russ
Solar Advocate
Posts: 63
|
Post by russ on Aug 19, 2019 17:46:21 GMT
Raydas, I'm at work right now. When I get home I will show you what the difference is with just your 50 foot run to two 100 watt solar panels, comparing series and parallel.
|
|
|
|
Post by tattoo on Aug 19, 2019 18:23:00 GMT
bupkis , Thanks. Hopefully they will get bored and dispense their snippy comments somewhere else. I figure if I share my experience, then somebody else might get some benefit. I'm pointing out to people that might read this thread not to do what your doing because it's dangerous and not productive to skimp on materials...... Like it or not it's the truth..... |
|
|
|
Post by mediadogg on Aug 19, 2019 18:38:32 GMT
bupkis , Thanks. Hopefully they will get bored and dispense their snippy comments somewhere else. I figure if I share my experience, then somebody else might get some benefit. Not bored, just frustrated. Perhaps you forget that in the beginning, when you were getting pretty much the same advice and warning from people, your response was sort of "thanks for your input, but I will do it my way." And any number of times you asserted that you were "assuming" and guessing about things that are well documented and known. It was only after the snippy comments, that you finally began to share the details that were requested in the beginning, so we could see what you were trying to do. That's What I asked for in the beginning - that you provide more information, and that you take advantage of the information being provided. You seem to be doing that now, but it was not the case in the beginning. You even said yourself at one point "now I'm awake." When someone is complaining of wires too hot to the touch, and continually ignoring advice about paralleling mis-matched panels and batteries, I was of the opinion that it was worth a bit of controversy to get your attention. That was really what it was all about. I thought you were not listening and doing dangerous stuff. It will not be hard to find lots of helpful information that I have posted on your behalf, and I plan to continue. Being rude is not my style. It was an intentional, calculated risk on my part, to try and get you to take heed and be more careful. Honestly. |
|
raydas
Solar Devotee
Posts: 166
|
Post by raydas on Aug 19, 2019 18:49:21 GMT
Thanks russ. As soon as I figure out the problem with my computer, I will be able to link into the Rover via RS232-USB, and start up the 'Solar station Monitor'. I have found out that the program is a very, very useful tool. I can get some real time data and verify some aspects of what I am doing.
A disclaimer, this thread contains material and discussions that is "...dangerous and not productive...". I guess that warning should satisfy everybody.
|
|
|
|
Post by bupkis on Aug 20, 2019 0:11:45 GMT
mediadogg, your are OUT, now keep out please or was that fake news!
|
|
russ
Solar Advocate
Posts: 63
|
Post by russ on Aug 20, 2019 1:20:52 GMT
OK, let's try and example with 10 AWG and two 100 watt panels at 50 feet:
Vmp 17.8 volts
Imp 5.62 amps
So, if the two panels are wired in parallel we double the current and the voltage stays the same.
2 panels in parallel Vmp 17.8 volts
2 panels in parallel Imp 11.24 amps
Voltage drop of 2.84 volts
Voltage drop percentage of 15.95 (Should be 4 percent or lower. That means the conductor is too thin for the length and current.)
Voltage at the charge controller end of the wires: 14.96 volts.
Now let's see what happens if the two 100 watt panels are in series:
2 panels in series: Vmp 35.6 volts
2 panels in series: Imp 5.62 amps
Enter the numbers into the voltage drop calculator and we get:
Voltage drop of 1.42 volts
Voltage drop percentage of 3.99 percent (which is acceptable)
So, you can see that it is more efficient to wire the two solar panels in series provided your charge controller can handle the input voltage. The Rover MPPT controller is rated for 100 volts at the solar panel input so the voltage of two 100 watt panels in series is not a problem.
If a wire is too thin for the current flowing through it there will be a high voltage drop. The voltage drop multiplied by the current with tell you how many watts of power are being converted to heat by the wire. In the first example, with the solar panels in parallel, the voltage drop is 2.84 volts at 11.24 amps so the lost power is 39.9 watts
2.84 V * 11.24 A = 39.9 watts
So, with the solar panels in parallel and working at optimum output, 39.9 watts of power is heating the wire.
|
|
raydas
Solar Devotee
Posts: 166
|
Post by raydas on Aug 20, 2019 12:15:01 GMT
Thank you very much russ for taking the time to detail the parallel vs series setup. Also you have provided a new tool for my collection, the 'voltage drop calculator'. Not to be too picky, did you, by any chance, validate the calculator.
