russ
Solar Advocate
Posts: 63
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Post by russ on Aug 18, 2019 7:17:41 GMT
My latitude is 42.48*. Yes, I am trying to determine the solar usable power aspect of my setup. My reasoning for panels in parallel, in the winter and the panel distribution, there is about 3 maybe 4 hours of good workable sun, of course, when it is not cloudy or snowing. So, my setup would be producing, maybe 10Amps. I think I need high amps in order to get the best charge on the batteries for the given time limit. I know there is charge time factor involved with charging the battery. At full sunlight, if you have all four 100 watt panels in parallel facing south, and at the correct angle, (and your battery system needs charging) you should be getting up to 18 amps at around 17 volts to the charge controller. If you have all four panels in series, which a 30 or 40 amp Rover can handle, you should be getting up to almost 5 amps at around 68 volts.
18A x 17V = 320 Watts (about 80% of 400 watts)
4.7A x 68V = 319.6 Watts
If the wire run from the solar panels is 20 feet then 10 AWG wire is adequate for 4.7 amps. (AWG = american wire gauge)
For 18 amps with a 20 foot run of wire you are going to need 1/0 AWG wire.
If the wire run from the solar panels to the charge controller is longer than 20 feet, you are going to need thicker wire than stated above.
Unless you have problems with shading or mounting locations, there is no advantage to facing your panels in different directions and wiring in parallel.
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Post by bupkis on Aug 18, 2019 12:50:31 GMT
so above it suggested 10awg x 4.7A x 20' yielding a voltage drop of .193v www.genuinedealz.com/voltage-drop-calculatorSo the power loss is .193 X 68v or 13 watts panels to CC. @ 17v, 13 watt loss = .765 volts, redo v.d. for 18A x 20' yields v.d. or .739v or ~13 watts! The CC will operate more eff transforming 17v vs 68v esp at low power conditions. The problem with using single parallel panels is panels get hot and Vmp drops. Paired series panels (w/mppt cc) solves that by doubling Vmp to >30v les v.d. |
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raydas
Solar Devotee
Posts: 166
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Post by raydas on Aug 18, 2019 13:13:48 GMT
The reason I have my panel pairs in different locations is because of shading. I will probably try to angle the panels at 55*, this will be about the best angle for a winter angle and probably an all year position.
Yesterday I noticed that some of the wiring going into the CC was getting very hot, never noticed that before, so today I have to rethink my wiring, and try to rewire if I have the materials.
In the conversations so far I have noticed that you guys are using fuses, I do not have any fuses anywhere. I made an assumption that the CC would handling that issue.
At this point it sounds to me like their would be a need for a solar station fuse box. The wire from the panels going in, passing through breakers, going to the CC. The wire coming out of the CC going to the box, passing through breakers, going to the battery. And maybe somewhere in there some terminal connections for accessing some regulated power, OK now I am awake.
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Post by mediadogg on Aug 18, 2019 13:43:21 GMT
The reason I have my panel pairs in different locations is because of shading. I will probably try to angle the panels at 55*, this will be about the best angle for a winter angle and probably an all year position. Yesterday I noticed that some of the wiring going into the CC was getting very hot, never noticed that before, so today I have to rethink my wiring, and try to rewire if I have the materials. In the conversations so far I have noticed that you guys are using fuses, I do not have any fuses anywhere. I made an assumption that the CC would handling that issue. At this point it sounds to me like their would be a need for a solar station fuse box. The wire from the panels going in, passing through breakers, going to the CC. The wire coming out of the CC going to the box, passing through breakers, going to the battery. And maybe somewhere in there some terminal connections for accessing some regulated power, OK now I am awake. Once again, you are substituting guesswork and assumptions for plain old study. There is so much information on the topic of putting together a DIY solar system, that there is no excuse for the things you don't seem to know or understand. Not all of the information out there is correct, but there is enough, so that you can soon begin to see what is "generally accepted" as the right way to do things, and tested alternatives to fit certain situations. You don't have to guess. There are enough things that can go wrong, even when you plan carefully, that there is no excuse for bumbling around. The fact that you did not realize that you need fuses confirms to me that, while you seem smart enough and capable enough to do this stuff, you do not seem to recognize the value of properly educating yourself to maximize the power of your capabilities, and minimize the chance of dangerous mistakes. I know that I am speaking harshly. But if it saves your life, I don't mind if you don't like me. |
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Post by tattoo on Aug 18, 2019 13:46:13 GMT
Yesterday I noticed that some of the wiring going into the CC was getting very hot, never noticed that before, so today I have to rethink my wiring, You need to rethink your entire system not just the wires........ It's getting hot because something is done wrong.......
