Inverter shopping

[markopolo]

I'm shopping for an inverter. Currently I have 240 watt Xantrex Modified Sine Wave inverter that I bought to run the TV in my RV.

I want to be able to run my microwave oven like I did in my Roadtrek. (see Where to put 2nd inverter in 2004 RT 190P )

If you're interested in doing this make sure you get an inverter that's rated for at least what current the microwave oven will draw. You'll have to read the back of the microwave oven or your owner manual. For example; A 700 watt microwave oven could easily draw 1200 watts.

A quick Inverter tutorial:

What is an Inverter?

Basically it is an electronic device that converts DC power from a battery into AC Power.

Two types of inverters:

Pure Sine Wave - this is equivallent to grid power.

Modified Sine Wave - this is similar but not the same as grid power. Most appliances will run when using a Modified Sine Wave inverter but some might not run well. I've noticed that when cooking microwave popcorn it might take 3 minutes on grid power but it take 4 minutes using the same microwave powered through a Modified Sine Wave inverter.

Here's what the waveforms look like on an oscilloscope:

Modified Sine Wave:


Pure Sine Wave


I've owned three inverters and they've all been Modified Sine Wave. I might get a Pure Sine Wave inverter this time. The prices are getting much better.

It's recommended that your turn your inverter off when you are not using it as it will continue to draw current from your battery when not in use but powered on. Sometimes that draw is 1.5 amps.

If you have a Tripp Lite inverter/charger (like what's in a Roadtrek) here's how you can make a switch to make it easy to turn it on and off:

http://www.classbforum.com/phpBB2/viewtopic.php?t=20

Feel free to add any info re: inverters to this thread.

[markopolo]

The APS1500 Pure Sine Wave inverter from PowerBright looks like it might be the one.

Continuous Power 1500W
Continuous Power (15 Min) 1800W
Peak Load Power Rate 3000W
No Load Current Draw < 1.6A
Total Harmonic Distortion < 3%
Input DC Voltage Range 10.7-15V

http://www.powerbright.com/aps1500.html

I like it's ability to handle 1800W for up to 15 minutes. That should be more than enough for a hairdryer and microwave oven etc.

$500 with free shipping

There's supposed to be an optional remote switch available. That'll make it easy to turn on and off.

[markopolo]

I ended up getting a Power Jack Pure Sine Wave inverter on eBay. It's only 1200 watts so it might not run my microwave oven but it will run everything else (TV, DVD, hair dryer on low, laptop etc.).

I was surprised to win the auction with a $152.50 bid having previously been outbid at $170. With shipping and UPS Fees it will end up costing a little more than 1/3 of what the PowerBright or Samlex would've cost.

http://stores.ebay.ca/POWER-JACK-SHOPPING-CENTER

[paulm]

My brother-inlaw gave me a virtually brand new(used once) 1750W MotoMaster Eliminator. I only have the box (no instructions) and see no mention of Modified SineWave. I do see, Non-Sinusoidal Output on the inverter itself (same thing I guess).

I like the eliminator inverters as they usally have a Digital Display. My 800 shows Input Volts, Output Volts and Watts. This one shows Battery Volts and Power on a Bar Graph and also has a remote switch on a 20' telephone wire.

On the down side of MotoMaster, is they seldom put out as advertized and I even wonder about the fine print. My 800 puts out 650 continuous and only 800 for a min. or two and about 1300 surge?? This 1750 is 1500 continuous and 3000 surge.

The price on this one was great and my 800 was like $39 on sale. But I don't think I'd pay full price for these babies, as I'm sure there are much better available.

[WAPITI]

Hi Marko,

I haven't been on-line for a while and just noticed you were asking about inverters. I was surfing Costco's web site and checked out inverters. They have a Xantrex XPower 1500 inverter for $124.95. It puts out 1500 watts continuous or 3000 watts surge. But, I guess you've purchased one already so probably aren't still looking! It dosen't say if it's sine wave or not either, but just thought I'd let you know. Sounded like a not bad price .

Brian

[markopolo]

Nice brother-in-law paulm

I think the Motomaster Eliminator line is made by Xantrex. They sell accessories for Eliminator Inverters. This is probably your 1750 watt:

http://www.xantrex.com/web/id/24/p/72/pt/29/product.asp

Max. continuous power 1500 watts
5 min. continuous power 1750 watts
Surge capacity (peak) 3000 watts

You can download a manual from their site. It is modified sine wave.

http://www.xantrex.com/support/web/prod ... isplay.asp

--------------------

That's a great price Brian. It's modified sine wave as well.





-------------------

I got it into my head that I wanted a Pure Sine Wave inverter this time.

Here's a bit more info from Xantrex re: Modified Sine Wave vs. True (or Pure) Sine Wave:
http://www.xantrex.com/support/readfaq. ... 268&p=1348

[WAPITI]

Hi Marko,

After checking out inverters, sizes, prices, etc., I decided to go ahead and order that Xantrex 1500 from Costco. They say 7 to 10 days delivery, so will have it in a week or so. I'll let you know how it works out. I was reading your posts about an on-off switch, and will have to look into what I can do in my Pleasureway. Also, will have to look at my power needs. I'm not sure about the modified sine wave as opposed to pure, but will have to see!!

