relay clicking

[elesaver]

I have a Classic 200 with 8 ea 300W panels of 35.7 volts going through a combiner and into the classic.   It is currently clicking...apparently at the relay...and the screen says "resting."  This lasts for only a few seconds and then it resorts back to Bulk MPPT.  When it went to float, of course the clicking stopped and 0.00 amp coming in.  It was doing this at 2 pm when there is full sun.  I noticed that it did this the other evening as the sun was beginning to go down.  In my mind, it should not have gone to "rest" at that point but I thought maybe the sun angle was less than necessary to do any absorb or float.  Does this mean the relay is going bad?  If so, what would I need to do?  If not, any ideas?  I hope I have given enough info.

[Resthome]

What is the battery bank voltage? Any shadows on PVs? What is the PV Voltage going into the Classic? What are your Absorb and Float voltage settings?

[elesaver]

Battery bank voltage is 24V and 938 aH when fully charged.  At 2 pm, there are no shadows at all.  I am in the SE of US and today was
clear and bright.  Float is set at 26.5 and Absorb at 31.5.  This is a forklift battery so I've had to increase the absorb voltage.  Things have performed well in the past, so this is why I am concerned. PV in varies, of course. 

[Resthome]

Battery bank voltage is 24V and 938 aH when fully charged.  At 2 pm, there are no shadows at all.  I am in the SE of US and today was
clear and bright.  Float is set at 26.5 and Absorb at 31.5.  This is a forklift battery so I've had to increase the absorb voltage.  Things have performed well in the past, so this is why I am concerned. PV in varies, of course.

That is a high absorb voltage for a 24v bank.  I run deep folk lift battery at 12v and the max I run is 14.7v + temp comp. You are running an Equalize voltage. Okay so PV varies. I am assuming you normally reaching float each day, not sure if you are using a WBjr with end amps or are timing Absorb.

What PV voltage is it showing at the time you see it going to REST?. What are the spec on the panels and how do you have them connected? I'm looking at what the total Vmp would be. You got 2400 watts of power and I assume the 35.7v is for one panel. Make and model of the panels is always helpful. Also what version of the firmware are you running. If you have the MNGP can you also capture the Reason for Resting when you see it resting. That number could tell a lot.

To get Reason For Resting (RFR), go to the main number one status screen and then hold down the Left-Arrow key and then tap the ENTER key. You will see a bunch of numbers. On the top line, right in the middle, if the classic has gone to Resting from some awake state, it will show a number which is the RFR.

[elesaver]

OK, Resthome.  I will gather the numbers for the questions you have asked.  Your help is appreciated.

Yes, I use WBJr. and have end amps at 18.5 and absorb time at 1:30.  The battery has been reaching float in the afternoons each
day...usually from 1 pm to 2 pm. 

The absorb voltage is high but that is what I have found works best after quite a bit of trial and error settings.

The panels are connected in 4 strings of 2 panels each.  They are Axitec panels AC-300P/156-72S. Maximum Vmp per panel is 36.73.

Because I have run this system for almost two years...started with different batteries with the forklift installed Oct 2015...and have
had this problem on one occasion but when I inquired at the northern az. forum, I was alerted that it was probably the relay clicking due to low light.  At that time, the low light made sense.  Now, however, at 2 pm, broad daylight, there seems to be no reason.

I'll try to check for the numbers displayed when the unit has gone to rest as you suggested.  The firmware number I'll have to check again.  I thought I had it written down.  I do not have capability to upgrade the firmware and that too, was verified as an OK firmware to run at Northern Az forum.

[elesaver]

Resthome,

Just went to the status screen, held left soft key and hit enter:

IN     4        BAT

Meanwhile, the voltage in was all over the place from 28.4 to 76.8.  The sun had not dimmed when the variables were showing.

Thanks again for your help.

[ClassicCrazy]

You checked all your connections from PV's back to Classic to make sure they are tight and no oxidation or anything ? Also at the breakers?

Larry

[Resthome]

Resthome,

Just went to the status screen, held left soft key and hit enter:

IN     4        BAT

Meanwhile, the voltage in was all over the place from 28.4 to 76.8.  The sun had not dimmed when the variables were showing.

Thanks again for your help.

