DC to AC inverter issues

[zero]

Some interesting and surprising observations (at least to me)  Inverters used to make DC power into AC power tend to come in three versions of quality. Cheapest are "modified wave."   Then for more money there are "true sine wave."   And then there are those that really make a perfect sinewave and often cost 10 times what the others cost (power company certified for grid-tie).  For RV use, or off-grid use in a solar home - it is usually one of the first two.  I have over two dozen that I've fooled with and tested under certain conditions.

My main point here is this.  The more expensive "true sine wave" inverters - in some circumstances - do not work as well as the cheaper "modified wave" inverters.  Note I stated "some" circumstances.  I just found a new "issue" that has me surprised.   Last week when camping in our Toyota - my Android cell-phone would not work right when plugged into AC power via it's little converter.  It was just erratic and hitting the buttons just did weird things.  This getting power from a Ramsond Sunray 3000 watt "sine-wave" inverter.  At that time, I thought my phone was going bad and did not realize the inverter was causing the problem.

Yesterday we were camping at our cabin in the Michigan UP and I just spent a week installing solar electric, battery bank, and a 2000 watt AIMs "sine wave" inverter.   Last night my wife plugged in her Kindle and it did all sorts of weird things and the swipe-functions would not work.  We then found out when we unplugged it and just ran off its own battery it worked fine.  After this - I did some more testing.  Ends up none of my "true sine wave" inverters will run any of our cell phones or the Kindle properly.   Note the inverter will charge them up fine. Just cannot use them while the charger is still connected.   I then tested the phones and the Kindle hooked to several cheap modified-wave inverters with their "inferior" AC power.  Both phone and the Kindle worked perfectly.  I tried my 10 year old Harbor Freight 2000 watt inverter. I also tried a 750 watt Vector. I also tried my 600 watt Duracell. All low-end mod-wave inverters and all ran our "devices" perfectly.    I guess the moral to this story is - the higher cost "sine-wave" inverters are better for some things, and worse for others. In many cases, a cheaper mod-wave is the way to go.

[jjrbus]

Thanks for posting, I sometimes forget some of the uncommon oddites that can happen and completely misdiagnose a problem. 

I had a Trace 3624DR modified sine wave that I was assured would destroy anything electric that was hooked up to it by the electronic pure sine wave snob crowd.   Everything worked with no issues except the clock on the microwave, it would go berserk on the inverter.   But the timer worked with no issues?   It would charge batteries, run TV, VCR, satellite dish, computer, lights all with no problems. Now the cheap apt size fridge did go belly up after 8 years so maybe they were right.

[zero]

I still have my 15 year-old Trace/Xantrex DR.  It's a DR2412.  Mod-wave with 5000-6000 watts of surge-power and a built-in charger that I never had a use for (won't work with many portable generators).  It has been pretty bullet proof.  Hard to tell if it has degraded at all over time. I had a small pancake air compressor that it ran fine for 10 years (mostly for my air-tools).  Then I started having problems with the compressor not starting and just humming.  I have no idea if the compressor got harder to start of if my inverter got a little "tired" over the years. I DO know this. I started using the same compressor with my Ramsond sine-wave 3000 watt inverter and the compressor starts with no issues.  I used my DR to power computers, TVs, devices, etc. with NO issues.  The only things it would not work with were hard-wired smoke alarms and any GFCI outlets (they'd buzz too much).  

[Maineah]

I can see where that could be a frequency conflict with two PWM devices.

[zero]

I had assumed (and wrongly so) that the power-supply for a cell phone or "device" is just that.  All it can do is make DC power, or not at the correct voltage.  It's DC output so no 60 Hertz Cycle to worry about.  I guess the output of these chargers must be too high or too low. I haven't checked.  In fact, it is kind of hard to do since I'd need to check under load and I don't want to start cutting off insulation on the charger cords to do so.  I am also surprised that a cell phone or device is so sensitive to the incoming DC voltage.  Often DC devices can work with a broad range just fine.