one or two Classics - optimizing system?

[binkino]

Hi

What do you think ...

I have 3x4 modules on my flat roof with S-SW orientation, and 4 modules with South orientation.
See attached picture

The 3x4 are from the installer, that gone bankrupt, and the 2x2 modules (also in series = 4) I bought later.

Actually all 4 lines are in parallel to my Classic 200.

As I have two Classic 200 (one is a 'lite') - would it be better to have the 2x2 on one Classic and the 3x4 on the other Classic?
I am thinking about, so one classic can track the 2x2 and the other the 3x4 for better energy?
If yes, I have to connect the both Classic with the "follow me" ?

The 3x4 have 2880 Wp (each 240Wp) and the 2x2 (each 255Wp) have ~ 1020 Wp (=3900Wp) with same volt.

Thanks

[Westbranch]

I would not put them in follow me mode as the orientation is different and they will each have different timing for max output.  In Follow Me one set of panels would be in max output and the other  probably an hour or more different... at any given time they will be working with a different MPPT calibration... specific to their array...
As long as you have the charging parameters set the same and they both read the same voltage when you check them, each will do its own thing and charge in a happy state...

[binkino]

Ok

Sounds good

my further thoughts,
should I only use the WBJR of one CLASSIC, so the charging current is in parallel with the other CLASSIC over the same SHUNT, right?
So I have all the data in one CLASSIC; Also the charge state of the battery is displayed correctly?


I will change to this wiring with two Classics, when I have the new batteries, so I don't have to think about the max-charging-current-limit of the AGM batteries now (Address 4405 in MNGP - the Classics will not share this setting, hehe)

[Westbranch]

If the WBjr is on the Full classic, and on the larger array, the Lite will happily churn out its max watts till the sum comes off the panels...

So by putting the WBjr on the Classic it should regulate EA based on the TOTAL Amps going into the battery... as long as the output of both panels  goes through the same shunt...

The only caveat I can see is that IF the max current acceptance of the bank is less than the small array's max output you would need to use 2 WBjrs...

BTW what is the AMP limit on those batteries?

I don't remember if I posted this list of doc.s before

http://www.cdtechno.com/resource/support_doc.html

You might find some pertinent info...
hth

[binkino]

The new bank will have 440Ah, and I guess 10% to 20% of it is max. charge amps, but they wouldn't go damaged if it is higher (not like this AGM batteries I have actual (230Ah))

This is like I was thinking to wire it, so the Lite will have the 2x2 array. Max output in Peak can be 20 Amps in very very best situation. But more like 10... some amps.
That is okay for a "good morning batteries warm up" 

So I will be safe here with charging in the morning, as the batteries will allways be discharged at night and evening before.
If the Full-Classic with shunt and 3x4 array will meassure the SOC is 100%, I can use the AUX to switch of the 2x2 array. But I am sure, this will not be necessary

okay this will work, great

thanks

[binkino]

SO used the free time to rewire

connect both classics with each its own fuse to one shunt (connected to the 'full classic')
and connect the 4.th array to the lite,
left the 1,2,3 array on the 'full' Classic.
Will watch tomorrow morning how it works, will be nice to see, when the lite comes up and the other follows later hehe

But one thing made me now really confuses, a bit of scary.
The lite shows voltage of battery correct.
The 'full' shows me -1 volts. So measured direct at the terminals, both terminals hat 48,1 volt,
but the 'full' had 47,1 Volt.
Have now set the 'Offset' value in the LocalApp ... but this is not really normal?

But how can this happen?
I remember my measuring some weeks ago, and the volts of the battery and in the App were +/- identical...

Or is there a difference, if the WbJr. is connected or not?
I don''t believe. Nothing changed at the 'full' Classic now.
The shunt is not used on the 'lite' ...

[Westbranch]

binkino, I just reread my earlier posts and should have been a bit clearer.

You need to have both chargers delivering their power to the shunt and WBjr if you want the true SoC from the Full Classic. 

The 'Full' Classic can keep track of the total battery state of charge, because it is seeing all of the input to the battery.

The 'Lite' does not see how much is going into the battery but it reads the battery voltage and that is what triggers it into Absorb and Float modes. Thus it uses (reads) the total voltage of both your Classics...  but does not know where it originated ie another Classic or a charger.

hth

[binkino]

That is how I did
possible my english skills...

both classic use the shunt of the 'full' Classic



I am only confused about the different volts, the two classic displaying of the same battery (48 and 47 volts i.e.), that I had to correct with the "Offset setting"

[Westbranch]

HMMM, the electron gremlins at work inside your Classic   

Yes, the offset is the solution. You may want to double check all connections , both old and new. 
One poster found a wire he had not touched, while adding more batteries, came loose and that solved his problem...

[binkino]

I have checked the connections
I measured at battery and at the blue terminals in the classics

yes these Gremlins. Sooo cute ... but ...
damn, the devil is inside hehe


Was there not a potentiometer, where it is possible to correct the value, too?
Somewhere in the forum I read somethinng like this ...

[Westbranch]

If there is it would have been posted by boB... did the LApp adjustment not work?

[Resthome]

If there is it would have been posted by boB... did the LApp adjustment not work?

Yeah boB posted a gain adjustment but if it was right on before the changes and is now off I wouldn't make that adjustment.  I'd be looking at what changed. The problem with the Tweat offset is it changes depending on current which kinda makes it useless. It would be great to see a voltage sense wire added to the Classic for this issue.

[binkino]

When I was measuring yesterday, there was no current that could dropping the volt
The measured voltage was not under load or charging, sun was down and the Classics in resting.  I measured at the terminals, so what I read there, the Classic should alo read

I was able to adjust it with the 'Offset option', yes

Both Clasics are very close in voltage reading, there is just a number on the right side of the dot, sometimes the 'lite' is 0,1 V higher now in charging, the 'full' follows this some seconds later.
This can be a normal voltage drop while charging. The 'lite' feeds 3,5A and the 'full' 10,4A in this moment.

Just an idea - how is the voltage setting programed? Is there a register value that has changed by ... what ever ... reason?
Will a complete reset of the Classic set all registers its factory value?
Or which registers can I check, what value do they have to have? 
Just a thought

[Westbranch]

Do you have the same FW in both units?

[binkino]

yes I have, version 2096 in both

just had a look, time for an update?
http://www.midnitesolar.com/firmwareReport.php?firmware_ID=9&firmwareProduct_ID=1&act=edit
Rev 2126 ... 1-17-17
(does this updater run in xp?)