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Power inverter

jonathon

jonathon

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I was given a reman'd Vector 700 watt power inverter, my plan was to use in my truck to power my laptop as well as anything else I might need. Now I was reading the directions, and it states that:

Certain rechargeable devices are designed to be recharged only by plugging them directly into an AC receptacle. These devices may damage the inverter. Do not use the inverter to recharge items that can be plugged directly into an AC receptacle.
Click to expand...

I'm not sure what that means :doah:Does that exclude my laptop with the factory power pack(which I think converts AC to DC power anyways..). If that's the case I'll have to get a car adapter it sounds like..

Now the other question I had is what gauge wire should I run? The booklet says 6 gauge for up to 10 feet, but I think 10 feet might be a little short for where I want to put it(in the rear cargo area of my burb).
 
I use a 750 watt inverter in my work truck to power my laptop computer and printer. I have a smaller inverter that I use while on vacation to run my computer while traveling (GPS program). I plug the AC charger right into the inverter. I didn't read the instructions, but have had no problems.

I ran #10 wire about ten feet because I don't plan on using it for anything more than the computer and a drill motor.
 
I have a 1000 watt invertor mounted under my front driver seat and i used 4ga battery cable. I have powered 1000 watt halogen lights, drills, saws, computer, TV's, VCR's, charger for my camera and have never had a problem.

Larger gauge wire never hurts a thing but using too small of a wire can cause electrical fires.
 
I am thinking 4 gauge would be best...

Thanks guys, appreciate it :D

Anyone got a prefered place for getting wire?
 
Since you're going from the front of the truck all the way to the rear i would use welding cable rather than battery cable. So hit up your local welding supply house. Oh and welding cable isn't cheap either.
 
If your mainly wanting to power just the laptop... I purchased one of those small inverters that is barely the size of the plug. I use it to charge my cell phones and run my laptop. It was right around the 20 dollar range at a truck stop. It wont power anything else, but it works great for the laptop.
 
DR said:
If your mainly wanting to power just the laptop... I purchased one of those small inverters that is barely the size of the plug. I use it to charge my cell phones and run my laptop. It was right around the 20 dollar range at a truck stop. It wont power anything else, but it works great for the laptop.
Click to expand...

Part of why it's going in the back is for camping.. lots I can do with it there.

I'm going to look into the welding cable.. sounds like it'll be expensive, but anymore I'm more into do it once, do it right :crazy:

I think the first order of business then of course would be at least a yellow top, if not dual batts since I want to run a winch later.
 
Equipment that pulls sudden loads, or is frequency sensitive is usually what has problems with inverters.
The power supply for your laptop is a switching power supply which usually will draw a large surge when first plugged in.
But, odds are the inverter will tolerate it ok.
If you are going to plug in more than one item, plug the computer power supply in first so the inverter can stabilize.

As for wire size, remember how power calculations work.
Power(Watts) is Volts times Amps.
Plus conversion loss.
A really really rough rule of thumb is to multiply the 110 volt amps by 10 to get how much 12 volt current you have to supply.
Actually you need to add about 10% to be safe.
So, 120 watts @120 volts, equals 1 amp.
120 watts @12 volts equals 10 amps
So, 700 watts @12 volts equals ~59 amps.

Don't forget, the smaller the wire, the more voltage drop you get. If the voltage to the inverter dropped to 10 volts, you would have to supply ~70 amps.
And the supply wire would get really hot, because it would be dissipating 2 volts at 70 amps which equals 140 watts.
 
Hijack

Whats the difference between jumper wire and regular electrical wire? My jumper cables say they are 4ga rated at 800 amps, but I used standard 6ga electrical grouding cable to hook up my 2000w inverter. The 6ga was about 50% thicker in the conductor section, just didnt have as much sheilding. I assumed that even though it was *smaller* cable, with more conductors, it should handle the load just fine. The distance between the batt and inverter is only about 8-10 feet.
 
