DC to AC inverter question
 

I noticed a DC to AC inverter on sale at Menards for about $15. It plugs into a car's cigarette lighter and allows you to plug in normal household items into it using your car's battery for power. I can imagine something like this being a real goldmine in an extended power outage. But I'm not familiar with how well they work and what their limitations are.

How much power can they handle? Could I run a blender with it? How about a microwave? I suppose using it to charge batteries would be a no-brainer. I just wouldn't want to burn the thing out, and maybe cause a fire, which could cost me my car, and garage.

Re: DC to AC inverter question
 

Start off by determining how many watts the inverter will handle.

Those small units are usually 50 to 400 watts, with 50-125 being available for that price range you stated of 15 bucks.

Then determine how many watts the device you want to run uses. If the device tell you how many amps it uses, the formula is AMPS X VOLTS= WATTS

This is the most valuable formula for electricity that you can know.

These units use what is called a modified sine wave, you can google this to tell you the good and bad of it.

Re: DC to AC inverter question
 

you just need to check the watt rating the cig lighter one i have is only rated
at 100 watts which is fine for some small chargers like cell phone
and probably some other ni cad battery chargers but it will not go close
to running a blender.just look at the watt rating of the device you want to use.

Re: DC to AC inverter question
 

also no matter what the rating of the inverter is you need the dc amps
to supply it and the corespondingly large cables and batteries to supply it.

your cig lighter in your car is probably fused at 15 amp with some very
small wires so the most you could draw would be about 180 watts
before the fuse blew. and you would not want to draw even close to this
for extended periods because of heat problems in some vehicals cig
lighter plugs and fuse blocks.

Re: DC to AC inverter question
 

They are good for about 150 watts continuous.....great for small TV or radio or computer....that kind of stuff. As others have said...you car lighter is probably a 15A fuse at about 14 volts....so just over 200W is the max you could ever run.

For bigger inverters you need some serious wire rdirect to battery.

Re: DC to AC inverter question
 

Thanks for all the useful information! I guess it would be good for charging batteries and supplying light, but not too much else. I imagine it could also do these things for a very long time too!

Re: DC to AC inverter question
 

One more thing.....

Could a battery be used without it being in the car? My car is a clunker and could give out any time, but the battery is new and I was wondering if I could just use it by itself to power stuff. What else would I need to do that, other than the battery itself?

Re: DC to AC inverter question
 

Batteries have amp-hour ratings....this is the number of amps of current they will supply over a 20 hour period and drop to 10.5V charge level.....which is fully discharged.....you probably could not start the car at that point in time....

So, if you have an 80 amp hour battery...that would be a good sized marine boat deep cycle battery.....you can draw 80 / 20 = 4 amps for 20 hours....it becomes less as you shorten the time....for example in 10 hours you could not draw 8 amps...it might be 7.5 and at 5 hours perhaps 13A......

I do not have a good feel for car battery capacities...but based on my example for a marine battery....you might be able to pull your 100Watts....which is about 8 amps....for perhaps 2 hours without risk to starting the vehicle........a little laptop computer might need 50W or so....so you could go 4 or 5 hours without risking needing a jump.

Most good inverters have a low voltage cut off....at 10.5 volts....they will shut off to protect draining the battery any further...

Re: DC to AC inverter question
 

110 watts = 1 amp

Also if you have an appliance that utilizes 1 amp ac remember that it is almost 10 amps dc if your talking a 12 volt battery.

My house runs on 48 volts battery bank converted to pure sine wave ac, so if I'm running a 1 amp item like maybe a 100 watt light bulb (which I don't) I will be pulling only a little more than 2 amps dc.

Simple rule for 12 volt dc to 120 volt ac is to figure the power usage in watts and just drop the zero.

So the wire in a lighter ain't gonna run shite.....well it'll run shite :wink:

Re: DC to AC inverter question
 

Standard size automotive battery, group size 24 is roughly good for 70 or so amphours.
but only a few times. the automotive starting battery i s not designed for continuous loads, or deep cycle service, and will not last through very many "cycles"
Microwave ovens are pretty power hungry devices, running one from batteries is possible, with a good solid inverter, but you will need a LOT of battery.
the wiring from battery to inverter needs to be sized correctly also. for example, say you wish to run a thousand watts from a 12 volt battery bank: 1000watts divided by 12 volts = 83 amps times 90 % efficiency = roughly 93 amps per kilowatt. assuming your inverter is mounted within a few feet of the battery bank, you will need a minimum of SAE one gauge wire. That is what i use for internet/computer backup at work, a small 1000 watt inverter, and a set of (3) 100 amp hour sealed lead acid batteries. a pair of 3 foot long one gauge jumpers connect the batteries to the inverter. this will run the coffee pot, and a small microwave if necessary, but is primarily for backup lighting and internet.
The little Xhinese mini inverters are probably worth what you would pay for them.

