Advice on RV Set up & Wiring?

[Carv]

All I can say is your assumptions and ignorance is costing you a lot of money.

Voltage loss is based on the size of the cable, amps flowing through it, and the length. So lets say you have a 12 volt 1000 watt Inverter and the cable 1-Way distance between the battery is 6 to 10 feet. The Inverter requires a 100 Amp Cable with 100 Amp Fuse. Now use the chart I gave you to select the conductor using the 3% column. What did you come up with?

It had better be 4 AWG. A hell of a lot less expensive and easier to work with.

You are not reading and understanding what you are being told.

I believe I understand most of it, what you're not understanding is that I ALREADY HAVE certain pieces that you consider a "waste of money". I'd consider it a bigger waste to throw it away to replace it with an inferior product. Does it really matter if I run the 4AWG you recommend or the 1/O welding cable I already have installed? I'm sure the 1/O welding cable which is compromised of #34 strands can handle much more power than the 4 awg (THHN or what ever you'd run) so why replace it and spend money twice? If you can acknowledge that I already have sunk costs in the system and we can discuss using the components I have then we'll be making good use of our time instead of giving non related examples. As I've said earlier there are other considerations that I'm aware of that I just don't need to write a book on for everybody here to read, but I need to consider when making a decision on how to put together my system.

For example; through I travel to the area where I need the system, I drive there 250 miles and I park for how ever long I'm staying and I drive back 250 miles, I don't stop fr a day or two drive some more, then stop, then drive, it's there stay come back. When I leave the batteries are already full, the spot I park in gets full sun all day as long as the sun is out (there is NO shade at all unless it's cloudy, BUT I've thought about not mounting the panels on the roof and setting up some kind of portable system like you described earlier BUT the fact I have to carry them in my trailer and I'm not sure how much abuse the panels can take bouncing around for 500 miles every trip (a trailer is not a smooth as a moho) plus I have motorcycles, sand cars, rzrs in the trailer all of which can move and smash the panels so making a portable system might work on some trips and on other trips it's not worth the risk of smashing my panels to carry them in the trailer. So there are benefits & costs associated with everything we're talking about here stuff you just are not aware of that I need to consider.

So as I've tried over and over to explain previously the "ultimate system design" is not always the best for everybody given their constraints.

[Carv]

Whoa, hold on. 1/0 cable may be rated for up to 350 A in a welding application, but not for continuous duty. Typically that would be 200 A, or somewhat less. The "rating" isn't driving the calculations though, the cross-sectional area and resistance are. 100 A over 10 ft on 1/0 will have a drop of 1.7%, more as the conductor heats up. That would leave 3.3% drop allowed for the battery, per the guideline to target no more than 5% drop so your inverter doesn't cut out. The problem is that 100 A on a 0.006 ohm IR battery = 0.6 V drop, which is 5% all by itself, and gives a total loss of (5 + 1.7 = 6.7... too much). Does that calculation make more sense presented this way?

I understand the resistance between the two pieces of the system, the battery resistance & the cabling. I specifically used 1/O welding cable as it is made out of strands of #34 or #36 wire, I get it for cheap, $2.41/Ft, I only need 10 feet, and I was told it can carry more amps than your standard THHN wire as electricity travels on the outside of the wire (surface area) and a 1/O made of #34/#36 has a lot more wire surface area than a 1/O made of what ever large diameter THHN is comprised of. So as I was told, and believe to be true, a 1/O welding cable can handle more amps than standard 1/O THHN house wire you get a home depot which is what most ampercity charts show.

But again all theory, I only need 200A max on my inverter per the manufacturers instructions so 1/O welding cable is more than sufficient.


Any possibility on getting my number of panels question answered from earlier?

sensij in your opinion, would you say I'm better off with the 2 250W 60 cells VS a single 330W 72 cell, because of the Voc limits on the CC AND the fact I'll have over capacity on the panels so if there are some inefficiencies it'll compensate for it them in production?

Thanks

[sensij]

Now back on Track

sensij in your opinion, would you say I'm better off with the 2 250W 60 cells because of the Voc limits on the CC AND the fact I'll have over capacity so if there are some inefficiencies it'll compensate for it them? (If my batteries can comfortably handle a C/5 charge rate and not the assumed C/8 (more than 30A charge) depending on what their resistance actually is, they may be able to use up to 45A charge, I'll research it and see)

Thanks

Yes, for those reasons, but also because having the extra PV power means you don't have to worry so much about orienting the panels perfectly south with perfect tilt for the latitude and time of year every time you want to use them. It isn't possible to hurt your battery by having too much PV power, as long as your cc is setup right. Having too little PV power is a sure way to be back here in the forum in a year or two, wondering why the batteries won't take a charge any more.

