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Hello all. Please bare with me as I know very little about solar and I will be attempting to put this system together myself. I live in sunny Southern Cailfornia out in the Temecula Wine Country. I live in my RV and hate giving my money to the power company. Here is what I have so far. I realize that my batteries are not ideal, but I buy them locally whenever they go on sale, and if and when they die(if within 1 yr), I can take them in and have them replaced for free. I plan on doubling the number of solar panels in the future and will one day buy the correct batteries as well. My question to the community is, what am I missing?
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OK first thing you need to know is anything you take off the grid and put on battery is going to cost you many times more than that greedy ole power company charges you. So if your idea is to save money forget about it as it is impossible. You will be paying at least 5 times more than you pay now for the rest of your life all up front in cash every couple of years.MSEE, PE -
When I say this is what I have so far, it means that I have already purchased these components. I forgot to add in the diagram that the inverter/charger will be connected to shore power. I will not be completely off the grid, but if I can keep from paying tier 2 and higher energy prices I will have achieved my goal. What I need to know is what other components like disconnects, combiner boxes, and fuses am I missing and where would they go in my diagram?Comment
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Another sucker.[SIGPIC][/SIGPIC]Comment
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I would recommend looking around and reading the FAQ and stick posts in the forum.
The short version is....
1. conserve energy it is cheaper
2. batteries are expensive, avoid them if you can
3. scope your project/estimate your needs before you start buying parts
4. you can't heat or cool you RV with batteries
RV implications:
Do you live in a RV park? If so you don't have much space for solar arrays, and if you are mobile you may need batteries and no grid tie program. You also may not be able to get your panels aimed south without shadows.
You needs may be smaller than others, do you heat with electric or gas? How many KWH do you use?Comment
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since no one else here will help you, and your attachment doesnt work.
In southern california you dont need AC, just get a swamp cooler. Get a 12 volt fridge or buy a cheap chest freezer and convert it to a fridge, that will easily run on solar. As long as you can reduce your power usage, which is something that can be done, why even connect to shorepower.
If on the otherhand you want to run a full size fridge, a plasma tv, washer and dryer, AC then your will always be relying on shorepower or generators.
If you got the room get 2x240 or larger panels and an mppt controller. And maybe 2 x 100 ah batteries or larger. As you get comfortable with what you can do with solar you can add more panels or batteries.
There is alot of space on the roof of an rv for panels, no reason you cant be 100 percent off-grid especially in sunny southern california.
Something people in this forum forget is that solar might cost money upfront but once you pay that, your only costs are the occasional battery changes years down the line. In 3 years I change 3 batteries, not because they were worn out, but just upgraded to larger or smaller batteries. I didnt whine about it or dreaded the decision, i dont pay a dime in electric bills, so the cost of new batteries is not a big deal to me.Comment
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Great idea on the swamp cooler, I have never used on before but I know misters help a lot in Eastern Washington.Comment
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Thank for for all your help.
What I have so far (the link was a diagram of these components)
(12) 12v 100w 36 cell solar panels
(8) diehard group 31 marine batteries
(2) mmmmmmf x ffffffm and mmf x ffm mc4 connectors
(1) outback powermaxx 80
(1) xantrex prosine 3.0 12v 3000w power inverter/charger
RV is equipped with
(1) 50 amp transfer switch
(1) Onan 5.5 kw generator (with 30gal fuel tank)
My RV is parked pointing due north and shade is only an issue in the early morning hours. I have room on my roof for up to 36 of the 100w solar panels that I've been buying. All of my lighting is leds and heating is with propane. My refrigerator unfortunately doesn't have a 12v option, only propane or 120v.Comment
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How many AH are the batteries?
It is recommended not to parallel multiple strings of batteries, but many do 2. You could setup 2x 48v strings with those batteries, but your inverter won't handle 48v. Your Powermax 80 will handle both 12 and 48volt. Max of 80 amps.
36x 100 watt panels is 2600 watts. If you use a 12volt battery bank, you have 216amps max. (2600Watts/12v). You charger can only use 80 of those 216 amps. If you use a 48v battery setup you have a max of 54 amps. This matches up well with your Powermax 80.
You will need to listen to someone who knows more on this than me, but you need to come up with the optimum solar panel setup with some in parallel,and some in series as in series they would ruin your Powermax 80. From the specs I think the Powermax likes 60v dc coming in, so that would be a max of 5 panels in series. 7 strings in parallel would allow you to use 35/36 of your panels.
I can't approximate your appropriate charge rate for you batteries without the AH rating.
Be very careful with this project, there are fuses and breakers that need to be in place to make sure you don't burn down your RV. Best case if things are connected wrong you ruin some of your new toys. I would recommend getting a charger/inverter that works with 48v. Without your normal load, we can't calculate how long your batteries last or recommend what size of inverter/charger.
Keep reading forums posts and you will learn more and more and find new questions to ask.Comment
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Well you have a few issues. You are using 12 volt battery panels which was an expensive mistake when using a MPPT controller. Battery panels are 2 to 3 times more expensive than grid tied panel, and much smaller in wattage. Secondly you have 1200 watts of solar panels, and your Outback Powermaxx 80 AMP controller can only operate at 1000 Watts maximum when operating on 12 volt battery so you will not be able to use all the panels. You should have gotten 4-250 watt grid tied panel would dhave cost you 1/3 of what you paid, would use a lot less smaller less expensive wire and a whole lot less hardware.
