system plan sound reasonable? (new to solar)

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  • mtdocmtdoc Solar Expert Posts: 600 ✭✭
    Re: system plan sound reasonable? (new to solar)
    I'm wrestling with this exact question on my own system and future expansion plans. It's driving me nuts.
    One EU2000i can drive 13 Amps @ 120 Volts. Two of them can put out double that (30 Amp outlet). So that's 1560 Watts & 3120 respectively.
    45 Amps on a 48 Volt system is roughly 2400 Watts on the gen peak, but it won't stay at peak the whole time. So do you run two gens until the power demand goes down and then shut one off (this requires a total shut down of both gens and a restart of one) or do you go for the 3000 model and let it idle back as needed? Without the demand on it, the bigger gen will burn more fuel than one of the smaller ones but less than two of the smaller ones. With the load on it will probably burn less fuel than the two smaller ones (because of not having to supply energy to keep twice the mass operating).

    If it were an "occasionally I need more power" thing pairing two 2000's would probably be the answer. Otherwise the one 3000 is likely better. A 240 Volt gen is even better, but I don't know of any inverter types with that output. Generators do not always play well with transformers either, although the inverter types should be fine.

    The expected load have to be considered too. This is what is tangling me up, because if I double the battery bank size I can still use one 2000 gen but have to limit my loads as the charge demands would go to 9 Amps AC leaving a very small amount for loads.

    That sure didn't help, did it? :p

    Funny, I went through the same machinations before deciding to buy a second eu2000i. I've had the first one for some time and prior to our solar/battery back up system it was the sole source of power for our frequent grid outages. I struggled with the same issues you state - considered buying an eu3000i (not enough power), and eu 6500i (too expensive) and the Yamaha 4000 watt inverter gen (also expensive). In the end buying a second eu2000i made the most sense to me. I like having the flexibility of running only one if I can and the redundancy of having 2. During our last extended winter power outage our local Honda/Yamaha dealer sold out of generators and without power their repair shop was not running.

    The Outback grid-interactive inverters are picky about their AC input and require an inverter genset. Mine won't work with the gas hungry, noisy, 7000 watt beast that sits in my garage/shop ( bought to back up our community water system which uses a well to storage tank/gravity system that will only hold out for about 1 week without pumping).

    Everyone's situation is different but it seems to me that many people purchase large, fuel hungry gensets - sized to supply occasional high surge loads - unnecessarily if they have an inverter that can power those surges and a small genset that can supply typical loads and keep the battery bank charged when the sun isn't shining. Meanwhile those big noisy gensets burn fuel $$$ - most of it becoming waste heat....

    Just my 0.02 of course.

    BTW - my experience with testing my 2 eu2000s in parallel is that if one shuts down the other keeps working fine - no need to restart.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: system plan sound reasonable? (new to solar)
    mtdoc wrote: »
    The Outback grid-interactive inverters are picky about their AC input and require an inverter genset. Mine won't work with the gas hungry, noisy, 7000 watt beast that sits in my garage/shop ( bought to back up our community water system which uses a well to storage tank/gravity system that will only hold out for about 1 week without pumping).

    Your inverter is a "G" - grid-tie. It's picky about the AC it will accept because it needs to avoid connecting to "bad grid" (anti-islanding). The off-grid ones have more latitude.

    Curious about the parallel Hondas. I can understand that if one ran out of gas the other would keep going, but to switch from two to one - just shut it off? I don't know enough about their sync system (AC coupling) but I think this is something you'd want to avoid; like starting/stopping under load (generally frowned upon for any type gen).
  • mtdocmtdoc Solar Expert Posts: 600 ✭✭
    Re: system plan sound reasonable? (new to solar)

    Understood about the G - tie issues.

    Curious about the parallel Hondas. I can understand that if one ran out of gas the other would keep going, but to switch from two to one - just shut it off? I don't know enough about their sync system (AC coupling) but I think this is something you'd want to avoid; like starting/stopping under load (generally frowned upon for any type gen).

    Good point. I hadn't thought about that. The 2 times I've had one shut down was exactly that - it ran out of gas (I'd just put a small amount in for testing or short bulk charging of batteries) while the other kept going with it's propane hook up. Maybe it's not a good idea to let that happen. There's a Honda eu2000i forum - I should see if anyone there knows if this has bad effects on longevity.
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