# Learning About Inverters And 12v Power



## ZHB (Mar 17, 2009)

OK~ I've been reading old posts about inverters, generators, and other fun stuff (the desire for good coffee in the OB started all this, which I've sated with a Coleman Camp Coffee Maker). I think I have a handle on some of the basics now. The devices I'm most interested in powering are 1. The 19" LCD TV, 2. Charging my laptop, and 3. a tabletop fan. The DVD Player runs off the battery, so it's covered.

So is this correct?

* The 12V receptacle near my TV should run 12V appliance directly, such as my cell phone charger.
* The 12V by the TV can run a SMALL inverter~ such as 150W or less~ which would run.... my cell phone charger? ;-) I'm sure the fan would be fine too.
* Just how much wattage should the TV require? (Yes, I know I could RTFM, but it's on the TT at the moment....)
* My laptop says 4.5A on the power label....how much wattage might this require?

And for the next couple question~ I have 2 separate 12V batteries, wired in succession.

* If I purchased an inverter, could I run it back to one of the batteries, leaving the other for the OB? 
* Should I disconnect them, or not? 
* Is there a real benefit to having 2 12V's wired together, or should I consider changing this somehow?

And to the generator question~ my wife wants the generator, but I'm not ready to plunk down that much cash, since she only plans to dry camp "occasionally." She wants the gen so that we would have all the benefits of hookup (read: Air Conditioning.) Am I right in what I've heard that a Honda E2000i won't run the AC, and that you'd either need 2 2000's wired together or a 3000 to run it?

TIA!


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## CamperAndy (Aug 26, 2004)

You may have answered part of your question yourself. If you only dry camp occasionally then you may not need either an inverter or a generator. That said a 150 watt inverter will handle your toys for charging but really should not be used for higher loads.

Those generators are a good investment for the trailer and the house incase of power outage.


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## Nathan (Jan 2, 2007)

For real simplicity, remember that Volts * Amps = Watts.

So a 150W inverter will provide 1.25 amps at 120V. It will also remove 12 AH out of the battery for every hour of operation.

Ok, now that you got the taste of it, read this: 12V Side of Life


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## ZHB (Mar 17, 2009)

Nathan said:


> For real simplicity, remember that Volts * Amps = Watts.
> 
> So a 150W inverter will provide 1.25 amps at 120V. It will also remove 12 AH out of the battery for every hour of operation.
> 
> Ok, now that you got the taste of it, read this: 12V Side of Life


So therefore, charging my 4.5A laptop will take 540 watts, right?

I'll check out that link~ thank you!


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## Nathan (Jan 2, 2007)

ZHB said:


> For real simplicity, remember that Volts * Amps = Watts.
> 
> So a 150W inverter will provide 1.25 amps at 120V. It will also remove 12 AH out of the battery for every hour of operation.
> 
> Ok, now that you got the taste of it, read this: 12V Side of Life


So therefore, charging my 4.5A laptop will take 540 watts, right?

I'll check out that link~ thank you!
[/quote]
I'm betting 4.5A is the DC charge going to the Laptop, not the AC draw. The Dell's at work here are drawing 1.5A of AC and outputting 4.6A of DV. If you can get a cord to charge directly from 12V, it will save power since you lose some in each conversion process.


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## CamperAndy (Aug 26, 2004)

ZHB said:


> For real simplicity, remember that Volts * Amps = Watts.
> 
> So a 150W inverter will provide 1.25 amps at 120V. It will also remove 12 AH out of the battery for every hour of operation.
> 
> Ok, now that you got the taste of it, read this: 12V Side of Life


So therefore, charging my 4.5A laptop will take 540 watts, right?

I'll check out that link~ thank you!
[/quote]

Must be DC draw as Nathan said. My Dell shows 65 watts AC for the charger.


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## ZHB (Mar 17, 2009)

OK, I'm learning here~ electrical stuff is not really my thing; I've always left it to the pros at home, except for simple repairs.

So yes, I see my laptop charger is 90W. I picked up from "The 12 Volt Side Of Life" that a 19" TV is estimated at 120W. Given a few other small items, I'm thinking that one of the smaller 400W inverters should be ALL that we would need. I think from this reading as wll that I can just attach the leads to my existing dual-battery setup and it will be drawing amps away along with the existing 12V appliances. And apparently, I can get a quality 3-stage charger with the inverter as well.

