Trying to figure of Inverter/Converter, etc.

[Vickie B.]

I'm trying to decide what to add/change/leave alone in my camper. I just Googled "what is the difference between an inverter and converter". I guess I kinda understand.

I think I have just the converter---at least the write up on my camper says: "110 volt to 12 volt converter". Does that sound right??? In terms of MY camper, what is that box doing?

Do I need an inverter, too? What would that inverter do for me?

And when we plug that cord into the campground box, is that just like a big extension cord? Is it going through that box? How does it work?

Sorry for such basic questions--I've been sitting here all evening trying to find answers on the internet (while the menfolk watch stupid football). I wish I could find a book that just had it all in one place with pics, etc. I'm trying to print out and Bookmark helpful stuff.

Thanks!

[pbraunton]

Hi
Let me start by saying I am not an electrician.......

But here goes; and inverter convers 12 volts to 110 (normal household power) and a converter does the opposite!!!

My trailer has a 110 volt wiring in it, so I have plugs/outlets just like a house, as well I have an electric panel and breakers too, my converter (110 volt to 12 volt) is plugged into one of these outlets, which in turn charged the onboard battery, the battery is hooked up to the interior lights of the trailer, so that if I am not hooked up to a power source the lights still come on, until the battery run out.

The electrical cord to plug your trailer in is essentially an extention cord, but a heavy duty one at that, thy come in all different amps and volts so you would have to match it to what the trailer is using and to what it is hooked up to at the post

Again my trailer has a 30 amp 125 volt cord it is then broken into two 15 amp 110 volt circuits inside the breaker box, the reason for only using 15 amps inside the trailer is because MOST household wiring you buy is rated for 15 amps, so the breakers are there to prevent the wires from being overloaded

Hope this helps? What are you trying to do? Re-wire the trailer? Or just trying to figure things out?

[pbraunton]

As for having both an inverter and converter? It is up to you, your converter will allow you to use 12 volt power when hooked up to 110 volt outlets (ie your campground post)

And an inverter will allow you to have 110 (household power) while running ONLY off battery power!


If most of your camping is done with electrical hookups then you would only need and converter (110 volts - 12 volts) but if your camping without hook ups you might consider using an inverter, but it takes a lot of battery power to use household appliances through an inverter


I am sure you have more questions so fire away!!!!

[Byron Kinnaman]

I'll try to help you bit here.
There are generally two electrical systems in trailers.
A 120 Volt AC system like your house has. This usually powers things like Microwave ovens, maybe a light, and other appliances like you would have your house, if carry those types of things. It also powers the "converter". If you have a 3 way or a 2 way refrigerator it powers that.
The other system is a 12 Volt DC system. Usually most of the lights are 12 Volt DC. A small fan if you have one. Sometimes there are 12 Volt DC outlets, they look like the cigarette lighter sockets. You can plug 12 volt DC devices into those just like you can in your automobile. The main source of the 12 volts DC is the battery. The "converter", when plugged in, charges the battery. If the connection between the tow vehicle and trailer is wired properly the tow vehicle will charge the battery while towing.

Basic definition of "converter" is it has an input of 120 Volts AC and an output of 12 Volts DC, hence convert 120 AC to 12 Volts DC.
Now for "inverter". The inverter is exactly the opposite of the converter. Typical inverter will have an an input of 12 Volts DC and an output of 120 Volts AC.

This would almost sound like you could power any 120 Volt AC item from your battery with an inverter. Unfortunately you can't.
Do you need an inverter. Probably not. However, there are times when a small inverter does come in handy. A small one can be used to charge batteries in laptop computers, cell phones, and etc.

I hope this helps a bit.

[Raya]

I'll add a few more "I'm not an electrician" notes from my point of view.

Basically, as others have mentioned, there are two different types of electrical used in our trailers (and on boats as well). 12 volt DC and 110 (or it can be called 120) volts AC. How and which you use in your camper is not a given, but depends on how you use the camper and what you want. Most people have some sort of combination.

