classic 150 and absorb settings

[elesaver]

Sunday evening with the sun down, I switched out a classic 200 for a classic 150 that I had purchased at the "garage sale" offrering a few months ago.  This is a 24V system using a forklift battery with 938 aH installed new in October 2015.  The 200 was working fine but I am putting some solar power into a small barn and decided the 150 would be better at the house since it can handle more amps and I may want to add more panels at a point so I am putting the 200 at the barn.

Now, to the problem.  I have programmed the same settings into the 150 that I had with the 200.

AbsV  31.5 for 4 hours and EA at 15    Float 28.2        Re-bulk 27.8

Both yesterday and today, the absorb stage kicks in before the voltage gets to 31.5.  The battery voltage is reading 27.6.  There is no gassing. 

The strange thing is that the SG was down on Monday morning (as expected with overnight use of about 100 aH) but it was back to 1.285 by Monday evening despite no gassing or reaching the absorb voltage.  The same thing happened today.

I am concerned that the 31.5 AbsV is not the trigger to start the absorb stage.  If I lower the voltage from the cc voltage battery reading, then BULK MPPT kicks in.  Example, if the battery voltage says 27.6 and I lower that, BULK MPPT will kick in.  The float voltage does not seem to be honored either.

Be advised that I know these values seem high for AbsV and Float but I've learned that with this forklift battery, I need the higher settings.

I do have a whizbang, jr and a hydovolt and have learned to watch the SG and not the cc readings but this seems odd to me and I'd like to understand what is happening and why this is happening if this is normal.

Thanks for the help.  I hope it's clear.

[Westbranch]

If you use the Local App use it  to check ALL the additional settings , one or more may be off by a bit like Temp Compensation or Battery Efficiency...  Hope you had them written down..

hth

[ClassicCrazy]

If the Local Status App was used all the exact settings could have been saved and then restored to the new Classic.

I was thinking it could be battery temperature sensor or setting .

Larry

[elesaver]

I do not use the local app and have check the temp compensation.  Battery compensation was at the default of 94% but I changed it to 96%.  Temp compensation is at 25C. 

Any other suggestions from anyone? 

[ClassicCrazy]

I do not use the local app and have check the temp compensation.  Battery compensation was at the default of 94% but I changed it to 96%.  Temp compensation is at 25C. 

Any other suggestions from anyone?

You want to find the one that is temperature compensation - usually defaulted at -5 mv / C/ cell  .

If you have temperature compensation set at 25 there and enabled there is your problem.

On MNGP the temperature compensation if in first menu Charge , then T-Comp - then it says COMP  -mv/ Deg C / Cell

Set that to -5 or whatever you battery manufacturer recommends.

Larry

[elesaver]

Thanks for the try, Larry.  At the Whizbang screen, push set up, push more, temp compensation is at 25.  At the charge screen, push temp comp, it is at -5mV/cell.

These are the same settings that were used for the 200 so I'm still confused.

Today, at 3:30 pm after TONS of sunshine, battery voltage is reading 27.2 and the absorb stage is still active eve  though the 4 hours of time programmed for absorb have completed. 

I also see that I've only harvested 2.6KW today which is FAR, FAR (did I say Far) below what should have been today with the amount of sun.  Battery SOC is only 95%.  AbsV should've been completed at least 2 hours ago.  EA is set at 15 so one or the other should've ended the absorb stage.

I really need some help on this.  I guess I'll check to see if midnite has a tech support phone line.

[Vic]

Hi elesaver,

First,  please remove the front cover of the Cl 150,  and measure the battery voltage,  and PV input voltages and record these.

Please check the PV in and Battery connections at the Cl 150 terminal block.  As you know,  they must be TIGHT.   Also check the other connections between the PVs,  plus the connections to the CCs battery breaker and its connection to the battery.

What are the versions of FW the the Cl 150,  and MNGP is using?
What does the Temp menu show for Battery Temp?

Please check the Tweaks menu Offset voltages,  and note.

When the CC is misbehaving,  what is the PV input voltage,  and what is the battery voltage,  and note this as well.

Also check battery terminal to cable connectors ...   know that this behavior appears to have followed the installation of the Cl 150 ...

Thanks for the info,   Tedious Vic

[mike90045]

using the Local App to read the registers and store them as .CSV file and then reload, is a REAL TIMESAVER
and you can print the listing out and read it in english, what all the settings are

[Vic]

elesaver,

Will add one more thing;

Was kind of heading in this direction with a couple of questions.  You may want to using Legacy P & O Mode,  particularly if some of  the lack of PV power production was caused by intermittent cloudy conditions.

You are probably working with MN Tech at this point,  but just wanted to throw out this as an additional thing to try.

We all are learning,  so,  hope you will keep us informed on what you have found as the causes of this situation.

Good Luck,   Vic

[elesaver]

My charge controller is "now on the way to the hospital."      After speaking with MidNite tech and describing the issues, it appears that there is a problem that can't be resolved with settings, etc.  I sent the CL150 today so it will be at least a week or more before any diagnosis can be made.

Just as an aside...yesterday evening, I was beginning to "power down" everything...taking loads off, etc.  I did not remove the cc until this morning but when I looked at the MGNP at 8:30 am (EST) with no sun of any substance on the panels, the unit was still in absorb!  Definitely a problem.

When I learn what may have been the problem, I will update.  Thanks for the willingness to help.

[Vic]

Hi elesaver,

Thanks for the info.  Too bad that the Classic needs to check in with the Hospital,  but sounds like that is what it really needed.

Always hope that just a few settings can be massaged,  and that will do the trick.

Good Luck with the batteries,  and the weather.   Thanks,   Vic

[elesaver]

I'm feelin' mighty fine.  My Classic 150 is in transit for return to me from Midnite Solar.  The board needed to be
replaced and they have done that under warranty.  I appreciate that from them.  I'm looking forward to
connecting the system again and seeing things operate correctly.  Thought you'd like to have a final update. 
Of course, if I don't get the outcome I expect, I may need help once again! 

[ClassicCrazy]

Midnite did some warranty on my Kid controller and I was amazed how fast they got it back to me - and amazed that our postal system could still do the job too !
Larry

[boB]

I'm just now seeing this...
Weird !  That is, if the reference temperature in the Whizbang Junior sub-menu is set to 25 degrees C
and the Classic thinks that the battery temperature is near 25 degrees C.   No compensation should
be happening.  There were some Classics set to reference of 10 degrees C that would have
caused this to happen but if that was at 25C,  and the TEMPS menu says something close
to 25C, then it is very weird indeed.

boB