Heck you have several things done wrong.....
You need to turn it off and start all over before you burn something up.............
I know the above was wasted words because you know way better what your doing than anyone else, but I felt that it needed to be said again....
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Post by tattoo on Aug 18, 2019 13:49:02 GMT
In the conversations so far I have noticed that you guys are using fuses, I do not have any fuses anywhere. I made an assumption that the CC would handling that issue.
No fuses? ? ? Really? ? I'm not surprised......
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Post by tattoo on Aug 18, 2019 13:53:19 GMT
Or even worse burn your house down........ I'm not sure at this point if he has fuses , breakers or any safety features..... Yep just as I thought.......... NO FUSES..........
That's not very smart,,,,,,,,,,
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russ
Solar Advocate
Posts: 63
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Post by russ on Aug 18, 2019 15:22:37 GMT
so above it suggested 10awg x 4.7A x 20' yielding a voltage drop of .193v www.genuinedealz.com/voltage-drop-calculatorSo the power loss is .193 X 68v or 13 watts panels to CC. @ 17v, 13 watt loss = .765 volts, redo v.d. for 18A x 20' yields v.d. or .739v or ~13 watts! The CC will operate more eff transforming 17v vs 68v esp at low power conditions. The problem with using single parallel panels is panels get hot and Vmp drops. Paired series panels (w/mppt cc) solves that by doubling Vmp to >30v les v.d. With 68 volt input about 13 watts loss due to voltage drop with 10 AWG wire at 20 feet.
With 17 volt input about 13 watts loss with 1/0 AWG wire at 20 feet.
Yes, at the higher voltage input the MPPT charge controller will loose something like 2 to 4 percent efficiently. As long as you can afford the cost of larger wire, connecting four panels in series parallel is more efficient. |
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Post by tattoo on Aug 18, 2019 15:27:19 GMT
I made an assumption that the CC would handling that issue. You do know what assume means? ? ? ? |
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russ
Solar Advocate
Posts: 63
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Post by russ on Aug 18, 2019 15:37:57 GMT
The reason I have my panel pairs in different locations is because of shading. I will probably try to angle the panels at 55*, this will be about the best angle for a winter angle and probably an all year position. Yesterday I noticed that some of the wiring going into the CC was getting very hot, never noticed that before, so today I have to rethink my wiring, and try to rewire if I have the materials. In the conversations so far I have noticed that you guys are using fuses, I do not have any fuses anywhere. I made an assumption that the CC would handling that issue. At this point it sounds to me like their would be a need for a solar station fuse box. The wire from the panels going in, passing through breakers, going to the CC. The wire coming out of the CC going to the box, passing through breakers, going to the battery. And maybe somewhere in there some terminal connections for accessing some regulated power, OK now I am awake. The rover manual includes information for determining what size fuse your system should have between the solar panels and the charge controller, and between the charge controller and the battery. The Rover charge controller will not protect against excessive current or and accidental short circuit. Excessive current can damage your charge controller. An accidental short circuit of the battery leads can vaporise the wiring, and in the case of the flooded battery, can cause a hydrogen oxygen explosion. You should take the time to read the safety information in the Rover owners manual. Although it may seem boring, it would be time well spent.
