Power Supply Questions

[Patricia Baxter]

Now that we have our Trillium home, it's time to get it ready for camping. I need some advice and tips as to how to provide electrical power and distribution; we're basically starting from scratch. I've done enough research to be thoroughly confused, but here are some areas where I could use some input from folks who have done this already.

Battery:

Has anyone mounted their battery on the tongue? Any concerns or disadvantages? I would mount it in a marine battery box, but the covers are vented, and I think provisions would need to be made to keep rain out.

Anyone have comments regarding Gel or AGM batteries, good or bad?

Converter:

Can anyone recommend a converter / power center (brand and model, please) that includes AC breakers and DC fuses all in one package, and does an efficient job of battery charging? The trailer is only 13 feet long; I think that a 30 or 45 amp converter should be adequate.

Wiring:

I'm a bit confused as to how to interconnect the circuits so that the 12 volt system is powered by the tow vehicle in transit, but switches to the trailer battery when parked.

Any advice would be appreciated.

Thanks,

Dale

[Ed Harris]

Dale
I can certainly tell you how the trill can be powered with the minimum effort and max effect given how I wired it.

All you really need to do what I did in it is:

A battery and a charger/supply.

If you wire a charger to the AC plug inside the cabinet and connect it to a battery then you will have a battery and charging system.

If you get a charger capable of supplying its full charging output as a power supply then you need nothing else.
There is a wire under the front bunk that feeds the 12volt panel above the closet and from there through switches and fuses, the lights and 12volt outlets throughout the trailer.
Connect this wire to the battery along with the wire from the charger and then you have an entire 12volt power system.

I decided to run ONLY 12volts inside while camping so if I needed AC I ran from a small inverter. The rope lights were run this way. This way they can be run with or without AC power to the trailer as the 12volt power runs them in either case.

When plugged into AC power from the cord in the side by the door,the charger will be powered and the battery will be charged. While connected to AC the charger still supplies 12volts for the lights,etc.

I used a sealed Gel battery and a high quality charger designed to safely charge it so I had no real concern for overcharging that would cause the battery to vent gas. This is why I designed the battery to go under the bunk.
If you do not want the battery there it is a simple matter to merely extend the wire from the 12volt panel and from the charger to the tounge or anywhere else you decide to put the battery.

This is a very high quality charger/supply designed to do exactly what I am explaining.

http://www.xantrex.com/web/id/185/p/1/pt/7/product.asp

They are available in different capacities and will not overcharge the battery but will supply constant power to do the job.
I felt 10 amps was enough for what I needed but the capacity can be simply determined by adding the 12volt loads you plan on using.

I hope this made sense,this is what I was explaining while you were here but it is a lot of information and there are other ways to go about it.
This is just how the wiring was installed and the most simple way to get it going.
It may seem long winded but all of the work is really already done! I was not kidding.

All you need is a Charger and Battery.

Please do not hesitate to call me to discuss it.

Ed

[MyronL]

Re: what Ed said.

I am currently in the middle of doing the same stuff with my 13 ft Burro. The wiring in mine is such a bowl of spaghetti I found it useful to create a drawing of my trailer appliance layout for myself, to help clear my path to understanding. It might help you to visualize, so here it is.

1. My original battery was located out on the rear bumper and I moved it inside.
2. There never was a converter, and I added one.
3. I have a ganged terminal block instead of a fuse panel
4. I eliminated the separate alternating current appliances direct lines and routing all through converter
5. The tail lights, exterior corner lights, brake lines, will all be a separate line direct to the tow vehicle.

All of this is currently still under construction.

[Patricia Baxter]

Ed:

I got a pretty good understanding of what you had in mind when we picked up the trailer, but it's good to see it written down; thanks. As we've started to figure out what kind of mods we want to do, we will probably be rerouting some of the wiring. For instance, we want the 110 line to come in from the street side rather than the curb side, and incorporate a breaker box. As you know, one mod leads to another, and a lot of your hard work may be further modified in the process. I will certainly call you if I get stuck.

