Give me a sine..
First, I need to give credit where credit is due. The Magnum Energy web site offers free access to their owners manuals and even though I can’t use their product, I think their owners manuals are really well written with a lot of useful information. One such manual can be found here:
http://www.magnumenergy.com/MMseries.htm
They do a really good job of explaining in simple terms the difference between a true sine wave inverter and a modified sine wave inverter. The following is taken directly from that manual.
“Today’s inverters come in two basic output waveforms: modified sine (which is actually a modified square wave) and pure sine wave. Modified sine wave inverters approximate a pure sine waveform and will run most appliances and electronics without any problems. These inverters are less expensive and, therefore, offer a viable alternative to more expensive pure sine inverters. The output of a modified sine wave inverter will run most electronic and household items including but not limited to TV, VCR, Satellite dish receiver, computers and printers. Some devices such as rechargeable power supplies for phones, drills, and such devices may not run or be damaged by modified sine wave inverters.”
To this I would add that I have heard of problems with video distortion on TV’s or monitors, audio distortion or buzzing, some appliances with motors making more noise, some appliances like microwaves having less than full power, and general loss of efficiency in the appliances themselves possibly resulting in their early demise. Mind you, this is all hearsay, not fact, and should be taken with a big grain of salt.
Using the Magnum products as a rough guide, The MMS Pure sine wave inverter/charger is rated for 1,000W continuous at $1,199. The MM1212 modified sine wave inverter/charger is rated at 1,200W continuous for $899. That’s 20% more power for 75% of the price, or in terms of watts per dollar, the modified sine wave unit provides 60% more value.
So the decision is obvious right? Exactly, I am going to use a pure sine wave unit regardless of the make or model. Why you ask? I would guess that a modified sine wave has a 90% chance of meeting all my needs and saving me money. Given my luck, that means I will buy it and find that it doesn’t work, then have to resell it at a big loss, and buy the pure sine wave unit anyway. Mostly I don’t want to risk the time or the money. I will take the 90% probability that I am wasting money to make a choice that I know will work, at least for this issue.
You may note that I didn’t mention the efficiency of the two types of inverters. That’s because I don’t think I can. The modified sine wave inverter might be more efficient on paper but it really depends on the load. If the load operates inefficiently because of the modified sine wave then it’s not fair to measure just the efficiency of the inverter. The bottom line is that I just don’t know.
Here are some possible inverters that I am considering, but not endorsing:
AIMS 1500 Watt, 12 Vdc, Pure Sine Wave Inverter 12 Volt. FREE Remote, Model #:PWRI150012. $449
http://www.theinverterstore.co...=pwri150012s-top-rgb
AIMS 2000 Watt PURE Sine Wave 12 Volt . FREE Remote. Model #:PWRI200012S, $599
http://www.theinverterstore.co...=pwri200012s-top-rgb
2500/5000 Watt Pure Sine Wave Power Inverter with 12V DC Port PE-2500PSW-12-110, $495
http://www.topsalesdepot.com/bwapusiwapoi.html
Those web sites also carry lots of modified sine wave inverters if you are luckier than I am and want to save some money.
To be continued…