Generator Hz Issues

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Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: Generator Hz Issues
    islandguy wrote: »
    Currently looking at the Yamaha EF1000is. Some users claiming 8000 hours on it.

    With charger loads sized at 800 watts this should work.

    You have to be a bit careful here... There can be a big difference between 800 Watt battery charger load, and upwards of:

    800 watts * 1/0.67 PF = 1,194 VA power supply load (pronouce VA or Volt-Amps)

    I would not suggest counting on running an 800 Watt battery charger on a 900-1,000 watt generator (really motor-alternator set) unless you have tested it and know it works.

    If I was doing this "blindly", would be looking for a ~1,600 watt or larger genset. For non-commercial generators, typically Max Watts=Max VA (i.e,. 1,600 watts maximum and 1,600 VA maximum).

    This goes back to the math of AC power and Power=Volts*Amps*Power_Factor

    Unless you have tested a genset before, running for hours >80% rating may be expecting a bit much from a typical consumer type genset. Battery Charger are "rough" loads--They can pull maximum rated input load for hours on end--Most gensets are not designed to power such loads near maximum rating for long periods of time.

    If you have a Kill-a-Watt type meter, measure both Watts and VA (or kW and kVA--depending on meter design).

    I would aim at 50-75% of rated load--Plus it gives you a bit of surge capacity and ability to run other loads in parallel with the battery charger (it is more efficient to run your AC loads directly from the genset vs Genset-Charger-Battery-AC_Inverter-load.

    My 2 cents--There are others here with much more experience than I. Hopefully, they can help guide you to your "optimum" solution.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: Generator Hz Issues

    Here is a quick example of how "harmonics" add to create non-standard output waveforms:

    Attachment not found.

    (these examples are from a site/forum on running Movie lights/equipment from portable generators).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    @chrisolson. Thanks - just finished reading a post on THD at field lines.com that you are probably familiar with.

    BB deciding between the ef1000is or the ef2000is. Will probably go with the 2000.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    BB from the cinematography site:
    The substantial reduction in line noise that results from using PFC ballasts on the nearly pure power waveform of an inverter generator creates a new math when it comes to calculating the continuous load you can put on a portable gas generator (in the case of our modified Honda EU6500is generator a capacity of 7500 Watts.)

    This means that a better wave form will also deliver more energy to the device you are powering? In other words my 2000 watt generator that I figured was good for 1k is actually delivering closer to say, 600 watts of power due to the crappy waveform?
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    islandguy wrote: »
    This means that a better wave form will also deliver more energy to the device you are powering? In other words my 2000 watt generator that I figured was good for 1k is actually delivering closer to say, 600 watts of power due to the crappy waveform?

    That's an approximation, but yes that's basically what you get.

    For your application it sounds like an inverter generator would be ideal. I think I'd get a bigger one than what you think you need and use the "eco throttle" feature on it. It should work fine that way because it doesn't sound like you got big surge loads. It's REALLY hard to find a quality conventional generator in the size you're looking for. There's a pretty good selection of inverter-type generators in the size you need, however, and if you size it to run at 50% load most of the time it'll be pretty efficient.
    --
    Chris
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: Generator Hz Issues

    It can... I will state up front that BlackCherry04 did some testing with an Iota (and one or two other battery chargers) and disagrees with my assessment that PF is, potentially, a big issue.

    So, anyway--Here is a thread that was dedicated to "getting the most" from an eu2000i genset--Went deep into the whole PFC (Power Factor Correction) issue:

    Question about battery charger selection with EU2000 generator.


    I think a well done PFC supply is worth (some of) the extra costs. Made shipping systems all over the world with different voltages/frequency/minimum line current much easier and allowed me to pull more "watts" from the grid without having to up size power feeds.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    BB. wrote: »
    Here is a quick example of how "harmonics" add to create non-standard output waveforms:

    Bill, thanks for that info on harmonics. When I design a new wind turbine generator I have to pay attention to pole and coil layout to prevent problems with the second and third harmonic or it will cause the generator to be a "moaner" at certain speeds, which gets very annoying to listen to. Depending on the natural frequency of the tower, the frequency the tower likes to vibrate at can match the generator and turn the whole tower into a giant speaker. Even some commercially built wind turbine generators (like the Skystream 3.7) have problems with harmonics and they're very noisy. When you rectify to DC downstream it doesn't cause any problems with equipment. But the constant vibration in the stator will tend to shake stuff loose on the turbine with time.

