[tighe]

This may be a dumb question but can you install solar panels as the first part of your electrical system and work down...even if the whole thing may take a few weeks to put together. I assume they are creating current as soon as they are out in the sun. Do you need to separate the end of the wires? Do the solar panels care if their charge goes nowhere? I said it was a dumb question. But i am serious. I'd hate to do anything to damage the panels.

 

[keeponvaning]

Not a dumb question! Yes they put out power when there is light available. Simply run the two leads from the panels into the van to where you plan on mounting the controller and put large wire nuts on the bare ends of the wires plus a little tape if you want. If you are just mounting them on the roof for now just make sure theydon't fly all around while driving and put a little electrical tape over connectors to clean them clean. That's all you have to do.

 

[GaryBIS]

Hi,
Agree with KOV approach, but the panels will not be damaged if you short the leads together.

Gary

 

[keeponvaning]

Gary I didn't say short them out I just said cover each bare end with a wirenut and some electrical tape.

 

[proeddie]

...but the panels will not be damaged if you short the leads together.

Gary, I have no experience with solar cells... I don't understand how they would NOT be damaged with a short across them... Every other voltage source I know of gets very upset with a short!

Just wondering...

 

[Quest4Adv]

If you have a spare Flux Capacitor laying around, you can hook it up and do some time travel with the spare juice!

 

[RDinNHandAZ]

Think grid tie!

 

[SteveSS]

Think grid tie!

When I think grid tie, nothing happens. Please explain.

 

[RDinNHandAZ]

A bit of Physics for the science minded.

Gary, I have no experience with solar cells... I don't understand how they would NOT be damaged with a short across them... Every other voltage source I know of gets very upset with a short!
Just wondering...

:nerd:
Unlike chemical or magnetically generated mechanical sources of power the Photo cells produce the extra electrons from the Photoelectric effect, explained by Albert Einstein in 1905 in his paper "On a Heuristic Viewpoint Concerning the Production and Transformation of Light". This remarkable explanation ushered in Quantum electro dynamics. Sunlight hitting the cells is absorbed by the semi-conductor and electrons move to the cathode and accumulate and are drained off by the appliance or storage device. There is no chemical involved nor magnetic field to push them they flow as they are generated and due to the light hitting the cell's surface. The light intensity determines the current NOT the circuit. A dead short will flow electricity but at the rate determined by the capacity of the solar panel and the light hitting it. In other words the current upper limit is self regulating and modest in our instaliations. If you had a very large installation of solar panels you could generate a very high current with a short and then the wires would burn and melt but the panels themselves would likely be fine. On our scale there is no danger, but KOV’s recommendation is the best solution.
If you want a further explanation of the photoelectric effect see: https://en.wikipedia.org/wiki/Photoelectric_effect

When I think grid tie, nothing happens. Please explain.

Perhaps I should have said “Do grid tie"

 

[GaryBIS]

Gary I didn't say short them out I just said cover each bare end with a wirenut and some electrical tape.

Hi KOV,

I think your method of putting the individual wire nuts on each lead is best, but I was just pointing out that solar panels don't care if you short them out. You could twist the two leads together and some current would flow though the wire, but the panels are self limiting on current and no harm would be done.

This plot shows it...
http://www.pveducation.org/pvcdrom/short-circuit-current

Unlike something like a battery where the current goes way up when you short it, the current on a pv panel is nearly the same at its nominal voltage as it is when shorted.
Its hard to damage them no matter what you do

Gary

 

[RDinNHandAZ]

SteveSS,
I wasn’t trying to be obtuse there. Grid tie is a system where dispersed solar is connected to the electrical grid with a special inverter called a “Grid Tie Inverter” It’s sine wave perfectly matches the grid's waveform and is controlled by the grid. It cannot produce power if not connected. This is very important as feeding the grid during a power outage could be very dangerous. Linemen would die if anyone with solar or other generating power was feeding lines they believe to be uncharged. That feature is called Islanding actually it is known as "anti-islanding". These systems are popping up everywhere but every power company I have ever heard of requires you to inform them if you attach one and then refuse to sell you power or connect you if you have one. Large systems can be permitted and many of those exist but tiny grid tie of a few hundred watts is pirate country. People connect via a 110 volt plug from their grid tie inverter and never tell the power company. The idea is they then supply some of their own power as the feed to the power company is apt to show their connection. Years ago I had some solar and the panels on my camper and I naively asked APS in AZ if I could do this. I have decided it is not worth the savings or the conflict to even think about it.
Now Winston could make some real money on his when he returns home!

 

[keeponvaning]

Hi KOV,

I think your method of putting the individual wire nuts on each lead is best, but I was just pointing out that solar panels don't care if you short them out. You could twist the two leads together and some current would flow though the wire, but the panels are self limiting on current and no harm would be done.

This plot shows it...
http://www.pveducation.org/pvcdrom/short-circuit-current

Unlike something like a battery where the current goes way up when you short it, the current on a pv panel is nearly the same at its nominal voltage as it is when shorted.
Its hard to damage them no matter what you do

Gary

Thanks Gary. Never to old to learn something!

 

[bigbill25]

These systems are popping up everywhere but every power company I have ever heard of requires you to inform them if you attach one and then refuse to sell you power or connect you if you have one.

In Oregon, the power companies are required to take it by law! Boom!

 

[GaryBIS]

Hi RD,
There is one exception to it not being cost effective to do your own small grid tie system.

You can use micro-inverters -- these are legal, UL approved, small inverters that are made to handle only one PV panel for each micro-inverter. So, you can have a system as small as one panel. The micro-inverter takes the DC power from one PV panel and converts it to 220 VAC that can be tied directly to the grid and the inverter does anti-islanding, so it shuts down if there is a power outage.

One nice thing about the micro-inverter systems is that you can start small and then add more panels later. Also simple wiring for DIYers.

You do have to go through the permit process, and the untility company will not allow you to hook your system up to the grid without a signed off permit. Usually they put in a new meter when you hook up that will run backwards and credit you for any excess power you produce. In some places this can be a hassle with some fees, but in MT its a $35 permit, and the inspector and the utility guy who approved my setup were very cooperative and had some helpful hints.

For power failures, on my setup, I have a way to disconnect the system from the from the grid and basically change a few wires around to convert it to an off grid system to supply power to the house via an extension cord (no connection to the grid) to run a few loads. I use the battery pack from our golf cart and a separate off-grid inverter -- but, I can do the whole change over in 20 minutes (by which time, the utility power is usually back

This is the system I did:
http://www.builditsolar.com/Projects/PV/EnphasePV/Main.htm

Its a 2200 watt system with 10 panels, but it could just as easily be one or two panels (or 30 panels).

There are also bootleg grid tie PV setups that are based on inexpensive anti-islanding inverters you can get on ebay. They are not UL approved so, the power company would not approve such a system, but they do let you get started or experiment with a grid tie systems on practically no budget.
http://www.builditsolarblog.com/2012/03/under-radar-plug-and-play-grid-tie-pv.html

Sorry about getting off topic Tighe, but I'm a solar junkie

Gary

 

[tighe]

Thanks guys. It took me awhile to find a Delorean with a flux capacitor but I did, and routed my wire across my garage through the sunroof down into an window screen I found, that should work as a grid right?, and then put the ends of the wires into some peaNUT butter, couldn't find any wire nut butter. So I think I'm good, right?

OMG I love the wealth of knowledge you guys have about this stuff. While off the original question it is a very interesting read. The above humor shows my comprehension of most of it though. Thank you for responding to my stupid question. Glad to know I can't hurt the panels.

sincere thanks