There is a newer Classic and MNGP firmware update if you would like to try it.
One thing it does is to add a battery selection screen in the VMM or quick setup screen.
After updating the MNGP and Classic, re-power the Classic, and when the MidNite Logo graphic shows up, hold down the LEFT and RIGHT ARROW keys till you see the first setup screen.
Lithium will also default the battery temperature range and Absorb time to 1/2 hour I think it is.
Keep an older firmware file around just in case it doesn't work good for you.
One thing I know needs fixing but is not a big deal is that when choosing a Lithium batter, the EQ voltage adjustment menu still shows up.
http://bob.midniteftp.com/Classic_Control_150_3485_11-8-2022.ctl
http://bob.midniteftp.com/Classic_Control_200_3485_11-8-2022.ctl
http://bob.midniteftp.com/Classic_Control_250_3485_11-8-2022.ctl
Let me know if you try it, please. Either here or bob--AT--midnitesolar.com minus the --
boB
Bob - I will try to load it up sometime in next few days and see if it works okay.
Is that the only thing different - is the defaults for lithium ?
Larry
Is this a Beta-ish version that anyone can try? I have a couple of friends that just went to lithium and I can see if they would like to test it out?
If reports are good, will this hit the firmware download page?
I will write up the changes tomorrow. Another change was the tightening up of battery voltage going in and out of Absorb to BULK MPPT. This is especially for Lithium, if the battery requires an Absorb time of any length.
boB
Bob - It will help if bulk to absorb is tightened up.
Here is graph of my lithium batteries from yesterday with Classic set for 56v Absorb, 3 min absorb time, and 15 ending amps.
In graph below orange line shows Classic getting to about 55.6v when it went to absorb.
I think I have the battery cables tweaked okay but all these settings just sort of have to be made up with trial and error to find out what works best for the batteries getting full.
It doesn't help that one of my batteries has a much greater cell imbalance than the other two.
I am going to remove that battery this summer and open it up to try and manually balance the cells or figure out how to have it's bms do the job on it's own.
All the photos below are at same point in time with peaks being at Absorb.
Larry
Larry, you set the startup VMM to Lithium first ?
BTW, there is a way to reduce the width of that Absorb hysteresis that involves going through the Modbus editor screen and we can play with that if you like.
Are you simply using the battery voltage meter on the Classic or are you comparing V to a Fluke meter (or equiv meter) ? If using the Fluke meter, the Classic battery voltage reading may be off a bit
boB
Bob,
I was using the battery bms reported voltage and the Classic reported voltages.
Weird thing is that same settings today - Classic reached different voltage at Absorb and tracked much closer to the battery voltages. I have no idea why. see photo
I will load the new software sometime soon and see how it compares.
Larry, how much elapsed time is there (about) in your voltage graph ?
I definitely see the battery voltage averaging from the Classic's reading.
The Classic averaging time should only be a couple of seconds as I remember so maybe these voltage readings are not many minutes or hours or something real long in your graph. I know the average is not THAT long :)
So, with the software you are running now, the old software, it is understandable that the Vbatt was able to go a few tenths below the desired absorb voltage. The newer software should tighten that up a bit if Lithium is selected.
Bob ,
Sorry I cut off the time on that - here is same screenshot with the time on it .
Also , your download for me on Firefox is showing up as webpage and a lot of numbers.
Should I save that as a text file , and then rename it as .ctl ?
You said we should update both the classic and the mngp - does your download contain both files needed ?
Yes, you can save as a text and rename or just right click and "save link as" I believe.
You are right ! I forgot the MNGP file !
http://bob.midniteftp.com/MNGP_3484_11-8-2022.rem
In windows, right click and save link as into the firmware updater directory.
The updater should choose the most recent file
boB
Bob,
Just did the update early morning here . It all loaded up just fine, and I did see the new lithium selection.
I restored the same settings as I had in before so should be able to compare with the last couple days when it comes into absorb, etc.
Larry
There was a mistake in the 3484 MNGP firmware that is now fixed...
