Shore Power from Truck?

[HandTurkee]

Hi there,

I'm quite a rookie when it comes to camper electrical so any advice is appreciated. I currently have a 2008 f250 and a friend gave me an inverter I plan to install.

My question: assuming the inverter meets necessary specs, can I run the shore power cable from the inverter to my truck camper? This would give me the ability to use standard 110 appliances when I run the engine which would be nice.

Thank you in advance

 

[Wandering Sagebrush]

Check the power consumption of your devices against the inverter output. My best guess is you won’t find it big enough or practical.

 

[ntsqd]

Short answer, yes if the inverter can put out enough power to meet the starting demand of whatever appliances you want/need to run it would work. Likely can only run one at a time unless the inverter is huge. Also note that some 120 VAC items need a pure sine wave inverter to run at all or run correctly. Those are a lot more spendy.

Before you do that you need to know if the alternator can keep up or not. Sounds like you're already aware that the battery(ies) won't last very long under that load. It is nice to have an inverter along, but I can't think of anything 120VAC that we regularly need to use that we don't have another solution for. I know that there are some exceptions out there (CPAP?) where there just aren't many non 120VAC options and an inverter is necessary.

 

[klahanie]

My question: assuming the inverter meets necessary specs, can I run the shore power cable from the inverter to my truck camper? This would give me the ability to use standard 110 appliances when I run the engine which would be nice.

For sure, that's what the inverter is for with the caveat you've given and there being enough 12V power supply.

If you locate the inverter in the engine compartment mind that there is adequate cooling for it. If located in the cab, there should be rubber knockouts/plugs in the body floor and rear wall to route the 110V cord thru to the camper.

Many (most ?) appliances will have a tag or otherwise be marked with the power required, often in watts. You'll want to check this against the output of the inverter.

 

[cwdtmmrs]

For sure, that's what the inverter is for with the caveat you've given and there being enough 12V power supply.

Toaster oven? Microwave? Coffee maker? You need a lot of 12V and big wires.

 

[klahanie]

Toaster oven? Microwave? Coffee maker? You need a lot of 12V and big wires.

LOL, of those, have only done the microwave. 0/2 was big enough, as spec'd in the inverter installation manual.

I'm thinking the OP might have something like a 400w model, complete with battery clamp on supply leads and a 110v receptacle. Have seen those at auto supply stores etc.

Or are we defining "appliances" as limited to the sort in your list ?

 

[HandTurkee]

LOL, of those, have only done the microwave. 0/2 was big enough, as spec'd in the inverter installation manual.

I'm thinking the OP might have something like a 400w model, complete with battery clamp on supply leads and a 110v receptacle. Have seen those at auto supply stores etc.

Or are we defining "appliances" as limited to the sort in your list ?

Thanks guys, all helpful info. I'll take a closer look at the inverter I was given and see if I think it is up to snuff.

 

[Optimistic Paranoid]

Also, be aware that some inverters produce a TRUE sine wave while others (cheaper ones) produce what is called a "modified sine wave" which is actually a modified square wave. Heating elements and most motors don't really care, but some sensitive electronics chokes on the "modifies sine wave".

Because 120 volts is ten times 12 volts, it's simple to calculate power draw. A device that needs 8 amps at 120 volts needs 80 amps at 12 volts.

The general rule of thumb is that the dc wires need to be as short, and thick, as possible. The ac wires can be long.

 

[ardvark]

If what you have in mind is something like a laptop computer, all it takes is a cheapie in the 12 VDC plug in the truck, which is what I do. When we camp, if near a TV signal, I use the same innverter in the truck camper for our little 16" Pyle flat screen.

In the olden days almost nothing liked the old square wave inverter power, then the modifieds came along and now it is really rare that things don't work with them. Of course the price has really come down for the pure sine wave inverters.

in our fifth wheel I can run everything including both flat screens, etc. other than the AC and water heater off the high-end modified sine wave inverter and even they would work but would drain the batteries too quickly.

The times they are a changing.

 

[ntsqd]

OP, your math is correct, but doesn't address the inefficiency of the inverter itself. An 8 amp @ 120 VAC demand on the inverter will mean that the inverter will need in the range of 90-100 amps @ 12 VDC to supply it. Nothing is free......

 

[klahanie]

If what you have in mind is something like a laptop computer, all it takes is a cheapie in the 12 VDC plug in the truck, which is what I do.

That's true. There are inverters with a cig plug cord end, up to around 300W I think. For these one could just plug into the 12VDC cig plug in the camper - if there is one or wire up a receptacle if need be.

Most of our use is for items using 60W and under: heat pad, small battery chargers, shaver. Even the curling iron is only 140W. Of course you don't want to be running the car just to shave or do your hair ! That's when the house battery comes into play - a whole different matter.

It is nice to have 'some' 110v. But 'more' can get involved.