12 volts DC is what the typical North American car runs on. It is low voltage. You can't plug in things with the normal North American "two prong" plugs but instead usually use "cigar lighter" plugs (like go into the lighter on your car). You usually get this power from a battery (similar to a car battery), and then re-charge the battery with solar, your car's alternator, or sometimes a generator. You have the battery as a middle-man.

110 volts AC is like what's in your house. The old two (or three) prong plug. You usually get this power from the power company or by plugging in your trailer to a "hookup." There is no battery to store 110 volts; it's directly supplied.

Now in most campers there are some things powered by 110 (outlets, maybe a light or two) and some powered by DC (usually some lights and etc.)

Where converters and inverters come in is when you have one power source (either 110 or 12v) but want to use the other items. With a converter you can plug into mains power (110 v) but still use your 12 volt lights and other 12 volt stuff. With an inverter you can use "two prong plug" items when you are NOT hooked up to mains power (blender, etc.).

Usually changing things from one type to the other comes at a cost of efficiency. Of course that's not usually a concern when you are plugged in, but if you are NOT plugged in, then using an inverter can be handy for small things, but is not something you would probably do too much of because you lose efficiency just when you need it most. For example it's more efficient to buy a 12-volt power cord for your computer than it is to plug it into an inverter (when you are running the trailer on 12 volt/battery). A 12-volt fan or blender is going to be more efficient running straight off 12 volts then it is to plug in two-prongers and use the inverter. BUT, most small appliances are set up for 110, and who wants to buy two of everything. Thus, for small quick uses, an inverter can be handy even when you are not rich with battery power.

Of course life is simpler if you always do one type of thing. If you ALWAYS were going to plug into mains power, well, then you could set up your camper with all 110 wiring and outlets and lights (of course you would still have 12-volt taillights and maybe fridge but they would be powered by the car through the hookups from the hitch).

If you ALWAYS were boondocking, then you might not have a 110 system at all, and you would have all 12-volt (or propane) stuff, and live off your batteries and then re-charge the batteries through solar, wind, generator, or with a charger when you plugged in at home between trips. You could still have a small portable inverter that plugs into a cigar lighter receptacle and powers small loads, but you would use it sparingly.

But most people aren't always doing one or the other, and so most campers have a combination of systems. That's where it can get confusing.

One way is to set up with 110 wiring and lights and then have a few 12-volt items and power them via battery when boondocking and converter when "plugged in." You could add an inverter for those small 110 uses when boondocking. This is probably most common (?).

Another way (more likely if you want to be in "boondocking" mentality and plug in only at home to recharge) is to run everything 12 volt, have batteries to power it, and then a charger. Then when you plug into mains power that power just charges your batteries but you still live off the batteries and use only 12 volt power directly.

I hope that all makes some sense. The reason it does not all sound neat and tidy it because... it isn't. Unless you are doing ALL boondocking or ALL plugged in to mains power, you will likely have some mix of systems. The trick is to figure out how you will camp and then to choose what suits you best. Sometimes that's hard to know until you have used your trailer for a while though.... and it might change over time anyway.

Raya

[Vickie B.]

Oh, thank you---those explanations help ALOT!!!!

PBRAUNTON--To answer you question (what am I wanting to do) ---familiarize myself with things to decide if I do, indeed, need to add/change wiring.

Byron---you mentioned something that brings up another question---the charge line from the car to the camper battery. Would you believe for the past year I've been trying to see if I have one/need one, whatever, and I can't get 2 answers that are the same! When I first heard of it, the person called it a Trickle Charge. I was later told that's not what it's called. When I asked my husband's mechanic if they could put one in---they looked perplexed. When I mentioned it to someone else---they said I should already be set up since I have the 7-pin.

So which is it? I have the 7 pin connector. I have a battery and an alternator in the truck (duh)---I HAVE NOT put in any extra wiring. Is my camper battery charging when hooked up to the tow vehicle, or not?

AND, what it this thing I've heard mentioned about having something special so the camper battery doesn't drain the car battery????

Can you, or anyone shed light on this?

