Looking for Generator Recommendations

fooddiva
fooddiva Registered Users Posts: 15 ✭
in General Solar Power Topics #1
We have been off the grid for 20 years now. Have a 24volt system, 16 panels/16 new batteries/a 4020 inverter/relatively new Xantrex charge controller. My question is over all these years we have had numerous generators as back up. The most recent one, a Honda EM6500SXIA has been a disaster since day one. It's still under warranty and still not working right. They replaced the governor twice already. We are looking to trade this thing in and get another one. I'd like to know if anyone in this forum can recommend one that you might be using or have had used that you would seriously recommend. People that don't understand PV systems or households just don't get it. The folks working on our generator kept blaming our system for it's malfunction. "Must be your inverter" they would say. I'm so tired of dealing with folks that don't understand this technology. I thought it might be good to hear from another PV user as to what generators have been known to work. Any ideas?

thanks
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  • Chuck46
    Chuck46 Solar Expert Posts: 95 ✭
    #2
    Re: Looking for Generator Recommendations

    We have used a Kohlar 11KW gen set propane fueled for the last three years with real good resualts. We used a Cummins diesel 60KW for almost 6 years and the fuel cost finally got to high plus the repairs on it were extreme and it was much noisier.
    My feeling is the Kohlar is great.
    Chuck
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #3
    Re: Looking for Generator Recommendations

    Fooddiva,

    I suspect I know what the problem is, but I need just a bit more information from you. Are you using the generator in 120 VAC mode to run the 4024 inverter/charger, or are you using it in 120/240 mode with a 240/120 transformer between the generator and the 4024?

    More later,
    Jim / crewzer
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #4
    Re: Looking for Generator Recommendations

    Fooddiva,

    OK. So, you’ve got a “6500 W” generator and a “4000 W inverter/charger. One would think that the generator would have no problem powering the inverter/charger. Unfortunately, it’s just not that simple. Here’s what I believe to be the problem, and a variety of possible solutions follows.

    One half of the problem is related to generator ratings and specs. For example, the “6,500 W” generator is rated for only 5,500 W if it’s run continuously (1/2 hour or more) at sea level. If you’re located at altitude in western MA, the generator power rating will be further reduced. Separately, full power is not available from any one outlet, although the four-prong outlet seems to be able deliver 240 VAC at ~20 A (~4,800 W). To use full power, you’d have to mix-‘n’-match several loads across multiple outlets.

    Assuming you’re running the generator in 120 VAC mode and are using the three-prong twist-lock 120 VAC / 30 A outlet to connect to your 4024 inverter/charger, then the sustained current limit from that one outlet may be no more than somewhere between ~22.8 A and 24 A, the latter being 80% of 30 A. All of this detail is discussed/inferred in the owner’s manual.

    Assuming the generator is connected to the inverter/charger’s GEN input connections, I suspect the other half of the problem is that the 4024 is set for its AC 2 (GEN) input current default of 30 A, and also for its charger input current default of 30 A. This basically means that the 4024 is trying to draw ~30 A from the generator whenever the charger is operating in bulk mode. Downstream AC loads will cause the charger to reduce charge current to the batteries so that the loads are powered but the total AC current load on the generator is limited to 30 A. These settings and the related operation are all presented in the owner’s manual.

    I suspect that the 4024’s attempt to draw 30 A from the generator’s 120 VAC / 30 A outlet is causing the generator failure. I presume this is manifested by a thrown circuit breaker. A low power factor could exacerbate the problem by drawing a bit more additional current. Accordingly, it could well be argued that the 4024, set to factory defaults, is indeed too big of a load for the 6500 W generator operating in 120 VAC mode.

    An immediate solution would be to reduce the AC2 (GEN) input current limit to ~20 A or so. This would prevent the 4024 from trying to draw more than ~22 A from the generator. It would probably be a good idea to reduce the charger input current to the same setting, although it would seem to me that the former would override the latter.

    A long-term solution would be to buy a 240/120 VAC autotransfomer to connect between the generator’s 120/240 VAC outlet and the 4024’s input. With the generator operating at 120/240 instead of 120, it could supply ~30 A of 120 V to the 4024. You could then raise the AC2 (GEN) and charger current settings back to 30 A.

    See: http://www.xantrex.com/web/id/114/p/427/pt/10/product.asp
    And: http://www.outbackpower.com/PSX240.htm

    Without the autotransformer, you’ll need to find a generator that can deliver 30 A to 35 A continuously from a single 120 VAC connector at your local altitude. This probably means a generator with a three-prong twist-lock outlet rated for 120 VAC / 50 A.