ReasonForResting = 4 Input V is lower than Vbatt while running

[Resthome]

As Larry has said check your PV voltage with a good volt meter at the Classic and at the Combiner. You could try setting Classic Mode to off and then open the PV Breaker to Classic. Then check voltage at Combiner for each string with Combiner breakers open, you should see 2 x Voc for each string. If that looks okay try closing one Combiner breaker at a time and close PV breaker at Classic and turn Classic Mode back on. If default setting the Classic should sweep once ever 3 minutes. If in Solar mode the sweeps would be pretty fast and after the sweep the PV In should be some where close to 2 x Vmp.  There is a status display on the classic that shows Voc that should be similar to what you measured at the Combiner. Check each string by itself this way.

Something is going on with the voltage In from the PV as you have noted. There have been posts of other with the PV voltage being pulled down near battery voltage, can't recall what the issue was at the moment.


PS. Not part of the resting problem but a suggestion. I would set your Absorb time at 3-4 hrs you may not be reaching end amps with that short of a absorb time. Absorb will go to float at 1.5 hrs even if you have not reach end amps. You also have a high end amps, maybe because of your loads. Check your S/G on you batteries to make sure they are good.

[TomW]

You checked all your connections from PV's back to Classic to make sure they are tight and no oxidation or anything ? Also at the breakers?

Larry

As you probably know, Larry but elesaver may not;

It is a generally a good idea to retighten connections occasionally. Copper is well known for "flowing" under the pressure of connections and becoming loose.  Loose connections cause resistance and associated voltage drop, possibly skewing the reading of The Classic in this case.

I always use No_OX or similar dielectric grease to prevent corrosion as well. Just an inexpensive step to eliminate future issues.

Tom

[elesaver]

Thanks to everyone for the tips.  I will work to check connections today although I had already checked the combiner box and found that each string seemed to be flowing OK.

Meanwhile, back at the ranch, where do you find all of the little "nuances" for the classic functions and values?  I have the manual but it isn't a great deal of help for the "finer issues."  I'd love to be able to learn how to find these additional measurements to troubleshoot or just to know that things are performing as expected.  These things can't be expected to last forever so it's good to know if things are beginning to malfunction before you get to the spot that nothing is working!

Thanks again.

[ClassicCrazy]

not sure how old the manual you have is , but check the Midnite website to makes sure there isn't a newer revision - I think there have been several.

Larry

[Resthome]

Thanks to everyone for the tips.  I will work to check connections today although I had already checked the combiner box and found that each string seemed to be flowing OK.

Meanwhile, back at the ranch, where do you find all of the little "nuances" for the classic functions and values?  I have the manual but it isn't a great deal of help for the "finer issues."  I'd love to be able to learn how to find these additional measurements to troubleshoot or just to know that things are performing as expected.  These things can't be expected to last forever so it's good to know if things are beginning to malfunction before you get to the spot that nothing is working!

Thanks again.

There is a REV 2056 Classic Manual, but you won't find the "nuances" there. Most of them come from boB and are posted here on the forum. Sorry I do not know if they have ever been consolidated. When I see one of bob's tricks I cut and past it and save it for reference.

There is one other thing on your panels if you have an amp meter available to check short circuit Isc current of the panel it could be that the voltages look fine unit they are drawing current.

[elesaver]

Yes, I had purchased a clamp meter for that very purpose of checking amps out of the panels.  Sadly, I am deficient in the use of it!  I continue to try to learn.  I don't want to disconnect the panels during the sunlight for fear of arching and then, when the sun goes down, I have not disconnected.  I guess I need to do that; then, when the sun if up the next day, I can check for output.

If there's an easier way to do this, I'm eager to learn.  My learning curve with all of this has been long and slow!  Fun, to be sure, but very slow.  When I began, I could hardly spell "solar," let alone install a system.  Miracles never cease. :-)

[Resthome]

If it is a clamp on amp meter all you have to do is open the clamp and place it around the negative cable. Select an appropriate meter scale for AMPs. Some clamp on meters have an arrow or some other indicator as to which direction to clamp the wire. You can try either direction.

If it is just a straight meter the MAX amps for Fluke meters is usually 10A and you have to use the negative jack and the special Amp jack on the meter. The meter would be connected between the positive and negative leads of the string to measure Isc (short circuit current)

I keep a couple pieces of large cardboard to throw over a string of panels if the sun is up. Then I can work on that string of panels.