inverter???

[MASTER Brian]

I am curious, are there any real differences between a marine 12v-110v inverter and one you might use in your car? .....besides probably having marine grade wiring! I am guessing the marine ones are GFCI protected and the others aren't but I really don't know.

Not many times I really need/want 110v on my boat, but curious just in case. I have a small "portable" one I use in my car at times, I also have a larger "hard-wired" one. Curious if either of those could be used in the boat, leaning more towards the portable one. Obviously, I wouldn't want to use one that isn't GFCI, unless I wanted to light up, which I don't.

I am also curious if anyone has any experience with these on a Evinrude XP150, basically is the charging system able to run one or would I risk damaging my electronics?

Thanks...

 

[seabob4]

Re: inverter???

I am curious, are there any real differences between a marine 12v-110v inverter and one you might use in your car? .....besides probably having marine grade wiring! I am guessing the marine ones are GFCI protected and the others aren't but I really don't know.

Not many times I really need/want 110v on my boat, but curious just in case. I have a small "portable" one I use in my car at times, I also have a larger "hard-wired" one. Curious if either of those could be used in the boat, leaning more towards the portable one. Obviously, I wouldn't want to use one that isn't GFCI, unless I wanted to light up, which I don't.

I am also curious if anyone has any experience with these on a Evinrude XP150, basically is the charging system able to run one or would I risk damaging my electronics?

Thanks...

Brian,
I think what you are referring to is "ignition protected". Now not too many inverters are ignition protected, but that requirement is only necessary where the inverter might be located in a compartment that could potentially trap gas fumes. Seeing as you are looking at using your portable, which I assume you'd plug in to a 12V outlet at the helm, I don't think you have to worry about that too much.

As far as your charging system on your Evinrude being able to keep up with the power being consumed through the inverter, that is all going to depend on what you are using and for how long you use it. The inverter itself only uses a minute amount of power, it is the AC appliance you are operating that uses the power.

And remember, some electronics don't like modified sine wave. You won't damage them, but they won't perform in the way they should. That includes laptops. They prefer pure sine wave, and you don't find that in cheap inverters...

 

[Texasmark]

Re: inverter???

I had a friend who bought an after market inverter for his 1/2 ton truck. We installed it and ran it. In short, for a 120V inverter to put out 10 amps, you have to have 120x10 (1200) watts input. Well, since the alternator puts out 12V (close enough for the point here) it would have to deliver 100 amps (plus additional amps for circuit losses). When is the last time you saw an automotive alternator actually put out 100 amps?

Needless to say the truck rpm was at redline trying to get usable output.

So then you ask yourself, what is the economy of performance here? I'm running a 400 hp engine to put out 1200 watts of power. As I recall 1 HP in electrical terms is 741 watts.

That means I am feeding gasoline to a roughly 50% efficient 400 hp engine to get roughly 1.5 w of inverter power......get the point?

Mark

 

[seabob4]

Re: inverter???

Current(I) = Watts/Volts

I have a 700W appliance. I am supplying it with 120V. Therefore the Amps I need to produce that requirement is 5.83, which I think any good size alternator can supply. It's not about the voltage the alternator puts out, it's about the amperage...

If what you said is true, nobody could use an inverter in a 12V system...

 

[KD4UPL]

Re: inverter???

Current(I) = Watts/Volts

I have a 700W appliance. I am supplying it with 120V. Therefore the Amps I need to produce that requirement is 5.83, which I think any good size alternator can supply. It's not about the voltage the alternator puts out, it's about the amperage...

If what you said is true, nobody could use an inverter in a 12V system...

What he said is true. Your 700 watt appliance draws 5.83 amps at 120 volts but the input to the inverter is 12 volts. Therefore the input at 12 volts will be 58.3 amps. Since the inverter is probably on 80% efficient then it will need 73 amps input from the battery and alternator. This is fine if your using a short duration appliance like a toaster or microwave. The excess current just comes out of the battery and is recharged later. If you're using a long term appliance like an air conditioner then you would indeed have to be getting 73 amps of output from your alternator.
This is why most RV's and boats with large inverters also have rather large house battery banks.
I had a work truck fixed up with a 3000 watt inverter and two deep cycle batteries to run tools on a job site. It worked good because power tools run for a short duration and then you release the trigger. Had I been trying to run something for hours at a time my batteries would have been depleted in short order.