Brian

[WAPITI]

Hi marko,

I obviously have too much time on my hands! I was surfing around the net and found this site. www.donrowe.com It has lots of info on inverters(and some good prices as well). Click 'power inverters faq' on the left side, and it explains a lot about the different inverters that might satisfy your needs.
Brian

[paulm]

Thanks for the info Marko. The manual had some good tips, including knowing your battery charge by voltage. And wire size.

12.7 - 13.0 100%
12.5 - 12.6 80%
12.3 - 12.4 60%
12.1 - 12.2 40%
11.9 - 12.0 20%

And some good read on Pure Sine versus Modified.

Thanks for the link Wapiti, wire sizes, eyelets etc.

[markopolo]

Originally Posted by WAPITI

...... I was reading your posts about an on-off switch, and will have to look into what I can do in my Pleasureway. .........

I wanted an inverter with a remote switch but the one I just bought doesn't have one. Wilton "paralleled" a second switch on his so that he could remotely turn the inverter on and off.

http://windsurf.mediaforte.com/roadtrek ... erter.html

I'll do that with my new inverter.

Thanks for the Donrowe.com link - lot's of great info.

[markopolo]

Handy voltage drop calculator:

http://www.nooutage.com/vdrop.htm

[markopolo]

My new inverter arrived today

I think the story of my winning the auction is worth telling. It is amusing to me

I had bid on it in a previous auction and lost. The seller offered me a second chance to buy it at the level of my last bid. When I went to exercise that option the time limit had expired. That was at $170 or so.

So....... In the auction I won (at $152.50), I was actually trying for second place - hoping to get another second chance offer. I never expected to win at $152.50. I had made the bid much earlier and many (probably most) eBay auctions are won by "snipers" in the closing seconds.

I have seen it go for less (like $139.) and for more (over $200).

I won it last Sunday night and it arrived today (Friday) - very good service considering it had to clear Canadian Customs etc.

I probably won't get to try it until April at the earliest.

[Big Ying]

I bought a 750 watt black and decker inverter from walmart for around $80.00. I have a 700 watt microwave and a 600 watt coffee-maker in my Ford Falcon. It worked great on a short trip I took recently. My method was simple, but effectice. I have an extra deep cycle batery in addition to the house battery. When I want to use either of the appliances, I bring the battery into the van, attach the inverter clamps to the battery, and than plug one of them in. Worked very well.

[paulm]

Well at least I left mine outside and ran a cord into the trailer. But right now my battery and inverter are in the spare bedroom, while I play.

I can't recall if my 1750 does, but my 800 watt inverter shuts down if the power drops below 10.5??. Not a problem, but I was trying to use it to keep my fridge going during potential power failures. But once the power returns and starts charging the battery, the inverter won't come back on line. One Friday night the power went out for 6 hrs, I didn't return until Tuesday and my fridge had been off the whole weekend. I hope my 1750 will restart, but until I kill the buzzer, the wife complains if I'm testing too much.

[g1g]

I think the pure sine is the way to go, especially if it is a good one. I had 2 - 1000 watt modified wave ones and the cheap one burned up while the good one barely ran a drill under load. Maybe some day I will be able to get a good pure sine wave one. I think once you have one you will never regret not having the modified wave. As long as you have the correct size.

[Ms&quot;B&quot;Haven]

Any more updates on inverters? I need to purchase one to power my TV and DVD at the same time. However, being able to power the microwave would be really neat too.

[markopolo]

The inverter I purchased works great so far. I have only used it for powering the TV and DVD player.

I had hoped to power the microwave oven but when I saw the 20 amp plug on the microwave oven I realized that my 1200 watt inverter wouldn't be able to do it.

For TV & DVD you won't need a large inverter. Read the labels on your TV & DVD or read the specifications in the owner manual to find out how many watts they consume. Add the two together and add a comfortable margin like 50% or even 100%.

Example:

TV 120 watts + DVD 80 watts = 200 watts + 100% = 400 watt inverter.

Running a microwave requires more planning. First off I'd only do this if you have at least 2 house batteries. Then you need to figure out how to get heavy cable (like 1 gauge) from the house battery to the inverter. The shorter the cable is then there is less voltage drop.

When I had my Roadtrek I added a 2000 watt inverter to run the microwave:

http://classbforum.com/phpBB2/viewtopic.php?t=33

[Big Ying]

So, Mark, is what I was doing on the earlier post a bad idea? It seemed to work fine the one short trip I tried it. I had to add extra time for the microwave heating times, but it still worked.

[markopolo]

You're putting me on the spot here Somebody who understands the technology of microwave ovens would be able to give you a better answer.

I'm surprised your 750 watt inverter powers your 700 watt microwave oven. But it's great that it works. I couldn't recommend it though. You're probably pushing it to the max.

If it were my setup, I'd continue to use it. It's normal to have to add time to microwave cooking when using a modified sine wave inverter. 3 minute popcorn used to take 4 minutes when I ran my microwave oven on my modified sine wave inverter.

Your results have convinced me to try to run my microwave oven off of my new 1200 watt inverter. I'll have to get a 20amp plug adapter. It occurred to me that the 20 amp circuit is probably only necessary when using the convection option on my microwave oven. I won't use that feature.

[Flipper]

A good rule of thumb for a microwave is what the output is the input wattage is around x2 so a 600 watt microwave is going to be around 1200w. This is usually on the label on the back of the microwave.