First off, great forum you guys have here! How many places are there where you can talk to the guy doing the programming? ;D Thumbs up! I have a classic 150 hooked into a 48v battery bank and 2 5.2 amp 50 volt panels in series. (Starting small. :) ) I've had the system up and running for about 3 weeks and I'm having a weird charging issue. At random points in the bulk cycle the classic will start reading incorrect amps and watts going out to the batteries. For example it'll be going along fine with 4.5 or so amps off the panels and 6.8 to the batteries and then (I'm assuming when it sweeps) the amps to the batteries will drop to 5 and the amps from the panels will remain at 4.5. (The watts will drop accordingly.) Now from what I've seen the batteries don't charge any slower. As in when this happens the battery voltage doesn't drop like you would expect it to with a loss of wattage. I would chalk this up to a logging/reading error except that it gets progressively worse in absorption. By the time the absorb cycle is about 2/3 done (I have it set for 90 min.) and the amps from the panels read 1.5, the amps to the batteries and the watts read 0. The absorption cycle continues from this point so current is obviously still reaching the batteries even though the classic reads 0 amps. Here's where my main problem is. As soon as the classic reads 0 amps out, the voltage of the batteries will jump from 57.6 (my absorption voltage) to 58.5. Still not a big problem, but when it hits float the voltage jumps up again to 59.5 and sticks. So basically the classic floats the batteries at 59.5. This usually only happens once a day and I can correct it by turning the mode off and back on but I don't want to come home one day and see my batteries floating at 59.5. I installed the latest firmware and tried a factory reset with no fix. Any explanation for this?
Hey, WB !
Not sure what the heck is going on in Float there ! Not really normal of course...
Is there maybe another charging source on your system bringing that voltage up ? Maybe an inverter or something ?
Probably not but I have to ask... If the wired came loose, the Classic would not have a load but may keep the output running
without the battery really connected. That still doesn't really say why the voltage would be so high though.
Have you checked the output voltage at or near the Classic's battery terminals to see if the Classic is off maybe in its battery voltage reading ?
59.5 V for Float would REALLY be high of course !
Also, check the output wire connections closely. When you catch the classic output voltage going to 59.5V, what is the PV input at that time ?
Your Voc of the two panels in series is around 100 volts so in normal MPPT mode the Classic input should be somewhere around 75 to 80 volts but higher than that when in Float or Absorb.
Also, do you have a battery temp comp connected ?
You can view the present voltage that the Classic is trying to bring the batteries to by going to the CHARGE --- T-Comp menu and then pressing the soft-right key labelled View. Temperature compensated or not, that will show what the Classic is trying to charge to.
Thanks for the fast reply! I do have an inverter connected to the system (of course :D) but it isn't on when this happens and thus no load either. I use a generator and the inverter to charge batteries on cloudy days but when I do I always hit the classic breaker. Other than that there is nothing else that could affect the voltage of the system. I checked all the voltages independently with a multimeter and the meter reads the same as the classic in all cases. I also completely rewired the classic and checked all other connections. My Voc is exactly what you say it should be. I use the battery temp cable. I wasn't aware of the T-comp menu soft key and will check that the next chance I get. (Thanks :) ) What I don't get is why it reads 0 amps out. ???
OK... I see now. Yeah, check the T-Comp view and see if it gives a clue.
You can also go to the TEMPS menu and see what temperature the Classic
thinks the batteries are at.
For the 0 amps thing, when the classic says 0 amps out and you think it is putting out something,
from the main status menu, hold down the left-arrow key and tap the enter key.
You will see a bunch of numbers. Either take a picture of the screen or jot down the numbers.
What we want to see, which is the real numbers behind the battery current, is the number right
underneath the BATT name in the "+" row. That is the raw A/D converter numbers from
the current sensors. At 0 amps, it will be fluttering or moving around 40 or so. When
the Classic isn't outputting much of anything, the 4 middle numbers should all be showing around 40.
It IS possible that you just have a bum unit of course, but maybe we can find something else.
I agree that the 0 amps is kind of confusing and we really want to find out what is going on there.
boB
It didn't act up today (of course ::)) but I will get those numbers for you as soon as possible. I think (??) I may know what triggers this. If I turn the mode off and back on first thing in the morning it hasn't screwed up unless there is a sudden change in voltage. Like if I turn the inverter on or a small cloud goes across the sun for a few seconds. This doesn't happen every time the voltage changes but it does seem to be the trigger. (Sorry I can't give you more concrete info.)