[Carv]

Thank you sensi J, that is something I can use.

[Carv]

Now back to the wiring business.

SK per your diagram(s) I need to make 4 runs from inside the trailer to the tongue where the batteries are mounted, 2 (Pos & Neg) for the inverter & 2 for the CC, am I understanding your diagrams correct?


Can SK or anybody else please tell me why this proposed layout will or will not work as I'm trying to limit the runs from the tongue to inside the trailer (& vice versa) where the components are mounted. Again it's not about optimal layout I have physical constraints here and making 4 runs through the trailer is not on the top of my list.

Two things to take in to account:
1) 300W panel might be changed out for 2 250W panels in series
2) The shared negative terminal is grounded/welded the trailer frame for the inverter & CC negative battery leads, it's not a 2nd ground for the batteries). Trailer -Solar Wiring Diagram.jpg

[sensij]

I understand the resistance between the two pieces of the system, the battery resistance & the cabling. I specifically used 1/O welding cable as it is made out of strands of #34 or #36 wire, I get it for cheap, $2.41/Ft, I only need 10 feet, and I was told it can carry more amps than your standard THHN wire as electricity travels on the outside of the wire (surface area) and a 1/O made of #34/#36 has a lot more wire surface area than a 1/O made of what ever large diameter THHN is comprised of. So as I was told, and believe to be true, a 1/O welding cable can handle more amps than standard 1/O THHN house wire you get a home depot which is what most ampercity charts show.

But again all theory, I only need 200A max on my inverter per the manufacturers instructions so 1/O welding cable is more than sufficient.

I'm not talking about THHN or NEC ampacity tables. Here is a typical welding cable data sheet.

https://www.iewc.com/-/media/iewcglo...ampacities.pdf

I'm not saying there is anything wrong with what you have got, just that when you describe it as 350 A rated, that is really a surge rating, not continuous. Clearly, if you are pulling 200 A from your inverter continuously, you are doing something wrong

[Sunking]

I believe I understand most of it, what you're not understanding is that I ALREADY HAVE certain pieces that you consider a "waste of money". I'd consider it a bigger waste to throw it away to replace it with an inferior product. Does it really matter if I run the 4AWG you recommend or the 1/O welding cable I already have installed? I'm sure the 1/O welding cable which is compromised of #34 strands can handle much more power than the 4 awg (THHN or what ever you'd run) so why replace it and spend money twice? If you can acknowledge that I already have sunk costs in the system and we can discuss using the components I have then we'll be making good use of our time instead of giving non related examples. As I've said earlier there are other considerations that I'm aware of that I just don't need to write a book on for everybody here to read, but I need to consider when making a decision on how to put together my system.

Sure you can use 1/0. Question is do you have the hydralic tools and skills to terminate it correctly which I highly doubt because the tool comes with a $2000 price tag, and requires some precise cuts and cable prep. If it were me I would find a local sparky and do a trade. Any damn sparky would trip all over himself to do a foot for foot trade with you. Hell he will even properly terminate the 4 AWG for you and throw in the $8 lugs that go with it for free. This is why I suggest all DIY buy terminated cables. DIY's do not have the tools and skills to terminate cables.

For example; through I travel to the area where I need the system, I drive there 250 miles and I park for how ever long I'm staying and I drive back 250 miles, I don't stop fr a day or two drive some more, then stop, then drive, it's there stay come back. When I leave the batteries are already full,

Do you have a contract with God like Wyrbread where the sun always shines everyday and fully recharges your batteries. The rest of us are not so fortunate and have to use a generator or Isolator to cover our butts for cloudy spells. I could care less if you destroy your batteries. Do as you please. You said you have a genny, so what is your problem?

As for me and Moron, we like redundancy and No Brainer tactics. We both wear suspenders with belts. We also use Gennys and Isolators. Moron travels thousands of miles with panel stored year round. I am just giving you other proven methods to consider. I can save you money and help you design a workable system with no flaws or cracks for less money than you can. At the end of the day I could care less about you and if you succeed or fail. Just trying to help you, but you refuse. Do it your way. Like the ole saying goes; " you have been told, now it is time you learned the hard way"

[sensij]

Now back to the wiring business.

SK per your diagram(s) I need to make 4 runs from inside the trailer to the tongue where the batteries are mounted, 2 (Pos & Neg) for the inverter & 2 for the CC, am I understanding your diagrams correct?

Can SK or anybody else please tell me why this proposed layout will or will not work as I'm trying to limit the runs from the tongue to inside the trailer (& vice versa) where the components are mounted.

You don't have a circuit, except through the frame. You should have a cable connecting the shared negative inside the trailer to the battery's negative terminal... 1/0 welding cable, if you copy the DC+ side.

