Confirming that End Amps setting is working (forces absorb to float)

[5 Minutes 2 Midnite]

So, I've been monitoring my new system for a few days and all is behaving well. What I have not yet seen however is the Aux 2 LED on the local app come on when End Amps is triggered. I have a wizbang jr. installed and the controller is configured for an End Amps value of 1 amp (per lithium ion battery vendor).

So far I have not been watching when the charge stage goes from Absorb to Float. So I may be missing it. I have checked a while after Float has been reached and Aux 2 is Off. (Bear in mind that Net Amps has fallen to less than 1 amp by the time I've checked).

So this sponsors two questions:

1) Once Aux 2 has been triggered, how long does it stay triggered?

2) Any way in the logs to view when the Aux 2 relay was triggered and for how long? I've been through Ryan's local app instructional videos, and have examined the several WbJr values that are tracked ... but not seeing a value corresponding to Aux 2 activation time and length.

[Vic]

Hello 5  2..,

If I understand your questions correctly;

The WBjr is a Sensor module,  which receives power from and communicates via Aux 2.

It is the Classic   and its firmware that interprets the data received from the WBjr.

As you know,   the Local App displays the battery current,   as does one of the Status screens on the Classic's  MNGP display.

Once the Classic transitions from Absorb to Float,   the WBJR continues to function,   still measuring the Net battery current,   weather it is positive,  negative,   or happens to be zero at any particular time.

Perhaps I did not read your questions properly ...

FWIW,   Vic

[5 Minutes 2 Midnite]

I'm probably not expressing myself well Vic. In rethinking my logic let's drop the part about the Aux 2 LED lighting up. Let me ask my question in a completely different way...

The spec sheet for my LiFePO4 batteries specifies to stop charging when amps in reaches 1 amp (the specific language is: 'stop at 1A charge'). I therefore programmed the End Amps setting on the Classic to "1". As it happens, I installed a wizbang jr to insure accuracy of current in/out of the battery.

I assume from reading that when the end amps value is reached the controller switches from absorb to float (regardless of if the absorb time has been reached).

What I want to do is verify that the controller is indeed switching from absorb to float when charge current has fallen to 1 amp. I have yet to be viewing the local app screen when that event occurs (absorb to float), so I'm wondering if the event is recorded in the logs. What I'd be looking for (I think) is net current into the battery around the time the charge state switches from absorb to float. Again, I wishing to verify that once the batteries are taking in only 1 amp of current that the controller goes to float.

[Vic]

Hi 5  2..,

The Local App allows recording and plotting data.   The resolution of data plotted by the Local App (LA) is not very high (in my limited experience).

You should be able to Export Data from the LA,   massage it a bit,   and bring that data into Excel,  or perhaps other similar programs for display and study.

I am not an expert on this.

Also,   believe MyMidnite has  fairly good resolution of values,   which are recorded at five or ten minute intervals ...   am not certain of the present interval.

FWIW,   Vic

[ClassicCrazy]

Yes like Vic said - when the Local Status App is running it is logging data which you can export to Excel and make graphs of the data.

But I find using MyMidnite a bit easier to see what you are talking about - though it does not have as good resolution as Local Status App data .

So  you can go online MyMidnite and then select the fields you want to see to the graph - helps to also check full scale box too. They as you pull mouse across the graph it will show the actual data on the left so you can see what state of charge, current , volts, etc   change across the course of the day .

Larry

[5 Minutes 2 Midnite]

Thanx guys. I have dumped the data being recorded by the local app and looked at in Excel. Wasn't seeing the telemetry I am looking for, but I may not have dug deep enough yet.

off topic, what I am finding in the export is the data is almost too granular. Not a complaint! But when you just want to graph your daily solar kWh it's rather daunting. But I finally figured out how to convert Universal time into something Excel can chart, and the next thing is to write an Excel macro that extracts only data with a value > zero and then graph that for kWh in (that's hint, in case anyone has already skinned this cat).

[ClassicCrazy]

Thanx guys. I have dumped the data being recorded by the local app and looked at in Excel. Wasn't seeing the telemetry I am looking for, but I may not have dug deep enough yet.

off topic, what I am finding in the export is the data is almost too granular. Not a complaint! But when you just want to graph your daily solar kWh it's rather daunting. But I finally figured out how to convert Universal time into something Excel can chart, and the next thing is to write an Excel macro that extracts only data with a value > zero and then graph that for kWh in (that's hint, in case anyone has already skinned this cat).

There is some small bug in that data download dump from local status app.
John mentioned it in another thread. I should dig it up and ask Kyle if they are going to fix that since they are working on Local Status app for Voice settings

found the thread with info on graphing and the bug
http://midniteftp.com/forum/index.php?topic=3137.0

Larry

[5 Minutes 2 Midnite]

Thanks so much for digging that up. Helpful thread.

I also made sure to check all the boxes this time on the app and then exported. There is indeed a field called 'Charge Stage', which I should be able to cross reference to current when Charge Stage changes from absorb to float.

