New LiFePO4 installation charge parameters

[Muskoka]

Today it happened maybe a minute or less into Absorb. I was watching for the current to start dropping and it just started the jumping around, like it was confused.

Yesterday the current did drop nicely until it was under 4 amps and end amps kicked in. That took 18 mins and it was around 45 a when it started in Absorb. That was with Absorb set to 28.0v.

Might add, both yesterday and today was totally clear blue sky when it transitioned to Absorb, no clouds, shading, nothing.

[ClassicCrazy]

You don't need to use end amps
Larry

[Muskoka]

Yes, I can just set Absorb to 15-20 mins, or the battery suppliers suggested 4 hrs, and turn off end amps, but I don't think that's the root of the problem. End amps worked fine yesterday, whether it's necessary or not, is another thing. 

The only thing that's changed from a properly functioning charge cycle on this battery is the Absorb voltage, 28.0v, ok, 28.2v not ok, 28.4v not ok, that's a problem. Especially when the battery supplier is telling me Absorb should be between 28.8v and 29.2v.

Now, whether that's too high or not can certainly be debated, but the battery should be able to go that high, even just for a test run, but it can't, because either something in the battery, like the BMS is causing issues, or the Classic is causing issues. Or, maybe the fact the charge cycle was a success yesterday at 28.0v, and end amps set, was just a fluke, I don't know at this point. All I do know is it did work.

Absorb of 27v, 27.6v, 28.0v, is irrelevant at the moment, they should be able to do 29.2v, but can't, that's a problem. Or, maybe it would work fine at 29.2v Absorb for a test, but I doubt it would transition through Absorb to Float nicely, because it can't currently do it with Absorb set higher than 28.0v.

This is me just thinking out loud.

[ClassicCrazy]

If it was me, I would open that battery and put in a proper active bms that can be programmed and monitored.
Larry

[Muskoka]

If it was me, I would open that battery and put in a proper active bms that can be programmed and monitored.
Larry

Larry, I'd love to, but I still have a 1.5 week window in which to return the battery for a full refund. I can't be messing it up.

[Muskoka]

Okay, another charge cycle today. A little late because the clouds didn't clear out until maybe 1.5 hrs ago. Perfectly clear blue skies now.

I'd say success, but sketchy. I turned End Amps off to start with. I set Absorb time to 30 mins to give it time to do "something". I'm posting a link to a 10 minute video on my Google Drive below, first minute is real close to the transition to Absorb from Bulk. Last 9 or so minutes are the controller current, and modes jumping around. There is the odd spike in voltage, but nothing tripped the inverter today. I'd say overall the jumping around was less severe with End Amps off.

I set Absorb to 28.6v, I still believe if it can't reach 28.8v to 29.2v something is wrong somewhere, we're getting closer. Not to say I'll keep it set that high, but it needs to be able to do it before I'll call this combination of CC and battery a success.

Here's a link to the video, please have a watch, and let me know your thoughts on what you see. I'm mainly concerned with the current, and modes jumping around, not where Absorb is set. And, the skies are clear, so the jumping around is not due to shading, or any loads. Only thing thats on is my inverter, and router. I did go into the controller once the current seemed steady, and basically staying below 2amps, and I set Absorb to 3 minutes so it could transition. It did transitioned to Float just fine. That was after the video was finished, I didn't want to interrupt it.

https://drive.google.com/file/d/1Hn1_pqCzDMkvZ_aJXaKfWEG9UyX5TdkS/view?usp=sharing

I see it says the video is still processing, may take a bit. It finished uploading from here a while ago. Should be ok to download.

[boB]

Waiting for your video to load....

If you want, you can try the new Classic firmware that fixes some things and also adds a Lithium selection in the VMM screen (Vulcan Mind Meld)  where, when the MidNite logo appears, hold down the LEFT and RIGHT arrow keys and go through the selections.

The battery regulation voltage should be a bit better (actually +0.1 V better) in all battery selection modes.

Also fixed a bug in Waste-Not
Battery temperature sense can turn charger off at high and low temperatures limits. Lithium turns off at 2 degrees C or so.

Some minor annoyances also tended to like the siren not going off when ENTER is pressed in main status menu to force an MPPT sweep.


http://bob.midniteftp.com/K7IQ/Firmware-Latest/Classic-3786/

MNGP and Classic will both want to be updated.

Will keep trying for the video until I can see it.

boB

[Muskoka]

Thanks Bob, will try the new firmware.

Here's a link to a much smaller video, I squashed it.

https://drive.google.com/file/d/1_A0UJSTNXwK-zUiN82TzD5eV9ekKpG_L/view?usp=sharing

It's been a while since I did a firmware update. Right click the 150 control and the MNGP file and save as? Then run the Classic programmer on a laptop connected through usb?

Lol, for some reason the video is mirrored, see if I can fix that. In Windows media player it's sideways lol. You can right click in Windows media player and turn it 90 degrees.

[boB]

OK, I am watching your video.  The first minute or so kind of tells what is going on...

The newer firmware I just uploaded may help "some".  Mainly in that for the Lithium setting, the difference between Absorb voltage and where it turns into BULK MPPT is tighter.  -0.2V instead of the Vabsorb -0.4 or  -0.5V  it is now which is mainly for flooded lead acid.

So, When the battery voltage is within a couple of tenths of the absorb voltage (just slightly below) and up to the actual absorb voltage, you have LOW battery current (< 2Amps) and higher PV voltage (closer to Voc) which is what you would expect for being in "Absorb" and low battery current needed.

THEN, when the battery voltage drops below the Absorb voltage "window", the Classic goes back to BULK MPPT (Vin of around 70V) and the battery current is maximum or around 45 amps.  Then it goes back to Absorb voltage again and LOW current and Vpv near Voc again.