Now I have two tools to work with, the 'voltage drop calculator', and the 'Solar Station Monitor'. Hopefully I will be adding more tools.
Just to clarify, again, the only place where I have 14AWG wire, is a six inch section that connects between my terminal block and the Rover CC. I looked at the insulation on the 14AWG wire, it does not show any signs of crinkling or warping or melt spots. The one thing to consider is the voltage drop between the terminal block and the Rover CC.
I am now, still thinking about a new design for section between the Rover CC and the terminal block. I have to consider a quick disconnect, diodes, and fuse.
The Rover CC has a sequence to attaching things to it, the battery is first and last, when detaching. My consideration is always safety, I want to make sue that if for some reason you have to disable the solar system, you can do this in a very simple manner.
Just for the curious, my system setup:
7:33AM
Array voltage(V) - 13.8
Array current(A) - .07
Array power(W) - 1
|
|
|
|
Post by mediadogg on Aug 20, 2019 12:56:15 GMT
mediadogg, your are OUT, now keep out please or was that fake news! Yes, it was fake news. As I told raydas, it was an act. No need to react on a personal level, because it had nothing to do with you. |
|
raydas
Solar Devotee
Posts: 166
|
Post by raydas on Aug 20, 2019 13:10:25 GMT
mediadogg, I have a suggestion for you, create your own thread called "bashing raydas", then you can carry on at your own pace and conjure up all kinds of "act".
In the mean time I have more important things to do.
|
|
|
|
Post by mediadogg on Aug 20, 2019 13:41:44 GMT
mediadogg, I have a suggestion for you, create your own thread called "bashing raydas", then you can carry on at your own pace and conjure up all kinds of "act". In the mean time I have more important things to do. I have no intention or no need to do that. I have been quiet for some time now. Yes, keep on doing your thing. But if you stop and decide to use your valuable time to address me in public, then I will respond. And I wasn't bashing "you" - I don't even know you. I was bashing what you said you were doing, on a technical level. That's why this forum exists. Go back and look at the beginning of this thread. I was the FIRST person to respond to your posts, and I gave you several paragraphs of (what I thought was) useful information and wished you well. And I still do. |
|
|
|
Post by tattoo on Aug 20, 2019 14:08:45 GMT
I was bashing what you said you were doing, on a technical level. That's why this forum exists. You are correct,,,,,,
You keep saying what you think needs to be said..... Because someone has to give him guidance....... Weather he listens or not that's up to him......
|
|
raydas
Solar Devotee
Posts: 166
|
Post by raydas on Aug 20, 2019 14:29:51 GMT
I was looking to see if there was some forum rules displayed. I think it is up Renogy to decide why this forum exists, we are only guests here.
So, I am not listening to what you have to say, so quit saying it here. You have nothing better to do with your time.
|
|
|
|
Post by mediadogg on Aug 20, 2019 15:26:22 GMT
I was looking to see if there was some forum rules displayed. I think it is up Renogy to decide why this forum exists, we are only guests here. Totally agree. I admit I was making an assumption. If and when such rules are posted, I will absolutely attempt to adhere to them. And I hope you will join me and kind of let this ... whatever it is ... rest for now. It is not fair to others I think. I would be happy to continue any kind of "personal" discussion with you via private message, and reserve our public conversation to technical issues. Even in the absence of official rules, we could mutually agree to that, right? |
|
|
|
Post by tattoo on Aug 20, 2019 16:05:12 GMT
So, I am not listening to what you have to say, so quit saying it here. You have nothing better to do with your time. It wasn't until page 4 before you started understanding and listening to anyone not just me..... It's my time and I will do it as I will...... Just like you wasting time trying to figure what something is doing on a chart....... The ONLY way to see how much power something is using is with a meter in real time because everything is different......
But you do what you will with your time and I will do the same.......
|
|
|
|
Post by tattoo on Aug 20, 2019 16:11:20 GMT
I was looking to see if there was some forum rules displayed. I think it is up Renogy to decide why this forum exists, we are only guests here. Totally agree. I admit I was making an assumption. Don't assume, you are right that's why this forum exist, Why else? It's here to help people get correct information, not to give bad or skeptical at best information..... |
|
