Classic 150 ignoring ABSORB voltage setting?

[Vic]

Hi Kevin,

OK,  so you have the Battery Temp Sensor (BTS)  mounted onto a battery near the center of the pack?

If you go to the Temp Comp (or,  is it T-Comp)  menu under Charge.  Press the right soft menu button,   what does this show?

Do you see an abnormal Float voltage,  as well?

If it is easy,  you could unplug the BTS,  while watching the Absorb or Float voltage and note its effect.

Believe that you mentioned that the batts are generally near 25 C,  IIRC.

Thanks,   Vic

[dgd]

Hi,

Disconnect the battery temp sensor from the Classic
Repeat the test and observe what voltage on the MNGP the Classic goes into Absorb
Using a decent DMM check the actual battery voltage .
Disconnect and do not use the Trimetric.

dgd

[k7zs]

Hi Westbranch

No unusual settings, did the factory reset, adjusted absorb, float, EQ voltages, and set the limits to match the EQ.  That's it.

I run the Local App on my system, but not on my friends (the subject system for this thread).

What item(s) would I look at on the Local App to tell me why, perhaps, the controller is triggering the absorb mode way ahead of schedule?

I can set it up if I thought I would learn something ... CARE to SHARE specifically what to look for?

Thanks in Advance!


-Kevin

[k7zs]

Hi Vic

The TEMP is exactly what it should be, just under 25C (and it was a little different today than yesterday, so I know it's actually following the temp).  Our daytime temps here this time of year are between 70 and 75 F.  The BTS is mounted near the + terminal of the first battery, the string is arranged in a straight line (no batteries side by side), they are in an open garage with ample space between each battery.  I think the reading is valid.  Hard to say what the 150 is doing with that info?

Other suggestions are to remove the BTS, and for some reason NOT use the Trimetric (sorry, going to keep the Trimetric, it has been my 'system sense' tool of choice for years, has treated me right.  Yes I also have a WBjr)  I have matched the voltages against a DMM I have used a lot, and all 3 agree.

I will disconnect the temp sensor, and re-test and report back.

-Kevin

[k7zs]

Vic, forgot to answer an important question: Float voltage is RIGHT ON.

-Kevin

[Westbranch]

The BTS is mounted near the + terminal of the first battery,

this tweaked me a bit, as all recommendations I know of is the BTS be mounted near the middle of a cell near the center of the whole battery  ...  I wonder if that first battery which gets the excited electrons is hotter than the rest??
Got  a laser thermometer?

[Vic]

Vic, forgot to answer an important question: Float voltage is RIGHT ON.
-Kevin

Hi Kevin,

So,  you are saying that the Vfloat is NOT BEING COMPENSATED at all,  because it is so close to 25 C (I guess).   Boy,  isn't that strange.

Will need to think about this some more.   Thanks,   Vic

[k7zs]

GM Vic

Yes, it appears Vfloat is not being compensated. Regardless of where the BTS is, it is reporting a temperature to the controller that should not invoke any compensation on the ABSORB trigger, which is set for -5mv per cell, the default.  Again, I adjusted only 4 parameters after setting the controller back to factory defaults.

AND, there ARE some references to mounting the BTS on the battery stud, XANTREX for example comes on a plate with a 3/8" mounting hold - the theory that the plastic case is enough of an insulator to introduce inaccuracies.  We are only concerned with HIGH TEMPERATURES here, and since heat RISES, we put the BTS on top of the batteries.  My own system has performed flawlessly for the last 3 years since going to the Classic CC.  1.5KW panels, 8 Costco Golf Carts (T-105's) in a 2x4 arrangement, I dip my batteries down 25 - 30% per night.  4 years now on the batteries, never missed a beat.

My last experiment will be to unplug the BTS and see what happens, but what will that tell me? That either the BTS or CC is bad, but not WHICH ONE!

I am only 1,000 miles from the nearest MS Dealer! (but only 90 miles from COSTCO!)

Stay tuned

-Kevin

[k7zs]

Last post I meant to say that the T-COMP isetting is the default -5mv/cell/degree C

-Kevin

[Vic]

Hi Kevin,

YES,  --5mV per cell per degree C is usually the correct setting for many Flooded batteries.

The experiment of unplugging the BTS from the Classic is a very good one  ---  because you can watch the effect,  in real-time on the Absorb voltage,  and see if it is Compensation that is causing the issue.

Still thinking on this ...  73  GL,   Vic

[dgd]

We are having a problem where we cannot get the batteries to charge up to proper specific gravity, and in adjusting the ABSORB voltage to raise it, the charge controller ignores the new settings, and continues to top out right around 58 volts, in spite of my continued upward adjustments, currently set @ 59.8v.

So you are doing this adjustment using the keypad and MNGP display on the Classic?
Are you sure you are saving the new setting once they are entered?
I have not done this for a while but I seem to remember that you need to press the enter key and then a message about new setting saving/writing will be displayed.
If you use the LocalApp then there is a return arrow button on the lower rhs that needs to be clicked to save the new setting.

dgd

[Resthome]

I think Kevin is able to change the Absorb voltage setting but it is going to absorb 1.6v before the actual Absorb Set point.

Kevin, some questions for a little better understanding.

What is the cable length from the Battery bank to controller and what AWG is the cable?
Where are you measuring the Battery voltage at with your DVM?
And what it the output amps from the controller at the time you are measuring the battery voltage?

[Halfcrazy]

On the classic when it is 1.6 volts low from the absorb set point lets go into the Tcomp menu and you should see a "View" button I forget the exact layout but it is in there some where (I can find it if needed) and it will show the actual voltage the classic is targetting.

Report back with that value:
The actual set point:
Battery temp as read on the Classics temp menu:
Then go into the limits menu and see what Max voltage is set to:
Then in the WBjr status screen there is a menu showing the Battery temp offset or neutral point. i have seen this set low by accident and cause this, What is that value? Should be 25C

[SuperTed]

Hi Kevin,
do you have a battery voltage offset set in the tweaks menu?
Cheers
Alister