SOC way off with WBjr - Pos amps issue??

[evster]

Hi all,
I'm just new to the forum and been with Midnite 150 CC with WBjr for just a few months now.
I've been scouring the posts looking for clues of what might be wrong but to no avail.. Hence this post.
A few months back I replaced 2x PL40s PWM CC in my standalone system with a single Midnite 150 CC.

Whilst the green LED on the WBjr flashes and I can read its screens, I have never been able to make sense of the State of Charge (SOC).
The remaining amps and associated SOC value continue to decrease each day even when the kWhr produced 6-8 per day are greater then what we consume (4kWhr)

My system was reading 35% SOC the other day yet my 24V system batt volts has been greater then 25V following sundown.
When my system goes to float the SOC is reset to 100% and the cycle starts again.. continually decreasing each day and practically ignoring the solar generation and just
tracking the amps out of the system.
Its like it's reading a 10th of what it should for positive amps produced from the solar array which is sized at 1920watt.
When I compare the A rating from the Classic for the batts to the WBjr they are markedly different.

Correct me if I wrong....the WBjr's first screen shows the absolute amps going into or out of the system. ~ amps in - amps out to the load.
In full sun for example I was getting 38.5A on the classic into the batteries. Pic 2. .
When I view the WBjr screen it was on 4.1A.
The load at the time (via the inverter) was about 0.5A so therefore i expect the WBjr should be reading 38A not 4.1A. Pic 1

The WBjr is installed on the recommended deltec 50mV 500A shunt on the batt neg lead, Aux 2 configured, batt Ahr rating setup etc.
Pic 3 says it all lifetime hrs in =366 AH  out =6554 AH

Any suggestions are most welcome.

[Tons001]

Based on the pictures you posted, you have 34.4a load on the system somewhere. I have my battery (-) on one side of the shunt and my (-) loads / Midnite (-) on the other side so I can see the what is going in or out of my battery bank. If you had your battery (-) / Midnite (-) on one side of the shunt and loads (-) on the other, I think you would only ever read the amps your loads are pulling.

Not sure though, there are way smarter people than I on here. Someone will have the solution. Your battery bank is massive.

[Westbranch]

you will need to post more details, but at first look you are not getting enough charge back into the battery.if , ''AFTER A FULL CHARGE'', you are reading only. 25.x VOLTS, IT SHOULD BE AT LEAST 26.4V.  Tell us your \cc settings , battery make etc...
Right  now you are deficit charging if the SOC regularly drops as described...

hth

[Resthome]

As Westbanch said we need a lot more information. Like AH size of your batteries, but most important how is the shunt wired into your system. One side of the shunt need to go directly to the negative side of the battery bank with absolutely nothing else attached to the negative side of the battery bank. All other negatives must be connected to the opposite side of the shunt.

There is definitely something strange with your system.

[Vic]

YES,  make certain that the WBjr is oriented correctly on the Shunt,  and that the Shunt is wired as shown in the diagram on the WBjr installation instructions.

It does look like the Classic IS reading the Shunt,  if the three photos posted were taken in rapid succession.  Looks like the Classic is in Bulk at the time of the pics.

The WBjr should be measuring the current flowing into or out of the batteries,  if you have the wiring of the Shunt correct,  and the WB correctly oriented on the Shunt.

Your statement that the battery voltage is above 25 V AFTER sundown,  is not necessarily an indication of a problem,  IMO.  Although,  this could depend on how long since the Classic had exited FloatMPPT,  how much load was on the battery,  and so on.

Your Charge settings, and battery Capacity and type would be helpful,  as well.

We could use more info.  Vic

[boB]

Did you do a VMM or factory reset from the MNGP just before you installed the WB Jr ?

Or, did this Whiznang Junior come with your new Classic ?  If it came with your
new Classic, then all settings ~should~ be good, but maybe you need to do
a Vulcan Mind Meld reset anyway ?