The charge controller should have a fuse or breaker between it and the distribution block, sized for the charge controllers rating. You don't want the charge controller, or the conductor feeding it, to become the fuse in the event of a partial short that doesn't immediately trip the 200 A breaker.

[Sunking]

Now back to the wiring business.

SK per your diagram(s) I need to make 4 runs from inside the trailer to the tongue where the batteries are mounted, 2 (Pos & Neg) for the inverter & 2 for the CC, am I understanding your diagrams correct?

Correct, there is no other fricking way to do it. You have no choice.

Can SK or anybody else please tell me why this proposed layout will or will not work.

Sure can, real damn simple, it takes two conductors to make a complete circuit. One is Supply, and the other is Return. You are only showing 1 Conductor, it takes 2 conductors to make a complete circuit. If you try to use the frame as a circuit conductor, it will not work and will fail period. Those days are long gone. If you run normal load current through your frame are asking for a for super accelerated corrosion of you chasis, frequent circuit failures, and malfunctioning electronic equipment including your ignition system leaving you stranded.

The only thing you use the vehicle chassis for is the 3rd wire called Ground. Ground has only one purpose, to operate the fuses if a hot conductor touched ground. Otherwise no current ever flows and ground does NOTHING, only used in an emergency to prevent a fire and operate the breakers and fuses. That is why you only bond the battery Negative Term Post in one place only. If you bond it twice, your frame and chassis become a circuit conductor. That is what your Inverter Document is telling your with ground loops. You did not understand what it was telling you, and what you do not understand now..

So you have 2 conductors from the panels to CC, 2 conductors from the CC to battery, and 2 conductors from the battery to load. You are being lazy trying to cut corners which is not possible, Using 1/0 is going to make it harder, tighter, and maybe impossible. Using 34 strand class B stranding is makes it real damn hard to bend as is is almost as stiff as a solid copper pipe. That is why we use Class H fine stranded cable that is super flexible and easy to work with. Your way is making it harder and more expensive if not impossible. If you trade it for 4 AWG keep a 3-foot section as it makes a real damn good head knocker. Like you said, "You made your bed, (bought before you planned or researched), now it is time to sleep in the bed you made".

Edit thought:

The scrap salvage value of the 1/0 will be more than enough to buy all your wiring and laeve change in your pocket. All you gotta do is think outside the box and use your head for something other than a hat rack. If you do that buy flexible cable stranding. A cable shop wil buy it at higher rates than a salvage yard if left in one long piece so they can use it. Would make both parties happy happy. Put it to you this way. If I were close to you I would trade you foot for foot 1/0 for 4 AWG and terminate it for you any day of the week. I could get be rich doing that for a living. Every 1 foot cost me 86-cents and you give me 2.56/ft. A whooping 254% gain instantly any fool would jump on.

[Carv]

You don't have a circuit, except through the frame.

Since there is no positive side connected to the frame how do I have a circuit through the frame?

After reading through SKs post:
What is feeding this circuit through the frame, the negative discharge from the components is trying to get back to the battery through the frame making a circuit?


Sk this is what I used:
1/O -1043 strands of #30 copper wire with a a EPDM jacket
http://catalog.anaheimwire.com/item/...es/10623001-00

Terminated with a dieless indent lug terminal crimper.

The wire is fine, it's staying, and I'm ok with the extra $15 I spent for bigger wire, so please drop it.

[Sunking]

Since there is no positive side connected to the frame how do I have a circuit through the frame?

C'mon this is getting. old. You simply have no knowledge of basic electrical circuits and are not understanding what you are being told. If you connect both positive and negative to the frame you have a dead bolted fault, and one hell of an explosion on your hands. Try this experiment Get your battery and a piece of copper wire and short the Positive to Negative battery term post together, and see what happens when you complete the circuit. I promise you will learn something and never have to be told again.

After reading through SKs post:
What is feeding this circuit through the frame, the negative discharge from the components is trying to get back to the battery through the frame making a circuit?

Hell yes as you have it drawn out.

Again you have no basic circuit knowledge. Your drawing shows using a wire to make the supply side of the circuit (positive polarity of the battery), and using the frame as the Return side to complete the circuit (negative polarity of the battery). You cannot do that today, it requires 2 wires, You do not have to understand it, just accept it as fact.

In the Stone ages when cars, truck, and RV's were made out of steel, high tech was tube AM radio, and ignition systems were a rotor, condenser, and points auto industry used the frame of vehicles are the Negative or Positive return conductor. Makes no difference which polarity you bond to the frame. Today Negative is default. They cut corners to save on material cost. and electrical loads were lights and a tube radio in the dash. That is ancient history.