    Harmonics in a generator winding are unavoidable. But careful design can prevent them from being a problem at the design speed and operating frequency of the generator. Whoever designed the little generator in question in this thread didn't pay attention to the details.

    Edit:
    Darn it, sometimes I forget to say what I was going to say :blush:

    Since this little generator is being used primarily for battery charging, why not eliminate the battery charger and put a full-wave bridge on it? Turn it into a DC unit. Then you don't have to run it at rated speed - adjust the throttle to a suitable speed for how many amps you want from it. And if the rectified voltage is too high, use a 150V solar MPPT controller on it. You wouldn't need an expensive controller like a Classic because it will be operating at constant speed, so a regular controller will have no problems "tracking" it. Might have to add a capacitor to the DC output of the rectifier to "smooth" it a bit to prevent damage to the input caps in the controller, being the generator is single phase.
    --
    Chris
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    Thanks Chris,

    Can you point me in the right direction for a full wave bridge? Quick Google turned up a radio shack part. The only thing I know for sure about it is that I probably don't add it to the gas. probably.

    Thanks again!
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues

    Those little square full-wave bridges that Radio Shack has are fine for 12 or 24V systems, straight up. They are rated at 25 amps and 50V and I've used them on wind turbines before. They are not really 25 amp - more like 15 amps - although they will handle 25 amps for a little bit. You can just parallel two or three of them - hooking the generator's hot to one AC terminal, the neutral to the other, and jumping from one to the other with the hot an neutral to parallel them. You get DC+ and DC- out of the other two terminals, and you parallel those on the DC side. A good heat sink is required for them - a 1/4" aluminum plate works, with a small fan blowing on it.

    If you want higher quality bridges you can go to a local motor rewind shop and they can probably get you some 600V single-phase full-wave bridges rated for higher amps, with a heat sink with fins on it. But the Radio Shack ones are only about $5 bucks each, so you're not out a lot of money to try it and if you burn one up, but it seems to work fine, then buy some higher quality bridges.

    The bridge is rated on the DC side. So, for instance, if you have a 12V system and want to charge at 1,000 watts, that's about 80 amps @ 12V nominal so you'd have to parallel about 6 of those Radio Shack ones.

    I would put a volt meter on the AC output of your generator and idle it down to see how low you can make the voltage go on it, and still have the exciter and AVR maintain output. The rectified DC voltage will be about 1.4x what AC is. So, for instance, if you get it down to 80 volts AC RMS, the peak voltage is really about 110V and that's what you'll get from the rectifier. Hooking it to a battery will "clamp" the voltage to battery voltage. So depending on how aggressive your AVR is will determine whether or not you'll have to use a MPPT controller on it. The MPPT controller would be recommended anyway because it will handle all the charge stages (bulk/absorb/float) and just unload the generator if the power isn't needed. But to try it you'd only need one bridge and a car battery or something to see how the generator reacts to running at slower speed and voltage.
    --
    Chris
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    Funny, I thought he said the gen was putting out 109 Volts RMS. Connecting that to a bridge rectifier rated for 50 Volts doesn't sound like a good idea to me. Oh, you're going to idle down the engine to reduce the Voltage first? Make sure that works before you connect the rectifier.

    Seems like a lot of rigamarole to me.
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    Funny, I thought he said the gen was putting out 109 Volts RMS. Connecting that to a bridge rectifier rated for 50 Volts doesn't sound like a good idea to me. Oh, you're going to idle down the engine to reduce the Voltage first? Make sure that works before you connect the rectifier.

    That 50V is the reverse rating where the diodes won't "leak". I've used those 50V bridges at 140 volts before on a Classic with a wind turbine and they work fine. But you don't want to hook them directly to a 48V battery bank.

    Basically, what will happen when you rectify the output of a generator connected to a battery is that the voltage will drop ("clamp") to battery voltage. The AVR will attempt to maintain voltage but it won't be able to under the load and the exciter hopefully will stay working to maintain decent flux in the rotor winding. Different generators react differently to that, but most of them will go down to 80V unloaded before the AVR and exciter stops working. At that voltage, once you "clamp" it by hooking the rectifier to a battery the flux will not change in the exciter winding, but the voltage will drop in the main winding under the load of the battery. To get more watts from it the voltage will have to be allowed to run closer to normal (MPPT controller).

    All you can do it try it - the deciding factor is whether or not the AVR and exciter will maintain output so you can idle the engine down using it as a DC unit.