Thanks!

[Ann B]

[QUOTE= When I asked my husband's mechanic if they could put one in---they looked perplexed. ![/QUOTE]

same thing happened to me!! got a look like "dumb female" also got this form a guy at West Marine --was ready to spend some $$ till he gave me the LOOK!! now I know & you know that the TV with the proper wiring can charge the trailer battery Why is it some guys just don't want to think a "female " might know something

[Raya]

A 7-pin connector means you can have a charging set up, but does not mean you do. It depends on how the wiring is set up. Likewise, it can power electric brakes if set up to do so. But you have to have the appropriate wires leading to the connector in your car, and to the connector on the trailer.

With a 4-pin flat, you don't have enough wires (not that you have one; I'm just saying).

There is some sort of blocking thing (might be a diode?) that you can have wired in to keep it so that the camper battery cannot "suck" the power out of your car battery if you keep the tug and tow hooked up. Of course if you unplug the two that also works (but you could forget).

Raya

[Vickie B.]

And Ann, the sad thing was---it wasn't because I thought I might know something----I got the feeling they KNEW NOTHING!

That's about the time I start hyperventilating and wondering WTHeck???

[Vickie B.]

Thank you, Raya So maybe I should find out if the Ridgeline might have that set up, since it has most of the brake controller stuff in place.

[Rick G]

Another point you should keep in mind is that the older converters do not put out perfect DC voltage. Instead, it looks a lot like AC voltage (you can see the waveform on an oscilloscope), but at 12V average instead of 110V. 12V incandescent light bulbs do not care, but your modern electronics sure do. My original converter from 1980 is set up to power only lights, as the fridge has a direct line to the battery for 12V operation. My first clue was the horrible buzzing sound coming from the car stereo the previous owner had installed (which will be coming out over the winter).

I would like to run our laptop, DVD player and new TV, kid’s Ipod or computer games, etc. off the 12V at times, and the converter I have would blow some of those circuits for sure. If you are going to run 12V for electronics, I suggest that you run only off the battery, and then charge up the battery as necessary.

To solve this problem on my trailer, this past weekend I took out the old converter and am in the process of installing a desktop computer power supply ($5 at a computer repair shop), using the original converter case so that it looks the same from the outside. It works great, giving a very clean DC voltage at a rock solid 12V and 17 amp maximum current, far more than the 12 volt, 10 amp circuit breaker on the converter output (which I will use). I am just finalizing the installation this week, and have ordered cheap digital panel meters from China that will allow me to monitor both the AC and DC voltage as well.

This is an advanced project not for the inexperienced, but it shows that you can get good 12V power in a trailer. I expect that a modern converter would be a good investment if you are planning to run electronics in 12V mode.

Rick G

[Carol H]

Geezz which I could give you a good answer the plug question. Suspect the answer *may* be to put a meter on the car side plug prong that is suppose to be charging the battery to see if it is acutally putting anything out when the car is running. I know that may be wrong and a few folks may be laughing but please keep in mind thats just the suggests of another "dumb female" with little electrical experence and few tools! lol

On the orignal topic though I can give some feed back to Vickie on what she may or may not need for power based on the "dumb female" view of camping. LOL

My trailer only has the converter built in, not an inverter. This for me means that when not connected to power all the water pumps, lights (with the expeption of one) and fan work fine as they are 12 volt. My fridge is three way 110/12v/propane so if no power it works fine on propane. I like to have the fridge on 110 when power is available so I don't need to worry about running out of propane in the middle of the night. I don't use the fridge on 12 volt when boom docking as it would drain the battery to fast. The only time I use the 12 volt option on the fridge is when I am towing for more than a couple of hours. My hot water tank also works off the grid as it runs on propane and the shower pump works as its 12 volt - nice to have on those occasions when a public shower is not close at hand. My furnace is propane but it does have an electric fan that will run when only on 12 volt so if not connected to power I need to be pretty carefull about how often the furnace comes on as that fan is also a big power eater - so its only used when boom docking if really really needed. I do have a portable solar panel that I can hook up if I know I am going to be boom docking for more than a couple of days or I know the heater is going to be needed.

