I shorted my Panels ... Are they Dead?

[NukeEngineer]

Short out a voltage source like a battery, and you are going to have a very bad day.

Or a very fun day! Just watch the videos on youtube of folks doing this.... some look moderately qualified (Photonicinduction or whatever), others... I'm just glad they aren't my neighbors or we could test the tables on panel wattage from neighbor's house on fire plus fire truck lights.

mod note - dont try this, or other you tube stunts. any fool with a camcorder can post something like this.

EDIT: Car battery fun: https://www.youtube.com/watch?v=AIT4BYJ2jCg

[Sunking]

I'm happy to report that my Solar Array seems to be producing up to spec. The short had not effect. I was very concerned last week before I got everything connected and up and running ... but it seems every thing on the Array side is OK. The inverter ... well that is another story for another post. But suffice-it-to-say I have been on the phone with Schneider ever day this week and it appears the inverter is not working correctly

Check your voltage at the INPUT of the Inverter. You should see roughly 27 to 30 volts on a 24 volt battery. Anything equal to or less than 24.4 volts is unacceptable.

[Matrix]

I'm happy to report that my Solar Array seems to be producing up to spec. The short had not effect. I was very concerned last week before I got everything connected and up and running ... but it seems every thing on the Array side is OK. The inverter ... well that is another story for another post. But suffice-it-to-say I have been on the phone with Schneider ever day this week and it appears the inverter is not working correctly

[Sunking]

Solar panels are CURRENT SOURCES and NOT Voltage Sources like a battery. You can short any panel out for a day, week, month, or year with no problems. In fact that is how you test a solar panel. As CURRENT SOURCE current is limited and in a solar panel is Isc. A shorted panel cannot even heat up its own wires.

Short out a voltage source like a battery, and you are going to have a very bad day.

[AzRoute66]

1. If a panel WAS damaged at Isc, it would be a good thing. It should be returned on warranty, the earlier discovered the better.
2. A better amperage test would be to put 9x285W = 2565W (plus won't hurt) load on the system during great sun, then it won't matter what the battery SOC is. Round up your vacuum cleaners and such and keep adding them until 'panel amps' levels off.

[Matrix]

Thanks ... i did not realize that. I was thinking that the PV current was what the panels were producing ... not what the controller was drawing. Seems I am OK. before I shut down the CC to drain the battery a bit ... It was up to 8 amps.

[sensij]

So I guess what I am asking, does a classic 150 limit the PV current if not needed to supply charging or load?

Yes, that is exactly what any charge controller is designed to do.

[Matrix]

Well maybe its just my lack of understanding how a solar system works ... and how it interplay with a charge controller. The amps dropped to 1.2amps .... but the batteries were fully charged. I turn on the inverter ... and immediately, the input amps from the array jumps to 7 amps and now I am producing 600 watts.

So does a Classic 150 limit input PV current if it is not needed? I thought that input amps was what was coming in from the array ... all the time as the sun was making power available. So I guess what I am asking, does a classic 150 limit the PV current if not needed to supply charging or load?

[J.P.M.]

So does that mean they were damaged ... ??

I don't know. I'm not there and experience has taught me that unless there's a no brainer problem, to not attempt to diagnose system problems without being on site. From what it sounds like your trying to do, what you've done, and the types of questions you're asking, I don't know what else you may have done that's possibly causing problems.

[sensij]

Looks like you might be in absorb, with the battery at 28.6 V. At that stage of the charge cycle, the controller dials back the PV power so that the battery only gets as much charge as it can accept.

What specific charge controller are you using?

[Matrix]

I am now a little more concerned. Without any real world experience ... on day one at 11 am in full N. Florida Sun, panels are at a 15.7 degree tilt and facing south ... I am not getting what I would have thought would be very good current or watt out put from the panels. I was expecting about 18 to 20 amps ... it would seem right now in full sun at 11am I am getting 2.2 amps and 200 watts from a 285 watt x 9 panel array. Out side temp is 82* F.

Would this be correct ... or do I have a problem?

[Matrix]

FWIW and a small point, real world or not, NOCT conditions are no more real world than any other reasonable set of test conditions with irradiance at 800 W/m^2 irradiance. STC is at 1,000 W/m^2. Other test conditions are different as well.

Panel current is pretty close to linear with respect to irradiance so your string current was probably about in proportion to the panel irradiance when you were working on them. If it was sunny and the panels were in their operating position, they may have been seeing ~ 800 -900 W/m^2 depending on a few variables like location, time of day, array tilt and azimuth and how sunny it was when you were working on the array.

So does that mean they were damaged ... ??

[J.P.M.]

Thanks ... that is what I was thinking too. The modules are new ... so I can only hope they are robust and healthy.

I also just re-read the spec sheet. And If I am seeing it correctly ... the Nominal Power Current @ STC is 8.95a and the Short Circuit Current @ STC is 9.49 ... a difference of .54 amps between the shorted current and the operating current. So very very close.

And interestingly, when I read the NOCT numbers for the same (which I assume the NOCT numbers are probably more real world day-to-day expectations for the panel) , The Nominal Power Current @ NOCT is 7.24a and the Short Circuit Current @ NOTC is 7.68a.

So would I be correct in assuming that my shorted current would have been probably around 7.68a .... which is actually LESS than the Nominal Power Current of 8.95a in the "lab" at STC ?

So my Short Circuit would have been lower than what would have been being produced in ideal conditions for normal use?

FWIW and a small point, real world or not, NOCT conditions are no more real world than any other reasonable set of test conditions with irradiance at 800 W/m^2 irradiance. STC is at 1,000 W/m^2. Other test conditions are different as well.

Panel current is pretty close to linear with respect to irradiance so your string current was probably about in proportion to the panel irradiance when you were working on them. If it was sunny and the panels were in their operating position, they may have been seeing ~ 800 -900 W/m^2 depending on a few variables like location, time of day, array tilt and azimuth and how sunny it was when you were working on the array.

[sensij]

So my Short Circuit would have been lower than what would have been being produced in ideal conditions for normal use?

Probably. Shorting the leads and measuring current is a normal diagnostic procedure. The panel is fine. The connectors, on the other hand, may not have handled it well. Making and breaking the connection in daylight can cause damaging arcs to the contacts in the connector housing.

[Matrix]

Thanks ... that is what I was thinking too. The modules are new ... so I can only hope they are robust and healthy.

I also just re-read the spec sheet. And If I am seeing it correctly ... the Nominal Power Current @ STC is 8.95a and the Short Circuit Current @ STC is 9.49 ... a difference of .54 amps between the shorted current and the operating current. So very very close.

And interestingly, when I read the NOCT numbers for the same (which I assume the NOCT numbers are probably more real world day-to-day expectations for the panel) , The Nominal Power Current @ NOCT is 7.24a and the Short Circuit Current @ NOTC is 7.68a.

So would I be correct in assuming that my shorted current would have been probably around 7.68a .... which is actually LESS than the Nominal Power Current of 8.95a in the "lab" at STC ?

So my Short Circuit would have been lower than what would have been being produced in ideal conditions for normal use?