 

[DavidGraves]

We have had a portable 300W inverter for years and it keeps all devices charged....it will even run our small Dometic although that is sort of stupid.....why convert 12V to 120V for a refer that will run on 12V itself ?

A small inverter is a useful tool indeed.

David Graves

 

[ardvark]

That's true. There are inverters with a cig plug cord end, up to around 300W I think. For these one could just plug into the 12VDC cig plug in the camper - if there is one or wire up a receptacle if need be.

Most of our use is for items using 60W and under: heat pad, small battery chargers, shaver. Even the curling iron is only 140W. Of course you don't want to be running the car just to shave or do your hair ! That's when the house battery comes into play - a whole different matter.

It is nice to have 'some' 110v. But 'more' can get involved.


I added a second one to my NorthStar. Easy enough to do for sure.

That's true. There are inverters with a cig plug cord end, up to around 300W I think. For these one could just plug into the 12VDC cig plug in the camper - if there is one or wire up a receptacle if need be.

Most of our use is for items using 60W and under: heat pad, small battery chargers, shaver. Even the curling iron is only 140W. Of course you don't want to be running the car just to shave or do your hair ! That's when the house battery comes into play - a whole different matter.

It is nice to have 'some' 110v. But 'more' can get involved.

 

[Andy Douglass]

I am by no means an expert but unless you are planning on idling your truck while using the inverter, all you are doing is converting the truck battery charge to line voltage for appliances. If it was me, I would install the inverter on the camper batteries and protect the truck's batteries which are more important.

If you are planning on idling the truck, you'll have an unhappy neighbors at the campground. I also would guess that the converting system that charges the camper off of the idling truck is more efficient than an inverter. If that is true, it would make more sense to install the inverter in the camper and just charge the camper batteries from the idling truck.

At the end of the day, I would recommend trying to get by using less electricity while camping or getting a generator if you have to.

 

[ntsqd]

Alternators on an idling engine don't produce much power. Look at their drive ratio, they need to spin much faster unless you had it re-worked, and even those re-worked to produce more at lower RPM don't put out anything close to their max rating while idling.

 

[corybrown50]

I saw CPAP earlier and wanted to share this warning....I burnt up a CPAP power supply on a trip to China doing this....had to go a week without it...let's just say I wasn't the best of company that week. There are CPAP that can run on 12v, please do so. I run mine directly off battery and it works great. Converters/ inverters are too inconsistent with power and can burn out electronic power supplies when used for extended periods of time.

 

[Old Crow]

I saw CPAP earlier and wanted to share this warning....I burnt up a CPAP power supply on a trip to China doing this....had to go a week without it...let's just say I wasn't the best of company that week. There are CPAP that can run on 12v, please do so. I run mine directly off battery and it works great. Converters/ inverters are too inconsistent with power and can burn out electronic power supplies when used for extended periods of time.

Also on the subject of CPAPs.....

One of my brothers has two ResMed CPAPs (an older one and its replacement) and he was planning to join me for ten days on my Florida trip so we had to figure out what to do. I was happy to find the 'ResMed Battery Guide: Using Stand-Alone, Deep Cycle Batteries'. It seems to do a pretty good job of laying out the alternatives and provides model-specific details and warnings.

I had looked for DC-to-DC adapters and they were in the 90-dollar range. But then the note in this paragraph (on page 2) caught my eye...

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"1. Do you have a pure sine wave DC-to-AC inverter with a continuous power rating of 300 watts and a peak/surge rating of 500 watts?
YES – Go to step 2.
NO – Contact your battery or electrical supplies provider for assistance in obtaining the appropriate type of inverter.

NOTE: The following ResMed devices without humidifiers can operate using a 150 watt modified sine wave inverter: VPAP III, AutoSet CS2, VPAP Adapt series. S9 series with H5i humidifiers can also operate from this inverter type. "

------

That at least opened the door to running a CPAP on a smaller, cheaper inverter (but it wasn't clear enough to go ahead). The older of the two CPAPs wasn't on the charts so I kept looking and found an older version of the Battery Guide. That one provided this chart:



GIven that info, we opted to plug the older CPAP's AC plug into the little 150W modified sine-wave inverter I keep in my electronics bag. That worked fine for the ten days we needed it. I suppose an argument could be made the inverter might cause problems over the longer run but we were comfortable with trying it given the manufacturer's documentation.
I guess my other point is there are many variables to consider-- like exactly what model the CPAP is, how it's used, what the settings are, etc. And the User Manual may not have the needed info... it may be in a separate 'battery guide' type of manual.

.

 

[klahanie]

Re alt output and larger inverters.

OP has a Superduty. Pretty sure 2008+ (and perhaps older) have a user switchable program in the PCM for Stationary Elevated Idle Control (SEIC) - mostly for PTO use - and Battery Charge Protect (BCP)

Bulletin

Can be nice feature to have and is fairly easy to hook up esp if their is an upfitters switch available. DIY write ups are online.
For those interested, here's a video of the BCP used with an inverter - demo'd on a newer truck but