Also, you can reset all of those Amp-Hour numbers back to zero from the LOGS
menu (the first logs menu) and pressing ENTER...   Then you can select what
values you want to clear.  The first couple of values to clear are the regular
Classic kW-Hour and Amp-Hour numbers which you probably DON'T want to
zero out, but above those are the WB Jr. statistics.

How long has this WB Jr. been connected to your Classic again ?  You have a lot
of Amp-Hours (+ and -) showing.  Mainly net and + ?

Also, what is the temperature compensation screen show and of course your
battery capacity and the battery temperature compensation percentage for
battery capacity with battery temperature change set to ?  Usually that reference
is 25 degrees C but that would be selectable from the SETUP screen which
I don't see in these pictures.

Those kinds of things can make a difference.  Also, do you see the Amp-Hours roll
by QUICKLY ?  meaning, do you see the Amp-Hours change by one every few seconds ?
There IS a test mode where that might be set but a VMM or factory reset of charge
settings should have already reset that mode flag from the factory or if you had
added the WB Jr. to an existing Classic and/or had updated the firmware for this
WB Jr.

So, a couple more things to look at here.
Sounds like this shouldn't be too hard to straighten out.

boB

[evster]

Hey Guys,
Thanks for the replies......I think its is now fixed .. 
Basically a wiring problem ... I feel like a bit of a numpty, as I did make an incorrect assumption.
Resthome your comment about absolutely nothing else being battery side connected - hit the nail on the head!!
Vic & Tons001 .. I think you were on this path also?
Perhaps this fact could be added to the doco as an improvement?

When I first noticed the issue .. I thought immediately about the wiring of the shunt and the WBjr and triple checked it all .. checked all the settings the battery temp correction and capacity, did factory reset etc.
Everything appeared correct, we have had good weather of late so was quite often hitting float every other day of so ... SOC would reset to 100% and everything looked correct ( apart from the total shunt current).and the cumulative A in the WBjr status screen.

The wiring problem was as simple as I had the neg from the solar array going direct to the battery bank. So the classic was measuring this and displaying it for me _ the battery bank was charging. I then incorrectly assumed that the classic did some basic math and read the load current from the WBjr to calculate an absolute A in or out of the battery bank.
The WBjr doco says connect inverter/ charge controller neg/ Loads here - which is exactly what I did.  I don't consider the neg from the array a load , so I left it where it was .. on the battery side. There doesn't seem to be any real mention of the array neg in the WBjr doco..and i don't recall that the full manual has be updated to include any reference to the WBjr
Now that the "penny has dropped" I realise that the WBjr needs the solar array neg connected to the load side so that it can directly measure ALL CURRENTS in and out of the battery bank.
It's quite simple .. and there is no maths function where the classic sums the array amps with the load amps separately and then calcs a total! doh...
Bob, Thanks for your input .... Your were right "Shouldn't be to hard to sort out " and it was a quick fix so thanks for all the responses..
I'm now especially enjoying the Midnite CC now that I know that ALL currents IN and OUT need to go via the shunt and the WBjr.

Now that I have the basics sorted I plan to investigate utilising the WBjr terminating charge based on end amps..
So I've got some reading to do and then perhaps I'll be back asking Qs if I hit and Hurdles?

FYI. I have also been considering up-sizing my array and the Midnite 150 now affords me this option since i replaced the 2 PL40s .... We are reasonably frugal power users @ 4kWhrs a day average and as mentioned our array is 1920 watts at 24V with a battery bank at 1860Ah. Still in the depths of winter we have had to resort to the petrol genny a little to frequently for my liking.
I've decided for now to try next winter as is with the new Midnite 150 MMPT in play( and keep everything else the same) and see if the theoretical efficiency gains of the MMPT over the PWM is noticeable..

Thanks again to all... much appreciated .. I have found reading posts on this forum extremely useful!

[Resthome]

Glad to see you got it working. I find the WBjr to be very accurate on SOC and pretty much in sync with my Link10 that is monitoring the same shunt and only slightly different on Net AH.

[Vic]

Hi evster,

Glad that you got this issue figured out.  The WBjr is a very usefgul accessory to the Classic and KID CCs.            Have Fun,    Vic