Did i break my panel?

[juiced]

I was using a little motor to check how much physical power i was getting. I had my multimeter hooked up, parallel and everything worked fine. I was showing about 11.8 (set to the 20 on meter) and the motor span. Now, although the panel isnt in direct light it is showing 12.9 and the motor wont spin. The multimeter drops to .02 when the motor is introduced.

    What the hell did i do?!

[juiced]

BTW, yes i did test the motor on a battery and it still works fine.

[laskey]

Your motor is trying to draw too much current from the panel.  The panel is not capable of producing enough current to overcome your motor's startup and run draw.

Try this.  Stick the panel in sunlight, hook your motor to it, and watch the voltage.  It's pretty low right, then spin the shaft on the motor, the voltage picks up for a bit, or the motor may even stay running slowly.

To run that motor your panels need to produce more than the motor's rated draw.

Cya,

Chris

[juiced]

The thing is, yesterday, a darker day it ran ULTRA fast, today it does too, but not off the panel.

   How can you test a panel to verify if it is functioning properly. Id goto the source, but they dont even know what a gel-cell is.

[ghurd]

Get a 25-ish ohm (2 watt, work fast, it can get hot) resistor, hook it to the panel in the sun, check the volts on the resistor.  Shoud be 5 to 7v is my bet.

Ohms law will tell the current, then watts, etc.

G-

[baggo]

Hi Juiced,

It's very unlikely you will have damaged the panel just by connecting your motor to it as solar panels suffer no ill effects even when running them short circuited. That's how the cheaper charge controllers (including those by ICP) prevent overcharging - by shorting the panel.

"Now, although the panel isn't in direct light it is showing 12.9 and the motor wont spin."

Don't forget that solar panels give negligible output unless they are in full sun. They will produce some voltage when open circuit but this will drop to nothing as soon as you connect a load to them. I have two 80W panels in parallel that produce over 8 amps in full sun but on a dull day they produce next to nothing.

John

[juiced]

So what it shows as open V is not what kind of amps its putting out?

  Once again guys, sorry i didnt come to the game with a full deck of cards... :p

  Im currently looking for my old text books to re-learn math and electricty. I only remember the very basics. Even though i have been 'researching' A.E. for four years, i have only recently settled down and started to get hands-on experiance.

[ghurd]

Target power is probably 7v at about .27 amps. (a guess, going by the earlier pic).

12. volts open, 0 amps, 0 watts.
    
0. 3 amps short circuit, 0 volts, 0 watts.
   
   

Testing is a balancing act to get a R to get the PV out to about target V, and figure the current. (Or measure the current and figure the V of the R)

If it is damaged, its probably the wires where they go into the PV.

If you need a new one, All Electronics, US$20+6 shipping, 7v, 0.280a, Siemans, neat little arm to mount it. Over priced maybe, but they are tough to find.

G-

[ghurd]

That 13 happened by itself, should be .3 amps.

I knew better.

[juiced]

its funny, but it blew the fuse in the 12v adapter and it still wont turn the motor. Could water have damaged it? Shock? amps too high for the motor? (would the motor be cooked after? it still turns off a battery)

 

[juiced]

now its showing 15.8 and it still wont turn the damn motor.

[bob golding]

remember you need all the panel in the sunight if you just cover a small  section of it with, say a finger the output will drop like a stone.

bob golding

[juiced]

That could be the exact cause. Would my meter still be reading those high numbers though?

  Thats part i dont get. High numbers that drop to nothing with a load applied.

[fuzz]

Just a thought:

Maybe you created a spark while disconnecting your motor which Voltage was higher then the reverse voltage of your protection diode in your panel (if it has any).

fuzz

[TomW]

juiced;



Thats part i don't get. High numbers that drop to nothing with a load applied.

High numbers as in plural? Or one high reading on volts? Amps is as big a piece of the puzzle as volts. What amps readings have you seen?

Well I will just toss out that volts without amps is pretty useless. Sounds like your panel simply doesn't have enough current [amps] capacity in the light its in to do the job. Even my 300 watts of panels will show open circuit voltage up near 15 to 20 volts on dark days and it doesn't push any power into the batteries. It simply does not have the power available even though in full sun I regularly get 18+ amps into low batteries.

Lots of folks forget that voltage with no load means about as much as a politicians promise.

A fairly well used up 9 volt battery will often times show a voltage of near or even above 9 volts but as soon as the load gets applied it drops drastically. Not necessarily a problem except the source is not able to provide the amps and volts to drive the load.

Work from electricity is measured in watts. Watts is amperes times voltage and there is no way around that.

T

[juiced]

Well.. would you belive i cant get an AMP reading? Ive tried looking on the net to verify how to do it, and at best i get .1 and it seems to flicker. !!

    Actually, now the more i think the more the covered portion of the panel explanation makes sense. I have it mounted in a window and portions (significant) of it are covered. I guess (no matter how its wired, parallel or series) the darkened areas would be 'vacum' and if had any availible; emit energy?

 

[ghurd]

Other ways to think about it. Best I can think of right now.

Think about it like a battery.

10 series 'AAA' batteries give you 15 volts.

Your car needs 12 volts to start.

Just because the 'AAA's are 3 volts more than is needed doesn't mean it has a chance of starting the car.

Think about it like air pressure.

Your bike tire has #50 of pressure.

Your spray gun needs #20.

That still doesn't mean you can paint your house with the air in the bike tire.

G-

[troy]

Voltage is meaningless without knowing the amps.  On my 24V system I have often read 26V open circuit voltage on a bright moonlit night.  But no amps and no useful work.

The ENTIRE panel must be exposed to bright sunlight or you will get trivial amounts of watts out (watts = volts x amps).

Good luck and have fun!

troy