When doing a VMM for whatever battery system, the MNGP would not send the proper Absorb time for that particular battery type. The Absorb time was always 2 hours as in, flooded. Lithium was supposed to be 6 minutes for instance.
Try this one to replace if you would like.
http://bob.midniteftp.com/MNGP_3700_6-12-2023.rem
The last Classic Control (V 3485) had a problem with Vbatt offset and possibly battery voltage reading altogether. Here, those are fixed...
http://bob.midniteftp.com/Classic_Control_150_3701_6-12-2023.ctl
http://bob.midniteftp.com/Classic_Control_200_3701_6-12-2023.ctl
http://bob.midniteftp.com/Classic_Control_250_3701_6-12-2023.ctl
http://bob.midniteftp.com/Classic_Control_250KS_3701_6-12-2023.ctl
Oooops and Thanks.
boB
I had not taken note of the battery offset I had in my original setup and the Local App doesn't save that. So I was playing around with the offset after last firmware and maybe that is why it didn't seem to work right.
I will load up the new one and see what happens.
Do we use the same MNGP update as last time ? Oh I see that newer mngp update in a previous post.
Larry
Quote from: ClassicCrazy on June 12, 2023, 08:04:03 PMI had not taken note of the battery offset I had in my original setup and the Local App doesn't save that. So I was playing around with the offset after last firmware and maybe that is why it didn't seem to work right.
I will load up the new one and see what happens.
Do we use the same MNGP update as last time ? Oh I see that newer mngp update in a previous post.
Larry
Yeah, I screwed up the Absorb time sending of data. I was set to 2 hours
Now it should send the proper time for a particular battery
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
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....
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
Well, looks ok except for that balance of the batteries !
Unless their voltage readings are just off a bit ?
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
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
Quote from: ClassicCrazy on June 14, 2023, 12:50:17 PMI 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.
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
Quote from: boB on June 20, 2023, 06:20:20 PMWell, 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
Quote from: ClassicCrazy on June 20, 2023, 10:11:29 PMI just did the update and will see how it goes tomorrow.
Larry
Thank you Larry !
boB
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
Looks OK Larry so far.
Will be nice to see a longer Absorb time with moving clouds throughout the absorb period.
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
Quote from: ClassicCrazy on June 22, 2023, 12:43:45 PMBob,
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
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
New code is working perfect here...
This looks beautiful, Jim, great work!! Vic
That's great, Jim !
Now we gotta figure out why Larry's is not quite getting up to the right voltage ?
I am playing ham radio this weekend but have a system at work I will look at monday.
Bob - I still don't get the controller going all the way to absorb point.
I had Classic absorb set for 55.7 v today. But I also had the Hawkes Bay set to 54.2v absorb and forgot to turn it off for testing the Classic. There were loads on all morning.
As can be seen in the graph the Classic stayed steady in voltage and according to SOC filled up batteries around 54.2v.
I added the Classic reported Charge state and SOC to the top of graph screens.
I will need to lower the Absorb voltage and shut off the Hawkes Bay tomorrow ( if it is sunny).
But I did just use the Local Status app to force it into Absorb but it always goes back to Bulk. I am able to force it into Float .
Larry
Larry, you should not have to turn OFF the Hawkes Bay. It helps the Classic to get closer to its Absorb voltage setting which is higher than the HB.
BUT if the voltage readings for Classic and HB are off kilter, then I suppose the Classic could think it is in Absorb when it is not.
P.S. HERE is a copy of an email from Steve Higgins from Surrette/Rolls batteries regarding lithium and Absorb settings for their batteries. This was posted today on the RE-Wrenches mail list.
We worked together for years at Trace Engineering and also OutBack Power Systems and he has become quite an expert in his field.
boB
For many LFP batteries, while some say you can charge at the C1 Rate, most want you to charge at the C2 or C3 rate.
While you don't have to get them full all the time like lead, as long as you are cycling regularly, it is still a good idea to get them to full regularly. Now if they are a backup system or not being cycled, they should not be held to full all the time. This can accelerate damage to the cells.