Myron:

Great diagram! Several questions:

What brand & model is the converter? Does it include spots for AC circuit breakers, or did you mount a breaker box elsewhere?

If I understand correctly, your tow vehicle won't be powering any devices in the trailer; just the exterior lights and brakes. Is that correct?

Thanks for your input, guys.

Dale

[MyronL]

Here is the "owners manual" for my converter, a Parallex 7400. It is solid state, and cost me $199 plus shipping. Being quite green, I bought this particular one for no particular reason so cannot advise you on it. Perhaps others will step in and identify the pros and cons of this choice. It is protected by two plastic fuses in back. Have no other breaker box in the trailer.

Somewhere down there under those wires in pix #2 is the mizerable little gang connection terminal junction-thing that connects this mess. I searched and searched but could not find the decent replacement I wanted. Then it dawned on me I could just make my own (super-sized) gang junction-thing. So I did.

Right. Unless someone explains how I'm making a big mistake, the only thing my tow vehicle will send electricity to is the outside (tail) lights, et al.

[Ed Harris]

I gues to take this a little further....
A converter is simply an AC to DC power supply. They do the same thing and for some reason in the RV world are called converters.

Often the converter will incorporate input breakers to protect the AC feedline and a few AC load breakers for the AC loads. These can also be added to any supply with a simple small breaker box as pictured below. This one has 2-15 amp breakers, I used one for the charger/power supply that makes 12 volts and for plugging in AC loads and the other for the kitchen loads.

On the output side of the converter/supply there will be fuses or breakers for the DC 12volt loads.
You already have these in the little panel above the closet. There is an additional advantage in that you can switch these loads independently as well.

RV converters if they offer battery charging at all are notorious for improper charging and can abuse the battery causing other problems too.

I recommend higher quality marine/rv chargers as they are designed for maximum battery conditioning and operation and they also perform the dual duty of the converter all in one.
When I was researching this it seemed clear to me that the RV units are designed to do the most for the least and are built accordingly.
I am not saying that they are all junk but while comparing the insides of several RV models to several Marine models it was clear which were higher quality.

There are a lot of methods to provide these power systems and all I did was construct my own with seperate components,most of which are ready to go.

If you want to move the feed to the streetside it would not require any new wiring at all other than the new feeder cable. The wire from the current closet connections can easily be re-configured to be fed from the streetside instead of feeding the streetside of the trailer.
The connections can be made where they already come together under the front bunk.

If you want to power the trailer with the tow vehicle it is a little more complicated.
You will need either a battery isolator of some sort to make sure the trailer battery and the Van battery can not interact or a transfer switch.

The alternator of the van is designed to charge your starting battery and will not be optimal for the trailers deep cycle battery and there will also be no intelligent muti-stage charging if the trailer battery sees the alternators output.

You can also just install a manual battery switch and switch the trailer beteen the two battery systems.

A really good reference for laying out these systems is the West Marine catalog. There are easy to understand yet detailed explanations with diagrams and pictures.
Everything is applicable to Rv's as it is to boats other than sitting in the water,I hope?!

Ed

[Steve L.]

Elsewhere, you asked for some input so here it comes, for better or worse:

First, I would point out the obvious. That this is electricity we're talking about. Approach with caution. Even 12 volts DC can hurt. Ask anyone who perhaps has shorted out a ring on a finger to ground through a wrench while on the positive terminal of a battery. You might weigh the consideration of having it professionally installed by an RV service center. Assess your technical know how and judge whether this is something you should take on. Perhaps a division of labor is in order. Perhaps have the AC brought into the trailer and the converter hooked up by an RV place. Then, you wire the AC receptacles and the DC applications??

Otherwise, I'm probably going to tell you what the others have said, probably in another way.