Re: DC to AC inverter question
 

You are only limited by the potential output of the inverter and the battery input.

In a "off the grid" situation, you could have a whole bank of batteries in you garage or shed etc.

Potentially you could power your whole house for awhile with the proper battery bank and inverter.

Re: DC to AC inverter question
 

Costo had some top notch inverters on sale earlier this fall made by Xantrex....they make them for large boats that have massive battery banks and cost several thousand dollars - so it should be a good manufacturer.

I bought a 1000W unit to install in my Pop-Up camper this winter...along with 2 big deep cycle maring batteries....either series 27 or 31.....in the end it will give about 180 Amp-hours of power.....allow up to camp off grid without running the generator too much. this will mostly be for running lights, radio, furnace blower, water pump.....but I did look and find a small 1000watt microwave at a garage sale this past summer....in case we want to pop some popcorn or something.

Camping/RV is like a little small scaled off grid experience....it will open ones evey to just how much water and energy one uses!

Fullpower - you are right on the money....requires some serious wire at low voltage to carry very much power!!! It's all Volts x Amps = Watts.

Nub - good rule - this is also in my "Farm Math" skill set....power / 10 = DC amps....roughly.....good rule....

Re: DC to AC inverter question
 

Like I said drop the zero it even allows for inefficientcy .

Also always keep the positive and negative dc current wires next to each other, there is a term for the power that is lost if you fail to do so......I can't remember the term for this.
Resistive loads like an electic stove or dc welding will suck a battery dry in no time, they are also the easiest or most forgiving on an inverter.....go figger,

Re: DC to AC inverter question
 

Living out in the country where the power goes out faily often we are pretty well prepared for short term power outages.

I think anyone who has not had their power gone for awhile should go throw their breaker for a day just to learn how it may be.

You will learn what you need very fast and give you a heads up on what you need to get started in doing.

In the city there is only so much you can do, but it might help you realize what can happen.

Even getting your candles, short term food-water, a small inverter for your car battery for charging cell phones etc.

It is a start.

Re: DC to AC inverter question
 

"Potentially you could power your whole house for awhile with the proper battery bank and inverter."
Yes, this is what NUB and myself do. NUB has a 48 volt battery bank.
My battery bank is 24 volts nominal.
am running an "Outback" brand inverter, made in Arlington, Washington, USA
It is connected with multiple runs of 2/0 cable to several sets of batteries.
The inverter will run the whole house, including a deep well pump, clothes washer, etc.
The only thing I cant run is the electric clothes dryer, which, at 6500 watts is just flagrantly excessive electrical consumption. even with local utility power it costs over a dollar per hour to run the dryer. to run the electric clothes dryer directly with solar electricity would take 39,000 dollars worth of solar panels. a little rich for me. I let wife string up a rope in the yard, for a bit less money. she hangs clothe s out to dry once in a while. when its not raining. or snowing. or cold..

Re: DC to AC inverter question
 

I've got one to run my laptop while in my car.
I spent like $30 at Wal-mart, it's 400 watts I think, but the instructions for it says if you draw more than 200 watts you're not supposed to plug it into the cig lighter. It came with heavier hookup wires you're supposed to connect right to the car battery terminals.

You can hook them straight to a car battery, when the battery is not in a car.

------

Most inverters have a couple limitations.

....Many of the cheaper ones are "square wave" and not "sine wave", and square-wave AC can cause some electronics devices problems.

....Also, anything with an electric motor will draw a surge of power at start-up. Many AC motors can use 5X or more their running power in the first instant they're turned on, and that surge can be enough to flip off the circuit breaker (or pop the fuse!) of an inverter that's not rated generously enough.

If you look at better inverters and generators, they will usually have two power ratings: one is the "constant watts", and the other is the "surge watts".

-----

For a cheap inverter, I would guess it would do okay with 50% or 75% load on it. I would not expect it to do 100% for very long.