    Edit:
    The other thing a rectifier does is cause the output of the generator to become more of a square wave - which is actually good for battery charging. The AC sine wave will have a flat top to it when connected to a rectifier that's in turn hooked to a battery due to the "clamp" from the internal resistance of the battery. The diodes in the rectifier will only conduct when the sine wave voltage is above battery voltage. So you get a long "pulse" with a flat top on the voltage (sine wave). The harmonics issues in the generator winding then become a non-issue.
    --
    Chris
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    I had a quick look through the thread but can't see any mention of what the DC system Voltage actually is. I think it may not have been discussed because it's all AC problems. If it's 12 VDC then the gen can probably be dialed back, but if it is 48 Volts it wouldn't work.

    The rectifier will be subjected to the Voltage peak from the generator, not the RMS. Something to keep in mind when making the adjustment. And fuses will not save you from applying too much Voltage to a device.
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    The rectifier will be subjected to the Voltage peak from the generator, not the RMS. Something to keep in mind when making the adjustment. And fuses will not save you from applying too much Voltage to a device.

    That is correct. Those 50V bridges aren't suitable for a 48V system, direct hooked. But on a MPPT controller they will be fine because most MPPT controllers I've seen won't backfeed their source. I was running a bank of 9 of those Radio Shack bridges (three on each phase) on a turbine here with a Classic running at 140VDC for almost two years without any issues.
    --
    Chris
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    At the moment everything is a 12v system.

    Chris, I'm interested in setting this up. At the moment it's a bit beyond what I understand how to do. As I get a better grip on generators it's the kind of thing i want to try though.

    I have a lot of fun hacking around with computers and software. Who knew you can be a power geek too!

    Thanks again.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    A suitable mppt controller would be something along the lines of a "Outback Flexmax 80 FM80 MPPT 80 AMP Solar Charge Controller"

    This would take the voltage from the radio shack parts.

    That would allow me to rectify down the voltage from these crappy generators to 12 volts. A more or less stable 12 volts.

    and would then operate as my battery charger.

    What I would need to do is make a box of rectifiers, heat sink and fan, parallel them, feed the output to the charge controller.

    Then almost any voltage into this would output clean 12v for charging? Is that correct?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    The output to the batteries doesn't have to be all that 'clean'. They are really strong 'filters' themselves.

    Output to an MPPT charge controller on the other hand ... they are designed to be power by PV's which produce very pure DC. There may be a problem with feeding one the somewhat unclean DC from rectified AC.

    A PWM type controller would not be as sensitive to the 'hash' and may be a better choice for regulating. This means the gen output would have to be dialed down to around 18 Volts.

    Efficiency is going to suffer. Although the generator is already a mess on those lines. But the engine would have been designed to produce its max HP at the rated RPM, and this is not a linear function. Turning it down to drop the Voltage will mean losing a significant amount of power so instead of it being 3kW it may be 300 Watt (not exact numbers; just an example of what could happen).

    Another reason why replacing the gen with one that works is a good idea.

    I'm also concerned about the risk of other people having access to this machine. Someone might decide "that's running too slow" and crank the engine speed back up. If that happens, things will fry.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues
    . If that happens, things will fry.

    Good to know.

    What I like about this project is the ability to take a variety of input voltages and Hz and utilize it. I just hadn't thought through the loss in efficiency, and risk.

    For practical purposes I've already decided on the Yamaha EF2000is.

    Still thinking through THD and how it relates to efficiency's in what I am trying to do. It really makes the small generators almost useless for what I am intending to accomplish.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues
    islandguy wrote: »
    Still thinking through THD and how it relates to efficiency's in what I am trying to do. It really makes the small generators almost useless for what I am intending to accomplish.

    A generator designed to be a small generator will be efficient for its output. It's when you take a large one and "turn it down" that efficiency suffers.

    For most generators THD isn't an issue either. It takes some bad design/poor construction/significant failure for a gen to be in trouble there. Generators are analog, and as such produce fairly smooth sine waves all on their own (unlike inverters which are digital and need 'smoothing').

    You have an unusual situation: a fixed RPM generator putting out incorrect Voltage and severely hashed frequency.
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    Output to an MPPT charge controller on the other hand ... they are designed to be power by PV's which produce very pure DC. There may be a problem with feeding one the somewhat unclean DC from rectified AC.

