ISTR a photo where the trailer was in a meadow and the panels were too. I don't know if it is an option to put the trailer over in the shade if any and leave the panels out there.
Then the new plan was/is to put the panels on the roof of the trailer. Would that provide enough shade for the trailer so it didn't get so hot?
Dogs? There's the rub! We got the Honda 3000 in the first place in case we needed to run the air conditioner for the dogs. We are ok with a fan or two, but not the dogs if they have been working. In fact, at events they have a water tank you can toss your dog into if needed. Stupid dogs will keep going in the heat till they up and die of it unless you step in. All focus on the job and no common sense!
If your inverter is "whole house" running everything 120v in the RV, then the converter must be turned off (various ways to do that) or it will use more battery juice than it can put back in, and your batteries will go flat--this takes a while so you do get a chance to notice the converter is still on and shut it off :)
You will want your fridge on gas, not auto, or else it will see 120v and run on that. Water heater on propane whenever you have that on. Air conditioner off. DW trained in use of microwave and hairdryer (you too :) )
Then for whole house, just plug the shore cord into the inverter.
Another way is to have just certain things run off inverter which runs a sub-panel (which does NOT include the converter!)
Another way is to have an inverter with a transfer switch so you can be whole or part house on inverter and the rest (or all of it) on shore power or gen
You can do anything you want really. Here is what I do as an example only, not recommending it unless it suits you too. In this case one inverter is whole house with shore cord into it and the other does only certain items that have been displaced from whole house for when off-grid (they usually go back to whole house when we have shore power but don't have to be--can still use the inverter method for them)
Good point about not having enough slack in the wire to do much with. You get your one chance and that's it. So a way around that is to use your one chance to add some wire.
Then use the new wire added on to connect to the light or whatever, with the connection type of choice. Later if need be you can afford to cut some off to do the replacement.
EDIT- I see the above poster slid in there with the same idea! :)
I was able to run a 1000w inverter clamped to my truck battery with 16" lengths of #1 gauge wires, but only if the load on the inverter was about 600w (a 35amp Vector battery charger)---answer follows how to use that instead of the OP plan which looks dubious.
If the load on the inverter got much more than that 600w the truck's voltage would drop off (needle drooping to the left instead of straight up) but it did ok for over an hour with truck idling (do turn off the climate control! That helps. :( )
You can run a small microwave on an inverter but my Xantrex 1000w inverter only runs the Danby 700w one with the inverter showing "overload" at 1050w, which it can do for five minutes before shutting down to cool off. So you need a bigger inverter than that.
That is with the big enough inverter on a big enough battery bank and wiring to be able run 100amp draws.
Your two 27s could briefly if they start out near full, but the alternator supply to the bank on a long #6 would have to supply an increasing proportion of the 100 amps and IMO would very soon run out of steam where the truck's voltage drops off to its starting battery's voltage, which will then fall, and you are losing. So--
You could do it this way--run the microwave off a big inverter properly wired to the two 27s. AND have another inverter up by the truck battery with a long 120v extension cord back to the battery bank where your 35amp Vector is clamped on. With the truck idling it can support that much load no trouble, same as mine did.
So now the 35amps is helping with the 100amp draw on the 27s leaving the net draw at 65a. So now it all depends on how long will the microwave be on before the 27s get down to 11 volts and the inverter alarm goes off?
I don't know about your TV but many 20"-26" LED TVs are actually 12 or 14vdc and use a wall wart to run off 120vac. You can actually bypass the wall wart and power them directly from the 12vdc supply, no inverter required.
If yours has a wall wart, look at the printing on it to see what the output voltage is.
Mena often makes the point that even if you do run the TV off 12v, the DVD still needs 120 so you might as well have both on the inverter. (also much greater choice in televisions at 120)
The problem is the 12v socket with its 8a is not enough power to plug the inverter in. So the inverter needs power from the batteries which can mean it must be close to them, while the 120v line to the Tv set inside is far away from the batteries. So a long 120v extension cord has to be passed through an open window or door, which lets all the mosquitoes in.
So the various cures come into play to get it wired up so you can close the door and windows while watching TV! What you do about that depends on the floor plan of your rig as much as anything. Finding holes or drilling holes to pass wires is all part of the fun.
About then you join the many who wonder if the people who design RVs have ever gone camping in one.
I got the F code and it turned out to be soot flakes falling on the burner. Cleaned it all up and good to go but then it happened again later.
