Classic 150 going to low input voltage

[Tinman]

For no reason I can see, in full sun the voltage drops to anywhere from 48 to 13 volts. I go to mode, set to off then on and it goes back to full power. It really shouldn't be firmware since this is a new situation. My revision is last one prior to current.

The Classic will sit at low volts until I reset it using the mode function. Where should I look?

Note, when this happens, I've checked the voltage at the breakers and it reads much higher than what the Classic is reporting. I changed out the breaker, didn't solve the problem.

[boB]

Tinman, this is kind of strange...

When you see higher voltage at the breaker than the Classic is reporting,
could you take your DC voltmeter and check the input voltage at the
Classic input terminals ??   If there really is a voltage drop, you may
have a bad connection, loose screw or something like that.
Also, try running the Classic in U-Set % Voc mode at around 75% or
80% and see if it keeps making good power that way.
You should not have to reset it of course.

boB

[ibeweagle]

I now too have the same problem with one of my classics set up in master slave wind 1 and wind 2 working seperately  wind 1 going into reset for input to low at 14 volts on a 24 volt system in wind operation reset power and it did it again have to see whats going on thanks Mike

[boB]

I now too have the same problem with one of my classics set up in master slave wind 1 and wind 2 working seperately  wind 1 going into reset for input to low at 14 volts on a 24 volt system in wind operation reset power and it did it again have to see whats going on thanks Mike

That sounds like the input has come disconnected on the Classic with 14 volts on the input with 24V battery.
14 volts is about what you would see with 24V battery and input not connected to anything.

Now, something else could be dragging it down of course, including the Classic itself, but
check for loose connection anyway, just in case.

boB

[Halfcrazy]

Also I see you say Wind and Master/Slave setup. I have to assume you are doing this like I have where Classic a works from say 48 volts to 100 volts and Classic B comes alive at 100 volts the voltage numbers are just for reference? It is important when doing this that they are setup like this if they are set the same then one will stay resting. It is also important that the Current limit of Classic A matches the last set point #16 (In my case we set both for 71 amps) what this does is tell Classic A to unload the input this causes it to allow the voltage to rise.

Classic B now needs its #1 voltage set point set set say 10-30 volts lower than the voltage on Classic A's #1 set point ( In my case Classic A #16 is set to 103 vdc and Classic B #1 is set for 85vdc) this allows Classic B to wake up a little ahead of time. On set point #2 the voltage should equal the voltage on Classic A's set point #16.

Here is a link to the power curves we run in My Neighbors 16ft turbine: http://dl.dropbox.com/u/31975941/johns%20curve.pdf

Ryan

[Tinman]

Here is what I think is happening and it is not the Classic, it is the type of panels.

Back contact mono panels require that the frames have a positive ground to dissipate the positive ions that build up on the frame/glass thereby reducing output. I went back over performance and discovered it happens about 1-2 hours after the sun comes up.

So the next question is: can the Classic support that configuration? When I spoke to the manufacturer, they said some charge controllers do not, especially Sunforce and some Morningstar in which case if whatever the panels are mounted to are not grounded from the frame (motorhome) the panel frames can be grounded to an isolated metal bar which would dissipate the positive ions (positive goes to isolated metal ground and so does ground from panel frames). Everything in conduit and box.

Any of that make sense? Attached is an image depicting what I was told. Also added an image of current wiring. Panels are currently negative ground.

[attachment deleted by admin]

[niel]

tinman,
it would seem you have sunpower pvs and they do require a + ground to work properly. trouble is is that everything will have this same requirement of a + ground so you can't go grounding the - battery lead.

btw page 19 of the latest classic manual does state it can be a +, -, or no ground on the classic. inverters can pose a problem if not able to be + ground.

[Tinman]

Grape panels. Very lightweight and very good power. I'm probably going to just run the positive to isolated metal to burn off the ions which according to manufacturer does the job. While that does put a positive wire into a sealed isolator box on a breaker, not much difference I can see between that and what is going elsewhere. The isolator box is non-conducting. They key is to switch the breaker off and cover the panels before opening it for whatever reason but then again, something you have to do anytime you go near the wiring anyway.

comments?

[ibeweagle]

all is well now operator error have to set charge amps and equalizing,float ,bulk voltages for both classics when updating firmware also thanks Ryan for the power curves will have to change them when I get up to clearwater again but everything is doing good for now thanks for the help all of you cheers Mike

[kitestrings]

ryan,

I assume it is just a typo, but I noticed on your attached power curve it say, "Set Clipping at 1336vdc".  I suspect it should be "136 vdc", correct?

Regards,

kitestrings

[Halfcrazy]

Good catch  Luckily the Classic is smarter than I am and will not let you go that high 

[Tinman]

Just an update and to close this issue. I placed a rather large copper bus bar in a sealed enclosure and ran wire to it from the positive output of the series (with breaker in-line of course).

To date I have not seen the performance drops recur. It seems that the bus bars are large enough to mitigate the positive ion build-up and overnight it seems to dissipate so I'm ready for the next day. I know the idea of a positive wire from the panels/frame might be a concern but that is the reason for the sealed box. I guess if one opened the box, touched the wire or bus bar inside and then to ground there is a hazard but surely no more than opening a combiner or junction box and grabbing the positive and negative wires on a live system.

On decent days I get 2.4 kWh from each 3 panel array (100 watts each panel, mono. 12 volt panels in series). I have no exact comparisons to other days where the bus bar wasn't in place, only seat of the pants experience. It does seem that overall I get about .2 kWh more than before on similar days. The manufacturer states the power losses could be up to 50% and although I saw short drops like that it never lasted long enough since I set the mode to off then back on. Maybe that caused the charge to dissipate but I'll never know. What I do know is that now it doesn't happen.

The back contact mono panels are still tops in my mind because they take up less space and have been super performers.

Of course, you need a top notch charge controller like the Classic 150 to realize all that.

Thanks for the input.