To answer the original question. Portable inverters for a boat or car probably aren't all that different. There are certainly good and bad ones thou. I would list Xantrex Samlex as too of the good one.
I know you're not asking about large, permanent models but since we're on the subject. If you get into hard wired inverter/chargers then there is a difference between mobile (car, boat, RV) and permanently installed units like you would use in a cabin or home. The mobile units' transfer switches handle the switching of the neutral connection and the bonding of the neutral and ground.

 

[Texasmark]

Re: inverter???

I am curious, are there any real differences between a marine 12v-110v inverter and one you might use in your car? .....besides probably having marine grade wiring! I am guessing the marine ones are GFCI protected and the others aren't but I really don't know.

Not many times I really need/want 110v on my boat, but curious just in case. I have a small "portable" one I use in my car at times, I also have a larger "hard-wired" one. Curious if either of those could be used in the boat, leaning more towards the portable one. Obviously, I wouldn't want to use one that isn't GFCI, unless I wanted to light up, which I don't.

I am also curious if anyone has any experience with these on a Evinrude XP150, basically is the charging system able to run one or would I risk damaging my electronics?

Thanks...

On your XP150, it is a matter of watts in vs watts out (plus losses....say 15%). 120v is 10x your battery voltage so your battery has to put out 10x + 1.5x the required current. If the engine were running and it's alternator puts out 10 amperes (for a number), 120 watts, you could roughly run an appliance requiring 120 vac at 1.0 ampere (120 watts....excluding losses).

If more amperage than that were required, your XP150's voltage regulator would limit output at it's set current so any additional current would have to come from the battery meaning usage of the appliance would have to be intermittent based upon the storage energy available from it, with the appliance being switched off while the alternator recharged the battery.

As far as damaging your charging circuit in your engine, it depends upon how thorough Evinrudes design engineers were in setting up the charging circuit and equipment, and how well YOUR engine still matches those design requirements. I'm going to bet that the equipment design for the charging circuit was based upon an assumption that the max output of the alternator/regulator would not be continuous, but decrease as the battery was recharged......think starting your engine, not running a boom boom box continuously) and therefore was not designed for sustained maximum performance.

Generating power involves losses and those losses generate heat. Heat kills wiring insulation and solid state components especially. Additionally, current through corroded electrical connections generates a voltage drop (heat) which eventually will degrade the terminal to an open circuit and possible fire.

HTH,

Mark

 

[sbklf]

Re: inverter???

I don't know of many inverters with built in Ground Fault Interuptors (GFI) due to the nature of an invertor which doesn't have a true earth ground.

As a general rule of thumb, to calculate the load on the 12 volt system take the watts of the device you are powering and multiply by 12. This will give you a pretty close estimate of the actual load on the battery and alternator. (Note: This assumes an inverter with 80% efficency.)

A GFI does not require a ground at all to operate.

? If you know the watts, that is the load. If you are trying to explain how to calculate the amps it is P over E (watts divided by volts).

 

[MASTER Brian]

Re: inverter???

I believe my large invertor, which I wouldn't use is 1200w, I believe my smaller, "portable" one is about 300w. The main thing I would be looking to power is my laptop, which does fine with the same invertor in my truck. Really all the invertor would likely do is keep it charged up.

The reason I ask about GFI/GFCI is that doing a quick search through Gander Mountain's website, they are a mile from my house, show's marine invertors and they had that type of protection, but they cost about $200-$300, which is more than i want to spend....

 

[chuckz]

Re: inverter???

Man are you taking the long route to power your lap top. Just buy a car adapter for your laptop. It runs off of 12 volts and will be much more efficient than using an inverter and your ac adapter.

Kensington for one makes them. Much cheaper and more efficient than an inverter.

 

[MASTER Brian]

Re: inverter???

Man are you taking the long route to power your lap top. Just buy a car adapter for your laptop. It runs off of 12 volts and will be much more efficient than using an inverter and your ac adapter.

Kensington for one makes them. Much cheaper and more efficient than an inverter.

Well, last time I checked on those, they were about $100, I do see they are a lot less expensive now. Even so, I was really just curious, there have been times I thought it would be nice to be able to power 110v items other than just the laptop. Just don't have any in mind at this point.

I use the one in my Suburban, a lot for various reasons...