To find out how many watts "stuff" draws, go buy yourself a Kill-A-Watt meter somewhere.

-end-

Re: DC to AC inverter question
 

I bought one a while back on eBay. It was the largest one there. 6 Kilowatts continuous/12 Kilowatts surge. Draws up to 500 amps continuously and can power all of the non-heating stuff in the house. I plan on building a bracket to hold three 200 watt car alternators wired in parallel run off the same belt. That way I can use them to feed the inverter with a 12volt marine battery across the input as a buffer to help hold the 12volt input more constant. Of course I'll need some type of engine (giant stirling or woodgas-powered) to turn the belt. Thinking about that now...

Re: DC to AC inverter question
 

I worked for Xantrex and was born in Arlington, WA. Basicly Xantrex went around and bought out Trace engineering, Hart, and other portable power companies and then fired anyone who made decent money, meaning all the people worth a damn. They just recently shut down the Arlington, WA plant which was formerly Trace engineering. I do beleive Outback power is a bunch of the guys fired from Xantrex but I've been out of that field for a few years now.

Re: DC to AC inverter question
 

At this point Xantrex still a pretty good product. Mine been ticking along without a hitch.

And thanks to the fusing, when I screw up with any wiring, out it goes before I burn anything up. Elect never been my big suit, one nice thing about DC, forgives me more than the AC does.

Re: DC to AC inverter question
 

You are correct sir, my big sine wave Trace is still working great, if I ever incur serious problems I'll most likely buy Outback.....but I'm not expecting problems for years to come.

I still have an old modified sine wave Heliotrope inverter that you couldn't break with a sledge hammer, so i suspect this trace will go a long long time.

Re: DC to AC inverter question
 

I had an old school trace it was an sw1512 I think, only rated at 1500 watts, 12 volt, "modified sine wave" I ran it with a random assortment of truck and marine batteries and a few solar panels powering a converted school bus for a few years.
I went to sell the old trace inverter, and the buyer wanted to see it work. so we hooked it up to a set of 4 L16 batteries we had sitting. 12 volt 700+ amphour battery bank, and we started plugging in stuff to the inverter. we had a coffee pot, a few 100 watt incandescent lamps, a toaster.... still holding 120 volts. so we added a worm drive circular saw ( 15 amps, AC) started that just fine. then we plugged in a 1500 watt electric portable heater ( in addition to everything else) still ran fine, voltage sagged to about 115 . we got as high as 500 amps DC load on the batteries, a bit over 5 kilowatts AC output from a 1500 watt rated unit, and the inverter never did shut down, we did get it warmed up though. Damn tough piece of equipment.

Re: DC to AC inverter question
 

Trace inverters prior to Xantrex were all built in Arlington. The circuit boards were stuffed there, transformers wound in house, and final assembley. When I worked there they started sending production overseas and then the products would come back to Arlington to be reworked. Transformer lugs not tightened at all, blood on the inside of the units where someone had busted their knuckles and missing hardware, etc. Oh, and the circuit boards that came down from Burnaby B.C. were wonderful. We would send reports back up there about components being put in backwards requiring units to be reworked and the response back would be them accusing us of not following ESD proceedures causing board failure. I personally saw the plant manager one day cut open boxes and then retape them so the QA manager would think they had been retested b/c there was a potential fault.

Bill843
Thats correct, and any inductive or capacitive load will also draw wattless power while operating. Thats the current that is used to build the magnetic (for inductive) or electric (for capacitive) field. Without going to indepth just be aware that any load other than purely resistive (i.e. a heater) will draw more current than is consumed in useful watts.

Re: DC to AC inverter question
 

I own 4 inverters. They are invaluable in a power outage etc. Ebay is about the cheapest place to buy them.
300 watt
400 watt
750 watt
1500 watt

All cheap but they work. Anything over a couple hundred watts should be wired directly to your battery and not run through a cigarette lighter.

Expensive inverters can be obtained from old ambulances if you can find one being junked.

Re: DC to AC inverter question
 

A Solar company recently told me that Schneider Electric just acquired Xantrex Technology this October and they have a quality control problem that starting early in 2008 with many returns. However, the older Xantrex stuff has worked great for me over the last 7 years. Recently -- I only buy Outback products, which have been super!

:shine:

Re: DC to AC inverter question
 

During Ike our generator died. I had as a backup a 2000 watt coleman powermate inverter.

figured, hey, lets hook this up, we can at least have basic lights and charge cell phones, etc.

