Advice appreciated - Solar Compatible Gen

First post here on Northern Wind and Sun.

I was hoping that I could get some information from some of you guys with more experience. I'm looking for a generator that is compatible with PV inverters. I think I've heard of a small Honda Gen out there that is capable of working with a PV inverter but I have not had any luck googling this. I'm also curious to know if there is more out there than this supposed Honda Gen. Any info out there? Any and all advice is appreciated. :confused:

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Advice appreciated - Solar Compatible Gen

    All generators are "PV compatible" to one degree or another, as they are simply a supplemental or back-up AC source. It comes down to a matter of how much power you need, what kind of fuel is best in your situation, and whether or not you need "auto start" - which is what I suspect you're asking after. In that respect it gets a bit more complicated, as you need a gen with remote start capability and a charge controller, inverter, or battery monitor capable of the same.

    As far as just supplying AC for when the sun doesn't shine, any gen will do providing it has sufficient output to run your loads and provide charging.

    The devil is in the details. You supply the details and we clever devils here will help you out! :p
  • BB.BB. Super Moderators Posts: 26,867 admin
    Re: Advice appreciated - Solar Compatible Gen

    A lot of times, it is the inverter/charger that is not really generator compatible... The standard generator can vary +/- 2-4 Hz and some inverter/charger units designed to run on Grid Power cannot "lock onto" that wide of frequency variation.

    My two cents, there are some good gensets out there an a lot of bad ones. Honda, Yamaha and many of the diesel units are there are pretty good.

    But you need to get one designed for your needs... If it is a backup up genset used to assist charging your battery bank every few days in the winter--then you can use an inexpensive portable generator pretty successfully.

    If, however, you are going to run it 10 hours per day, then you probably need one rated as a "prime mover" -- designed for 24x7 operation and typically turning at 1,800 RPM instead of 3,600 RPM (for 60 Hz).

    The main thing we usually stress here is conservation and intelligent design.

    Conservation in that it is almost always cheaper to conserve a Watt vs generating a Watt. A very rough rule of thumb--An off-grid solar electric system with backup generator will cost you around $1-$2+ per kWhr--About 10x what your home electric power costs you. So dumping unneeded electric heating loads (cooking, coffee making, etc.) is a good start (some microwave use can be OK).

    Next, sizing your system to your needs--if you have reduced your power needs to a minimum amount, have solar panels+batteries that power your loads most of the year--then you may not need much in the way of a generator...

    Instead of the really nice 8kW propane/diesel genset, you can use a Honda eu2000i (1,600 watt) inverter/generator. Stable electric power, very quiet--And for me, much more fuel efficient.

    For example, your cabin may get away very nicely with 400-1,600 watts of generator power. The Honda, running at 400 watts will use roughly 1.1 gallons of fuel for 15 hours of run time. (rated at 4 hours on 1.1 gallons of fuel at 1,600 watts).

    That 8kW genset may use upwards of 1/2 per hour of fuel whether you are using 4kW or 400 watts or less.

    Sometimes, people need more power (shop, emergency power, running some large power tools, etc.). In that case, many times it makes sense to have two gensets... One small Honda for battery charging and running the electric clothes washer. And a second 5kW noisy/cheap genset for when you need a few hours of a lot of power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 3,328 ✭✭✭✭
    Re: Advice appreciated - Solar Compatible Gen

    Just to be contrarian I would say design so that you do not need a generator!
    Some locations do not need them if the owner is not clueless. Educate the owner!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Advice appreciated - Solar Compatible Gen
    Just to be contrarian I would say design so that you do not need a generator!
    Some locations do not need them if the owner is not clueless. Educate the owner!

    While I agree with the principal, that can be really expensive for many people. Like that "three days without sun" concept. That means 3X the batteries and 3X the panels to recharge them with. It's usually cheaper to have a small gen and burn a couple litres of fuel every now and then as needed. Conservation has limits too.

    Just to be a contrarian. :p
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