New-ish Classic and MNGP code update for trying

[ClassicCrazy]

I just did the updates to 3700 and 3701 . I saw the 6 minutes default for Lithium setting.
I probably didn't notice what ever it was last time since I restored my previous settings.
I am using the Local Status app to tweak the battery voltage offset. Not sure if that is working right or not. I will find out tomorrow and set it if I can catch the peak charge voltage when it is in absorb. It is different between Absorb and Float that it is tough to predict.
Larry

[boB]

Larry, are you using lithium now ?

I need to check to make sure if I added the tighten up Absorb voltage regulation while in lithium mode.

It won't make any big difference either way but....

[ClassicCrazy]

Yeah I use lithium .
How can we tell the regulation ? Or what capture will help you see it.
It was sort of cloudy this morning as it came up to absorb . The Classic is orange line on voltage graph. The peak is Absorb set at 56v  6min absorb time ending amps 15 . I have -.2v for cable offset.  You can see that Jakiper battery two is not balanced and the cells really split apart at absorb by about 150v differential. I hope to take that battery out and try to give fixed current to see if bms will balance the cells - or to open it up and manually balance each cell.
By the way - the graph below is not pure Classic - I have the Hawkes Bay on it too. I can always shut that off if we just want to see what the Classic is doing.
Larry

[boB]

Well, looks ok except for that balance of the batteries !

Unless their voltage readings are just off a bit ?

[ClassicCrazy]

The "smart" bms of each battery are networked together so the bms will keep each of the three batteries pretty close in voltage. 
The software ( which Graham figured out) shows the bms reported voltage of each of the 16 cells in each battery. There is also battery current information.
I turned off the HB pv input and will leave it off until batteries are full via the Classic so we can see better how the Classic voltage regulation is. I can get a screen shot later on of how that did.
Larry

[ClassicCrazy]

I don't know what happened here -
Set for 56v absorb , 6 minutes absorb, 15 amp ending amps
-.3v cable offset
I guess it never got to 56v so it kept charging .
Battery 2 went to overvoltage protection and bms shut it off charging. You can see the high cell went to 3.7v .
Maybe I should have had 0v for cable offset. I just changed that . And for tomorrow I will lower the absorb voltage.
It really takes a bit of tweaking and not using actual voltage readings for charging lithiums when the controller can not see the actual lithium battery voltages. Get it right for the absorb and then the float is off, or vice versa.
But the change did seem to help in that it used to seem to go into absorb too soon , now it seems to hang in there until it gets much closer to the absorb setting.
Larry

[boB]

I don't know what happened here -
Set for 56v absorb , 6 minutes absorb, 15 amp ending amps
-.3v cable offset
I guess it never got to 56v so it kept charging .
Battery 2 went to overvoltage protection and bms shut it off charging. You can see the high cell went to 3.7v .
Maybe I should have had 0v for cable offset. I just changed that . And for tomorrow I will lower the absorb voltage.
It really takes a bit of tweaking and not using actual voltage readings for charging lithiums when the controller can not see the actual lithium battery voltages. Get it right for the absorb and then the float is off, or vice versa.
But the change did seem to help in that it used to seem to go into absorb too soon , now it seems to hang in there until it gets much closer to the absorb setting.
Larry

Great on that last part about not going into Absorb too soon.  That would be possibly due to the tightened up range ?

IF you are using the Vbatt Offset  adjustment in Tweaks, I would think that would cause an over-voltage when current into the battery goes lower when it is in Absorb.  At that time, you don't have the voltage drop that was needed to get to the first part of Absorb when the current was higher.
Then the actual battery voltage is closer to the  voltage at the Classic terminals.

[boB]

Well, there was a slight screwup in the last code update.

Here is a new one to try.   Update the Classic and then the MNGP.

This has to do with the transitioning from Absorb back to Bulk MPPT and back and forth.

Lithium will be a tighter voltage range than lead acid from the new register address, 4394...

Sorry and thank you !

boB

http://bob.midniteftp.com/Classic_MNGP_Update_3702-3703_6-20-2023.zip

[ClassicCrazy]

Well, there was a slight screwup in the last code update.

Here is a new one to try.   Update the Classic and then the MNGP.

This has to do with the transitioning from Absorb back to Bulk MPPT and back and forth.