Where we see the major mistakes are the absorb timer settings. Too many people are setting the absorb timers too short, especially if they have parallel modules and are not running closed-loop communications, or the batteries can't communicate with each other or the chargers.
In these cases where you have 2,3,4... more batteries in parallel, the absorb timers can help balance them as the batteries that don't need balancing stop charging, while the cells that need the extra time get that time if you have longer absorb timers.
We advise for our LFP drop in's that you have the following. Assuming that you are charging at least the C2 Rate.
1 Parallel Connection = 30-45 mins absorb timers.
2 Parallel Connections = 45-60 mins.
3 Parallel Connections 60-90 mins.
4 Parallel Connections 90-120 mins
Steve Higgins ⋅ Technical Services Manager
t +1.902.597.4020 m +1.206.790.5840
f +1.902.597.8447 e steve@surrette.com
"But I did just use the Local Status app to force it into Absorb but it always goes back to Bulk."
That is a Local App "mis-print", it's not FORCE ABSORB it is really FORCE BULK...
I am not certain about this but here is my understanding of the "Force" options in the local app. I could be very wrong on this and if I am I hope someone corrects me - please.
The force float is used to "terminate" an active charge cycle, so if you are in bulk or absorb it will force down to float.
Force Absorb is to -bypass the midnight timer reset, so if needed you could perform a second charge cycle in a single day. More like a rebulk setting than force absorb. If you are already in Bulk and force absorb, I believe it will return to bulk. If in absorb it will stay in absorb. If in float (after a full charge cycle), then it will allow a return to either absorb or bulk dependent on the battery voltage and you specific absorb/ float setting. Not necessarily forcing the voltages to the battery to be set to your absorb setting but instead simply telling the midnite that it is okay to run another charge cycle even if the midnight timer has not been reached.
????
Again, I am basing this simply on what I have seen my classic do so please, those who know better, please correct my misunderstanding. :)
I work for Midnite, have for over 10 years now. I just wrote some code for the COMBOX to integrate CHARGE STATE from the New Hawkes Bay & Barcelona into the Classic's "Follow-Me" network. MODBUS register 4160 is where I force charge state in the Classic. As you can see there is no "FORCE ABSORB" command, like I said, in the Local App is's a mistake. We can force FLOAT or BULK or EQ. Code 0x40 forces a new BULK/ABSORB cycle, BULK will always start and when the battery reaches the ABSORB voltage set point it will transition to ABSORB. Sometimes this happens so fast the MNGP does not pick it up. That's why ABSORB is not a "follow-me" stage, each Classic has to reach it's programmed ABSORB voltage independently.
ForceFloatF
0x00000020
Force battery charge stage to Float
ForceBulkF
0x00000040
Force new Bulk/Absorb charge stage and reset timers
ForceEqualizeF
0x00000080
Force new Equalize stage
ForceNiteF
0x00000100
Force a new day (saves daily logs, resets daily kW-H)
Quote from: boB on June 27, 2023, 03:22:11 PMLarry, you should not have to turn OFF the Hawkes Bay. It helps the Classic to get closer to its Absorb voltage setting which is higher than the HB.
BUT if the voltage readings for Classic and HB are off kilter, then I suppose the Classic could think it is in Absorb when it is not.
P.S. HERE is a copy of an email from Steve Higgins from Surrette/Rolls batteries regarding lithium and Absorb settings for their batteries. This was posted today on the RE-Wrenches mail list.
We worked together for years at Trace Engineering and also OutBack Power Systems and he has become quite an expert in his field.
boB
For many LFP batteries, while some say you can charge at the C1 Rate, most want you to charge at the C2 or C3 rate.
While you don't have to get them full all the time like lead, as long as you are cycling regularly, it is still a good idea to get them to full regularly. Now if they are a backup system or not being cycled, they should not be held to full all the time. This can accelerate damage to the cells.
Where we see the major mistakes are the absorb timer settings. Too many people are setting the absorb timers too short, especially if they have parallel modules and are not running closed-loop communications, or the batteries can't communicate with each other or the chargers.