This says to me that you have some kind of load on the battery turning ON and OFF that is dragging that battery voltage down into the BULK MPPT region again.  Then, all of a sudden the load (or whatever is dragging the battery V down)  turns OFF and it goes back to LOW current and high Vinput (Vpv) and back to Absorb again.  This is what it tells me in the first minute or so of your video.

Now I need to go back and watch the rest of the video.

Also, I do notice that there may be a slight delay when the MNGP display shows Absorb but I see the BULK MPPT numbers (45Amps) just at the MPPT to Absorb transition.  The MNGP should update around 3 to 5 times per second which should be fast enough not to notice but I may be slow

This video is exactly what we needed !  Good job !

boB

[boB]

Thanks Bob, will try the new firmware.

Here's a link to a much smaller video, I squashed it.

https://drive.google.com/file/d/1_A0UJSTNXwK-zUiN82TzD5eV9ekKpG_L/view?usp=sharing

It's been a while since a did a firmware update. Right click the 150 control and the MNGP file and save as? Then run the Classic programmer on a laptop connected through usb?

Lol, for some reason the video is mirrored, see if I can fix that. In Windows media player it's sideways lol. You can right click in Windows media player and turn it 90 degrees.

Yeah, copy those .CTL and the .REM file(s) either to where your update files were OR just take the whole thing, including the programming EXE file to a new directory.

I am using windows 10 here and I notice that I have to turn the Classic OFF and ON several times before the program will do what it is supposed to.  It might just be me or my cable or something.
Let the Classic sit with the battery breaker OFF for several seconds before turning it back on when the update program isn't responding the way it should.

The program will see that that Classic is connected when it is ON but when you turn the Classic from OFF to ON and the Classic boots up where the FANS turn ON, it did not "catch".  It's those first 3 or so seconds when the Classic powers up and the 3 LEDs inside the Classic's air window go on left to right that it is looking for the program to connect and upload.   This works the same when you are updating the MNGP.

Your first video (the only one I've seen so far) does not look mirror imaged to me.  Looks good.

boB

[Muskoka]

I can assure you there's no load on that system, not enough to pull anything down, 50-55 watts is it, my inverter, and my router. I'm the only one here, in a camp I built in the bush, no appliances except a fridge I run in the summer, it's been unplugged since November. No tv either, watch everything on a tablet. I do have a gaming computer, I like flight, racing simulators, but it's off. I'd turn the inverter and router off if I could, I want the inverter on to see it it trips, and I need the router for the local network so I can monitor the system while charging on my phone or tablet.

So I can do the firmware update over my netwrok, the Classic is connected? (disregard)

Ah ok, the second video (same video just compressed) was called Midnite (200mb), for some reason when I click on the google drive link from here it plays mirrored.

[boB]

OK, if not loads, then what does your battery system consist of ?

What batteries are you using and how many batteries are connected together ?

I was thinking that if you have more than one battery and BMS in parallel that maybe one of them is turning OFF and ON and OFF ?   That would also cause this.  Remember that when a battery is low in charge, it is a load.

But when its BMS turns it off, it is not a load at that time.

Had to ask.

[Muskoka]

I have 2 totally independant system's, one 24v, the other 12v.

The system I'm talking about here is (1) REDODO LiFePO4 24V 200ah battery bought Jan 10th this year, I received it on the 15th of Jan, 1540watts of panel, Classic Lite wth a MNGP, wBjr, and a 24v 2000w inverter.

[boB]

OK, well it doesn't sound like a single Redodo battery/BMS  should have this issue UNLESS it is turning itself OFF when that 28.5V absorb is reached ?

Try turning down your Absorb voltage set point by, say, 0.5 volts and see if things STAY at high current.

What makes me say this is that maybe when the Classic is in Absorb and you see the 1.7 amps or so, that could be your loads like the inverter etc.  and when the BMS in the Redodo turns back ON again, it starts charging at 40+ amps again ?

That's about all I can think of at the moment.

Going to lunch.  Will check back in just a little bit, Muskoka

[Muskoka]

I don't want to lower Absorb, I want to raise it to the level the battery supplier is tellimg me to use, 28.8v to 29.2v, as a test. I likely won't leave it that high, but this CC and this battery should have no problem going to 28.8v to 29.2v, and transitioning smoothly from Bulk, to Absorb, to Float. That's the way it should work, but something in the mix is causing grief. Turning End Amps off seems to have helped some, but it's still kind of erratic when transitioning.

To recap:

When Absrob was set to 28.2v the Classic did the cycling thing, very erratic. Voltage spiked high enough to trip my inverter, 30.5v. I did have end amps on.

When Absorb was set to 28.4v the Classic did the cycling thing, very erratic. Voltage spiked high enough to trip my inverter, 30.5v. I did have end amps on.

When Absorb was set to 28.0v the Classic did not do the cycling thing, it transitioned to Absorb smoothly, and the current dropped until End Amps (4a) was met, and it went to Float.

When Absorb was set to 28.6v, the Classic did do the cycling thing, but less dramatic than before. Only difference was End Amps was turned off.

So, I'm still not at 28.8v, which is the recommended low end, Absorb of 28.8v shouldn't be a issue for this battery or CC. I'm going to get the new firmware installed tonight, supposed to have sun tomorrow. I'm going to leave Absorb at 28.6v, and see if it's any smoother, I'll take another video.

Might get another test day Wednesday as well, and then that looks like it for at least a week.

I guess the point I'm trying to make is, running at Absorb of 28.0v or below should be a choice, one that extends the battery life. It shouldn't be something I'm "forced" to do, because of a limitation, or problem with the CC, or the battery. Hope that makes some sense.