage sensor on it. At least you know how to get it going now, at the cost of some extra fuel. But you want to address the balance issue someday
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • ki7xhki7xh Posts: 6Registered Users
    Vic, you mentioned AC2 IN being more tolerant; that's great news. Finding an acceptable balancing load is possible, but certainly wasteful when you don't really need it. My water-still at least creates water I can use in the batteries, but I'd rather not have to rely on using it. Plus, I'd rather have the full ~5kW available, balanced, to my inverter and its loads, instead of just half of it. Everything will be much happier that way.

    At this point, I think I'm going to do the following, unless one of you guys sees a problem with it...
    1. install a 20A two-pole breaker in my main distribution panel and feed a PSX240 with it (this is the panel with the single-pole breaker that feeds AC1 IN)
    2. wire the 120VAC output of the transformer to AC2 IN on the SW4024
    If I understand this correctly, I will then have all of my normal grid/gen-capable 120/240 circuits available when the generator's running, and have the full output of the generator (minus transformer loss, of course) available to the inverter for both charging AND pass-through to my inverter loads - through the "Inverter Capable" 120 VAC distribution panel.

    This means I would have, from the same 120/240 sub-panel, L1 feeding AC1 IN, and L1-L2 feeding the transformer, then feeding AC2 IN. When the grid's up, I'll keep the two-pole breaker supplying the PSX240 off, so it's not idling for nothing. When I need to use or test a generator, I'll kill the single-pole breaker feeding AC1 IN and turn on the two-pole breaker to the PSX240 and AC2 IN. Is there any problem with that that I might not be considering, by having both AC1 IN and AC2 IN connected to the same sub-panel?

    If that's okay, I'll make it happen this week. When this is sorted out, I need to replace my bank of 85N-33s. I'm on year 19 now.

  • nsxnitronsxnitro Posts: 5Registered Users ✭✭
    Ki7xh,
    Just read thru your comments. Have you resolved the issues?
    I'm 100% off grid with 4000w 24v inverter sw4024 and tied ac2 with auto gen start.
    Per manual, ac1 can also be 2nd generator tied well as grid tied. However if ac1 is tied to grid. Ac1 becomes primary 1st and ac2 become secondarily.
    Do you think that would throw the charging issues that your having?
    Thanks
  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    Ki has not been back since March of 2015.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nsxnitronsxnitro Posts: 5Registered Users ✭✭
    edited September 10 #22
    Thanks,
    I have a gen set mcculloch fg5700mk. I believe its 120v single phase.
    How do i wire to sw4024? I'm sure ground is common ground and hot into ac1.. Correct?

    Resolved!
    Earth ground to gen set and bounded to common ground. With fuse box conduet.
  • geosierranevadageosierranevada Posts: 22Registered Users ✭✭✭
    edited September 11 #23
    Nsxnitro,
    If you use the generator thru the SW4024 on auto start, make sure you fuse between the two units ( control circuit ). Also use AC 2 for auto start usage.

    Have a nice day     George
    Off grid for 16 years. 5KW panels, Trace sw4024, Bergy wind generator, forklift battery.  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
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