Amp limit must be set low to keep the Classic 150 from resting

[Drew]

Howdy all, after playing phone tag and trying email support with no luck, thought I would try the forum instead.

After changing from a 12v 420Ah battery bank to a 24v 210Ah one and going through the wizard, our controller's Amp limit needs to be set close to what the panels are currently putting out in order to keep it from resting.  So in the morning I set it a 5 amps and progressly raise it throughout the day to about 21 amps.  If the amps shown on the bottom right of the status screen go below my set point, the controller goes into resting. I have to lower the amp limit down to get it to cycle back on. It also constantly says PV Shading even on a clear day. Both of these never occured with the 12v battery setup.

I have upgraded the firmware and the MNGP. Our solar array can put out 1200W under ideal conditions.

Any ideas what could be wrong? Thanks in advance for your help.

[Vic]

My guess would be that your panels do not have sufficient voltage to charge the 24 V bank,  unless the current is low.  Only a guess.

What is the PV input voltage to the charge controller.  What are the panels and the Vmp of each,  AND how are the strings arranged?  Vic

[Drew]

Vic thanks for the reply. I talked to Tom and Midnite and he referred me to Ryan but I have not spoke with him yet. Tom said my setup looks correct.

My panels are as follows: 4 Kyocera 185W, Vmp 23.6V - two wired in a series and the two series in parallel. Also 2 Mitsubishi 165W, Vmp 24.4V wired in a series, and 9 Harbor Frieght panels 15W, Vmp 17.5V - three wired in a series and the three series in parallel. Then the three sets are mixed in a combiner box near the controller.

We tried isolating the problem by using each array by them self but still had the same problem. Since each array is putting out near 48V, should have no problem charging 24V system.

Again this all worked fine with a 12V battery bank. We may wire it back to 12V just to see if it would work correctly again.

[Vic]

Drew,
  Thanks for the added info.

Went back to read your ofiginal post.  Had misread it a bit.

The FW that shipped in my Classic 150,  had a bit of a bug where the CC would cycle through a number of msgs,   including Panes Shading.  This was XA Dec of last year.

This situation was only on 48 V banks,  or at least not seen on 12 V banks.

I dunno.  Have nothing more on this.  Ryan,  or boB,  and others here  folks should be able to help.  Good Luck,   Vic

[boB]

Hi Drew.  It was good to talk with you today.

Do you remember what the MPP Voltage (PV input)  was when you had it all hooked up to the 12V battery ??

It sure seems like it should be OK though with a MPP V of 2 in series = about 46 Volts.  Can't remember what your Voc was ??

Could it be that you have a loose connection on the input  some how   If you have an Amp clamp you could removed the PV input wires from the Classic, short them together (with the PV disconnect off) and see what the short circuit current is.  Just an idea.

Here's another thing to try...  Change the mode to U-Set and 100% Voc.  The Classic will turn on and sit at Voc.  In the main status menu, you can then manually bring the PV input voltage down by the Soft-Left button by repeatedly pressing it or just holding it down and see what happens with the output power and current.  You can raise the voltage again by using the soft-right key.

boB

[Tinman]

"could it be that you have a loose connection on the input  some how   If you have an Amp clamp you could removed the PV input wires from the Classic, short them together (with the PV disconnect off) and see what the short circuit current is.  Just an idea."

Yup, check your connections. I had something similar happen. Went through all the connections and voila, problem gone. If you use stranded wire it is not uncommon for connections to come loose after a rewire or reconfiguration. The smaller the wire the more prone to this problem. Once I went to larger wire #4 at the panels (overkill I know) getting real solid connects was easy.

My Classic was going to rest midday (12 volt bank, 36 volt string). Put mighty muscles on the splicers and problem solved.

[Drew]

Well here is the latest on the issue. First, thanks Tom, Bob, Ryan, and those who responded in the forum for all your help.

