Cargo Trailer Camping Converting

[UrbanElite]

I sure do! Every other person with an rv thinks exactly the same way, myself included. It's all cost/benefit analysis. It's hard to imagine that's not obvious to anyone, but alas.

I like the benefits of solar, I could have went and bought a generator but that's annoying, cost of fuel every weekend running and I like the project of building this trailer with the system in it, but at the end of the day it has to be cost effective.

[UrbanElite]

600 watt Xantrex ProWatt Might start the fridge OK, if there is nothing else running and the batteries are fresh. Personally, I'd use the 1Kw inverter and not worry about the fridge starting if some other devices were on at the same time. Remember, transistors have hard limits on what they can do, unlike the dynamos at Hover Dam.

Thanks for the reply, I was kinda thinking around the 1000 watts as well for the extra juice, price wise won't be too much more either.

[UrbanElite]

Given everything you've written, if you go with the S-550's and 640 W of panels, I think you should be looking at the Victron Mppt 100/50 charge controller, $315 on Amazon.

Put the panels in parallel with the simple Y combiners recommended earlier, one each for the plus and minus side. I'd use 10 AWG for the runs from the combiners to the charge controller, buy a pre-made cable twice the needed length and cut in half to get a male and female lead.

The only fusing you need is right on the battery terminal. Look at Blue Sea Systems dual terminal fuses. One of the slots would be for the charge controller, a 50 A fuse with 6 AWG if the run is short. The other slot would be for the inverter, size TBD.

Yeah I'm thinking I'll need at least 50A charge controller, I'll take a look at that unit and get back to you. Looks like about $400 Canadian unit, anyone have any other recxomendations as well?

even if I don't need it what size of fuse should I put off the positive on the solar panel lead? I would still like one there since it's a source of power. 50a fuse and 6 AWG going from the controller to the battery's?

[SunEagle]

Given everything you've written, if you go with the S-550's and 640 W of panels, I think you should be looking at the Victron Mppt 100/50 charge controller, $315 on Amazon. For $150 more than the 40 A Tracer might cost, that extra 10 A is assurance that you'll be able to push C/10 charge current into the batteries in good conditions. Another $75 or so gets you to the Morningstar 45 A mppt, better quality if you want to throw even more at it, although I'd struggle to spend that much for only 5 A more capability than the Tracer.

Put the panels in parallel with the simple Y combiners recommended earlier, one each for the plus and minus side. I'd use 10 AWG for the runs from the combiners to the charge controller, buy a pre-made cable twice the needed length and cut in half to get a male and female lead.

The only fusing you need is right on the battery terminal. Look at Blue Sea Systems dual terminal fuses. One of the slots would be for the charge controller, a 50 A fuse with 6 AWG if the run is short. The other slot would be for the inverter, size TBD.

Good action plan. All of that equipment should work for the OP without breaking the bank.

Nice find on that Victron CC. It is hard to find an MPPT CC between 40A and 60A that is not a low quality product.

[sensij]

even if I don't need it what size of fuse should I put off the positive on the solar panel lead? I would still like one there since it's a source of power. 50a fuse and 6 AWG going from the controller to the battery's?

No fuse on the solar panel lead to the charge controller. It isn't a question of whether or not it is required, it truly serves no purpose when you are using only two panels. There is no source of power large enough to blow the fuse, even in a fault.

Yes, 6 awg wire, 50 A fuse between the charge controller and battery. Use the type of fuse that mounts directly to the battery terminal.

[Wrybread]

Good to know about the inline fuses when using just two parallel panels, thanks for the great info as usual Sensij.

And to the op here's a link to the battery terminal fuses that Sensij is talking about. Note that these don't come with the fuses, but they're at the link too:

https://www.amazon.com/dp/B002INJXO6..._FJQnzbVV6CW6D

[Sunking]

Batteries. I brought up the S550 cause they are high AH, 6v and a decent deal around $320 a battery. Doesn't mean I'm set on them I have also looked at the s290s. But any other recommendations I would love to hear as well...

