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Old 12-23-2008
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peteaeonix peteaeonix is offline
Former Bird Owner
Join Date: Jan 2008
Location: Ridgefield
Posts: 2,010

There's good advice in the previous posts ... watching for how the wiring is 'plumbed' is critical.

True sine wave vs. modified sine wave: Things with electric motors will last longer when true sine wave power is used -- they'll also use less power (think refrigerator) as the motor converts more of the electricity to heat with modified sine wave. Of the items you listed, the computer printer is the one thing that is most subject to problems with the modified sine wave.

I've used uninterruptible power supplies with my computers for years. These devices are, essentially a small inverter and battery with a very fast power sensing switch to flip the power source before a drop out screws up the computer. They all use modified sine wave inverters -- and I've never had a problem with a computer using the UPS. I note that the instructions for all the UPS units I own suggest "do not use with a printer" -- at first I thought it might be due to the power draw exceeding the capacity -- but I actually have some rather high-capacity UPS units that could handle the load -- but in an experiment, a small laser printer was clearly not happy with the modified sine wave power (it wouldn't run)... and I presume that the motors in the printer simply had to have something that resembled a true sine wave for them to work.

It is "good practice" is to unplug sensitive items (like the laptops) when switching energy sources -- I had a mother board fried in my laptop by my brother-in-law flipping circuit breakers while I was using the computer... when switching occurs, you can get some very significant voltage spikes. This has not proven inconvenient for us, since I don't normally run the computer while driving over the road -- so I just use the laptop battery to fire it up at a rest stop, if needed.

Computer power supplies generally convert the AC into DC anyway -- so the sine wave isn't much of an issue. (Circuits inside a computer generally require 5 and 12 vdc.)

One of my dual 2500 watt inverters quit during my last trip -- I'm going to pull it and do some testing (might be a switch or relay problem) -- and if it's truly bad, then I'll most likely make a straight-across replacement with a similar Heart (modified sine wave) rebuilt inverter -- that way I won't have to mess with the wiring and circuit protection. However, I _could_ convince myself to put in a true sine wave unit to make the electric refrigerator operate a little more efficiently.

Since your OEM inverter is 2800 watts, replacing it with a 2800 or 3000 watt inverter should not be a problem, assuming that the circuit protection is done properly.

Pete Masterson
(former) 95 WBDA 42'
(now) 2011 Roadtrek RS-Adventerous
Ridgefield, WA
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