Power supply disconnect sequence?

[Bill]

Autosnap -

Your posts earlier in the thread suggest that you could use some help understanding the way power flows in the TM electrical system. Since I was already in my Tech Stuff album, I pulled up the summary diagram that may help. Grab it here

https://www.trailmanorowners.com/for...pictureid=1969

I think it will immediately show why the electrical system worked or didn't work, when the power cords were plugged in one way or another. If still not clear, let me know, and we'll walk through it together.

Bill

[Autosnap]

Rick and Bill, thank you so much for this great information! I do have the blade style holder, so there's one thing I can check off as not needing to change. Should I look at possibly using larger size cables in the future or are these adequate size even if I add a battery or go up to the double 6v later on?

Awesome things to think about with the soft start. I got it mainly for the inrush currents from the compressors on the ac and fridge. Mainly so I can run it off my 20amp sources, my house (until i can get an electrician to come out and add a30amp supply) and my truck generator without overloading them. I gave no thought to it being oversized. I saw 30 amp and said to myself... the TM runs off 30, so I'll just get that one. I gave no thought to the fact that it might cause problems on lesser supplies. I'll check with the manufacturer, I may need one for 20 amp for those other applications. I like it for the surge protection and app feedback at the campground.

I can't belive the knowledge available on this forum. Thank you guys for being here! They don't give you near enough information when you buy an RV, and the learning curve is steep...

Thanks again!

[Autosnap]

Hey Bill,

I've been looking over your tech stuff. I love the diagram, that helps an awful lot. Do you know where the solar panel might fall in there?

[Bill]

I love the diagram. Do you know where the solar panel might fall in there?

I am not the solar expert on the Forum, so I invite others to comment or correct me.

Discussions of solar systems often get bogged down in details very quickly. The details are important if you are installing a solar system, of course, but the diagram you asked about shows things at a summary level. There are two things going on in the TM electrical system - keeping the battery charged, and providing operating power to all the TM load devices.

Charging: In the diagram, you see the TM battery down at the bottom. You see that there are two sources of charge current for the battery. One is the charge line coming from the tow vehicle. The other is the TM's built-in battery charger, physically located in the converter. These two sources are connected directly to the battery, and the battery accepts charge from either or both. A solar system, panels and charge controller, is just a third source of charge current, and like the others, it is also connected at the black-circle junction just above the battery.

Powering the TM: At the same time, you can see that there are two arrows above the battery, one in each direction, showing that the battery can either accept charge current from those sources, or provide load current to all of the TM electrical devices. This, of course is what you expect from a battery, and why you have one.

These two functions happen automatically, as needed, and in the amount needed. In fact, most often, some of the current from the charging sources goes directly to the TM loads, and some of it goes to the battery to top up its charge. The battery doesn't know or care, and neither do the sources or loads.

I hope this clarifies that at a conceptual level, all of this stuff is simple. If I've caused more confusion than clarity, please feel free to ask - either here in the thread, or by PM.

Bill

[rickst29]

Bill knows far more than he admits too

But in either case:

Solar panels can be used to provide additional "12 Volt DC" power into that system. A "Solar Charge Controller" (SCC) is ALWAYS needed to reduce the voltage from the panels (they're typically 18-40 volts each), to a lower voltage which the batteries or 12v appliances can accept. That's typically around 14 volts.

Most SCC units can vary that voltage a bit, depending on whether they "think" that the batteries need charging. Like the 12-VAC "power converter" unit, they do this by sniffing the output voltage wires from time to time. When both are active, they can slightly confuse each other, but such confusion lasts only for short periods of time - and solar isn't really needed needed when you have plug-in power.

Unlike batteries, and unlike a plugged-in converter, Solar Power (from panels, through the SCC is only available for a few hours per day, and needs bright sunshine to work. The brightness and length of day are best in mid-June, and your daily power will be much less in other seasons (e.g., if camping in late September).

As Bill described, there are some subtle issues involved in choosing an SCC (I actually have two of those), and also choosing how to wire your panels together. SCC units come in two types. The inexpensive "PWM" SCC units rapidly connect and disconnect the high-voltage panels, in order to make the average output voltage lower (near the 13-14 volts which the TM requires). But power being made in the panels during that "disconnected" portion of time is wasted.

More expensive "MPPT" controllers use complicated electronics to convert power received at high voltage into more current at low voltage, using more than 90% of the panel power when your batteries are willing to take in in. But they are less reliable, the electronics generate some heat, and they cost much more.

The proportion of "wasted power" (using a PWM controller) is relatively constant, around 20-30%. If you install less than than "200 Watts" of panels on the roof, PWM saves money at purchase time, while loosing only a small amount of power per day.

But if you have installed more than 300 Watts of panels, that 25% proportion becomes fairly large (viewed as a total amount of lost watt-hours). I recommend MPPT controllers for those larger configurations, and also for configurations where a large single panel is used - thos "bigger panel run at higher voltage, often increasing the PWM power loss proportion to more than 50%.

Like the power converter, A SCC unit presents output power on a "12v" output wire and a negative gounding port. They ultimately need a path the the battery terminals "+" and "-", but they can be connected elsewhere - may people connect the +12v on a WFCO fused port, with the "-" wire on the grounding bus bar behind the WFCO unit. I think that TM installs the factory controller (a cheaper PWM type) to feed in at the WFCO "12V" circuit board.

I have about "800 watts"of panels, using two MPPT units (one for front shell panels, the other for a rear shell panel). I almost never actually get more than 450 watts of power, and that's only for a few minutes near "solar noon" on a perfect day. But it all adds up over time - I can usually run the Air Conditioner for a couple of hours each day, even without plugins or a using a generator. I have a lot of other 120-VAC appliances as well, also running from my batteries through a big Inverter unit.

It was costly to build.

[Autosnap]

Again, such good info. I'll reread when I get home, camping now, lol. This is the installed from the factory system. It's stuck to the roof such that half is covered when it folds... so not completely well thought out. The reason I asked is that even with the fuse to the battery blown, it shows the battery fully charged when hooked up to ac... something I wish it wouldn't do... anywho, thanks again! I'm interested in adding more as I think it's just 100w and the controller, I think can handle more. Hard to know as there was no info on it in the manual I received.

Best

[Bill]

Rick -

As always, you have provided some really good info, most of which is beyond my level of knowledge. Thanks.

Autosnap, you asked

Do you know where the solar panel might fall in there?

Summary of my simple answer.

In the diagram, you see the TM battery down at the bottom. You see that there are two sources of charge current for the battery. One is the charge line coming from the tow vehicle. The other is the TM's built-in battery charger, physically located in the converter. A solar system is just a third source of charge current, and is also connected at the black-circle junction just above the battery.

Bill

[JerryN]

Are you still in or near the GSMNP? I am in north Knoxville, just off of I75. I will be happy to help if you don't already have the electrical issue resolved.
Jerry N
2006 2720 SL