There is the trap you are building, and wyrebread does not understand. Those batteries require a minimum 50 amps up to 100 amps of charge current. Now 640 watts of panels will do just barely do that: 640 watts / 12 volts = 53 amps

What you are wyebread do not understand is all components have to match to work with each other. A pair of Rolls S-550 requires:

Panel Wattage min = 600 watts, max 1000 watts
Controller size 50 to 80 amps
Max inverter size = 1000 watts

Now you say maybe S-290 and that changes everything.

Panel Wattage min = 275, max = 450 watts
Controller size 25 to 40 amps
Max Inverter size = 600 watts

So how do you size the batteries. Simple you must know your daily watt hour usage and how many days of autonomy is. The acceptable range so everything works together is 3 to 5 days. Guess what? You have not answered that question. Until you know that, you cannot build a system. At least not one you know will work and not cost a penny more than necessary.

So when you figure out how many watt hours you need, the rest is simple. Say you decide the number is 1000 watt hours. For a part time system you can go with 3 day autonomy which gives you 2 usable cloudy days of power before you have to shut down and wait for 2 sunny days to recharge.

AH = [3 days x 1000 wh] / 12 volts = 250 AH.

Panel Wattage is easy in an RV, you want a charge rate of C/10 to C/8, preferable C/8, and C/8 = 250 AH / 8 H = 31.25 amps.

Panel Wattage required = 31.25 amps x 13 volts = 406 watts.

Then you go shop for a 30 amp controller and 400 watts of panels.

[sensij]

Some battery / charge controller / inverter combinations /PV power combinations to consider, depending on where you decide you want capacity to be, and the prices of equipment local to you. 12 V systems should pretty much collapse down to these options for most normal circumstances, I think.

30 A CC - Tracer 3210A
2 x Trojan T-105RE or 2 x Rolls S-290 = 225-230 Ah
2 x Rolls S-330 = 250 Ah
Max inverter = 600 W
Min PV power = 360 W
Max PV power = 720 W (depends on orientation)

40 A CC - Tracer 4210A
2 x Trojan L16RE-A = 325 Ah
2 x Trojan L16RE-B or 2 x Rolls S-480 = 370-375 Ah
Max inverter = 800 W
Min PV power = 480 W
Max PV power = 960 W (depends on orientation)

50 A CC - Victron MPPT 100/50
2 x Rolls S-550 = 428 Ah
2 x Rolls S-605 = 468 Ah
Max inverter = 1000 W
Min PV Power = 600 W
Max PV power = 1200 W (depends on orientation) [4 x Canadian Solar 280 MS, wired 2S2P, for example]

Any of these is compatible with 2 x 340 W panels in parallel, although you may be starting to get thin on PV power for the biggest batteries.

[Sunking]

Good to know about the inline fuses when using just two parallel panels, thanks for the great info as usual Sensij.

If you had ever bother to look at the drawing or thousands of post I have made you would have already known that, and the part numbers. Where do you think Sensij got it from?

Batteries are the source of power, not the panels. 1 or two parallel strings of panels require no fuses, 3 or more do require fuses. The battery fuses are installed directly on the Battery Term Post. Otherwise they are worthless as you will leave unprotected wire between the battery term post and the OCPD. Like I said the schematic wiring does not change, just the values.

[Sunking]

Some battery / charge controller / inverter combinations /PV power combinations to consider, depending on where you decide you want capacity to be, and the prices of equipment local to you. 12 V systems should pretty much collapse down to these options for most normal circumstances, I think.

30 A CC - Tracer 3210A
2 x Trojan T-105RE or 2 x Rolls S-290 = 225-230 Ah
2 x Rolls S-330 = 250 Ah
Max inverter = 600 W
Min PV power = 360 W
Max PV power = 720 W (depends on orientation)
320 watts wasted and never seen or used

40 A CC - Tracer 4210A
2 x Trojan L16RE-A = 325 Ah
2 x Trojan L16RE-B or 2 x Rolls S-480 = 370-375 Ah
Max inverter = 800 W
Min PV power = 480 W
Max PV power = 960 W (depends on orientation)
200 watts wasted and never seen or used.