Today we have computer controlled ignition. megawatt stereos, camera systems, Entertainment systems, heated seats, power windows doors and locks with very high power demands. Today's vehicles are made form a myriad composite materials and dissimilar metals. If you use the chassis and or frame today you generate corrosion on all electrical connection points, generating tremendous electrical noise that will completely wipe out all the electronic systems including your ignition system. In the mean time the corrosion builds and circuit resistance rises rendering your circuit conductor to useless capacity. Today you must use 2 real conductors whether you like it or not. Get that through your head and accept it.

Sk this is what I used:
1/O -1043 strands of #30 copper wire with a a EPDM jacket
http://catalog.anaheimwire.com/item/...es/10623001-00

Terminated with a dieless indent lug terminal crimper.

The wire is fine, it's staying, and I'm ok with the extra $15 I spent for bigger wire, so please drop it.

I could care less what you use. You do not understand the consequences of your actions. It is your problem to deal with. You made your bed, and now you have to sleep in it. It is pointless trying to help you.

Good Luck, you are going to need it.

[Wrybread]

C'mon this is getting. old. You simply have no knowledge of basic electrical circuits and are not understanding what you are being told. If you connect both positive and negative to the frame you have a dead bolted fault,

Huh? He's not asking about connecting both the negative and positive to the frame. Just the negative.

Again you have no basic circuit knowledge

That's a little over the top. Recommending that he not use a chassis ground because vehicle materials have changed is one thing, but launching into yet another Dramaking temper tantrum over it is a bit much.

And besides, do we even know what year this vehicle is?

[Carv]

Huh? He's not asking about connecting both the negative and positive to the frame. Just the negative.

That's a little over the top. Recommending that he not use a chassis ground because vehicle materials have changed is one thing, but launching into yet another Dramaking temper tantrum over it is a bit much.

And besides, do we even know what year this vehicle is?

It's a trailer so year does not matter.

What does matter is and how SK should have explained it instead of launching in to one of his ego driven tie-raids;
Is that both components need a complete circuit to work and when each component discharges in to the frame that current will seek an outlet and since the batteries are also grounded to the frame the currant from the components will Loop back to the batteries through the frame making a complete circuit and electrifying my trailer frame, which carries it's own issues such as electrolysis of the metal. So instead if I make a return run to the batteries it will take the frame out of the "Loop" and the single ground at the batteries will only act as a discharge point as there are no other place for the currant to loop back in to the system.

You know Sk if I'm too dumb to help or you fragile ego can't take the fact I'm not going to follow your exact instructions word for word please just stay off my thread. You have a lot of information to share but the way you share it is soooooooo convoluted and full of disdain for anybody below your knowledge that 95% of your post content does not help.

Either get to the point or get off the thread, it's now almost 6 pages long and most of it is arguing with you and your condescending posts about how stupid my plans are. Now nobody wants to read through all of the pages of BS so in the end I really won't end up getting any help with the project which is why I came here in the first place. I've read a lot of threads on this forum and I've seen you alphadog just about everybody who asks a question to the point that nodoby else wants to respond, you are absolutely right I ONLY HAVE A BASIC UNDERSTANDING ABOUT ELECTRICITY THAT IS WHY I'M HERE! I've seen this is how you are and I'm surprised any new people even want to come on this forum and put up with your condescending crap just to get some information.

Unless you have some direct, absolute non-changing information to share, you can get straight to the point, and your ego can handle the fact I'm not going to spend days trading wire to save $15 I already spent, and the fact I might use #4 instead of #6 wire on my system please quit mucking up my thread so I can get some real help.

Thank you


Mods please clean up any BS back & forth as this thread has derailed a long time ago and I'm sure nobody wants to sift through all the crap to get the nuggets.

[Carv]

For those of you who can handle it, are there any issues with wiring the system this way?

Trailer -Solar Wiring Diagram -3.jpg

[Wrybread]

please quit mucking up my thread so I can get some real help

Amazing how often people tell him exactly that. Been there done that!

I'm sure it's just a typo, but of course you'll need the negative line from your panels to the charge controller. You can't use chassis ground for that, as I'm guessing you know.

And if you want to save a few hundred dollars you don't need so fancy a controller, this one will do fine with the added benefit of having an affordable remote monitoring box:

https://www.amazon.com/gp/product/B015ZBOHKC/

That said, the Morning Star is definitely better and if you don't mind the extra $$ for the project you won't regret it, especially a year from now when you have a different project in mind. The downside of the cheaper controller is that it's 100 volts instead of 150, so doing 3 panels in series is pushing it.

And if you're just doing two panels and have room, personally I'd get the 300 - 310 watt panels.

Edited to add: on the off-chance someone reads only this post without reading the rest of the thread, read a few posts down for some warnings about two 72 cell panels with a 100 volt controller.