Combination Converter/Charger/Breaker/Distribution

You asked for a common package. Parallax (used to be Magnatek) is in scads of RV's, probably just because they offer just such a combination package. I had an earlier 6300 series converter but upgraded to the 7300 series. To be precise, the 7345RU unit is just the converter that you wire into the space the old 6300 series converter was. It reuses the circuit breakers and fuse panel. The circuit breakers are for the 120vAC and the fuses are for the 12vDC.

The newer 7300 series has filtered DC current to all the fuses which in my case eliminated electric noise in the radio and TV. It also has a smarter charger that is less likely to cook the battery.

Are there smarter converters out there? Yes, but none that I know of with the combined converter/charger/distribution package. Ed references marine chargers and they do tend to be better in that they recharge faster. (I like Xantrex) However, there is an attraction (for me) to having it in all one package like the Parallax.

In this case we're talking about the Parallax 7345, about $270 without the AC circuit breakers. Circuit breakers are about $5-$7 each at the home store.

Ed's 7400 model simply has the "guts" of the 7300 without the distribution panels. I say panels since there would have to be an AC panel for shore power. The 7400 would plug into a receptacle fed from the AC panel or be hard wired into one of the panel's circuit breakers. Then, the output of the 7400 would go into a DC panel for distribution. Here's the system diagram from Parallax.



Speaking of the 7300 series: In broad terms, the AC enters the converter/charger and into the circuit breakers. Some is split off through the circuit breakers to pass on the 120v outlets. Usually, one circuit breaker sends AC to the charger/converter side. That's because, even though it's one box, half of it is AC (and it's distribution) and half is DC (and it's distribution). The converter/charger get's its AC input from a circuit breaker. It's sort of the door between the two halves. This is so you can disconnect/protect the converter/charger side of the box.

I would suggest placing the converter/charger as close a possible to the battery. Parallax recommends 8 ga. wire if the battery and distribution panel is next to the converter. I'm conservative by nature and would upsize the wire (a smaller number) if the battery were more than a foot or two from the converter/charger.

Given a 7 pin connector, one of the wires is often labeled battery charge. It goes (eventually) to the plus side of the battery. There will also be a negative or ground. (Geekiness follows DC battery sources (battery, charger or alternator) are like buckets of water. Imagine 3 indentical bucket of water, each filled to a different height with water. Pretend that 12 inches of water is 12 vDC. A battery has 12 inches of water, A charger or alternator, when turned on, have 13 inches of water. Connect all three together and then connect to a spigot. The buckets will always try to level out. The buckets with 13 inches will try to flow into the 12 inch bucket (battery) AND out the spigot (to the lights, or a fan). Turn off the spigot and all the 13 inches will try to go to the battery until it gets to 13 inches also.(This does NOT work for alternating current).

If you turn off the alternator (disconnect the tow or turn off the charger) then the battery is now the deepest bucket and all the water to the spigot will come from the battery. It's all automatic by itself. The tow vehicle's positive wire usually just connects to the fuse panel at the same place that the trailer battery positive wire connects. Same thing for the negative wire.

Some tow vehicles have one way valves (diodes and relays) to make sure water won't flow the wrong way, back from the trailer charger into the tow vehicle. Some don't. If your vehicle didn't come already wired this way, the ultimate one way valve is to disconnect the trailer from the tow. Pull the plug when you stop. Put a little tag by the speedometer or ignition key to remind you to reconnect before you drive away.

As for the battery on the tongue. I have no problem with that. Marine boxes are a good start. It's not essential that the box be weather proof. I might be sure there are one or two weep holes in the bottom if driving rain entered the box.

[Steve L.]

FWIW,

As I read through my previous post, it occurs to me that I actually offered little or no actual advice. That makes it a fairly successful post from my perspective.

I mentioned what works for me. I described how my system works, or least seems to work. I've managed to go deep into my 50's without actually having taken responsibility for much more than a pet. And it wandered away, forever, while we were camping and I still feel a bit of a ne'er do well. ("Shouldn't that cigar-smelly food-guy come rescue me now?") I'm reluctant to change.

