Good brand of power inverter - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 19, 2012, 02:54:00 am
content: What's a good brand of power inverter? I've read a lot of good stuff about Xantrex, but detailed reviews on inverters seem to be scarce. I need 12V input and 120V at about 1000-1500VA for operating power tools (such as a table saw) away from access to mains power.How much difference does pure sine wave make? I once thought that it makes a large difference for motors, but after reading that the Prius inverter outputs square waves at high speed (http://techno-fandom.org/~hobbit/cars/ginv/VH.html), maybe the only real disadvantage is noise? I have also read that the fast edges cause problems when driving long lines, but I can put in series inductors to slow down the edges.It would also be nice to have V/Hz overload avoidance (throttle back voltage and frequency if the load is too large, like the starting inrush of a motor). Unfortunately, I have yet to see that advertised on any consumer inverter (since most users would have no clue what that is and why they might want it!) but a few inverters do advertise soft start features. Is that a "consumer friendly" name for that feature?

author: FenderBender
author_rank: Super Contributor
timestamp: July 19, 2012, 10:07:22 pm
content: I don't have any personal experience with them, but I think Tripp-Lite is typically a good quality manufacturer of power related stuff. Might want to give them a peek. I looked for teardowns, but I found none.

author: Monkeh
author_rank: Super Contributor
timestamp: July 19, 2012, 10:10:27 pm
content: Why do you want an inverter?If you're planning to be running this off a vehicle, just buy a portable generator instead. More reliable, more portable, and much more efficient.You'll need more like 2500VA to cope with a table saw anyway.

author: FenderBender
author_rank: Super Contributor
timestamp: July 20, 2012, 12:58:10 am
content: 2500VA? I think no more than 500VA. 15A saws are pretty typical?

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 20, 2012, 01:02:30 am
content: I have made a soft starter that connects a hair dryer (a small yet high power resistive load) in series in order to limit the inrush current, then bypasses it once up to speed.I don't plan on using it all that much for power tools (a few times per year), so a portable generator would not be a good option.

author: Monkeh
author_rank: Super Contributor
timestamp: July 20, 2012, 01:11:44 am
content: Quote from: FenderBender on July 20, 2012, 12:58:10 am15A at 120V. That's 1800VA. You need headroom for inrush current, not to mention not running max capacity all the time.

author: FenderBender
author_rank: Super Contributor
timestamp: July 20, 2012, 01:44:15 am
content: Good Lord. I don't even know what I was thinking. Yes I'm quite aware VA is vRMS x iRMS....Yeah don't know what happened there.So yeah you're right.

author: saturation
author_rank: Super Contributor
timestamp: July 20, 2012, 09:56:26 pm
content: Power inverters are very popular consumer items, alas I think most are made by ODM for many brands, Tripp Lite included. I wish we had a tear down of any Tripp Lites to be sure.That said, check Amazon reviews. Its not technical, but there are a lot of opinions about how it they hold up.The only real issue is whether you need full or modified sine wave, the latter being far cheaper.For resistive or inductive loads, ac motors or universal brushed motors, modified sine is very cost effective.Go Power is a Canadian company with a good line of various power ratings that are well documented, and very affordable.http://www.gpelectric.com/products/1750-watt-heavy-duty-modified-sine-wave-inverterIf you know your specific inrush current limits, these inverters are specified at continuous output and are also specified for the extra headroom needed for surge.

author: bilko
author_rank: Frequent Contributor
timestamp: July 20, 2012, 10:42:53 pm
content: Xantrex tech support sucks, its non existent, they just refer you to their dealer network. Mostly board swappers who want to sell you a new board when a small $1 component fails. I have Xantrex inverters but wouldn't buy an more.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 23, 2012, 01:43:00 am
content: I did try reading reviews, but it's hard to figure out if an inverter is any better than the rest. A lot of bad reviews would probably point to a bad design, but if the rate of bad reviews is about average, it would be hard to tell if those bad reviews were due to actual problems or incorrect usage.I'm not concerned at all about tech support after the warranty runs out, since like any real engineer, I prefer fixing stuff myself. In fact, if I modify the unit, I can get many of the features I want for cheap, but doing so would void the warranty. So I'll definitely put it through a "break in" period before any modifications just to be sure I won't end up with a defective unit that I can't warranty.