In these cases where you have 2,3,4... more batteries in parallel, the absorb timers can help balance them as the batteries that don't need balancing stop charging, while the cells that need the extra time get that time if you have longer absorb timers.
We advise for our LFP drop in's that you have the following. Assuming that you are charging at least the C2 Rate.
1 Parallel Connection = 30-45 mins absorb timers.
2 Parallel Connections = 45-60 mins.
3 Parallel Connections 60-90 mins.
4 Parallel Connections 90-120 mins
Steve Higgins ⋅ Technical Services Manager
t +1.902.597.4020 m +1.206.790.5840
f +1.902.597.8447 e steve@surrette.com
I wish he would have mentioned some setpoints he uses .
My batteries are kind of messed up because as they get full the cell differential is too much.
I just got the Neey balancer which Off Grid Garage did video on. And I just hooked it up on my most out of balance battery and trying out today. It is a miracle worker compared to the bms to get the cells balance since it works at 4 amps from high to low cells - compared to bms bypassing only 75ma per high cell.
If the Neey work out okay - I may just put on in all my present lithium batteries to make them decent. Then I can set the controllers with a legitimate ending amps to make sure they get full.
I am still learning all the ins and outs about lithium.
But what he says could explain why my batteries stay in bulk - they just are not full yet.
Larry
Quote from: Wizbandit on June 27, 2023, 05:26:05 PM"But I did just use the Local Status app to force it into Absorb but it always goes back to Bulk."
That is a Local App "mis-print", it's not FORCE ABSORB it is really FORCE BULK...
Thanks - that makes sense about forcing bulk . I was just used to it working more like force absorb when I had the lead acid batteries.
Larry
Quote from: Wizbandit on June 27, 2023, 06:09:10 PMI work for Midnite, have for over 10 years now. I just wrote some code for the COMBOX to integrate CHARGE STATE from the New Hawkes Bay & Barcelona into the Classic's "Follow-Me" network. MODBUS register 4160 is where I force charge state in the Classic. As you can see there is no "FORCE ABSORB" command, like I said, in the Local App is's a mistake. We can force FLOAT or BULK or EQ. Code 0x40 forces a new BULK/ABSORB cycle, BULK will always start and when the battery reaches the ABSORB voltage set point it will transition to ABSORB. Sometimes this happens so fast the MNGP does not pick it up. That's why ABSORB is not a "follow-me" stage, each Classic has to reach it's programmed ABSORB voltage independently.
ForceFloatF
0x00000020
Force battery charge stage to Float
ForceBulkF
0x00000040
Force new Bulk/Absorb charge stage and reset timers
ForceEqualizeF
0x00000080
Force new Equalize stage
ForceNiteF
0x00000100
Force a new day (saves daily logs, resets daily kW-H)
It will be nice to try out the combox when they become available.
Larry
Thank you,
That makes much more sense of what I was seeing in my classic, and makes the charge cycle process, as well as the force processes clearer.
Thank you for correcting my misunderstand.
Will add, that when ' Force Float ' is used in the Local App, the Net Ah value is NOT set to zero, as would be the case, if the Classic went to Float, based on its Absorb termination settings.
Not a big deal, just something to remember, as this non-zero can affect the following day Wb values.
FWIW, Vic
Bob ,
I still don't understand why my Classic with the new firmware never shows Absorb for me.
Today it looks like it gets to Absorb voltage wise and dropped to Float voltage wise but it only ever goes back to Bulk . I had added the graph of charge state and think it is accurate representing what happened over time. The Classic is set to Absorb voltage at 54.2v which is first peak in voltage. I think the second peak in the voltage is the Hawkes Bay going to Absorb that I had set for 54.7v . I just wonder why the Classic never goes to Float .
Example below in screen shot.
Larry
Larry, What happens if you disable the Hawkes Bay from charging ?
How much time is your Absorb set for ?
Also, did we figure out if you are using any temperature compensation ?
And you did select Lithium battery type, right ?