50 A CC - Victron MPPT 100/50
2 x Rolls S-550 = 428 Ah
2 x Rolls S-605 = 468 Ah
Max inverter = 1000 W
Min PV Power = 600 W
Max PV power = 1200 W (depends on orientation) [4 x Canadian Solar 280 MS, wired 2S2P, for example]
Acceptable utilization of assets

Any of these is compatible with 2 x 340 W panels in parallel (or series assuming the controller can do it) , although you may be starting to get thin on PV power for the biggest batteries.

See comments in red. I know where you are going with this, but is a terrible waste of money on two examples. At least you understand Charge Current must match battery limits, Inverter limits of battery capacity, and know to NEVER EVER PARALLEL BATTERIES. Wyebread does not get that. Not until we told him.

[sensij]

See comments in red. I know where you are going with this, but is a terrible waste of money on two examples.

"wasted and never seen or used"? So you live in a world with no clouds and perfect 25 deg C weather every day, where all PV systems are mounted on 2 axis trackers? Must be nice.

You should try to get out of the STC box and look at real data from real PV systems sometime.

[Sunking]

"wasted and never seen or used"? So you live in a world with no clouds and perfect 25 deg C weather every day, where all PV systems are mounted on 2 axis trackers?

No sir that is where wyebread lives. That is why he never needs a genny or alternate source of power like a $50 Isolator to save your butt when those cloudy days roll in and your batteries go dead.

You should try to get out of the STC box and look at real data from real PV systems sometime.

You should try to think outside the box and know you are throwing tons of money away that gains you very little. Throwing 720 watts of panels into a 30-amp controller designed for 360 watts is a huge waste of money. There becomes a point you are wasting money and valuable space. Like I said I can see over powering up to a point say 400 and 500 is a stretch. You are recommending a full 100% over the line and that is just plain horrible advice, and well outside any standard practice.

The OP stated 2 to 4 days out just like wyebead says he does. Well guess what Sensij, if you size the batteries properly, you have no need for solar to begin with. My approach is sensible and gives the user the most bang for there buck and redundancy that completely escapes you. . Example with your 30 amp model.

400 watts Panel
30 amp controller
250 AH battery
600 watt Inverter
50 amp Isolator.

A heck of a lot less expensive, and if those cloudy days roll in you got backup power to recharge. Your and wyebread way is to sit in the dark and wished you had done things differently minus a whole bunch of cash you wasted on panels you do not need or doing you any good. My way is a much wiser and sound design with redundancy. I thought you were smarter than that. I can only guess your position being in the biz to sell more stuff and line your pockets with customer cash.

The OP wants the most bang for their dollar, meets their expectations, functional, and I am giving that to them. That is what I have always done, and its SAFE. You are pissing away money right and left. and no back up.

[sensij]

No sir that is where wyebread lives. That is why he never needs a genny or alternate source of power like a $50 Isolator to save your butt when those cloudy days roll in and your batteries go dead.

You should try to think outside the box and know you are throwing tons of money away that gains you very little. Throwing 720 watts of panels into a 30-amp controller designed for 360 watts is a huge waste of money. There becomes a point you are wasting money and valuable space. Like I said I can see over powering up to a point say 400 and 500 is a stretch. You are recommending a full 100% over the line and that is just plain horrible advice, and well outside any standard practice.

I did not recommend 720 W. There are very real world conditions in which 720 W *could* be appropriate on that charge controller, especially if the RV/camper can't be parked somewhere that assures perfect south-facing exposure for the panels. I'm not disagreeing with the value of an isolater at all. I'm saying that if the difference in cost between 400 W and 600 W of panels is minimal (and it frequently is), the charge controller *will not be hurt* by choosing to put up the higher wattage array. Documentation from every legit mppt charge controller I've looked at agrees on that. The OP *already has* 640 W of solar. My point is that panels of that size can be used with any of those controllers with no fear of damage.

