generator confusion

Re: generator confusion

In general, any "decent" genset works for most all applications.

People talk about needing an inverter-generator for electronics--In reality, most modern electronics are very tolerent about their AC power... It is not uncommon for modern computer supplies to take anything from ~95 volts to 264 VAC, from 45-400 Hz, and even DC voltage (again, the details matter, not all power supplies have these capabilities--But many larger power supplies do).

And, in some cases, inverter-generators have been known to cause radio inference (HAM radio, etc.) because of the inverter's switching noise.

Where inverter-generators really are nice (the gasoline/propane powered ones) is that when operated below ~50% of rated output, they slow down the motor and are more fuel efficient (i.e, a Honda eu2000i will run ~4 hours on a gallon of fuel at 1,600 watts and around 9-10+ hours at 400 watts or less). The same genset without the inverter may run ~8 hours at anything less than ~800 watts of rated load).

When charging batteries, you may spend 1-2 hours at high current (charging to ~85% state of charge), but 2-6 hours at a declining current (as battery approaches 100% SOC) or during extended equalization (2-5% rate of charge vs 10-20% or so for typical AC battery charger setup).

If you have large loads that run for long periods of time (~50% or so minimum rated genset output), then even a standard genset will be just as fuel efficient or possibly even more fuel efficient than an inverter-genset.

Note that Inverter-Gensets generally have poor surge performance (motor starting)... And the "ECO" throttle (if "on") also hampers surge performance too.

For many--Get a smaller inverter-genset (i.e., ~2,000 watt or smaller) for small/random/varying loads... Genset will use much less fuel than the large (3.5, 5kW or larger) gensets. And get a larger genset for heavy power needs (charging a large battery bank that is below ~80% state of charge, large shop/power tools, etc.). Also gives you "backup" in case one genset fails.

-Bill

Re: generator confusion

If you have diesel--They run much more efficiently than Gasoline/Propane gensets at lower output ratings.

Old diesels ran "badly" at less than 40-60% of rated power--But one poster here said that modern diesels should not wet stack even at low loads. Don't know about cylinder glazing issues (lots of long, low output, power operation).

-Bill

Re: generator confusion

However, some families of AC inverters seem to have very "tight" frequency requirements (i.e., +/- 0.5 Hz). Which smaller mechanically governed AC generators have problems holding that tightly. In some cases, this is because the inverter may have been setup for Grid Tied (feeding back to the grid or as a "Hybrid" inverter--GT requires that tight of frequency spec.).

That has been one thing that has confused me about the Outback inverter families--Most seem to have tight frequency tolerances (when I last researched them a few years ago)... The only one that did not was an export model (120 VAC 60 Hz) for South America (not intended for sale in the US).

-Bill