    HTH,
    Jim / crewzer
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  • fooddiva
    fooddiva Registered Users Posts: 15 ✭
    #5
    Re: Looking for Generator Recommendations

    Thanks for the detailed message. We actually are plugged into the 240 and have changed the inverter settings so many times to accomodate this generator it's pathetic. My husband understands the technology of the inverter and generator but this particular generator has just been a lemon. Believe me after 20 years of dealing with generators you eventually begin to understand what is going on and what you really need. THat's why I'm trying to get some opinions on what other folks are using with their PV systems. For comparison reasons. Over the years we have toyed with possibly finding a DC generator, diesel, propane as compared to an AC generator. We thought this one would work fine as a backup but it just hasn't now we need to find another. If you have any other suggestions, I do appreciate it.
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    #6
    Re: Looking for Generator Recommendations

    As a backup, I am using a model 6692110100, 1800 RPM, Generac 15KW LP, SG015 with the new H-100 Digital Control Panel with weathertight sound accentuated cover. The unit also incorporates manual or laptop/software programming/monitoring/diagnostics.

    I believe it's available in smaller kws'.

    After a lot of research it was recommneded to me by both our solar and electrician folks.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • PhilS
    PhilS Solar Expert Posts: 370 ✭✭✭
    #7
    Re: Looking for Generator Recommendations
    fooddiva wrote: »
    Thanks for the detailed message. We actually are plugged into the 240 and have changed the inverter settings so many times to accommodate this generator it's pathetic.


    As Jim said, if you aren't using a transformer to load both legs of the generator's output, you are only using half of the generator's windings and potential power even tho you are plugged into the 240V outlet. This is not conducive to long generator life.

    I've been off-grid for 30 years and used up a few generators during that time. My biggest problem with Honda brand has been internal connecting plugs which seem to form some sort of corrosion (not visible) when not used for a few months. I've spent hundreds of $$ replacing voltage regulators until I learned that I have to unplug and reconnect those connectors for the output to be correct. Of course, when you replace a voltage regulator, you must unplug and reconnect these same connectors so the problem appears "fixed". I only threw one [probably] good regulator ($300+) away before I learned this lesson. Now I simply unplug and replug the connectors before use (this Honda goes years between uses, it's a backup to a backup).

    Phil
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  • fooddiva
    fooddiva Registered Users Posts: 15 ✭
    #8
    Re: Looking for Generator Recommendations

    Out of curiousity, where did you purchase this generator? Is it online?
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #9
    Re: Looking for Generator Recommendations

    Just a thought,

    You didn't describe what the problem is and how it is failing, but I had a problem with a Misubishi 2800. The problem is detailed on a thread on generator grounding.

    The problem is that there was a grounding loop between the generator and the PV panels. The DC side of the panels was ground looping to the AC side of the voltage regulator on the generator.

    Smarter minds than mine figured it out, including Niel and Crewzer here.

    Perhaps this will help.

    Good luck,

    Icarus
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  • James
    James Solar Expert Posts: 250 ✭✭
    #10
    Re: Looking for Generator Recommendations

    what about something like this, assuming you can do without the ac output.
    these are built to supply heavy amps for long durations.

    this would of course, elimate to use of the inverter's internal charger, and it's nice charge control function, but maybe there is another way to regulate it.

    brute force power but control may be an issue. i'm not sure if this is single stage charging. i suspect it is because these were designed to start 24 volt military vehicles.
    i believe i read in home power magazine the several folks have used these

    just an idea.....

    http://www.galleria-e.com/cgi-bin/Colemans.storefront/en/product/240701
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  • Chuck46
    Chuck46 Solar Expert Posts: 95 ✭
    #11
    Re: Looking for Generator Recommendations

    Well here is a DC generator I have been looking at. Just an idea
    http://www.shawneepower.com/dccharger.html

    Chuck
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  • dhill
    dhill Solar Expert Posts: 47 ✭
    #12
    Re: Looking for Generator Recommendations

    I'm using a Coleman 11kw propane gen. I use the 240X transformer with it. I've had no problems with this gen in the 2 years I've been using it. From my estimations, the gen burns about 3 gal of propane per hour. I can top my batteries in about 2 hours. I have 8 6v exide 225 ah wired for 24v. I spend about $600 per year on propane, largely used on my generator. I need the gen to charge the batteries during the summer months when I'm running a/c in my house. During the winter months, I charge mainly during periods of cloudy days when my panels aren't producing quite enough to keep the batteries full.
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