Hooked it up to battery... INSTANT POOF. gone in a ball of smoke.

It was cheap junk.

Sometimes you need a backup to the backup to the backup. :)

Re: DC to AC inverter question
 

Are there any cheap inverters that can be hooked up to a battery seperately and not designed to handle big loads but are mainly for charging batteries and maybe lighting a 15 watt light bulb? Something like that could last a loooong time! My idea is to simply have the battery (a car battery) in the house and just charge up my flashlight batteries and maybe run a lamp with a 15 watt flourescent bulb.

Re: DC to AC inverter question
 

something like this would do nicely...

http://www.basspro.com/webapp/wcs/st..._SearchResults

Re: DC to AC inverter question
 

You can just go get any small-wattage inverter. The battery doesn't need to be hooked up to a car for the inverter to work.

On that note, I bought one of the Xantrex/Duracell Powerpack 600HD's to run my telescope, but the powerpack can run whatever else too. It's more expensive per-amp-hour than a bare battery+inverter would have been, but then the powerpack has a couple nice features built-in and is a lot more convenient to move around, too.

There are smaller & cheaper power-packs out there--Harbor Freight sells a smaller-capacity one for only $50--but most of them have reputations among the astronomy crowd for not lasting very long. This is partly two causes I think--one is that people underestimate the power draws of their equipment (because there's no simple way to test 12VDC power use) and the other is that these units are all built cheap, and simply can't put out 100% of their rated power for very long. If you buy one of the small cheap inverters, plan on it putting out about half what it's rated for.

A bare battery+charger+inverter is usually cheaper per amp-hour than a power pack, but there are dangers with using bare-battery setups. Wet batteries can leak and spill (most of the powerpacks use non-spillable batteries). Hooking up the charger wrong and running the battery down too far are two common errors that can ruin the battery, the charger or both. Better inverters have a low-power alarm built in, but the cheap ones usually don't.


-end-

Re: DC to AC inverter question
 

Amazon has the Xantrex Technologies XPower Plus 400-watt inverter on sale for $24.99 thru Dec 17th. Note that it's really only a 300 watt inverter -- from the description on amazon: "400 watts for 5 minutes, 600 watts surge for easy startups, and 300 watts continuous power."

"http://www.amazon.com/Xantrex-Technologies-851-0400-400-Watt-Inverter/dp/B0001DVQNG"

Re: DC to AC inverter question
 

Have had a Xantrex 600 powerpack downstairs with the trickle charger plugged in[as they said in the instructions that I could do]for three years as a power back-up for my computer. I had just tested it with a few items when I bought it then left it sitting plugged into power. Last week a power line went down and I tried to use it for real for the first time~~~zit a big buzz and the fault light came on~~~the battery is bad. Which I found out after unscrewin about three dozen little screws to get at the damned battery.


BTW I pulled out the little 1000 watt two cycle chinese generator I had bought at deep discount for $89[about half of what I paid for the POS Xantrex] Four pulls on the cord and it ran all the computer equipment in my office like a champ. Suppose to get 10 hours on a gallon of gas at full load; used a pint in four hours with my 500+-watt load.

Re: DC to AC inverter question
 

I did the same thing with my little 400 watt. My fault though, I accidentally reversed the polarity when I attached to the battery.
Big spark, and Poof! I fixed it though..it just blew the fuses...
two 25 amp automotive type fuses hard wired into the circuit.
I had to desolder the blown ones and solder in new ones.
Cost about $1 to fix and about 15 minutes work.

I had a three hour power failure a couple weeks ago.
Just brought a spare auto battery into the house,
hooked up the inverter and had a couple of 18 watt
mercury vapor lights and a radio going for the duration.
When I put the battery on the charger later...it showed
very little drawdown for the three hours.

I suggest having some of the mercury vapor bulbs
around...18 watts bulb puts out as much light as
a 60 watt incadesent..(or is it 75?) .the 26 watt is equal to a
100 watt standard bulb. You can probalby run
an 18 watt bulb for about 15-20 hours on a fully
charged auto battery.

Re: DC to AC inverter question
 

Inverters need to used only in a "friendly" dry, clean, enviroment.

I prefer the smaller ones for Laptops and electronics.

I have a big inverter with welding cables and clamps to serve as a portable generator with my truck battery.