Listing a minimum and maximum does not imply a recommendation. Despite the carelessness with which you typically recommend array sizes, I strongly encourage folks to look at where they are likely to put their panels before recommending a size (within that min-max range). Are the panels facing east and west? Mounted flat or mostly standing up? Lots of cloudy weather? Very hot or cold daytime temps? There are conditions which should push a recommendation toward the maximum, and others which push a recommendation towards the minimum.

The only responsible way I see to deal with all those variables is to present the range, and try to give guidance on how to select within that range. Cost effectiveness is one of those variables. Find a pair of 320 W panels on sale for $0.50 / W or less, delivered? Go for it. It might even cost less than the 400 W of panels you'd prefer.

[Wrybread]

Sunking, it's one thing to disagree with people's equipment recommendations and approaches, but you're simply lying when you say this:

Your and wyebread way is to sit in the dark and wished you had done things differently

As I've explained a bunch of times, I've never run out of power in the year that I've had my current system. I haven't spent a single night in the dark. I love everything about my solar system and wouldn't change a thing. You saying otherwise is beyond misinformation at this point and is actually lying.

And by the way, I have a battery isolator in my RV, I've just never used it when I'm parked for weeks at a time, since I simply don't need to. I've never once needed to start the engine to charge up the batteries. What part of that do you not understand???

You can disagree with my equipment choices and all that, but please keep the discussion honest, so we can all learn from each other. Otherwise you're just subjecting people to your prejudices.

320 watts wasted and never seen or used
200 watts wasted and never seen or used.

You can argue that having more panel wattage than the charge controller is rated for is dangerous (which I disagree with, but that's beside the point), but you can't really argue that overpowering a charge controller means someone is always throwing away power. In the real world there's cloudy periods, sometimes multiple days, and panels are usually flat mounted, and having extra wattage means the controller is putting out max amperage more often. Arguing otherwise is shockingly ignorant of real world realities.

if you size the batteries properly, you have no need for solar to begin with.

You give yourself away with this statement. You don't want people building solar systems for their RVs, because you don't know how well it can work, because you have no real world experience with RV solar. Because you don't own an RV and never have.

In the real world, solar is infinitely easier than plugging in and charging before a trip, especially if the trailer or camper isn't stored near shore power. And besides it gives the flexibility to stay on the road longer and for plans to change. Furthermore it's much safer for the batteries since you're far less likely to run them low. You really should stop acting like you have a clue about the real world factors involved in owning an RV.

It would be one thing if solar were really hard to build or really expensive, but it's dead simple and dirt cheap.

minus a whole bunch of cash you wasted on panels you do not need or doing you any good.

Solar is dirt cheap! I spent about $500 on my solar system total, including the charge controller, panels and wiring. I spent more on my stereo. Hell, I spent more on my roof rack. My two 300 watt panels were all of $150 each. That's not "a whole bunch", and definitely not "wasted". It is, in fact, the single best feature of my RV in terms of return on investment, BY FAR. You arguing otherwise when you've never owned an RV is pure stubborn ignorance.

I think you should stick to Ohm's Law. When you go off script you simply have no idea what you're talking about, and are actively spreading misinformation.

[UrbanElite]

So how do you size the batteries. Simple you must know your daily watt hour usage and how many days of autonomy is. Guess what? You have not answered that question. Until you know that, you cannot build a system. At least not one you know will work and not cost a penny more than necessary. So when you figure out how many watt hours you need, the rest is simple.

I already did answer that question in a pervious post already..... So from a really good site I figured out: 1200 watt-hours give or take with using 50 watts. Running withothe sun for 2 days.

5741 watt hours = Battery Bank of 479 amp hours, 390 watt in panels needed, running 2x 320 watt panels = 54 amp controller....