Problems with Directly Connecting pos & neg in Parallel on Solar Panel?

[Canine]

Am playing with the idea of making a solar tracker. Not sure of the possible harm to the motor and/or panels.

Let's use two mini solar panels, 12v @ 80 ma. I place the panels at 45 degrees to each other. If the panels are receiving the same sun exposure, they will make the same amount of juice of course. If they are faced so one panel gets more sun than the other, then one panel will make more juice compared to the other.

When connecting those panels directly to a motor, my understanding is that the motor doesn't have a dedicated positive or negative terminal. You pick on and make that the negative, and the other one the positive. Then the motor will turn in one direction. Reverse the leads and the motor reverses.

Here is where it gets a little weird for me. I hook up both panels, taking a positive lead from one panel and a negative lead from the other panel then connecting those two opposite leads together on the same terminal on the motor. (I feel bad for connecting a positive lead from one solar panel directly to a negative lead from another solar panel in parallel.) Then I do the same for the other terminal on the 12v motor. Then if one panel has more sun, and is producing more juice, then the motor will turn in one direction. If the other panel gets more sun, then the motor turns the other way. When the panels get the same amount of sun, the motor stops. I'm pretty sure that is what will happen.

But am concerned about burning the motor up. 80 ma is a measly amount of amperage, but should I still be concerned about overheating the motor by having two 80 ma panels feeding into the motor at the same time all day long? How about two 160 ma panels?

Do I need to worry about hooking up a positive lead of a solar panel directly to the negative lead of another solar panel in parallel? Do I need a diode to protect them? The amperage is so small, it doesn't seem like it would hurt anything, but I don't know for sure.

When the panels are not directly facing the sun, which would be 99.9% of the time, the panel voltage will drop. Would 9 volts or less all day long on a 12 volt motor burn it up?

 

[TMG51]

Haven't you described a dead short? Maybe I'm not understanding something. But surely both panels would be producing some current even when one panel is getting more sun than the other.

 

[VJG1977]

What TMG51 said. ^^^

When you connect the positive lead from one panel to the negative lead of the second panel, they are in series.  When you connect the two remaining leads you create a short circuit.  

Google "diy solar tracker"  no need to reinvent the wheel.  

http://engmousaalkaabi.blogspot.com/2015/05/solar-tracker-circuit.html

The two photo cells are mounted in tubes that are angled away from each other. When both cells receive the same amount of light the motor is stationary.  As the sun moves across the sky one cell will get more light.  This will cause the motor to turn until both photocells again receive the same amount of light.  This has to be reset each night to point the panels back at the morning sun.  
This is a very basic description of what is going on.
The size of the panels would dictate how strong the motor needs  to be.

 

[Canine]

Yes, it is a direct short to the panels. But since electricity follows the path of least resistance, it should flow into the motor and not short out. And voltage does the pushing, so if one panel is making more voltage, then it will do more of the pushing.

Putting the panels at 45 degrees does greatly reduce the output, but that is the point. I want one panel to put out more when it is facing the sun more directly. The panel that has increased output will make the motor spin in one direction until both panels have the same output.

Here is a picture.

 

[VJG1977]

Yes, it is a direct short to the panels. But since electricity follows the path of least resistance, it should flow into the motor and not short out. And voltage does the pushing, so if one panel is making more voltage, then it will do more of the pushing.

Putting the panels at 45 degrees does greatly reduce the output, but that is the point. I want one panel to put out more when it is facing the sun more directly. The panel that has increased output will make the motor spin in one direction until both panels have the same output.

Here is a picture.

In this drawing each panel is shorted.  The motor will not turn.

 

[Canine]

VJG1977, But I won't be connecting the panels is series. Just in parallel. The picture should demonstrate that better. Yes, I could use photocells to do the same thing, but I'm not sure using circuit boards and such is necessary for such small amperage. If I wanted to move large arrays, then the method I'm describing won't work. At least not for long until something burns up.

 

[Canine]

Did the drawing wrong. Hold on a second...

 

[Canine]

That's better.

 

[VJG1977]

That's better.

Again, [font=Verdana, Arial, sans-serif]When you connect the positive lead from one panel to the negative lead of the second panel, they are in series.  When you connect the two remaining leads you create a short circuit. The motor is not the path of least resistance.  [/font]

[font=Verdana, Arial, sans-serif]Try this, substitute two batteries for the solar panels and use a small motor.  Let us know what happens.[/font]
[font=Verdana, Arial, sans-serif] [/font]

 

[Canine]

The panels would be 90 degrees from each other. They would be 45 degrees from the sun when facing directly at the sun. I'm not trying to maximize the output of these panels. They are used only for powering the motor. As long as the motor is able to turn so that whatever it is that I want to turn is directly facing the sun at all times then I've accomplished my goal. At least on one axis for this example.



Yes, it is a short, but that's the point. I want a short. Ignore the motor for this example. If I connect a 300 watt panel in a direct short to a 1 watt panel, assuming there are no diodes, the big panel will fry the small panel in less than a second under full sun. The little panel does absolutely nothing to the large panel because the voltage, or the "pushage" is too weak.

With the 80ma panels I'm using as an example, it is like a couple of really weak fairies trying to push each other. No damage is going to occur no matter how hard to frail fairies push because they have such a small amount of energy. You take a couple of high wattage Sumo wrestlers, and you are going to see some effect.