First though I'd like to verify the legend for the Charge State field. A total of five values show up in a sample dump for a full day: 0, 4, 3, 5, 6.

0 is the value from midnight to about 7AM, so clearly this is a state of No Charge.

0 changes to 4 at 7AM, so 4 should be Bulk MPPT.

4 changes to 3 a little before 1PM. One would assume 3 is the Absorb state. However, battery voltage at that point is 54.8, and I have absorb set to 55.2 on the controller. So what is state 3?

State 3 changes to state 5, inferring a transition to float state.

Later in the day state 5 changes to a state of 6, which I infer denotes a full battery that has been returned to Bulk MPPT mode.

But again, if someone could verify/correct what I have for mapping values to charge state that will be helpful. Not seeing where this is documented.

[Resthome]

Thanx guys. I have dumped the data being recorded by the local app and looked at in Excel. Wasn't seeing the telemetry I am looking for, but I may not have dug deep enough yet.

In the LA data dump you want to mark it to chart all data values so that when you dump the data to the csv file you will have the column labeled Charge Stage. Just look for when the value changes from Absorb (3) to Float (5)

[5 Minutes 2 Midnite]

Thanks John. Has anyone ever told you that you remarkably like ... oh never mind.

Do you happen to know what charge stage the value "6" maps to? My dump starts at 0 and increments to 4, 3, 5, 6 throughout the day. The mapping of number to charge stage is pretty intuitive besides 6. It's likely a unique for absorb after float, but there may be other possibilities...

If I watch the app for long enough it will be clear, and support is looking into it.

[WizBandit]

Just curious, did you set the ENDAMPS to use the SHUNT and not the internal CLASC shunt?

[WizBandit]

Thanks John. Has anyone ever told you that you remarkably like ... oh never mind.

Do you happen to know what charge stage the value "6" maps to? My dump starts at 0 and increments to 4, 3, 5, 6 throughout the day. The mapping of number to charge stage is pretty intuitive besides 6. It's likely a unique for absorb after float, but there may be other possibilities...

If I watch the app for long enough it will be clear, and support is looking into it.

[5 Minutes 2 Midnite]

That does it. Thanx.

[5 Minutes 2 Midnite]

What I want to do is verify that the controller is indeed switching from absorb to float when charge current has fallen to 1 amp. I have yet to be viewing the local app screen when that event occurs (absorb to float), so I'm wondering if the event is recorded in the logs. What I'd be looking for (I think) is net current into the battery around the time the charge state switches from absorb to float. Again, I wishing to verify that once the batteries are taking in only 1 amp of current that the controller goes to float.

So now that the log output file is decoded I can confirm for myself that, yes, the controller is obeying the End Amps setting. There's a bit of a time buffer, but shortly after the WbJr amp reading falls to "1", the charge state changes from Absorb to Float.

====================================================================================
Having arrived at that I learned something unexpected. I don't have all my panels installed yet, and around the time of day the charge state is shifting from absorb to float, it's well after noon, and the output from the panels has dropped precipitously. In fact, shortly after the charge state goes to float the WbJr goes negative amps... the system is drawing out more than is going in.

I am tentatively concluding therefore that the reason End Amps got triggered was NOT because the batteries were no longer thirsty for more than 1 amp of charge, but rather that with the amount of power being generated vs load, the charge available to the batteries has fallen to 1 amp or lower. I would suspect the controller would be unable to discern the difference, and could do little about completing the charge even if it could make the distinction.

If my theory is correct, I guess I could disable End Amps, but would it even matter? At that point the load exceeds the power in. I guess the solution is a few more panels for the current daily load if I want a full charge every day.

Learning is fun.

[Vic]

Hi  5 - 2 ..,

A couple more things;

When the Classic has made a transition to Float,   and there is insufficient PV (or other power) to maintain Vflt,   the Classic will display Float - MPPT.   This might the additional code that you are seeing.

If you have set ReBulk to a relevant value,  then it is possible for the Classic to try to start a new Bulk charge,   but,   near the end of the day,  this is not likely what you are seeing.

When the Classic goes to Float,   the Classic will produce no power from the PVs,   any loads on the system will cause the WbJr to show -- Amps.   This is caused by Surface Charge in Lead Acid batteries.   I am unfamiliar with Li batteries,   so do not know the extent to which this might apply to your batteries.   The Surface Charge causes the battery voltage to be above the Vflt setting,  and the loads will remove the Surface Charge.   Your system has Vabs and Vflt separated by only 0.1 volts IIRC,  so if this effect does apply to Li batteries,   the duration of this event will probably be short ...

Also,  if the Classic is NOT in Absorb,   it ignores the battery current from the WbJr,   and the transition to Float will not be triggered regardless of the WbJr current being below the EA setting.

As you know,   the set EA,   and the Maximum Absorb time are an OR function  --  whichever occurs first will trigger the transition to Float,   as long as the CC is still in Absorb at that time.

Vic