Second issue is all the batteries. 8 parallel strings you will soon discover wire in parallel will only last you a year or so. Again another very expensive mistake. You should be using either 2, 4 or 6 volt batteries of appropiate capacity so you only have one single string. At 1000 watts on 12 volt DC you should be looking at a 800 AH cells like a Rolls 6CS259 a 6 volt 820 AH battery and would last around 5 years with TLC.
A 3000 watt inverter at 12 volts on this system is way too large and you should be looking at a 1000 watt unit. RV's don't really even need an inverter because everything for an RV is made to operate on 12 volt house batteries.
Lastly I do not se any type of battery Isolator included to allow you to charge the house batteries from the vehicle alternator. If you have one of those most of th echarging is done by the vehicle alternator thus eliminating the need for solar and such a large battery bank.MSEE, PEComment
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You can use a Midnite MNPV3 to combine 10 of the panels to 2 parallel strings of 5 in series. As said, the charge controller can only handle 10 of them, although if you are mounting them flat on the roof instead of tilted south, you won't be getting their full rated output, so you may be able to use all 12 of them in 3 parallel strings of 4.
Since you already bought the batteries, the way to make the best of a bad situation is to wire them all to a heavy bus bar to get them in parallel, rather than wiring one to the other. This will help reduce the amount of uneven charging across the strings. See Midnite's battery combiner box for an example, http://www.midnitesolar.com/productP...tOrder=4&act=p
When you replace the batteries, be sure to get low voltage, high amp hour batteries that can be wired in series rather than parallel.Solar Queen
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The spec sheet on the flexmaxx states this:
Voltage Step-Down Capability Down convert from any acceptable array voltage to any battery voltage. Example: 72VDC array to 24VDC battery; 60VDC array to 48VDC battery
Am I reading this wrong? I was planning on setting up some of the panels in series to make either 24v or 36v strings. I thought that when you connected solar panels in series, that the voltage doubled, but the amps stayed the same. Wouldn't I be able to use twice as many panels in a 24v string and three times as many in a 36v string?
The panels already come with a junction box and MC4 connectors, can I not simply connect the male MC4 of one panel to the female MC4 connector on the other to make it one 24v panel?
The reason I ended up with 12v panels is bc my 5th wheel RV came equipped with a Go power 12v 130w solar charging system when I bought it. I just simply started adding 12v panels until I maxed out the 25 amp charge controlled that came with that kit. I later replaced the 25 amp charge controller with a 40 amp one and added more panels. I maxed that one out as well and now have ordered the Flexmaxx 80.
Everything in my RV is 120v with the exception of the blower on the furnace and 95% of the lighting. It has a 8 cu. ft. refrigerator in the kitchen, a 3 cu. ft. refrigerator in the garage, a 19" lcd tv with dvd in the garage, 32" tv and blu-ray in the living room, a 1200-1500w microwave, a ceiling fan, and we occasionally plug in a toaster, a blender, waffle iron, rice cooker, crock pot, projector for outside movies, etc.. I was using a Xantrext Prosine 1800w inverter, but it wasn't enough so I ended up with the 3000w one instead.Comment
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12 volt battery panels is the last thing you want to use. Battery panels are 2 to 3 times more expensive than Grid Tied Panels. To use Grid tied panels you have to use a MPPT controller which you have. Your MPPT controller can take a input of 150 Voc or 120 Vmp. This allows you to connect your panels in series to operate at higher voltages and lower current. That means a lot smaller less expensive wiring. The amount of power the controller can handle is dictated by the battery voltage and controller output amperage. For your 80 amp controller and 12 volt battery straight from the manual the maximum input is as follows.
12 volts @ 1000 watts
24 volts @ 2000 watts
36 volts @ 3000 watts
48 volts @ 4000 watts.
You are trapped in a 12 volt box you put yourself in. You do not know anything other than 12 volts which is why you choose 12 volt batteries when you should be using 2, 4 or 6 volt batteries for the capacity you need. You failed to do research and homework first. Now you are going to spend a lot of money needlessly. You wil be replacing all those batteries you bought in a year or two. If you had done your homework they could have lasted 4 to 6 years.MSEE, PEComment
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Right, so if you do 5 in series, by connecting the plus of one to the negative of the next, etc, you will have a nominal 60V array being reduced by the charge controller to a 12V battery bank. In doing so, by reducing the voltage at the output x5 from 60V to 12V, it increases the current x5. Since power = volts x amps, you have to do the opposite of one that you do to the other (volts/5, ampsx5). The charge controller is rated at its OUTPUT capability, not input. So if you are doing 2 parallel strings of 5, and each string has an Isc of 5.75A (that's a guess, don't know your exact number), then 2 x 5.75A = 11.5A in x 5 = 57.5A out. You have to add 25% of the Isc to allow for the fact that the charge controller is going to run continuously more than 3 hours (NEC Requirement), so 57.5A x 1.25 = 71.87A. The charge controller is rated for up to 80A.Solar Queen
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