This illustration is if you connect all four panels in series. Although this illustration doesn't show a fuse in line with the inverter, I would recommend installing one appropriate to the size of the inverter.
Take a look at this illustration to get an idea about fuse placement: |
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russ
Solar Advocate
Posts: 63
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Post by russ on Aug 18, 2019 15:40:24 GMT
Yesterday I noticed that some of the wiring going into the CC was getting very hot, never noticed that before, so today I have to rethink my wiring, and try to rewire if I have the materials. What size and type of wire is going into the charge controller, and how long is it? |
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Post by tattoo on Aug 18, 2019 15:43:03 GMT
Yesterday I noticed that some of the wiring going into the CC was getting very hot, never noticed that before, so today I have to rethink my wiring, and try to rewire if I have the materials. What size wire is going into the charge controller, and how long is it? You know another question would be is...... What kind of wire is he using? ? ? Since he's using what he has on hand...... |
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raydas
Solar Devotee
Posts: 166
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Post by raydas on Aug 18, 2019 16:05:41 GMT
Since I have six panels, I have 12 wires coming in, and I have a fairly heavy duty terminal block where the wires are connected. At one end of the terminal block I have two diodes, one on the +, and one on the -, that plug into a quick connect. The other side of the quick connect I have the two wires going into CC panel connect. The diodes, if I remember correctly are rated at 30Amps/1000V. So at this quick connect point, I guess, I will be able to contrive some kind of fuse connection.
I am also using a quick connect between the CC and the battery, for a quick disconnect of power. I guess the quick connect could be a place for the fuse.
This morning I noticed that the CC was showing 7.68Amps from the panels, and the battery array was at 13.2V. So, I did a disconnect of the panels and after about an 1.5 hour time lapse, I checked the battery voltage and that was 12.8V.
I looked outside at the panels, this morning, and my east facing panels, 2 100W, had full sun, and my SE facing panels, 2 50W, were also full sun. Now I am going to wait for the sun to move some more to where the 2 100W panels are sunless, connect up the panels to the CC and see what kind of amps I am getting from the SE and south panels.
The CC Load was showing .20Amps, so I guess that is why the battery array got charged up fairly quickly.
As for the computer shutting down, the other day, when connected to the Load, the computer itself needs to have a regulated 12V power source. The CC load , like the battery, is not a regulated power source, at least not when it is connected to the CC. Now I have to find a decent DC-DC regulator rated at 12V 2.5 Amps, this is what the computer needs.
The wire that comes from the panels is the wire that I bought from Renogy, which is 10 gauge, I believe. Now the wire that I have that connects between the terminal block and the CC which is on about 6" in length, is a 14 Gauge, which I am now going to change to a 12 gauge. I do not have any 10 gauge wire, so I will see if the 12 gauge does the trick.
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Post by tattoo on Aug 18, 2019 17:01:32 GMT
Now the wire that I have that connects between the terminal block and the CC which is on about 6" in length, is a 14 Gauge, which I am now going to change to a 12 gauge. I do not have any 10 gauge wire, so I will see if the 12 gauge does the trick. That is to small but what kind of wire is it? Braided, solid? They make all kinds of wire...... Aluminum, copper? |
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raydas
Solar Devotee
Posts: 166
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Post by raydas on Aug 18, 2019 18:02:59 GMT
The 14 gauge, which is in there now, is solid core. The 12 gauge is multi strands, not sure if you would call this braided.
It got very cloudy now, with no sun popping through, but fairly bright, the CC is showing 1.78Amps from the panel array. I am sort of satisfied, so far, with the parallel panel setup.
Since I have a pwm CC, I might have to separate the batteries and the two 50W panels, and have the pwm CC tied into the flooded battery. Now I have to think about how to have the two CC units tied into one Load point.
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