Trouble was the chimney still had flakes up there that kept coming loose, so I banged the heck out of it and got that solved mostly. Once in a while it happens again and I bang on the chimney and clear it up.
Just because you cleaned it once, does not mean you got it all :(
The only connection between the gens and the inverter will be that the batteries will be being charged through the trailer inverter while the gens are running. Does that make sense or am I just making it more complicated?
It is still not clear that when you are on shore power or generator, that the TV etc will not be powered the normal way instead of by the inverter, and that the inverter output is not tapped into the RV 120 receptacle circuit somehow.
If it is, AND you run the inverter, they will get two doses of 120v at once and fry who knows what on 240v. That is what a transfer switch is for.
You can run just the TV etc off inverter. You must not tap the inverter output into the regular RV receptacle that the TV is plugged into. The TV has to go into the inverter output directly via an inverter receptacle (perhaps extended as needed)
Its funny I have a switch for the panels output just haven't installed it yet...
So, your suggesting read the raw voltage and current from the arrays output?
I find it useful to know the panel's Isc of the moment when noting amps to the battery. If the Isc is at or above rating that says the panel is getting full insolation so I should be getting full amps.
With PWM you should be getting the same amps to the battery as whatever the Isc of the moment is.
With MPPT if the Voc is below rating by a few volts (34 instead of 37 eg) but the Isc is above rating that says the panel is hot ( as is normal) and it will mean less than full amps, but that nothing is wrong. It is just the MPPT suffering from panel temperature lowering the voltage.
I always want to know if I am getting as many amps as I should be, so I measure things quite often--not that I am paranoid or anything.
You want a switch on one of the two wires going into the controller from the array. Some controllers don't like running a load while the battery is disconnected.
Also you can then "turn off" the solar to see what any other 12v sources are doing or to see what the solar itself is doing by comparing when it is off or on.
If you can get your meter across the array side of that switch and the other wire's terminal at the controller, you can measure array Voc and Isc with the switch open without having to go to the panel and disconnect that to measure there.
BFL13 thanks for the explanation. I didn't think it would be that simple. lol
It is simple if you ignore that the Earth is pear-shaped fatter in the Southern Hemisphere, and a bunch of other things.
Having screwed all that up, I suppose I should retract my 45 degrees for RJ and say he should do 55 instead after all! :)
You can get an idea of the time to recharge your pair of 6s from this ugly graph. This also lets you decide what is "worth it" for getting more amps of charging in terms of cost of the charger, enough generator to run the charger, and the time it takes.
The key thing is the diminishing returns in time saved as you go higher in charging amps. EG useful in deciding if you would be better off with an 80 amper instead of a 60 amper on a pair of 6s compared with on four sixes.
Note- at the same amps, double the battery doubles the time, but on the same battery size, doubling the amps does not halve the time.
I'm thinking something along these lines:
That is pretty much what I have attached to my set-square. You set it on the panel and read the angle. Works great. Or you can just wait till high noon with no clouds just then and play with the tilt until it shows the rated panel Isc. That's your angle for high noon.
You need to know where South is too. It is where the sun is at 180 True, which is also at pretty much its "high noon" altitude. "Noon" on your clock is what it would be in the middle of your time zone, so if you are not there then noon is earlier or later--if you are west of the middle it is later. So where we camp in the summer it turns out that "noon" is more like at 12 after 1.
Interesting, some 8 years ago I designed my winter tilt for Quartzsite (Lat = 33.43 degrees).
There's a few different methods to calculate tilt angle. Some very simple (for winter):
1. latitude + 15 deg = 48 deg
2. 0.9 * latitude + 29 deg = 59 deg
I use a more complicated calculation and got 56 deg.
The tilt angle for high noon anywhere is the same calculation as finding your latitude from your noon sight. People have been doing that for thousands of years, using various gizmos to measure the sun's altitude above the horizon at high noon.
It is mostly about the Declination that day, which changes about 8 degrees a month going up and down over a six month period, changing about 23.5 degrees every three months. EDIT however it is not linear as is shown above--good post showing that!! :)
That 15 degrees you see a lot of for this, is just a sort of middle point chosen for Declination between 23.5 and zero. 15 degrees is approx two months worth (linear--but it's not linear) so it would be for around mid- May or mid- July in summer so it fits as a good number for many people's RVing "season"
What do you guys use for fixing the angle? Level and angle finder, cardboard cut-outs, trig, or what?
