Inverter Questions

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A generator can certainly run an A/C if it's large enough.  Generally, you will need a 3000W unit for that.

I'm not familiar with the Wagan brand.  I assumed RV use as this is the RV Forum :)  But the same rules apply to a tent or a boat.
 
Ned said:
I'm not familiar with the Wagan brand.? I assumed RV use as this is the RV Forum :)? But the same rules apply to a tent or a boat.
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Thannks, Ned.  Glad to hear I can use it in my covered wagon <smile>!

About the size.....would a 700/1800 watt modified sine wave model for $50 be plenty?  Or should I spend $140 and get a 2000/4000 watt model?

Mainly for TV and maybe my laptop.

Jim, hanging on in New Mexico Winds
 
would a 700/1800 watt modified sine wave model for $50 be plenty?  Or should I spend $140 and get a 2000/4000 watt model?
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Jim, I've never seen those sizes of inverters for those prices. Divide the watts by 10 or multiply the prices by 10 and you'd be closer to what I'm used to seeing. Are you sure they're inverters?
 
Jim,

I have never heard of inverter rated at 700/1800. What exactly do you mean by that? The 2000/4000 sounds more reasonable if you're talking about 2000 watts continuous and 4000 watts peak, but I've also never heard of one that would have a peak rating double that of the continuous rating. 2000 continuous and 3000 peak is more reasonable; 700 continuous and 1800 peak is unheard of - unless it's only for 1 millisecond or so.

Also be aware that some home appliances do not take kindly to modified sinewave, especially if they have electronic controls like electric blankets, clock radios, automatic coffee makers with digital start time controls, and even some microwave ovens. I speak from experience, having burned out one electric blanket, two Mr. Coffee coffee grinders, and have a Magic Chef micro that works - but only at about half power and with lots of groaning noises :mad: Incidently; just tried one of those new-fangled tower fans with a remote control. Works great on the generator or shore power but started putting out a bad (read: frying electronic components) smell almost immediately. My coach came with a 2 kW modified sinewave inverter and does an admirable job with most electrics, but if I were to do it over, I would bite the bullet and go with pure sinewave right off the bat. More expensive, but you wouldn't have the above mentioned problems.
 
desertjim said:
Our concerns are: ?AC when necessary and an Electric Blanket when necessary, TV, and lights. ?
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Jim,

Unless you have an old electric blanket without electronic control, there is a very good chance that it will not work on a modified sine wave inverter. We just went though this and after trying four different model electric blankets, we decided to purchase a pure sine wave inverter just for the electric blankets.

Richard
 
I looked at the Wagan web site and see the 700W continuous/1800W surge inverter.  I don't see a 2000/4000W model, however.  Here's what the web site says about this model:

2016 ? 700 Watt Power Inverter
Sustained 700 Watt; 1800 Watt peak surge power
Powers: above and... 1/2 HP Induction Motor, Belt Sander, Single Range Electric Stove, 1/2 HP Electric Power Saw, Blender.
(cables included)

This is nowhere near enough to power an electric blanket all night and as others have told you, the modified sine wave will burn out any electronic control on the blanket.  Also, $50 seems too cheap for even a 700W inverter.  Where are you getting your prices?
 
You guys are mixing up your fancy Xantrex/Heart/Prosine inverter/charger systems with plain vanilla modified sine inverters. You can find dozens of brands of inexpensive <1KW inverters  for under $100. And it is popular marketing these days to give them super high peak ratings, so oddball ratings like 700/1800 have become common as well. As Karl says, the peak ratings are of very short duration, but that's OK if it is just starting up a tv or small motor.

The cost difference is easily explained by the lack of a built-in charger and the lack of an integrated transfer switch.  I built my own "system" using a 2000/4000W inverter, a separate transfer switch and a good 3 stage converter charger and it worked out about half the price of an pre-packaged inverter/charger from Xantrex.  But for basic needs, adding an inverter while retaining an existing converter/charger is both simple and effective as long as you remember to never, ever have both shore power and inverter power routed to the same circuit at the same time. Easiest way to do that is to unplug the appliance from the house circuit and plug it into an extension cord that runs to the inverter.  That way, you can never make a costly mistake.
 
