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1500 W 12V Real Sine Wave Inverters?

4K views 31 replies 10 participants last post by  sww914 
#1 ·
I need a simple (no charger, just inverter) 1500W pure sine wave inverter. Not modified sine, but pure sine. The actual load will be 1000-1200 watts, so I'm figuring a rating of 1200-1500 continuous duty is what I want to shoot for, among other things to keep some motor tools happily ignorant of their power source.

I've heard some comments about problems with Xantrex equipment but a lot of the alternatives seem to be unreviewed units from obscure Chinese sources.

Anyone had a unit like this for some time, and have some comments about how well it has or hasn't worked out?
 
#3 ·
Maine Sail likes that one as well Marty.

I have no real issues with Xantrex inverters. I have installed both inverter chargers and inverters only. The only issues I have seen on boats were on units not properly installed - things like combining in and out neutral wiring and DC cabling that is way too small.

I will probably install the one you linked to on my boat.
 
#4 · (Edited)
I'd have to go with the 2kW model, as putting 1200 on the 1kW model on a regular basis is at least on paper not a good idea.

And then again, Xantrex seems to think their Xantrex XPower 1500 will run all the same stuff--with great faith in their modified sine wave. Anyone seen a wave trace of that to see just how close it comes?
 
#17 ·
We've used Xantrex MSW inverters for years (two 10,000W DRs, stacked) for our house & cabinet shop. The waveform of most MSW inverters is pretty crude (roughly three steps per pi/2 radians), but very few items seem to care. We run all normal kitchen appliances, a deep well pump, fluorescent lighting, and a shop full of big 240VAC tools.

Things that theoretically don't like MSW power: compressors and pumps (which start under load); mid-range electronics panels (anything with a blue LCD readout;)) like modern washing machines; some digital clocks; raster televisions.

Computers scrub their power. LCD screens don't show horizontal lines. Motors may draw a little more current & run hotter, but otherwise are fine. We had one digital clock run fast (but two others are accurate), and our Kidde smoke alarms read the MSW as voltage spikes, tried to clamp it, and nearly burned the house down.:laugher

Otherwise, we've been very happy with our MSW inverters.

BTW, even True (or pure) Sine Wave inverters aren't. A static solid-state device cannot produce the smooth curves of a rotating armature. TSWs simply make more, smaller steps that closely simulate utility power. Typically around 24 or 48 steps per pi/2, rather than 3 for MSW. I'd advise talking to someone who has MSW on their boat, driving loads similar in size and type to what you plan, & see if MSW has worked for them. The cost savings can be hundreds, or even thousands for larger inverters. The only TSW inverters on the market when we built our system that would handle big tools driven for 12 hrs a day would have cost ~$4000 more (for two) than our Xantrex DRs. Which are simple, yes, but also v. robust.:)
 
#5 ·
Brian,

Good to know "someone" likes this model. I'm recalling a thread I did a year ago January I was needing something like 300-400 watts, so the 1000w should work for my use and need. HS will assume he has done his homework for needing the 2000w unit.

Do not remember the conversion, but isn't it about "10w per amp" so if using 20-25 amps, 300 watts generally speaking?

I liked this one as it is reasonably priced for a true sine, I could get away with a modified, but price is on par with this one. This one also has gfci plug ins, vs many of the MS versions are general plug in's no GFCI. This is my own reasons for liking this particular model(s).

Marty
 
#6 ·
Easy way to figure DC load is 1000 watts AC is 100 amps DC. 300 watts AC is about 30 amps.

I will probably get the 1000 watt version. I don't have any power tools that use even that much power.

This reminded me of an inverter I swapped out on a big Sea Ray last year. Customer called and said he wanted me to replace his Xantrex with a Magnum as it had given up after 4 years. 2500 watt Freedom. First thing I said when I saw the inverter was that his DC wires were too small, only 1 awg - his answer was that it was professionally installed. After a while I convinced him to upgrade the wire size. It was a longish run and went through a bulkhead to the big battery bank between the diesels. We pulled the old wires out to get the proper lengths. The section of negative cable nearest the battery was stiff and charred for about 3'. That convinced him. We went with 3/0 for the new inverter. Also there wasn't a fuse but there is now.