Quote from: wildblue on August 08, 2012, 09:13:14 PM
It didn't act up today (of course ::))
Of course ! That's usually the way it happens !
OK.. Thinking...
boB
Some new (if still incomplete) data. It happened again this morning and I have some numbers for you. I wasn't able to let it complete the charge cycle but here are the numbers I do have.
From the status screen:
Before--- IN BATTERY
90.6V 50.5V
1.6A 3.1A
VOC108.6 Bulk MPPT
157 Watts
During the fault--- IN BATTERY
87.6V 50.5V
1.6A 1.8A
VOC108.6 Bulk MPPT
90 Watts
And here's the numbers when I hold left and tap enter from the status screen.
After(don't have these numbers before)--- IN 16 BATT
60 + 77
23 - 7
40 508
During the fault--- IN 5 BATT
60 + 75
23 - 9
40 508
After I turn the mode off and back on the status screen numbers are----
IN BATTERY
90.6V 50.5V
1.6A 3.1A
VOC108.6 Bulk MPPT
157 Watts
Hope this helps (and makes sense :) ). I'll get these numbers while it is in absorb and float as soon as possible.
Ok, here's the absorb and float numbers.
Faulting in absorption; status screen---- IN BATT
100.1V 57.4V
0.9A 0.0A
VOC102.2 Absorb
0 Watts
And left+enter screen---- IN 5 BATT
50 + 60
30 - 22
40 576
Faulting in float; status screen---- IN BATT
100.6V 56.4V
0.7A 0.0A
VOC104.1 Float
0 Watts
And left+enter screen---- IN 5 BATT
50 + 60
30 - 25
45 565
Not 59.5V in float but still too high. I was monitoring the numbers and noticed that for most of the absorption stage the (-) numbers in the left+enter screen both read 0. I have the PV negative wire hooked into the classic common negative; could that have something to do with it?
Still thinking? :)
Quote from: wildblue on August 14, 2012, 08:55:23 PM
Still thinking? :)
Oh... Yes. Thank you for those screens ! Those really do tell a lot and you copied them down and entered
them perfectly !!
I can tell that the current sensor is working OK from those 4 middle numbers in the Left-arrow, enter screen (the secret screen)
One number that I question is the bottom left number... It always seems to be around 40 or so... Could you do one more
capture of that screen but turn the MPPT MODE to OFF ?? I am curious what the lower left number shows when it is
sitting there off.
Thanks for the excellent posting of that data.
boB
Quote from: boB on August 15, 2012, 01:43:02 AM
Quote from: wildblue on August 14, 2012, 08:55:23 PM
Thanks for the excellent posting of that data.
boB
I figure accuracy is best in these cases. ;D Here are the numbers.
Mode OFF---- IN 16 BATT
40 + 44
42 - 40
0 505
I noticed that the number between IN and BATT is 16 normally and 5 when it's faulting. What does that number represent? (Just curious. :) )
Quote from: wildblue on August 15, 2012, 04:43:58 PM
Quote from: boB on August 15, 2012, 01:43:02 AM
Quote from: wildblue on August 14, 2012, 08:55:23 PM
Thanks for the excellent posting of that data.
boB
I figure accuracy is best in these cases. ;D Here are the numbers.
Mode OFF---- IN 16 BATT
40 + 44
42 - 40
0 505
I noticed that the number between IN and BATT is 16 normally and 5 when it's faulting. What does that number represent? (Just curious. :) )
That number in the middle at the top is what we call "Reason For Resting", or RFR...
I should post a list of what they mean, but 16 means that you just turned the MPPT MODE to OFF manually...
5 or 1 would be Low Light usually at the end of the day, etc.
OK, so 0 (zero) in the lower left corner and around 40 for the middle numbers are exactly what I would expect to see
when mode is off. So, now I guess I do not understand what is causing the weirdness in voltages.
It may be time for an RMA. I will talk with Ryan, which happens to be here at the plant this week.
boB
I suspected as much :(. I'll await further instructions. Still glad I went with midnite. No other company I've seen is as customer friendly as you guys. :)
Quote from: wildblue on August 15, 2012, 06:23:27 PM
I suspected as much :(. I'll await further instructions. Still glad I went with midnite. No other company I've seen is as customer friendly as you guys. :)
Thanks W B !! Appreciate that. We'll get you up and running without overcharging ! I'm very curious to know what
the problem is with this one ! You got me stumped I think.
boB
So... RMA?
Looks like that is the best plan of attack Email me at ryan@midnitesolar.com and I will get you going
Ryan