I did have a few loose connections coming from the positive PV leads going into the breakers. However, after tightening the loose connections after my thorough check, nothing changed. Ryan said to try other modes besides "solar" and the only one that would work was "legacy P&O". Even in that mode it went to "float" and turned off with the sun still shining. So we put a load on the batteries to knock it out of float but nothing. So we turned the mode off and back on and it kicked in again but it still showed "float". When we put a load on it, it would show "float MPPT" although it seemed to be in bulk mode by the watt and amp readings. The reason for resting on the menu was number 9, but it has also been 4 and 26. At night the amber light flashes, but maybe it always did and I didn't notice before.

Those who were asking about VOC it's 50.9 when the sun is bright and is usually around 48 to 50.9.

Tomorrow I will try the 12V setup again and see what happens. In the meantime Ryan has sent me out a replacement Classic to help troubleshoot the problem. Thanks Ryan now I can get some sleep. 

[Buzz]

I'm having similar problems with a Classic 250 KS.  Some days, I chase settings all day long, getting "Low light" at high noon even though the sky is clear.  Other days, the output is consistent and it doesn't go into Resting.  It's not any loose connections, and it's not shading.  Legacy P&O usually works, but after I get it to "find" the VOC by using WIND mode.

[Drew]

Buzz what is your setup? With our 12v battery bank and panels set up at nominal 48V (48-50.6 VOC) everything worked fine. When we went to a 24V battery bank, we ran into trouble.

Today we did a test going back to a 12V battery bank and the  VOC was 63V with good sun and everything seemed to work fine in Solar mode which we had trouble with at 24V. So it looks like you need a VOC well over 50 to charge a 24V bank with the Classic in Solar mode. Once we receive the replacement Classic we will be able to confirm if this is indeed the case.

Looks like the Ryan's hunch of not enough volts may be the answer.

[Buzz]

The Total Panel VOC is 200 v and it feeds a 120 V Battery bank.  I saw what you did with the math, so I would just multiply by 10.   The 250 KS is made for a 120 v battery bank,  but a Classic 250 goes into hyperVOC at 250 V, which is 1.25 x 200; so a 500 v panel setup would not fix it.  In other words, 200VOC is the max for a Classic 250KS.

I'm going to try lowering the Amp LIMIT tomorrow, that's one I didn't try.  How did you come up with that idea?



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[Halfcrazy]

The Total Panel VOC is 200 v and it feeds a 120 V Battery bank.  I saw what you did with the math, so I would just multiply by 10.   The 250 KS is made for a 120 v battery bank,  but a Classic 250 goes into hyperVOC at 250 V, which is 1.25 x 200; so a 500 v panel setup would not fix it.  In other words, 200VOC is the max for a Classic 250KS.

I'm going to try lowering the Amp LIMIT tomorrow, that's one I didn't try.  How did you come up with that idea?

Can you give me a description of the array as detailed as you can (Size, Brand and configuration)? It appears this issue may be related to miss matched panels I was able to recreate it here with a system running a "Solar Salad" consisting of 4 different brands and size of panels. I also have a system running a group of the same panel with a low VOC and the Classic behaves fine. The more details you can give me the better and I will work directly with boB Today to see if we can get to the bottom of this?

PS Buzz the Classic 250KS can stand a VOC of 298vdc but will not turn on until it reaches 250vdc. Where are you at that 200 is the limit without routinely going over 250 in the cold months? Can you give me the average cold there as well as the record cold? One of the things I like to do when designing around a Classic is to use the average cold (0F here)this ignores those 3 or so record breaking cold mornings (-30F here). What happens is on the -30F morning the Classic is in Hyper VOC for a hour or 2 until the panels warm slightly. Let me know your 2 temps and I will do some math there as well.

Ryan

PS I looked up the temperatures for this and assuming I got the location correct here is what I figured.

