Magna SF2700 generator

[ShrimpBurrito]

Bill - I think you are referring to this picture:



..which is understandably misleading. That picture was taken from a view close to the hand, which makes the fist looks large and the generator small. That's why the fist is out of focus and the generator is clear.

The link countrygirl posted has more proportional pictures, including one with someone towing it behind them with their hand visible. The hand appears much smaller than the generator in that image.



Dave

I'm willing to give a thumbs up for these Chinese knock offs. I sold my Yamaha 2400 to Wayne's friend for a bargain price. I'm glad it went to a fellow TMer. It was simply too big for me to bring on trips with my full family and relatively small vehicle. I then bought a Chinese version of the Honda 1000 which fits in the rear compartment of my 2720 with lots of room left over. The gen won't run the air of course but it does charge the TM, run a variable mixer, variable speed jig saw, and digital projector. So it seems to have a proper inverter. It's very quiet and has a switch for eco (variable) throttle or full. Only thing I don't like is the cooling air intake is on the bottom so don't run it sitting on dirt or sand.

I had some cash left over to buy xmas gifts! Pix in my TM gallery. I can't link 'cause I'm posting from my cell phone.

[rickst29]

mostly, because I'd need to have it right in front me, and borrow some really expensive testing stuff from a neighbor-- the one just finished a job as the electric crew supervisor in a big power plant upgrade nearby.

But, here's something which should be in consideration when you go into an "A/C Generator shoot-out" comparison.

"Peformance" and "Reliability" are not just the motor, the maximum output, and the various features (quiet, runtime, electric start, pretty handles....) The biggest difference between the premium Yamaha and Honda products, versus the garbage I can buy down at "Harbor Freight", lies in the quality of the Generator/Inverter.

The "consumer" Yamahas have really "clean" output, generating nearly perfect sine waves: proper height (voltage), proper shape (low harmonic distortion), and proper length (frequency stability). They've got fancy feedback loops which allow the engine run slower when less power is needed, but they maintain that nearly perfect sine wave quality even through sudden, LARGE load changes.

Like for example, starting up your air conditioner. You can cause pretty bad harm (maybe even fatal) to both your consumer equipment AND the generator itself by putting the same enormous stress on one of those "dumb-as-brick, engine-needs-to-run-at-3600-RPM-all-the-time" generators (the ones in which A/C electrical frequency frequency (60 cycles) is determined from RPM, it's a divide-by-60 mechanical interlock. Or all those cheapo "modified sine wave" products where the "curve" consists of just a few big rectangular chunks, sudden square-wave "leaps" pretending to be nearly the same.

This magna CLAIMS "pure sine wave", but I don't see of the buyer reviews talking about actually even plugged in a 10$ voltage meter. (And for the kinda things I'm whining about, "harmonic distortion", and etc., the test equipment is $$$$$.) As do-it yourself lawnmower guys, a lot like me, they talk about "I kicked it, found no loose screws, it runs without sputtering too bad, seems to have plenty of power..." and they're not relaying any fatal horror stories (you know the sort: "....it died while farting out enormous clouds of horrid black crud, with chunks and parts too"; or "there was a loud sickening CLUNK, then silence....").

But there's only one step-down engine power level, and the guy who talked about that in detail said that the RPMs weren't smooth when running that way-- even though the elecrical load probably WAS.

So, if I was keeping a nice 120v LCD TV in the TM (I don't), I'd pull the TV plug out of the TM 120V outlet before I plugged in this generator-- I've got way too much suspicion about low-quality, cheaply-designed "mystery meat" PWMs maybe running the electricla show inside that thing.

If you take a look, you'll see that Yamaha has more powerful and less costly "industrial" Inverters in their own product line. Remember-- one of the main reasons behind the much higher "price per watt" with the 2400iS is is the fact that it's built to support stuff like high-end electronics, Plasma and LCD TVs, and computers. But if you're intending to use it at a remote building site, where you just need to turn on a few lights and run some drills and and saws and grinders similar tools, and you're wearing earplugs anyway, you don't need all that quality-- it's a waste of money.

Originally Posted by rickst29

So, if I was keeping a nice 120v LCD TV in the TM (I don't), I'd pull the TV plug out of the TM 120V outlet before I plugged in this generator-- I've got way too much suspicion about low-quality, cheaply-designed "mystery meat" PWMs maybe running the electricla show inside that thing.

Once upon a time I studied electrical engineering, but can't remember very much of this stuff, but I think you have a point.

But consider this...

Instead of running the television off of the 120v from the generator, what if the only 120v appliance running off of the generator is the converter that is charging the batteries. Then run the other 120v appliances (television, DVD play, computer, etc.) off of a high quality inverter?

This only makes sense if you already have the inverter so you can run 120v appliances when the generator is not running.

If you do not already have the inverter, then you would be buying a cheap generator and a quality inverter, which would perhaps cost more than the Honda or Yamaha.

[rickst29]

and if you're running only one really sensitive device, (e.g., the TV or your $$$ laptop computer, not both) you do have a financial "win". If you only need 300 continuous watts, (and nearly all 37" LCDs are in the range of 160-220w during operation), a high-quality pure-sine-wave inverter can be had for about $150.

But, if you travel really "heavy", as me and my DW always do, there might be a bunch of other things in your TM which would benefit: fancy toothbrushes (we own Sonicaire, and you CAN'T replace the battery after you've fried it); cordless razor; and, if you use one to raise the TM, your cordless drill.

But now, let me just move ahead to the bottom line: I, and my various professional neighbors (people working with EXPENSIVE tools at job sites without grid-provided power), like this store best:
http://www.donrowe.com/inverters/puresine.html
(Fine products, great prices.)

The DonRowe site also offers this checklist:
* Laser printers, photocopiers, magneto-optical hard drives
* Certain laptop computers (you should check with your manufacturer)
* Some fluorescent lights with electronic ballasts
* Power tools employing "solid state" power or variable speed control
* Some battery chargers for cordless tools
* Some new furnaces and pellet stoves with microprocessor control
* Digital clocks with radios
* Sewing machines with speed/microprocessor control
* X-10 home automation system
* Medical equipment such as oxygen concentrators.

It hides out at http://www.donrowe.com/inverters/inverter_faq.html

[rickst29]

CNET measured a whole bunch of Televisions, and created this list. If you don't know how your TV lines up, it might be there.

I can't comment on the Magna, but the little one I have has a variable throttle like the Yamaha 2400 I had. It ramps up and down based on load. This one happens to have a switch to force it to max output too. I tried several variable speed devices and they worked as they should where they wouldn't work well with my cheapie square wave inverter. I haven't scoped it to see what really comes out. At no load, it hunts on the idle but evens out as soon as even a small load is applied.