So, yes, I'm am purposely creating a short, but is that going to burn anything up with the small amperage stated? And while the wires are technically shorted, wouldn't some of that flow into the motor? I can tell you first hand if you touch two wires together from a household plug in then touch that with your fingers, it will feed into you. I can't see how it would be any different with these puny panels.

I can probably find a motor from something and use a 9 volt battery to represent one panel and use a 1.5 battery to represent the other panel. I won't be using lithium! This will give me real world results without having to order panels. Good suggestion!

Is the following in series or parallel? Just because a positive wire is connected to a negative wire, it doesn't mean it is in a series. It seems to me this is parallel, but connected incorrectly.

 

[TMG51]

I see what you're thinking, but I'm pretty sure that setup isn't ever going to turn the motor. The electrons will be way happier with your motor body and shorting out on it.

 

[VJG1977]

The panels would be 90 degrees from each other. They would be 45 degrees from the sun when facing directly at the sun. I'm not trying to maximize the output of these panels. They are used only for powering the motor. As long as the motor is able to turn so that whatever it is that I want to turn is directly facing the sun at all times then I've accomplished my goal. At least on one axis for this example.



Yes, it is a short, but that's the point. I want a short. Ignore the motor for this example. If I connect a 300 watt panel in a direct short to a 1 watt panel, assuming there are no diodes, the big panel will fry the small panel in less than a second under full sun. The little panel does absolutely nothing to the large panel because the voltage, or the "pushage" is too weak.

With the 80ma panels I'm using as an example, it is like a couple of really weak fairies trying to push each other. No damage is going to occur no matter how hard to frail fairies push because they have such a small amount of energy. You take a couple of high wattage Sumo wrestlers, and you are going to see some effect.

So, yes, I'm am purposely creating a short, but is that going to burn anything up with the small amperage stated? And while the wires are technically shorted, wouldn't some of that flow into the motor? I can tell you first hand if you touch two wires together from a household plug in then touch that with your fingers, it will feed into you. I can't see how it would be any different with these puny panels.

I can probably find a motor from something and use a 9 volt battery to represent one panel and use a 1.5 battery to represent the other panel. I won't be using lithium! This will give me real world results without having to order panels. Good suggestion!

Is the following in series or parallel? Just because a positive wire is connected to a negative wire, it doesn't mean it is in a series. It seems to me this is parallel, but connected incorrectly.

They are in what is call series - parallel.  two sets of panels are in parallel and those are then in series.  You will destroy the panels.  If it helps,draw arrows showing the flow of current.  If you have the panels just go ahead and connect them they only cost about $25 each on Amazon.

 

[Canine]

Ok. I wasn't sure about the damage to the panels, but there it is. I'd have to use diodes to protect the panels, but then the motor is getting hammered. The diodes might not stand the strain, either. Maybe it would work, but it wouldn't be worth it if it lasts for just a short bit. Thanks for the info.

 

[highdesertranger]

my brain is burning. highdesertranger

 

[GotSmart]

It needs controllers to keep from being shorted out.   :dodgy:  What you are proposing is  :huh:   :s not logical...

The positive wires (red) need to either all go to the same terminal, or be set in series.  Same with the black.  :idea:

Crossing hot leads only destroys electronics.

There are dedicated controllers for aiming solar panels. They have been around for many years.

 

[highdesertranger]

I was wondering what that smell was! Ever thought of adding a brain cooler?

Guy

that would be a swamp cooler. lol. highdesertranger

 

[Canine]

GotSmart, I'm not sure a 12 volt, 80 milliamp solar panel needs a controller. You must be thinking the panels I want to cross wires with at the motor were big panels.

My apologies for the confusion. As you can see, I sometimes have difficulty communicating. In my mind it is a simple process and easy to understand, but what comes through the keyboard is another story. Sorry for the brain pain!

Because of the confusion, I may just make one. If it works, I'll bring it to the RTR so you can see it.

 

[highdesertranger]

hey Canine no apologies needed, I was just messing around. I say if you have the time and money go for it. after all it took Edison hundreds of tries to get a light bulb to work. highdesertranger

 

[Canine]

HDR, thanks. There are a couple things I don't understand at a fundamental level here. Maybe at the electron level possibly. Sometimes I have to get hands on before I really get it. We'll see what happens.

 

[GotSmart]

GotSmart, I'm not sure a 12 volt, 80 milliamp solar panel needs a controller. You must be thinking the panels I want to cross wires with at the motor were big panels.

My apologies for the confusion. As you can see, I sometimes have difficulty communicating. In my mind it is a simple process and easy to understand, but what comes through the keyboard is another story. Sorry for the brain pain!

Because of the confusion, I may just make one. If it works, I'll bring it to the RTR so you can see it.

INMO, that will not work.  I am not a electrical wizard like Stearnwake, but have a lot of training and experience.  It looks to me like it will heat up until something gives. (Fire, melt, or short) 

Trackers.  That is the term needed to look up.

http://www.solarchoice.net.au/blog/nextracker-independently-powered-horizontal-axis-trackers

If you can build a better system, go for it.  I have more confidence in you experimenting and making something work than  ~~~ some of the other members.

It is strange ideas that have made the wealthiest people.  

A talking mouse (Disney) Flavored carbonated water. (Coke, Dr Pepper, Pepsi)  I worked for a guy who made a freon separator for cascade systems. He is getting millions in royalties for a few pieces of tubing of varied lengths with holes drilled in them soldered together.   :idea:  

RTR 2017.  We can have a cold one, (or two) and laugh about this.