Lithium will be a tighter voltage range than lead acid from the new register address, 4394...

Sorry and thank you !

boB

http://bob.midniteftp.com/Classic_MNGP_Update_3702-3703_6-20-2023.zip

I just did the update and will see how it goes tomorrow.
Larry

[boB]

I just did the update and will see how it goes tomorrow.
Larry

Thank you Larry !

boB

[ClassicCrazy]

Bob,
Here is with the newest firmware but wasn't the best test yet since I had to tweak some settings like offset, absorb setpoint, and float. And I also cut it short by forcing it to float because I had to go somewhere.
Part of the reason I had to tweak my settings is because in past it would never get the true setting for absorb - but maybe it is doing that now . A few more days and I will find out when I can watch what is going on.
Here is from today as it climbed up to absorb. The small hump before the big rise is the Hawkes Bay going to its absorb which I have set much lower.
Larry

[boB]

Looks OK Larry so far.

Will be nice to see a longer Absorb time with moving clouds throughout the absorb period.

boB

[ClassicCrazy]

Bob,
I gave it another try today but had to Force Float again because the batteries were full before the setpoint I had of 55.2. They seem to have gotten close to full at 54.8 so I set it there. The current into the lithiums dropped down to almost zero and the Classic hung on at Bulk. We will see what happens tomorrow at the new 54.8 absorb point. Not sure if this point changed because of the heat in the battery room. I also put the ending amps to zero now. You can see that the cells are not so balanced and I am working on correcting that.
Larry

[boB]

Bob,
I gave it another try today but had to Force Float again because the batteries were full before the setpoint I had of 55.2. They seem to have gotten close to full at 54.8 so I set it there. The current into the lithiums dropped down to almost zero and the Classic hung on at Bulk. We will see what happens tomorrow at the new 54.8 absorb point. Not sure if this point changed because of the heat in the battery room. I also put the ending amps to zero now. You can see that the cells are not so balanced and I am working on correcting that.
Larry

What is your absorb time set to ?   Which reminds me, I meant to reduce that time to be able to go to zero.  Or at least less than 3 minutes.

Do you have a battery temperature probe connected ?   The new lithium setting should now allow a setting of 0 voltage change with temperature but be able to view the battery temp and also to turn off charging when the battery temp goes below zero degrees C  or whatever you have it set to.

Are you sure you don't need to keep the battery voltage up at absorb longer so that the BMS's can have time to balance the batteries ?

boB

[ClassicCrazy]

Bob,
I don't think this firmware is working right.
My battery filled up ( according to SOC and current dropping )  , though at a lower voltage than I had Absorb set for. The Classic was holding it at a lower voltage than 54.4v absorb was set for. Not sure why the full voltage keeps dropping - maybe battery temp?  I turned on the Hawkes Bay charging which I had off, and the voltage started rising on batteries. I lowered Absorb setpoint on Classic to the 54.4v that the batteries were holding at , then i saw Classic briefly display Absorb but then go back to Bulk. I had absorb time set for 6 minutes.  I kind of wondered the last two days why I never saw it go to Float and had to force it there.
I did just confirm that the battery temperature is showing with temp compensation disabled.
I guess I could dip the temp sensor in some ice water and see what happens.

screen shot below shows battery charging Classic only , small peak where voltage climbs is when I turned on the Hawkes Bay, and then the drop off is when I forced Float on Classic.


My batteries bms balancing is something I just posted a video about. It has been confusing to figure out from available info. I took one of the batteries out of the rack and have it now with regulated power supply. The bms will begin balancing on charge of the balance setpoint but then go off balancing when charge stops. The manufacturer had said to let it go to overvolt protection which seemed weird to me. I had heard that the battery will continue to balance without being in charging state, but I just found out that it only continues to balance if it is in OVP state after the bms shuts off charging. I just confirmed all this by hooking up power supply , manufacturer software which shows balance on or off, and experimenting. The bms will only passive bypass balance at like 75 mv which isn't much for 100ah cells. That video is here https://youtu.be/Oz8bZhvrA6s

Andy from Off Grid Garage also has recently analyzed the operation of these Pace bms in my battery. I did just order a 4 amp Neey active cell balancer that he talked about and it is supposed to be delivered here today.

Larry