Hey guys.

I've done LOTS of searching and found MANY threads on the low capacity 150w 115V outlet.

Now with this being said. I want to upgrade it to lets say 300 - 400 watts.

I've read and understand that the gauge of wire isn't going to handle 1000 or 1500 watts. I don't want that either. I don't need to run power tools on it either! I simply want to be able to run my nebulizer for my asthma. I know that my 300 watt one works and this 150 watt one doesn't.

Thoughts about tapping in a bigger one? But not a TOO BIG of one?

I'm VERY inclined with electricity and understand what I'm doing. I just want thoughts on if anyone has done it before.

The truck I'm doing it on is in my signature.

 

You could probably feed a 300 watt unit with the existing wire and a 20 amp fuse. Beyond that, the wiring would overheat.

 

I am afraid you will not be able to upgrade your existing unit no matter what gauge wire or type fuse you use. The current limitations of this unit are implicit by design; you would need to re-engineer the whole thing using higher power switchers etc. One could do that, but it would not be worth your time. Your best bet is to just purchase one of a higher capacity that plugs into your 12VDC outlet or wires into your system. The good news is they are relatively inexpensive. I bought a 300W unit for my 04 Ram and it was under $60 as I recall. A quick search should yield lots of choppers in your wattage range.

 

You cannot go from a 150w rated wiring to 300w and simply add a 20A fuse. that's ridiculous. Your pulling twice the current and you'll melt your wiring after awhile, especially if you know 300w is needed.

I would leave whats in the truck there and add a higher powered 500w unit.
A 300w unit doesn't offer a true 300w btw and if you run it at or near max capacity, you'll likely burn it up quicker because it'll be running hot all the time to squeeze out every drop. Also, if you run an inverter above 70% output capacity, the power signal gets very distorted and you'd be feeding your breathing pump dirty power and thaqt could effect the lifespan of your medical equipment.

Go buy a descent 500w unit, hoo it directly to the post on the tipm module(fuse bbox under hood) and add an outlet where you can easily access it. They make those extensions, this way you can put the inverter underneath one of your seats and run the extension to your console or lower dash if you'd like....OR replace the existing outlet with your aftermarket one.
But Id leave stock wiring as-is and not alter it.

 

Thanks for all the helpful insight guys!

I'll continue using my inverter then

 

No, you probably could go up to 300 watts with the overdesign built into the wiring. No more than that though.
I would agree to just add the larger inverter as a separate add-on.

 

Totally agree with dirtydog, your gonna burn up your wiring over time. Not to mention the switch is probably not rated for the increase current as well.

The other thing I would be a little weary of too is if this system is controlled through the computer in any way, which in these trucks is a good possibility. You don't want to pull more then the computer was originally manufactured for.

I would just put in a 500W too, as dirtydog said you don't want to put your inverter into overhaul. I'm not sure tho that I would hook it up directly to the fuse box. I get a little uptight about these new electronics and the effects inrush current can have on it. 500W is a fair amount, although it is a fuse box and probably would be ok, its connected to the computer in some way. I have heard way to many horror stories about people who just connect wires to a power source. I would run a relay off the box to control the power to the inverter. The relay is what handles that inrush current, not only is more designed for that, but its cheaper to replace a relay then a computer...This is just my opinion (I am a little **** haha), and I am an electrician so a relay is nothing for me to wire. It can be overwhelming for some people, but I think a relay can save a bunch of money on some of these new vehicles.

 

If you need more AC, add a separate inverter and hook it up to the battery + terminal with a fuse. The basic formula is P(watts)=V(voltage)xI(Amps). So on the 12V side of things (inverter input) you've got a load of 500 watts (500=12xI(amps)). Solving for amps (I), you divide 500 by 12 and you get 41.7 amps on the wire sourcing the inverter. For this kind of amperage, I would use a 2 AWG wire (.4 volts drop for 10 feet for 50 amps) to the input of your inverter. You can get away with a 4 AWG (.16 volts drop for 10 feet for 50 amps) wire also if you keep it 10 feet or less long.

 

I'm talking about the fuse box distribution bolt. The one that the battery and alternator get bolted to. This doesn't effect anything in the fuse box itself! It's essentially the same as hooking to the battery directly. Instead, you have an easy vantage point of a nut to take off and a ring terminal to slide over it. Very easy. I'd assume 09+ has a very similar set-up as my '08 does? Here's a pic.
DSCI0506.jpg?t=1257978905


and PedreDog, DC line current is slightly different than AC line current. Although the calculation is correct, an 8guage wire would actually be able to handle that 40A of current. Think about your alternator that puts out 160A. It's only a 4awg wire, 2awg at best in vehicles...for 160A!

 

Agree with dirty dog on the wire size for shorter runs. I'm being conservative in that the wire running into the cab for the inverter is much longer than the one from the alternator to the battery - better safe than sorry.