I have an angle of the dangle thing on a set-square from years ago, but somebody posted the other day you can do it with your cell phone.
With the slope of the RV roof it can be tricky with no level horizontal, so some kind of gravity gizmo is easier.
Humor me guys, I do not have solar yet but I am hoping to have one in the real near future. I will be getting a portable system since I camp mostly in the southeast, lots of trees.
Now to my comment considering the subject. Why not adjust the panel angle for the highest voltage reading? I understand there are premium times of day for the best performance, say noon time, set the angle at noon and then the performance would average out between daylight and evening. Just curious.
Yes you can pick the best angle at any moment by aiming it and watch for highest Voc and Isc, but that is not how it works for highest daily AH haul.
EG in the summer the sun goes around more than 180 degrees so it can get behind the tilted up panel facing South. To beat that, you pick an angle lower than what is best for high noon to get more time with more amps in the shoulder hours. See that link above on "optimum tilt"
The best thing is to keep the panel aimed at the sun all day, but that is not practical. You can move the panel three times a day and do almost as well. At dusk, aim it SE for next morning, then S mid-morning, then SW mid afternoon. Good enough.
To get a bit more with those three moves, have two tilt angles. Lower for mid-day and higher for SE and SW.
If you have trees on one side and open on the other, you might do better if using a fixed panel to aim it in the middle of your open sky spot and set the tilt for in there. That tilt would be higher than if aimed South. (The sun being lower in there at the open mid-point).
That 53 degrees is interesting. (IMO RJ should not use that though)
High noon tilt angle is your Latitude and your Declination. Then you compromise when Dec is North by lowering the panel a bit for all day best results for AH haul.
Declination goes from zero 21 Sep to about 23.5S on 21 December and back up to zero 21 Mar. Macslab uses its "winter" angle from 7 Oct to 5 March, which is longer than 1/4 the year, notice. The middle of that period would be around 6 Jan. Declination then is only two weeks after max on 21 Dec or about 4 degrees worth (very approx.) so maybe 19S ?
So at 32N tilt then would be 32 + 19 = 51. Macslab says 32 x 0.89 and add 24, which is 52.48 for high noon.
So there is no allowance for shoulder hours really, which makes sense because the sun can't get behind the panel in the winter like it can in the summer.
However, if you are planning to be at 32N from now till mid March, what to pick? Declination goes from 23.5S back up to maybe 2S so half way is say 11 degrees so tilt would be 32 + 11 = 43
RJ is seeing the other guys there now with tilts all a bit different so maybe they are staying different lengths of time and so their middle time average tilts are all different. Of course they have all done their math on this. :)
But in any case, based on all that, RJ should pick something less than 53. IMO 45 degrees would be a pretty good number depending on how long he is staying.
I have the Xantrex PROwatt SW 1000.
Sorry, I can't say with any certainty, as to the 120v draw. I've been meaning to confirm with my kill-a-watt, but according to the display on the Xantrex, the 700w Danby pulls over 1200 watts. BFL has the same microwave, and he said that seems too high? Ours are both rated at 1080w, I think it is? What's worse, the Xantrex doesn't even register anything under 18w, so that could push the wattage up even higher.
As for 120 line voltage (drop), that too needs to be confirmed with my kill-a-watt. And if I remember correctly, the Trimetric's display says the microwave pulls in excess of 90a?
Vbatt drops to the low 11's, on say a 90% bank.
But I knew going in, I was taxing my system by using the microwave. At some point, it just makes more sense to run off gen power. For example, 5 minutes of microwave time can easily turn into 20-30 minutes of gen run time, to replenish the Ah's used. Same goes with any high power-hungry appliance. But running the gennie for 5 minutes is quite ridiculous, as well, so...
To clarify, my inverter is a Can Tire 1000w PSW made by Xantrex. It has a continuous rating of 1000w and it will run on overload for 5 minutes.
When I ran my Danby 700 the inverter red light was on for overload. The watts readout was 1050w approx. (from memory) I did not have the MW running more than 5 minutes for that test. Trimetric amps was close to 100 (high 90s ISTR) Inverter connection to batteries is two 16" (approx from memory )lengths of store-bought #4 starter cable.
Manual says after the 5 min of overload you have to wait 15 minutes before it will do that again.
The manual does say the wattage it can do varies with temperature but not by how much. Rating is for 77F.