Anyhoo, you all are considering what for some, depending of experience, is a pretty signficicant project. Be careful out there.

[MyronL]

Fair enough, Steve. It never hurts to approach with caution, particularly things electrical. Therefore, and in that spirit, your formula for success in life duly and respectfully noted, I hasten now to humbly seek responsible advice from you and from all, on the following......

This diagram illustrates my current configuration. Note none of the wires for the exterior corner/brake lights, etc. powered and controlled by the 7 pin round going to tow vehicle are connected to anything else. Should they be?? If so, what would you advise?

Looking for brevity here, not sophistry

[Patricia Baxter]

Steve:

Thanks for the excellent summary, per your usual standards. This will be very helpful. But I'm disappointed that you didn't suggest ways to make it more complicated and acquire several gadgets in the process.

Thanks again.

Dale

[Steve L.]

My preference is to have electric circuits make a full loop. All the lights running lights (and stop, turn and backup) must go to ground, probably the trailer frame. I'd connect the frame to the negative on the 7 pin plug. I'd like the trailer frame and the tow frame to be at the same level of "ground". We do this on boats as well. It stops stray current which can be corrosive to metal parts.

[Byron Kinnaman]

My preference is to have electric circuits make a full loop. All the lights running lights (and stop, turn and backup) must go to ground, probably the trailer frame. I'd connect the frame to the negative on the 7 pin plug. I'd like the trailer frame and the tow frame to be at the same level of "ground". We do this on boats as well. It stops stray current which can be corrosive to metal parts.

Sorry Steve, but doesn't seem like a very good way if you want to NOT have current flowing in metal parts like the frame.

Byron's advice on grounds (note ground on a vehicle is nothing more than the negative battery connection). Run wire for connections of both negative and positive. Connect the frame to negative at one point and [b]one point only. That connection should be near the coupler to minimize "loop" currents flowing in the frame.

[Victor Benz]

This diagram illustrates my current configuration. Note none of the wires for the exterior corner/brake lights, etc. powered and controlled by the 7 pin round going to tow vehicle are connected to anything else. Should they be?? If so, what would you advise?

I am not an expert, and I am learning as I go on this, but with no connection (other than common ground) between your trailer batterty power circuit and the 7-pin Bargman towing connector, you will not charge the battery with the tow vehicle alternator while towing.

For me, this is an essential feature. We have gone on road trips for up to five weeks and never tied into power, staying at various site 1-5 days. It was the charging during towing between these sites that allowed us to have a fully charged trailer battery.

I do not know how to make this tie-in, and would defer to experts. Related issues are the capacity of the tow vehicle alternator, and the risk of draining the tow vehicle battery if left connected to the trailer.

Victor

[MyronL]

AH! So Vic, you are suggesting if I connect the white and black wires in the pentagon shape (7-pin connection) to the distribution panel in trailer I will gain the advantage of my tow vehicle's alternator charging up my trailer battery while we are driving?

And that would be a good thing? No undesireable consequences from this...like overcharging the trailer battery? Once parked the 7-pin would be disconnected from tow vehicle, so no chance there of drawing off tow vehicle current.

Any experts care to jump in and confirm this? Still proceeding with caution, of course.

[Victor Benz]

AH! So Vic, you are suggesting if I connect the white and black wires in the pentagon shape (7-pin connection) to the distribution panel in trailer I will gain the advantage of my tow vehicle's alternator charging up my trailer battery while we are driving?

And that would be a good thing? No undesireable consequences from this...like overcharging the trailer battery? Once parked the 7-pin would be disconnected from tow vehicle, so no chance there of drawing off tow vehicle current.

Exactly. I do not think that overcharging the trailer battery is an issue, unless your tow vehicle overcharges its own battery.

We always started each trip with a fully charged battrery at home, not relying on charging it as we drove.

I think the key issues are using the proper wire gauge, precise connection instructions, and the capacity of your tow vehicle's alternator.