The items that will not work when not plugged in due to only have the converter are the one light already mentioned and two 110 electrical plugs. For me this means I can't use my electic toaster, coffee maker or watch chick flicks on the TV when not connected to power. Even if these items were 12 volt or if I had an inverter I would not use them when boom docking anyways as they are big power drainers. When not plugged in I use a french press for making that one item I can't live with out -coffee.

I do have a two small portable inverters though that plug into the 12volt plug - the thing that looks like a cigarette lighter plug. One takes two prong and the other usb connections. They work great for charging cell phones, ipods and laptops if these are must have items for you. Oh and I will admit to having used them for the hair drier once or twice :-) You can buy these inverters at any automotive store.

If you put in all 12 volt lights, pumps and fans and a converter with a couple of 110 plugs in the trailer and a 3 way fridge and carry a small portable car inverter, you should find you are good to camp just about anywhere.

[Frederick L. Simson]

Originally Posted by Vickie B.

When I asked my husband's mechanic if they could put one in---they looked perplexed. When I mentioned it to someone else---they said I should already be set up since I have the 7-pin.

So which is it? I have the 7 pin connector. I have a battery and an alternator in the truck (duh)---I HAVE NOT put in any extra wiring. Is my camper battery charging when hooked up to the tow vehicle, or not?

AND, what it this thing I've heard mentioned about having something special so the camper battery doesn't drain the car battery????

Can you, or anyone shed light on this?

Thanks!

Here is a picture of what's under my hood:

The lower label is supposed to say, "CHARGE LINE".
It is connected directly to the Battery's (+) Positive Terminal.
It meanders up to the "BLOCKING DIODE" on the right, and connects on the right terminal (Input). The Output of that diode disappears into the wiring harness, and then re-emerges from the wiring harness and connects to the "BLOCKING DIODE" on the left (Input). The Output travels under the car somewhere to end up at the 7-Pin Connector.

Here's a picture of the BACK of my 7-Pin Connector.

I have labeled each wire with its function.

[Robert Johans]

Hey Frederick!
Did your Odyssey come equipped with a FACTORY tow package? It's my understanding that modern cars/trucks with the package do not require the blocking diodes. What's the skinny? (BTW, I added a diode to my vintage Bronco to protect its battery...)

Curiously, a cursory search of the internet shows practically nothing about blocking diodes and their relevance to CAR batteries. (Evidently, they're mostly used in solar panel applications.)

I did find this:
Blocking Diodes

[Robert Johans]

Rick,
Your post is interesting. Do your concerns about poor and inconsistent power to modern 12V-powered electronics apply only to "older" converters?

Conversely, can you say that a new, quality converter with properly fused circuits will work just fine?

BTW, got pix of your set-up?

[Roy in TO]

Originally Posted by Rick G

To solve this problem on my trailer, this past weekend I took out the old converter and am in the process of installing a desktop computer power supply ($5 at a computer repair shop), using the original converter case so that it looks the same from the outside. It works great, giving a very clean DC voltage at a rock solid 12V and 17 amp maximum current, far more than the 12 volt, 10 amp circuit breaker on the converter output (which I will use). I am just finalizing the installation this week, and have ordered cheap digital panel meters from China that will allow me to monitor both the AC and DC voltage as well.

That's a great idea! I know it won't fully charge a battery to the 13+ Volts you get with a battery charger, but it will definately allow one to install a USB port to charge all those little 5V things when hooked up to the Grid.

Does anybody make something that functions as a converter putting out 12V DC for the system, more as a smart battery charger, a solar charge controller and something that automatically switches over between the various combination of input / output. If so, what might it be called?

[Byron Kinnaman]

Originally Posted by Vickie B.

Oh, thank you---those explanations help ALOT!!!!

PBRAUNTON--To answer you question (what am I wanting to do) ---familiarize myself with things to decide if I do, indeed, need to add/change wiring.