I am working on another revision that may or may not help ?
When you see the battery voltage at NEAR Absorb but still in MPPT, you might press the MNGP's soft-left or soft-right keys to verify that the PV input voltage is picking the proper Vmp.
If you are using Solar mode, you might try Legacy P&O ?
Sorry for all the questions but I just need to make sure I know what's going on.
At this 54V area, does the Classic read close to the right voltage ? Same with the HB
Quote from: boB on July 06, 2023, 05:46:40 PMLarry, What happens if you disable the Hawkes Bay from charging ?
How much time is your Absorb set for ?
Also, did we figure out if you are using any temperature compensation ?
And you did select Lithium battery type, right ?
I am working on another revision that may or may not help ?
When you see the battery voltage at NEAR Absorb but still in MPPT, you might press the MNGP's soft-left or soft-right keys to verify that the PV input voltage is picking the proper Vmp.
If you are using Solar mode, you might try Legacy P&O ?
Sorry for all the questions but I just need to make sure I know what's going on.
At this 54V area, does the Classic read close to the right voltage ? Same with the HB
Absorb was set for 54.2 16 minutes absorb time. no ending amps
I have disabled Hawkes Bay in past but don't think I saw any different results.
I will turn off the pv to Hawkes Bay tomorrow.
Zero temperature compensation and yes it was set to Lithium after I did firmware update.
It was reading close to the battery voltage. I had set the absorb lower on Classic than Hawkes Bay and even after the Hawkes Bay pushed it up it still didn't go to Float. I am going somewhat by what my monitoring reported in that graph where it showed it went to absorb but then went back to bulk - so maybe that absorb was some kind of error on my monitoring.
I just changed it from Solar to Legacy PO mode so will see what happens tomorrow.
So for tomorrow this is what I will have Classic set for ( Hawkes Bay pv off until batteries are full)
Legacy PO mode
Absorb 55.2v
Absorb Time 15 minutes
Float 53.8v
zero temp comp
zero ending amps
Larry
Quote from: ClassicCrazy on July 06, 2023, 09:10:12 PMAbsorb was set for 54.2 16 minutes absorb time. no ending amps
I have disabled Hawkes Bay in past but don't think I saw any different results.
OK, I am seeing what kind of looks like starting 54.2V rising up to 54.35 V for several minutes and then it stops and goes to Float ?
How long is that time that the voltage is at 52.2V to 53.35V ? That isn't 16 minutes, is it ?
If you set the Absorb time for longer, does that time widen up maybe ?
I am working on tightening up the voltage range again BTW. I noticed that the Classic would Absorb at the set point V minus 0.1 volt. For lithium battery selection, the Classic is allowed to go back to Bulk MPPT mode at 0.3V below set point, but right now, for you with the -0.1V offset, it would be -0.4 V below set point to go back to BULK MPPT.
This will be better in the next day or two for you.
boB
Quote from: boB on July 06, 2023, 10:23:18 PMQuote from: ClassicCrazy on July 06, 2023, 09:10:12 PMAbsorb was set for 54.2 16 minutes absorb time. no ending amps
I have disabled Hawkes Bay in past but don't think I saw any different results.
OK, I am seeing what kind of looks like starting 54.2V rising up to 54.35 V for several minutes and then it stops and goes to Float ?
How long is that time that the voltage is at 52.2V to 53.35V ? That isn't 16 minutes, is it ?
If you set the Absorb time for longer, does that time widen up maybe ?
I am working on tightening up the voltage range again BTW. I noticed that the Classic would Absorb at the set point V minus 0.1 volt. For lithium battery selection, the Classic is allowed to go back to Bulk MPPT mode at 0.3V below set point, but right now, for you with the -0.1V offset, it would be -0.4 V below set point to go back to BULK MPPT.
This will be better in the next day or two for you.
boB
I have never seen the Classic go to Float on it's own using this firmware. No matter what I have tried it stays in Bulk or goes back to it after Absorb. There was no float time on the Classic at all today. But I will watch and see what happens tomorrow.