Not sure that you have the wire gauge correct. The smaller the number the larger the diameter of the "WIRE" excluding the sheathing (insulation). So 4ga wire is larger in the "wire" (conductor) than 6ga wire.
 
One of the issues with most "smaller" inverters is that they do not provide a "clean" enough power signal to safely power sensitive electronics. True AC will have a nice smooth sine wave, the AC you get from most inverters is a clipped sine wave that can actually damage some sensitive electronics.
That being said, I have no problems running my computer, flat screen tv, DVD player, microwave, coffee maker, cell phone chargers, Xbox 360 . . . off the inverter in my semi. Now granted that is a 3000watt modified sine wave unit meant for these kinds of loads. But even then I had 2 300w units before the microwave and the only issue I ever had was a 60 hertz roll on my TV, and that was easily solved with a ground lift adapter.
If anything your power supply for the laptop may not last quite as long when using it with an inverter.

For me, I have never used anything less than 2 awg when hooking up an inverter. My current one has 0 awg due to the higher load and almost constant run time it sees now.
 
Jumper cable makers like to play fast and loose with wire sizes. AWG, American Wire Gage is the offical size of wire, and has a definite definition. So, 4awg wire is going to be the same size conductor no matter who makes it. The actual wire size may be different depending on the amount and type of insulation.
Ga and Awg should be the same, but sometimes are not. Jumper makers know that the heavier the conductor the better the cable in general, but wire costs more than insulation. So the cheap ones will measure the outside of the wire and crossreferance that size with the equivilent awg conductor size and claim that that the size of the cables.
I once bought a set of jumpers that claimed to be 2ga. They were huge! But for some reason they were not all that heavy.
I tried to jump a Jeep off and they would not do it. The Jeep owner pulled out a set of the cheap 6ga aluminum cables and they got the job done.
Thinking I might have a bad connection at a clamp, I pulled the handle cover back and found that the huge cable I had consisted of 8 indivually insulated 12 ga cables. Basically it was an 8 conductor extension cord. All the size was caused by the insulation around the 8 conductors. The actual size of conductor was probably about between 10 and 8 ga.
After that I went and bought a set of 2 ga NAPA cables about 20 ft long, and had trouble picking them up<G>.

J.
 
That might be the issue here. So knowing that, I will try to get some larger cable, or double run the 6ga (I have a decent sized spool).

Another question: How important is it to run the negative cable back to the battery? I have a solid ground point with a six inch long chunk of 0ga battery cable.
 
On an Inverter, I think it would be super important.
I wouldn't risk it on a piece of equipment like that, the chances of starting a fire is just too great imo

All of mine have always had equal runs of both positive and negative cable, fused the positive or used circuit breakers too.
 
Mine isnt hooked up right now simply because I dont need it yet, but I was planning on using some sort of fuse or breaker before I put it in service.

Well I s'pose I'll have to run to the local electric supply, cuz Lowes doesnt carry anythin larger than 8ga cable. Maybe they'll have breakers too.





Hijack over.
 
If it's a larger invertor it will already have fuses in it. My 1000 watt invertor has IIRC 3 seperate fuses. My invertor also has a low voltage cut off and an overheat cutoff built into the unit. Mine also has a digital readout on the front so i know what the incoming voltage is. IIRC the brand i have is designed to cut off power when the incoming voltage reaches 10 volts. I also would definately make a full run of ground cable directly to the battery.
 
You need the inline power fuses on the battery cable coming from the positive. Go to a heavy truck equipment place and get the fuse block and fuse used for a liftgate. The 250 amp model is what we use at work on inverters. Looks like this http://www.littelfuse.com/part/157.5701.6251.html
And these are the holders we use. In the pic you can see the fuse installed, all you do is hook one end of the pos cable to each end of the holder. In other words it goes inline. http://www.littelfuse.com/part/177.5741.0001.html
 
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