I also prefer a backup 12 volt lighting system (and cheap tiller engine/delco alternator) as opposed to being dependent on inverters.

As a backup to the backup "generator" for lighting is a Coleman Powerhouse Dual Fuel lantern (hang it outside the livingroom window I suppose ... ) darn thing is still in the box and has never been fueled up ...


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Re: DC to AC inverter question
 

I agree...the inverter is not a good backup in any long term
power outage. I also have a gasoline powered Coleman generator
for longer term needs. Its a bit of a hassle to get it gassed up,
wired into the house circuits and running...hardly worth it for
the less than 12 hour or so power outage. The inverter is ideal
though for the short power down times...for simple lighting
and maybe a radio or small TV.

Main thing is to run the well pump and refrigeration longer term.
Two or three hours a day should keep those neccessities
abvailiable. My generator is 3500 watts, uses about a gallon
every three hours. 10 gallons will last about 10 days.

Re: DC to AC inverter question
 

I can't help but think, all those "state of the art" off grid power systems has an Achilles heal ... those high dollar electronic inverters.

Once it goes POOF, you're screwed.

Re: DC to AC inverter question
 

http://www.donrowe.com/inverters/xpower_1500.html i just got theys for xmas i hope they work good they well be my first ones i well be getting , have any of you guys used they before thanks mick

Re: DC to AC inverter question
 

bring back up

Re: DC to AC inverter question
 

Good find Mick. What batteries are you using? I have a solar setup now I am working on. Question for others, what is an effective minimum amp rating for panels to charge deep cycle batteries?

Re: DC to AC inverter question
 

still working on getting all the other stuff , hoping some one on here like tn well help ,

Re: DC to AC inverter question
 

http://www.northerntool.com/webapp/w...8565_200328565 i am looking at this for charging the batteries , the price is not to bad http://www.northerntool.com/webapp/w...8565_200328565

Re: DC to AC inverter question
 

Congrats, you just melted all the skinny ass wiring under your dash. You are limited by the weakest link. Run heavy wire from the battery to the inverter if you're gonna get wild and monitor heat issues. Something will get hot. But do NOT just plug a big ass inverter into your ciggy lighter and run something big.

Most auto inverters are cheap square wave POS's... keep this in mind when attempting to run sensitive electronics. You get what you pay for.

All fwiw.

Re: DC to AC inverter question
 

i have a small panel about 1/4 amp which keeps the charge up in a 200 ah bank in one of my trucks and it would charge if need be but is close to useless for most items i would want to run from it.and it would take a very
long time to fully charge a totally flat bank like 160 days

a better question to ask yourself is how much you want to use your battery
bank and what you need to run from it on average

Re: DC to AC inverter question
 

C-10 to C-20, its 10 to 20 % of the battery's capacity in amp hours.

A 100 AmpHr battery can be charged between 10 and 20 amp rate without damage.

Too low of a charge rate and the battery sulphates, too high and you boil out the acid.

But sometimes a good boiling is needed.

This means a periodic equalization charge, if you get a battery in the bank that does not keep up with the rest of the batteries you'll need to "cook" the bank .... run the charge rate up to about 18 volts and let it boil for a few hours, re check the individual batteries and repeat if needed.

This is for flooded lead acid only.


.

Re: DC to AC inverter question
 

thanks for the help do you have any sites i can read more on this , like i said i am learning from you guys , an i am hoping to do this right the first time

Re: DC to AC inverter question
 

bring it back up

Re: DC to AC inverter question
 

http://www.homepower.com

http://www.otherpower.com




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Re: DC to AC inverter question
 

Whoops, meant to quote mick silver's original "inverter post"
As to the "3000" watt "continuous power"...a standard car battery will go
stone dead putting that much power out in about 6 minutes if the car is not running. Even if its running, I don't think even a heavy duty
alternator puts out more than maybe 300 watts continuous.
I don't know how much a big truck rig generating system turns
out...but I would suspect that even using this in a big
truck might be hazardous to the electrical system.

I would suggest that you don't load this with more than
500 watts or so. I did notice that the specs make no
mention of how many amps you can load on this before
it blows its fuses. Remember that any device that
uses an electric motor draws a relatively high surge amperage
when you first wwitch it on.

Re: DC to AC inverter question
 

did you see the post on the inverter i got they have spec on them

Re: DC to AC inverter question
 

bring it back upppppppppppppp