Good points, Gary.  However, cheap or expensive, if the inverter isn't sized to the load, it won't work well, if at all, and the batteries have to be sized to the expected maximum inverter load.
 
Also looked at the Wagan site and found something interesting:
2015 ? 175 Watt Power Inverter

Sustained 175 Watt; 500 Watt peak surge power
Powers: above and... laptop computer, Fax/Printer/Copier Combo, Battery Charger, 13" Color TV, Hi-Fi Stereo, Camcorder, Toll Battery Charger.
Click to expand...

Hmmmm... plug it into your cigarette lighter socket and charge your battery with it - Prepetual Motion!!!!
 
Well, guys, this is getting too technical for me.? Maybe I should just go and purchase everything AC/DC (smile).

Here's the info I get on the 700/1800 model:
=================================
? ? * Operates most power tools, color televisions, TV/VCR combos, and home computers
? ? * Low battery alarm and shutdown
? ? * Battery cable clamps
? ? * Cooling fan
? ? * Moisture resistant circuit board
? ? * 1800W peak
? ? * 2-1/2 ft. cord
Wagan Tech# 20162

And here is the spec sheet:

http://www.garlic.com/~jimd/700-inverter-specs.jpg

Is there more I need to know about it?? Or be aware of?

Thanks,

Jim

 
desertjim said:
Is there more I need to know about it?  Or be aware of?
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Nothing more than we've already discussed.  One thing that bothers me is it's fused on the DC side at 30A which would indicate a maximum input of 360W.  I don't see how you can get 700W out from that.  Something isn't right here.
 
Jim,

Apologies if the discussion is getting too technical. I just have a couple of comments/questions:

  • When you do your calculations, use 700 watts, not 1800 watts. You cannot continuously power 1800 watts from that inverter.
  • I assume you have a separate charger for your deep cycle batteries. If not, how will the batteries be recharged?
 
Must be the new physics.  But I saw the same info at the Wagan web site in the 2016 manual (see http://www.wagan.com/downloads/2016%20manual.pdf page 5).
 
You're right Ned, it's new physics aka 200% efficiency.
 
Ned wrote:? "Nothing more than we've already discussed.? One thing that bothers me is it's fused on the DC side at 30A which would indicate a maximum input of 360W.? I don't see how you can get 700W out from that.? Something isn't right here." ?

Then it's false advertisement or what? I don't know anything about these things, so I ask here.? And I appreciate all your info.

Tom wrote:? "Apologies if the discussion is getting too technical. I just have a couple of comments/questions:
When you do your calculations, use 700 watts, not 1800 watts. You cannot continuously power 1800 watts from that inverter.
I assume you have a separate charger for your deep cycle batteries. If not, how will the batteries be recharged?"

Yes, I know the 1800 is just the surge wattage. As to the re-charging, they'll be recharged either as I travel, when I'm plugged in to electricity, or with my generator which has a 12v charging outletDoesn't it sound like I should contact Wagan to see what's up with the claim?

Thanks,

Jim

?

 
I would certainly ask them about it.  The math doesn't work, you can't get out more than you put in, and generally less because of internal losses.
 
Is there more I need to know about it?  Or be aware of?
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No, not with regard to that particular inverter.  But you DO need to be aware of your own intended use, i.e. the loads you will put on the inverter and the amount of battery capacity you have to sustain those loads.  That's what we have been trying to point out, though straying into the "technical" stuff when doing so.  For those accustomed to merely flipping switches in an all-electric home, living with limited electrical power can get very frustrating.

I know you were joking about the AC/DC,  ;) but I want to point out that the technical stuff regarding amps, amp-hours, battery discharge, etc. would be pretty much the same whether using an inverter or AC/DC appliances. There's no free lunch with power - the power that comes in has to equal the power that goes out, plus a little extra for losses along the way.
 
Ned said:
I would certainly ask them about it.? The math doesn't work, you can't get out more than you put in, and generally less because of internal losses.
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I guess, though, that it might be enough to run the TV and a couple of lights.?

I'm sure glad I don't intend to do much dry camping? ;D.? Just now and then when we want to grab a quick overnigt spot.? How in the world would we get by a whole evening without TV :p.

Regards,

Jim
 
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