So for those of you who are much more knowledgeable~ do we have quality converters in our Outbacks? (I have an '09 300BH) Do they have a separate charger? And for someone without an electrical background, but who is handy around the house - is installing an inverter a manageable job?


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## CamperAndy (Aug 26, 2004)

ZHB said:


> OK, I'm learning here~ electrical stuff is not really my thing; I've always left it to the pros at home, except for simple repairs.
> 
> So yes, I see my laptop charger is 90W. I picked up from "The 12 Volt Side Of Life" that a 19" TV is estimated at 120W. Given a few other small items, I'm thinking that one of the smaller 400W inverters should be ALL that we would need. I think from this reading as wll that I can just attach the leads to my existing dual-battery setup and it will be drawing amps away along with the existing 12V appliances. And apparently, I can get a quality 3-stage charger with the inverter as well.
> 
> So for those of you who are much more knowledgeable~ do we have quality converters in our Outbacks? (I have an '09 300BH) Do they have a separate charger? And for someone without an electrical background, but who is handy around the house - is installing an inverter a manageable job?


Check your 19" TV for the actual usage, if it is a LCD it should not be that high.

Yes the installed converter/charger is a quality 3 stage unit.

Installing an inverter is also very easy and should not really tax you too much.


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## sengo (Apr 14, 2008)

I did something like your description.
On my 23rs I did not 12 V plug close to the tv (next to cabnits on kitchen only front bed room). 
I split the 12 volt wire going to the stereo 15 amp fuse dc main board 15x12=180watts, and install 12V plug. 
Plugs small true sine wave inverter 150watts to run tv, dvd, laptop.
In front storage I had a second inverter 1500W modifie wave (less cost$$$) w/ remote control inside the TT,than install two separate plugs for 120V, one above the existing one on kitchen and the other front bed room . 
( was fun running wires for plugs thru walls TT ).
The reason I d'not want use transfer switchs or flip circuit braker. This way I have two separate systems 120V.
Batteries I have two 6V trojan 145 and one 2000 honda genetrator. 
I only used one time the AC last year , on my case I dont see the need for second 2000 generator$$$ to run the AC.

Sengo


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## MO7Bs (Apr 11, 2009)

Another thing to keep in mind is...

Be careful not to draw your batteries too far down too often.

If you are running a 400 watt inverter at 75% capacity, then you are pulling about 4 amps (12v*300w*1.1(conversion overhead)=~4amps

Add to this the energy used by your all the appliances on your rig, water pump, water heater ignition, refrigerator (yes is uses some electricity when not on), lights (non-led's pull a lot of juice), etc, etc, etc.

You will probably be pulling a lot more out of those batteries than you think, just sitting back watching tv.

When we did our test, granted we had the heater on because it was ~50 degress outside, and several lights, watching tv on our lcd running a 400 watt inverter...we only lasted about 45 minutes until we were at 1/3 of a battery.

If you can afford a nice quiet 3000 watt generator, then that's not a bad idea. If you can't, then get a smaller one that you can use to recharge the batts when needed.

Just some thoughts, I am really wanting to set my rig up for some more 'rough' trips with me and the 3 boys (wife considers full hook ups in a resort park roughing it) to some national parks, etc. But I want to convert the lighting to LEDs, add another deep cycle battery, get a good quiet 2000-3000 watt generator for the hotter days and cooler nights and maybe add some solar panels to help keep the batts charged.

Paul

Oh...I almost forgot the biggest reason to get generator...The wife already hinted at it...that's all it takes around here!


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## Gilligan (Aug 25, 2006)

On the Minnow, we used to plug a battery charger into the inverter, and connect the charger cables to the battery to keep it charged. It never seemed to work, though.









Gilligan


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## Oregon_Camper (Sep 13, 2004)

Bricker417 said:


> Oh...I almost forgot the biggest reason to get generator...*The wife already hinted at it*...that's all it takes around here!


Get out of your chair...and go buy it now.


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## Just Add Dirt (May 5, 2009)

I just bought this great little generator at Amazon.com, it's very quiet, powers the A/C, TV and Microwave all at the same time and the price was RIGHT. you stand next to it and hold a conversation in a normal voice, while it is under load. http://www.amazon.com/gp/product/B001L5TPCC
They missed sending the wheel kit though; a phone call and a email fixed that.
Was an easy fix for dry camping...
Just add mud... (soggy from all the rain)


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## outbackgeorgia (Jan 28, 2004)

I have that generator and it runs the A/C just fine, as well as TV, etc.
Just don't try the microwave too!

Dave


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