    A Classic will take it with no problem. I've run both single and two phase wind turbines on a Classic and it don't even affect it. Not sure how tough the Outback is.

    The limiting factor from the generator when being rectified to DC is the winding size in the head and how many parallel windings they got in it. If it's a 2,000 watt generator at 120V (theoretical) the windings are probably good for about 15 amps continuous. So at 14.5 volts the generator would only output about 200 watts. That's why you need the MPPT controller to get the voltage up to closer to normal.

    All a battery charger has in it is a transformer to step high voltage AC down to low voltage AC and then it feeds it thru a couple button diodes. And there's a control board to control charging voltage. That's it - it's pretty simple. The control board is what goes ka-blooie (and sometimes a diode) in a battery charger. The transformer rarely fails in them, although the transformer is a big source of heat.

    All you're doing by rectifying the output of the generator directly is eliminating the transformer step and replacing that transformer, and the control board, with a MPPT controller. Rectifying high voltage AC to DC is way more efficient than rectifying low voltage AC to DC the way a battery charger does it. And that's because of the ~1.4V forward voltage drop in your diodes and how much power they dissipate as a result of the product of voltage and amperage (watts).

    On the generator side it don't matter if it's permanent magnet type or wound field type. Diodes don't care where the AC comes from or what's producing it, or how "dirty" it is. The peak voltage could be up ~170 VDC (assuming the gen head can actually produce 125VAC). That won't hurt a Classic. I know because when I've had clippers evaporate in high wind I've fed well over 200 into a Classic 150 with wind turbines and it never hurt it. Again, not sure how tough a Outback is in that respect.

    BUT - I'm sure the AVR on that generator has an adjustment screw (most of 'em do) and you can usually turn 'em down as low as 100-105VAC @ 60Hz. And most gen heads with an exciter winding and AVR will produce voltage with the engine idling at 2,200-2,500 rpm with no problem. Brushless heads with a PM exciter won't produce any voltage at engine idle speed, however. But I don't think that's a brushless generator head on that little genset.

    So, basically, if I had that generator and it's primary duty was battery charging (either thru an inverter or a plug-in battery charger), and I wasn't happy with its output because it's a cheap unit - that's what I'd do with it. I'd have it all set up and working inside of an hour and a half with a Classic 150 to try it. I even found a couple of those Radio Shack bridges in a drawer in the shop - never know what you might need one for :cool:

    Attachment not found.

    The totally best option is to still buy a nice little inverter gen because this sounds like an ideal application for one. But if you don't want to throw that cheap generator out and still might want to find a use for it, with a few modifications and fiddling around I'm 95% certain you can turn it into an off-grid DC genset.
    --
    Chris
  • mike95490mike95490 Solar Expert Posts: 8,468 ✭✭✭✭✭
    Re: Generator Hz Issues

    Generator frequency - I suspect it's not as bad as you are reading. Most air cooled engines use a vane in the airflow, to keep RPM's in the ballpark. +- 10 Hz should be well within that simple vane governor. I'd suspect your meter, or that you are grossly overloading the alternators to the point where the resonant field waveform is distorted and creating a wacky AC output.
    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 ,

  • mike95490mike95490 Solar Expert Posts: 8,468 ✭✭✭✭✭
    Re: Generator Hz Issues
    islandguy wrote: »
    Currently looking at the Yamaha EF1000is. Some users claiming 8000 hours on it.

    With charger loads sized at 800 watts this should work.

    EXCEPT the charger may have bad Power Factor, and that may throw the actual load well over 1KW. and fry the alternator head of the generator.
    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 ,

  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    Of the two I am looking at one is outputting @100 hz. Its in the local shop being looked at.

    The second is the APA 2000 watt. With the 55 amp charger and the inverter-charger plugged in the rpms droped. After a couple of hours, rpms back up, I measured the Hz and it was back to 62.

    The initial readings of @200 Hz seem to explained by the multiple spikes in the waveform. However that generator damaged an inverter and burned out two Powermax chargers.

    I doubted the meter too. So I took multiple readings. Grid power and from the two good inverters on site all of this came back right around 60. As soon as I get it back the pm3-45 gets connected to this generator. It will drop off 200 watts. That should be well within the capability of this little gen then.

    The Yamaha EF2000is looks like the best choice here for the small charger generator.

    I am putting together panels to display volts and Hz output from each generator. Hopefully I won't lose gear again if I can monitor the output.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    Here's the outcome.