A windlass is only on for a few minutes at a time, a thruster even less, but on a big powerboat with a huge battery bank the inverter could be on for a long time - long enough to get the wiring pretty warm if it's too small. He had 8 or 10 golf carts and said he was going to add more.

I still have the section of burned cable in my van as an example.
 
#7 ·
Brian,

That is scary. I have right now a size 24 house battery, may put another with it, or go with two 27's or golf carts to get about the same power or a bit more. Reality is, the 24 works fine. For me it would be christmas lights with the motor running, music if need be.......a power tool, but I have plenty of battery operated ones to not worry too much. LT can go on the 12V charger.....

The 1000 should do the trick if properly wired etc. I have a BIL that is/was an electrical engineer, Dodenja is across the slip from me, also an EE........figure I can get the wire part figured out easy enough, as the inverter will be with in 10' at most wire length from the battery(s). I know the 12V wire at 14 or 16 is way the heck tooo small for what I even hope to do! I'm not planning on much! I'm thinking at least a 10 if not an 8 or 6 from the battery pack. Wire is cheap! Got a new job the other day, so get a pretty good employee discount on this type of stuff.....so not worth the scrimping!

marty
 
#20 ·
WHo said I do not have LED lights on the boat, over 3000 of them little buggers! Yes, even LED lights use power at some point of quantity!

I use 2 15amp circut breakers, can not use just one or I blow the one up!:eek::eek::eek::rolleyes::rolleyes::laugher:laugher

May have to put in a new house battery, as it was acting up last weekend. So may get an AGM in a size 31......should help a little over the size 24 flooded battery.......

now back to regularly scheduled programing!

marty
 
#8 ·
10' one way or there and return? for 100 amps @ 10' total with 3% voltage drop you need 4 awg wire - if the total distance is 20' it should be 2 awg.

Best to put the inverter as close to the batteries as possible but not right over them - the AC wiring is carrying only about 8.5 amps so can be 14 awg.

And don't forget an ANL fuse in the positive close to the battery.
 
#9 ·
Should be 10' one way per side. I'll probably mount next to or really near the charger, IIRC I did that with a 6-8' run. Less than 2-3' as the crew flies per say. Down 2, over 2 up 2', maybe 3' per up/down etc.

David said he could help. That is what he does at Boeing.

Marty

PS

Sorry for the hijack HS!
 
#11 ·
Maybe.....
Battery is under the nav desk seat, could put the inverter on the wall outside...that would get in the leg way and/or door to the head. So best on the nav desk....could be the wall inside the head, also less than 6"........hmmmmm.......nah!
 
#13 ·
Where did you get a pic of my nav table? or is that yours? if so, you CS looks like my jeanneau......

ANyway, the charger is under the table on the back left, the side you see next to the manual pump is my two small uniden portable radio's.......Could go below them or maybe below the Heart 25amp charger.......

In general, the pic shows about where the thing would go, ie about 10 or a bit less as the wire goes, 3' as the crow flies per say..........
 
#16 ·
That works - I would use 2 awg wire anyway - bigger is better. That will give you less than 2% voltage drop and the inverter will be happier. Your battery isn't huge - you don't have many amps to lose.:)

And now back to your regularly scheduled programming.:D
 
#19 ·
"BTW, even True (or pure) Sine Wave inverters aren't. "
True, it is a matter of degrees. No pun intended. How many pulses they use, how they shape the pulses, in theory "pure" sine wave would be modified sine wave anyway, unless someone was using a real waveform generator and then pushing the power to follow it. At least in theory that's possible too.
 
#21 · (Edited)
bob-
I took a look at Xantrex's web site, found their "Tech Dr" articles. Found that according to the waveform that they post, their Modified Sine Wave is...a crock. It isn't a modified sine wave at all, it is a modified square wave, no way any kind of emulation of a sine wave. A true "modified sine wave" at least uses multiple steps, multiple pulses, not just a simple square wave with delays. No matter how many vendors pretend it is.
So while their own talk says their MSW will run anything just like a real sine wave...I'm not buyin it. Literally or figuratively. Those guys are talking out of both sides of their mouths. I'll gamble on something else. I've had mixed results with square wave in the past, quite some time back in the past, and if it has a money back guarantee...I may gamble, but not with Xantrex. I don't like smoke and mirrors, and anyone who calls a modified square wave "modified sine wave" can be glad I don't work at the FTC.
 