Larry
Quote from: ClassicCrazy on July 06, 2023, 11:48:15 PMI have never seen the Classic go to Float on it's own using this firmware. No matter what I have tried it stays in Bulk or goes back to it after Absorb. There was no float time on the Classic at all today. But I will watch and see what happens tomorrow.
Larry
Well, you have given me some things to look at.
On my work bench, I see the Absorb timer working normally and going to Float like normal.
BUT maybe something changed between the one you have now and what I have now ?
Making sure the NEXT one you get works better !
Saw your video of the BMS in that battery box.... If that is just a passive (resistor based) balancer then maybe there is an open dump resistor ? OR bad transistor that turns the resistor on ?
boB
Quote from: boB on July 07, 2023, 12:39:35 AMQuote from: ClassicCrazy on July 06, 2023, 11:48:15 PMI have never seen the Classic go to Float on it's own using this firmware. No matter what I have tried it stays in Bulk or goes back to it after Absorb. There was no float time on the Classic at all today. But I will watch and see what happens tomorrow.
Larry
Well, you have given me some things to look at.
On my work bench, I see the Absorb timer working normally and going to Float like normal.
BUT maybe something changed between the one you have now and what I have now ?
Making sure the NEXT one you get works better !
Saw your video of the BMS in that battery box.... If that is just a passive (resistor based) balancer then maybe there is an open dump resistor ? OR bad transistor that turns the resistor on ?
boB
The battery bms has passive balancers. I think just small bleed resistors of about 50 to 75ma each so it can do each cell as needed. But with cells out of balance like mine are , it will never do that job for 100 ah cells. So I took Off Grid Garage advice and bought a Neey 4 amp active balancer. It only does on cell at a time but can dump a lot of power quickly from high cells to low cells. I made a video on that which I should post.
Not sure which video you watched about battery - this might be a second video https://youtu.be/Oz8bZhvrA6s
Larry
Here are results of test today so far at 12:30 pm
I think what may be going on is that the batteries fill up and then the current ramps down to zero because of that ? So cell voltages wont rise higher maybe and never get to absorb voltage.
The two batteries I have on now are really not cell balanced very well so that doesnt help - you can see the differential is pretty high. But still if I was to put on my other battery charger I think it would run the voltage up higher even if they were full , and then cut off.
Now it was sunny , then got a bit hazy out here - but still the Classic SOC shows it getting to about 100% at same time current is tapering off to zero ( batteries full) .
The voltage offset was not very good on this today - I have it set more so that it would be about right at 56v .
Anyway here are the graphs .
Bob,
I went back to the last regular Classic firmware from Midnite because it works better.
It lets all the power available to the batteries, and then will go to float.
Your newish lithium firmware just would not go to Float. I had watched it go to Absorb and then back to Bulk. With the regular firmware I know it sometimes wouldn't reach the Absorb setpoint and would go to absorb before that , but I could compensate for that by setting a higher setpoint . I know you pointed out in the other post that someone had said people don't set a long enough absorb time, but what I see on my batteries is that by the time they get to the voltage the cells are full. Any longer time than that and they wont accept any more current anyway once they are full.
The Neey cell balancer I installed on the most imbalanced battery I had, seems to have worked. It is battery 2 in this graph.The batteries did jump up to 150mv differential at peak, but I think that will come down if I tweak the absorb voltage down. Or else that is normal cell differential at the peak ( I am trying to look that up).
Larry
classic regular firmware.jpgclassic regular firmware 2.jpg
OK Larry. Thanks.
I will have another one to try soon. Maybe not this week though.
Appreciate your tests. I have been working on this code though and have found a couple of things and one of them may be related to what you are finding.
Thanks !
boB
Quote from: boB on July 11, 2023, 04:29:20 PMOK Larry. Thanks.
I will have another one to try soon. Maybe not this week though.
Appreciate your tests. I have been working on this code though and have found a couple of things and one of them may be related to what you are finding.
Thanks !
boB
Always happy to test the new firmware. Enjoy the summer while it is here !
Larry