Inverters again

[james tillitt]

I am looking into inverters, I have read about them somewhat on this site and links from this site and have a couple of questions. 1) What is "modified" sinewave? 2)Is a 400 watt "modified" sinewave inverter a sound investment at $59 (Bi Mart) or is this something I'd be regreting soon? 3) If I got one of these and found that I needed more wattage can you add a second inverter down the road?

Thanks for your input.

[Ken A Hood]

I haven't got a clue but here's a helpful website...

http://bart.ccis.com/home/mnemeth/12volt/12volta.htm

[diverguy]

dont know about adding a second inverter, but i dont know why you could not replace it with a larger better unit at some point.

i am a simple person so here is my simple take on the other ?.

most expensive inverter
if you look at the cycles on an oscilator. a sin wave would look like perfect rolling hills. 60 cycles a min. or correct me if i am wrong 60 hrtz. this is household. the elc coming through is nice and clean

med price inverter
a modified sin is pretty close but the cycles are not a clean. you may see this as very thin wavy horizontal lines on a TV. or maybe a very low (minimal) buzz or humm in radio. very minimal but not perfect. i have a modified sin and i have to look very close to see any distortion on my tv
. i am happy with this.

el cheapo
on a non sin wave inverter, the cycles are very blockish. looks like a castle top when viewed on an oscilator. this causes a lot of distortion in electronics. and is not recomemded. blender, frige, ect should work fine. but on a tv you would get a lot of thick wavy lines, and/or loud buzz on radio. could cause possible damage to high end electronics. dont waist your money.

just my take on the matter.

[cleonard]

In general you cannot parallel two 400 watt inverters to get 800 watts. Only some extremely high end units allow for such use.

In reference to Diverguy's post, the "modified sinewave" inverters are almost all in the "el cheapo" category. However, as stated they do run most equipment just fine.

$59.95 is a pretty high price for a 400 watt unit. I usually see these for $40 to $45 at the local auto part store chains like Pep Boys.

[madjack]

60 bucks seems a bit pricey...I paid 25 bucks for 500watt model at Sam's Club a couple of years ago(just before Katrina)...it was a mod-sine unit branded by Vector and it ran my fans and 13"TV just fine.......
madjack

p.s.... keep in mind, wire sizing...there will 10 times the amperage coming into the unit(12VDC) as there will be going out of the unit(120VAC)...example...with your 400watt unit, there will be around 3A of 120VAC going out...but to get that 3A of power, the invertor will pull 30A of 12VDC...a 10 to 1 factor of DC to AC power..........MJ

[james tillitt]

"60 bucks seems a bit pricey...I paid 25 bucks for 500watt model at Sam's Club a couple of years ago(just before Katrina)...it was a mod-sine unit branded by Vector and it ran my fans and 13"TV just fine....... "


I guess this is what I was getting at. In the articles I read, the prices they were talking about were higher for the wattage rated. They talked about "Cheapo" inverters, and $25-$60 seemed pretty cheap, so I didn't what to buy some "snake oil" inverter.

As far as two inverters goes I wasn't planning on using two in parallel (should have clarified this), but one to run one appliance and one to run another.

[madjack]

...here is a 400 watt Xantrex on Amazon for less than 37 bucks...Xantrex is one of the highest rated units on the market...60bucks is still too much to pay!!!!
madjack

[Alphacarina]

Keep in mind that a 400 watt inverter operating at it's rated output is going to draw about 40 amps DC from your battery - It would take a pretty large battery to put up with that for any amount of time unless you have an engine running and an alternator to keep it charged

Don

[james tillitt]

Actually the one at BiMart was $29 and they have a 700(750?) watt inverter for $49(not $59). Anyway, I went ahead and bought the 400 watt inverter. I guess if I do outgrow the 400 watt inverter I can always use it in my truck.