#25 · (Edited)
HS: Semantics. 'MSW' is rendered as 'modified sine wave' by its proponents, 'modified square wave' by detractors. In the end, it comes down to this, as I said above: NO solid-state, static inverter can produce a true sine waveform. Then it's down to how small & how many are the steps per pi/2 radians, as I said in my post. The basic MSW inverters use about 3 steps per quarter wave. The so-called 'pure' or 'true' sine wave inverters do exactly the same trick, tho at 8x or 16x higher resolution.

If anything, I would accuse them of deceptive advertising, for claiming 'true' and 'pure' when it is no such thing. Educate yourself, and make your choice. ALL static inverters are square wave; some are squarer than others.

My central point is this: don't needlessly buy into the hype around 'pure' sine wave inverters. For most applications, their higher resolution is superfluous. I detailed the loads that mislike MSW. We have now run a full household and professional woodworking shop for nine years on the crudest Xantrex MSW waveform available -- seriously, literally, two steps above square wave. And you know what?

We haven't noticed any squareness.

Really. I'm listening right now to the most pristine remastering of Cannonball Adderley playing 'Corcovado', with an RF-noise-free fidelity to make the heart bleed.:) We're running the dishwasher, two computers, and some CF lights. Square wave? WHAT square wave?;)

Point is, MSW (call it modified square, call it modified sine) is good enuf for nearly everything you will plug into it.

Here's another piece of hype to watch out for: don't oversize your inverter(s). Where Wh are precious (as aboard a sailboat), you want your inverter to be large enuf to handle your maximum sustained demands -- but no larger.

Inverters near the top of their range are >90% efficient. With loads below 50% rated capacity, you may see 40-50% efficiency. That means you are expending 2 Ah of battery capacity for every 1 Ah you pull thru the inverter. A rare case where overkill is bad policy.;) Size your inverter to your median demand. If you exceed its limits, it will let you know -- by kicking a thermal circuit breaker.

So I guess my take-away is this: 1) Don't dismiss crude waveforms because they are crude. Semi-square is probably good enuf for your needs. 2) IF you really want 120VAC power aboard a boat at all (and millions of people get by without), choose the smallest inverter (of either type) that will meet your needs.

Counter-intuitive, but true.:)

(Honestly, you wouldn't believe the number of people who have told me our off-grid setup cannot possibly work. "You can't run a tablesaw off batteries & MSW. You'd need $10k in TSW inverters." But I researched the hell out of this stuff, chose our systems for robustness rather than bleeding-edge technology, and everything has worked just peachy.)
 
#26 ·
bob-
"Semantics"
No, really, I've had the pleasure to meet topologists. Square is square, got those nice neat 90-degree corners and uniform trace lengths. Sine isn't. If you push around the lines on a square wave, you get modified square wave. If you make the picture "fuzzy" and somehow you can blur the lines into something that looks like a sine wave--you get modified sine wave. You can do that, the same way you can make a digital version of analog music, by chopping it up into time slices and approximating the curves.

But modified square wave doesn't do that. No matter how much your squint, it never looks "sinish".

And the folks who push it as MSW, also keep muttering vague mystical spells about how important TSW is. At the same time.

Kinda like a florist trying to convince me a bouquet of roses really SHOULD come with all that fresh manure still clinging to the bottom of the bouquet, you know?

I DO hear you, about MSW working so well. And I suspect the old unit I barely remember was plain square wave, not even modified. Still, real sine wave shouldn't be impossible at a lower price point. I think some of the "no name" brands are probably doing this perfectly well, while the branded players are simply making a much larger profit on their true sine wave products.

If I find a modified version, with a good return policy...maybe I will take the chance.
 
#27 · (Edited)
A little late to the discussion, but my two cents: We resell inverters, but excessive return rates on Xantrex make them not worth the bother. Xantrex bought the excellent Heart line many years ago, but they're no longer the same quality, and the Heart guys went off to start Magnum Energy. Xantrex costs a fraction of what the quality units do, but the good ones will last 15, 20 years or (hopefully) more. Interestingly, a charger/inverter costs hardly more than a good inverter once you've hit the 2000w level.
 
#29 ·
Victron. Will have to check it out. I have a small pure sine wave inverter (don't remember the brand) which raises hell with my SSB/Pactor signals. I have to turn it off to be able to get Wfax. Thanks for the info.
 
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