It looks like according to the internet the average cold is around 41F and the record cold is around 21F with the average high being 80F so an array with a VOC of 200 will have a MPPT voltage of around 150vdc in the 80F weather and a max VOC of 216vdc at 41F and 228vdc at 21F

I would be inclined to shoot for a VOC of 225vdc for this array this will result in a VOC of 243vdc at 41F and  256vdc on the record cold mornings of 21F.

[Drew]

Would the following be normal? Again our 48V array charging a 24V battery bank with a VOC from 48V to 50.6V during full sun. Then at night the amp light flashes, the VOC is 553.5V, and the reason for resting is 17. Now if I turn off anyone of the three breakers for the arrays at night the VOC goes to 1V to 3V. But as soon as I turn it back on it goes right back to 553.5V and it doesn't matter which array.

[Buzz]

Brand:  Custom 

The shapes may differ but everything is in series and the cells are all the same:  8 amp polycrystalline 6.125"x 6.125" in series.   If BYD made 16.8 VOC panels, then I'd have 12 of them, and they would each put out an Isc of 135 watts.   My panels are smaller because I am not strong enough to lift big panels.  The panels are oddly shaped because I have limited space to fit them.

Can you see the jpg that I uploaded? The CLASSIC doesn't have the setting for the small voltages that I actually have (eg: 9.6 VOC)  All the panels in each half is wired in series, so I did some math and lied to the CLASSIC.   I'm telling the CLASSIC that each half is a string of 12, 16.8 volt panels and 135 watts.  The math works out, but I've got panels in the darndest places.

This particular Classic starts HyperVOC at 246v.  It's got a personality like my uncle.   And once I TWEAK the voltage down by 3.4 v, to stop HyperVOC, sometimes Classic says that is "not enough light" (5).  Other days it locks onto the watts and does fine.  Right now at 3:11 pm the IN reads 199.4 v.  It will lock in on the watts being produced on some days and read right past the watts, which I can see on the MNPG, on other days.  Today is an "other" day.  It goes to BULK MPPT and there is plenty of voltage (200-245 v), but no watts are being drawn down.   So after a few minutes it goes to RESTING (5).  Fair skin burns in 10 min and the Classic says there's not enough light?

Some days the Classic works awesome, even collecting moonlight and lamplight at night.  I have a hard time believing it could be the panels. I have clicked a lot of buttons, trying to get this to work.  I have probably given it a digital ulcer.

I tried lowering Amp limits, but got confused because there are 3 AMP LIMIT categories.

It barely frosted this morning and is around 75 F right now.  It rarely gets down below zero, like every 50 years, but it did last year.   Inulation is 6.8.  Days like this will usually produce 600 watts at any given time for each half.

I downloaded the  11-9 Update and ran it.  Then I rolled it back to the 9-24 update.  Then I ran the 11-9 update again.   Since this is an "other" day, it didn't fix anything.

Tonight, I switched the 391 out with the other Classic (CLOO390).  As I followed the set up instructions, I realized that I may have pushed too many buttons and that would be where the problem is...I forgot to turn the MODE off before changing the mode, for instance.

So do you have a  :-[go-back-to-factory-settings setting?

[boB]

Would the following be normal? Again our 48V array charging a 24V battery bank with a VOC from 48V to 50.6V during full sun. Then at night the amp light flashes, the VOC is 553.5V, and the reason for resting is 17. Now if I turn off anyone of the three breakers for the arrays at night the VOC goes to 1V to 3V. But as soon as I turn it back on it goes right back to 553.5V and it doesn't matter which array.

Andrew, this is NOT normal.

That number,  5535   (553.5)  is  16 bit number that is ALL ONES.  Without the decimal point and with the significant digit shown, which it isn't in this case, that number is actually  65,535 and  you are seeing this which is NOT normal, so I believe another Classic is in order.

I think this is in process now so please let us know how that works out.

boB

[Buzz]

fFter some more experimentation, I found that my issues are because the WIND TRACKING function is interferring with the SOLAR and P&O.  A video short on the CD explained how too set the wind-tracking MODE curve.  I have now set it and will see how that goes.