Byron---you mentioned something that brings up another question---the charge line from the car to the camper battery. Would you believe for the past year I've been trying to see if I have one/need one, whatever, and I can't get 2 answers that are the same! When I first heard of it, the person called it a Trickle Charge. I was later told that's not what it's called. When I asked my husband's mechanic if they could put one in---they looked perplexed. When I mentioned it to someone else---they said I should already be set up since I have the 7-pin.

So which is it? I have the 7 pin connector. I have a battery and an alternator in the truck (duh)---I HAVE NOT put in any extra wiring. Is my camper battery charging when hooked up to the tow vehicle, or not?

AND, what it this thing I've heard mentioned about having something special so the camper battery doesn't drain the car battery????

Can you, or anyone shed light on this?

Thanks!

If your tow vehicle, I think you said it was a Ridge Line, has the tow package factory installed it's a pretty safe bet that the charge line is installed. One way to check is to unplug the trailer from 120. Wait a half an hour or more then measure the battery voltage. It should be a little over 12 volts. Now connect the tow vehicle and measure again with tow vehicle running. The voltage should measure between 13.8 and 14.2 Volts DC. If it measures the same or lower than when nothing was connected there's no charge line.

If you don't have a voltmeter it would be a good idea to get one. They're very cheap, some as low as $10.00.

Hope this helps a bit.

[Byron Kinnaman]

Originally Posted by Rick G

Another point you should keep in mind is that the older converters do not put out perfect DC voltage. Instead, it looks a lot like AC voltage (you can see the waveform on an oscilloscope), but at 12V average instead of 110V. 12V incandescent light bulbs do not care, but your modern electronics sure do. My original converter from 1980 is set up to power only lights, as the fridge has a direct line to the battery for 12V operation. My first clue was the horrible buzzing sound coming from the car stereo the previous owner had installed (which will be coming out over the winter).

I would like to run our laptop, DVD player and new TV, kid’s Ipod or computer games, etc. off the 12V at times, and the converter I have would blow some of those circuits for sure. If you are going to run 12V for electronics, I suggest that you run only off the battery, and then charge up the battery as necessary.

To solve this problem on my trailer, this past weekend I took out the old converter and am in the process of installing a desktop computer power supply ($5 at a computer repair shop), using the original converter case so that it looks the same from the outside. It works great, giving a very clean DC voltage at a rock solid 12V and 17 amp maximum current, far more than the 12 volt, 10 amp circuit breaker on the converter output (which I will use). I am just finalizing the installation this week, and have ordered cheap digital panel meters from China that will allow me to monitor both the AC and DC voltage as well.

This is an advanced project not for the inexperienced, but it shows that you can get good 12V power in a trailer. I expect that a modern converter would be a good investment if you are planning to run electronics in 12V mode.

Rick G

I hope you're not charging your house battery from that computer power supply. Charging circuits require a bit more to control the charge current and shut off when fully charged. No control usually means over charging, meaning boiling dry. Not good for batteries.

[Matt in SV]

Originally Posted by Byron Kinnaman

I hope you're not charging your house battery from that computer power supply. Charging circuits require a bit more to control the charge current and shut off when fully charged. No control usually means over charging, meaning boiling dry. Not good for batteries.

That 12.0 volts is a problem, too. Nominal open circuit battery voltage is 12.6 volts at room temp. At 12.0v the charge is about 45 percent of capacity - about the level we'd typically want to start charging, not stop.

I think the battery will actually never completely charge with 12v.

Regards,

Matt

[Bill K]

Vickie B,
You can buy a tester that plugs into the seven pin connector on your car. It looks like the plug that is on your trailer but has no wire coming out of it.

There are seven lights that will light whenever one of circuit's is turned on.

I bought mine at a store that had trailer hitch's and other parts for towing.

I hope this helped a little and did not confuse you more.

Bill K
QUOTE=Vickie B.;227607]Thank you, Raya So maybe I should find out if the Ridgeline might have that set up, since it has most of the brake controller stuff in place.[/QUOTE]