    The Wen had the exciter cube?, generator head? measuring around 20volts or so, it should have been 12. The Local Honda shop, who told me they don't work on Wen, ran some tests last night and again today. Wouldn't take any money for the service work, but did talk me into buying the honda 2000w inverter Gen.

    Ran it in Eco mode today and it ran longer then the APA 2000W unit and put out more power. I think. Anyway to anyone who is trying to work through multiple cheap generators VS 1 good inverter gen, get the good Gen. I'll be looking into THD and compare the results from the Honda Vs the APA

    The new Wen came in today and I am using the 220v option to run the well pump and do some watering in the garden.

    Thanks again for all of the input. Learned a lot over the last few days!
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    islandguy wrote: »
    Anyway to anyone who is trying to work through multiple cheap generators VS 1 good inverter gen, get the good Gen.

    That's about as well put as anybody could put it :cool:

    --
    Chris
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: Generator Hz Issues

    BT, DT, bought 2 Hondas, 3 if you count the quad...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • ShadowcatcherShadowcatcher Solar Expert Posts: 228 ✭✭✭
    Re: Generator Hz Issues

    The generator is Chinese country of origin and not noted for high quality, it may be repairable, or it may not.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    Shipped off the Wen to the company at their request and their shipping cost. They checked it under load and reported that the Hz was 62.

    The only helpful info I got from them was that I should check the Hot & Neutral wire when taking a reading. That checking hot and ground would probably give me false readings.

    Also it was recommended that I not ground the generator. That the problems he is aware of are when the ground and neutral are connected through a mains panel. The ground and neutral are separate on the Generator.

    As far as tying it into a Mains, he just said it was outside the intended use for the generator.

    However during this spring I did manage to fry 1 inverter and three Battery chargers using this generator and or the APA 2000w

    So the likeliest culprit would be a grounding problem caused by the battery chargers - post, connecting to the - post on the inverter then to the House mains Neutral ground connections. Does this make sense to anyone else?

    While I am presently using the Honda, happily, I am interested in sorting out why so many of the chargers fried. Also why I was getting Hz readings so far out of spec. One though that occured to me was to connect a resistive load to the generator, maybe a 500 watt heater, while running the battery charger.

    Thanks.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues
    islandguy wrote: »
    Shipped off the Wen to the company at their request and their shipping cost. They checked it under load and reported that the Hz was 62.

    Somewhat hard to believe. :roll:
    The only helpful info I got from them was that I should check the Hot & Neutral wire when taking a reading. That checking hot and ground would probably give me false readings.

    Well, yes; with the ground not bonded to neutral you shouldn't get any sensible reading between it and hot as it isn't connected to anything.
    Also it was recommended that I not ground the generator. That the problems he is aware of are when the ground and neutral are connected through a mains panel. The ground and neutral are separate on the Generator.

    That doesn't make sense to not ground the gen. What are ground lugs for? I suspect either there is an N-G bond (which can be determined) wherein you wouldn't attach ground to a rod because of already having a bond at the main, or they don't know what they're talking about.
    As far as tying it into a Mains, he just said it was outside the intended use for the generator.

    This is called an "excuse". "It doesn't work right because it's not supposed to be used that way." Much of the time that is a valid explanation. But in the case of a generator supposedly putting out 120 VAC @ 60 Hz (utility spec power) it should not matter through what loads are connected; extension cord or main service panel. If the wiring is correct it will work. It's like invalidating the warranty on a gen because it isn't designed for "off grid power". Well, what is a generator but off-grid power? :roll:
    However during this spring I did manage to fry 1 inverter and three Battery chargers using this generator and or the APA 2000w

    So the likeliest culprit would be a grounding problem caused by the battery chargers - post, connecting to the - post on the inverter then to the House mains Neutral ground connections. Does this make sense to anyone else?

    I'd say the most likely culprit is that the gen is out of spec, despite the maker's claim to the contrary. You can get some unusual results if you've got a ground loop in there, but if there's no N-G bond at the gen and/or no second ground rod then there's no loop and there should be no problem. Really it is highly unlikely that you could have hooked it up in a manner that caused the failure.
    While I am presently using the Honda, happily, I am interested in sorting out why so many of the chargers fried. Also why I was getting Hz readings so far out of spec. One though that occured to me was to connect a resistive load to the generator, maybe a 500 watt heater, while running the battery charger.

    Thanks.

    There you go: the Honda works, the other fried something. Why? What is different between the two? That's where the answer lies.
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