modified Sine Wave inverter question

towpro wrote:
If anybody has any small units they are happy with, feel free to recommend them (we love Amazon)

300 watt GoPower was my choice for small items. Has lowest idle draw and provision for a remote switch.

Started in the late 1980's with a Heart Interface MSW 1800 watt for our cabined boats and our RV's and never have a single problem with them running everything just like when plugged into shore power. EVERYTHING!

We have been running many MSW 400 thru 2500 watt MSW inverters off 12V DC batteries ever since and still am and have yet to have any TV with lines, items/motors or circuits getting hotter, LEDs not working properly, microwaves, or any of our heated mattress pads or electric blankets not working fine and normal on the MSW inverters.

Even had a fellow RV'er tell me I was crazy since this stuff doesn't work on MSW so I invited him inside and showed him. He claimed I had a mislabeled inverter and it was actually a PSW for all that stuff to run or run right and quiet. So wrong! Finally he agreed that my sealed case MSW wasn't nearly big enough to be a PSW inverter. Then he said it won't run his stuff so I took my spare 2000 watt we carry over to his RV and he attached his wire cables to it and plugged the plugs to his TV in thru an extension cord and then his microwave using the extension cord and Whamo, everything he tried worked just like ours including his wife's electric blanket.

Everything tried worked just like they did on his PSW. Talk about egg guts running down a face, he won the prize and I sure would have loved to have a pic! Then he admitted that everyone told him that a MSW won't run most of the stuff on his RV and he'd believed them and now he felt lied to!

Some of our AC items including the mattress pads and electric blankets are digital and some are analog controls and both work exactly the same on shore power or the MSW. One is now over 20 years old and still works fine. Just bought another electric mattress pad from a Walmart here in Northern Florida in Jan as the old one had a fabric starting to rip apart and the new one works just like the old one did for years now.

I have no reason at all to change to a PSW inverter and cost is not any part of the reason either. My MSW's do work just fine and always have! If they didn't, I'd replace them all in a heartbeat with PSW's. A one time cost! But why?

Thanks everyone. My design has changed a little, so I will only need a small one. Makes pure sine more affordable in the 350w range.

If anybody has any small units they are happy with, feel free to recommend them (we love Amazon)

there is so much junk out there you never know anymore.

So far our VertaMax Pure Sine 1500 watt inverter hasn't had a hiccup using it for cooking, coffee, computers etc.

This is the unit we have.

https://www.amazon.com/gp/product/B01KUASPS8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

The ONLY thing I've found that doesn't work on a MSW inverter was electric blankets. Not a single one I tried worked on MSW. I have enough batteries to light a small city, so ya, I run my electric blanky all night.

And as most have already said, I have also found that microwaves take ~2x as long to heat up anything stuck in them, and buzz while doing it.

I have a 3k Magnum Technologies PSW Hybrid Inverter/Charger in the TC and a Prosine 1800w PSW in my shotwagon.

The Magnum inverter is probably the best investment I've made in my TC, love it.....

Magnum Technologies 3kw Hybrid Inverter

Most electronics now a days use switch mode power supplies. These work acceptable with MSW inverters, probably because they are so low power.

What does NOT work well with MSW inverters are motors (like refrigerators or A/Cs) and microwave. These items will not perform as well and will run hotter.

With modern technology (chips) PSW inverters SHOULD be dropping in price, but I have not seen that.

For 8 years I worked at Heart Interface, 5 years of that was in the sales/tech support department. I talked to a lot of customers during those 5 years. I attended at least 5 FMCA rallies too, doing service calls. Xantrex bought all three major inverter manufacturers that existed in the Pacific NW in about 2001 or so. The swallowed up Heart, Trace and Statpower.
Heart had a LOT of inverters in many, many DP coaches. Heart was the primary OEM supplier of inverters. All they had at the time was MSW.

Everything worked fine on MSW for the most part. Some brands of microwaves wouldn't keep proper time on MSW. Dewalt tool charger from that era (1995-1999) would cook themselves on MSW power, Makita charges always worked fine.
Some brands of CPAP machines had power supplies that didn't like MSW.

Those are the only things I recall as far as issues with MSW.

If you equipment works fine on MSW now, and you'd rather have a larger inverter at a lower cost, then go MSW.

I install off grid solar systems for a living. I've had a lot of customers with MSW inverters. I warn them some things don't like the power. I know one customer who destroyed the electronic components in 2 new gas ranges from Lowes before he realized it was the inverter. I have heard ceiling fans hum loudly on a MSW, I switched the customer to a PSW and the humming stopped. One of my employees, against my warning, plugged his apple laptop into a MSW inverter. He had to buy a new computer.

My experience is that any Inductive type load is going to experience a shorter life expectancy, especially anything with a motor. That said, microwaves tend to die quicker on modified sine wave inverters as well.. Electronic items are somewhat hit and miss. Power supplies are pretty good nowadays and adapt to a wide range of frequency and voltage conditions. Square, or stepped sine waves can mess them up however. With Pure sine inverters being relatively cheap anymore I see no reason to go with a modified device.

When we used to have a MSW, the clock on the microwave would hum at a high pitch that drove me crazy. It was all the time, even when the microwave was not in use. Also had one TV that would hum with the MSW.