Inverter Shore Power (but not what you might think)

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Diggs

New member
Joined
Aug 28, 2022
Posts
2
Location
Auberry CA
Hello, new guy here who only boondocks.
I have a question where I can’t find the answer across the far reaches of the inter-web. It’s a simple concept to me, but perhaps there’s a reason I can’t find anybody doing it. So here goes…
One end of the shore power cord plugged into the outside of my slide-in camper (where it normally plugs in with 15 amp adapter) and the other end plugged into my 3000W inverter in my pickup.
Start the truck up (so the alternator is running) and let the camper think it’s plugged into a 15 amp wall outlet. While the truck idles for a couple hours, my camper battery bank can charge and maybe I’ll go ahead and flip the breakers on for a couple lights too. This is just my backup plan on days I can’t use solar. Any foreseeable hang ups?
Secondary question: Being a modified sine wave inverter, not pure, would any components in the 2005 camper be effected in a negative way?
Thanks in advance for input!
 
I've done this tent and popup camping for decades. It works fine but you're burning more fuel than you would in a generator, plus hours of run time on your truck. As a backup though I don't see any downside to it and there can be a few advantages.

Mark B.
Albuquerque, NM
 
Being a modified sine wave inverter, not pure, would any components in the 2005 camper be effected in a negative way?
Very unlikely. I have been using a MSW inverter in my Y2K RV and never had an issue running anything at all. However, not all are equal. And IMO, they should be called "Modified SquareWave Inverters" as that is what they really are.

My Y2K inverter waveshape looks like this. They are not all the exact same waveshape. More steps in the waveshape will be better in some cases.

-Don- Reno, NV
 
My first concern is the exhaust from the truck engine running for hours. It wouldn't be good if it makes its way into the camper.

In my particular case, on days where the solar is insufficient, I adjust my power use. LED lighting consumes very little and the fridge works off propane. The ambient heater is my main concern during high elevation winter camping but even then it will run for many days.

In terms of the modified sine wave, it's unlikely to affect any of the 120VAC accessories. Most items are going to be on the 12V DC side.
 
Diggs,
You don't know me, but suffice it to say I was an engine guy in Detroit for lots of years.
With older engines, this would not be recommended.
All the newer engines have much better ignition and fuel control that used to be. This is why some manufactures now recommend much longer lube oil change out intervals. If you can be sure to keep the engine running until it is fully hot, there will be little harm. Exhaust system used to go out fast on vehicle that had high idle times, but most new systems are some variety of stainless that won't rot out very fast.
If I get this right there is very little in you TC that can't run just fine from the MSW inverter. Refrigeration compressors some times run a little warmer than on shore power, but even that has to be measured to be sure it is not your imagination.
Matt
 
What truck do you have that has a 3,000W (250amp) alternator?

Also, can't you achieve basically the same thing by using 12V jumper cables right to the battery bank. Or if the trailer plug is wired for trailer power just plug in the trailer plug.
 
MSW/PSW.. While there are advantages to PSW most modern electronic devices use power supplies that don't much care which.. Some very old equipment might not work well with MSW. but we are talking "So last century" here.

I've used both types
But MSW may cause a whole lot of interference to television, satellite, Radio (Especially AM modes) and even WI-Fi reception that's the biggest disadvantage.

NO damage.. just RFI.
 
What truck do you have that has a 3,000W (250amp) alternator?
Ford gassers offer a 2.0kW or a 2.4 kW "generator". The hybrids go as high as 7.2kW.
They also claim that the Lightning can power your whole house from 3 to 10 days depending on power rationing.
 
The inverter might be "optimistically sized" and would rely on the battery for any output greater than the capacity of the alternator/engine RPM. Since a typical RV converter plus some sundry loads probably wouldn't exceed a kW, this is a workable scenario. I wouldn't want to make tow vehicle charging my primary source of power on a regular basis but once in a while or as a backup it works.

I've also done it connecting the house battery directly to the vehicle. It works, but not all that great. Unless the cables are really short and really fat, voltage drop is enough to reduce the charge current to a fairly tepid level and you'll be there for hours just to restore bulk amps. Using an inverter/converter you can effectively dump more bulk amps in a shorter time and it allows the use of a basic 120V extension cord for trailer connection.

Mark B.
Albuquerque, NM
 
The inverter might be "optimistically sized" and would rely on the battery for any output greater than the capacity of the alternator/engine RPM. Since a typical RV converter plus some sundry loads probably wouldn't exceed a kW, this is a workable scenario. I wouldn't want to make tow vehicle charging my primary source of power on a regular basis but once in a while or as a backup it works.

I've also done it connecting the house battery directly to the vehicle. It works, but not all that great. Unless the cables are really short and really fat, voltage drop is enough to reduce the charge current to a fairly tepid level and you'll be there for hours just to restore bulk amps. Using an inverter/converter you can effectively dump more bulk amps in a shorter time and it allows the use of a basic 120V extension cord for trailer connection.

Mark B.
Albuquerque, NM
I tried this setup 20 years ago (inverter on tow vehicle powering the trailer converter to bulk charge the trailer batteries). The biggest problem was unless the engine was turning well above idle speed, the alternator couldn't keep up and the inverter drew down the starting battery fairly quickly. This tripped the inverter's low voltage shutdown, stopping the process.
 
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