I've finally got my lithium system up and running and need a little help finalising the programming on the KID. I should state up front that I have a 100ah lithium system with a House Power BMS for monitoring cell voltages.
After the initial setup, the KID performs a bulk charge cycle, then switches to float mode and basically stays there. Is this normal? The only way I can figure out to get the KID to switch to bulk mode is to do a factory reset. It will then charge to whatever I have set for the absorb, then switch to float indefinitely. I'm guessing this has something to do with lithium's flat voltage discharge curve (but can't say for sure).
My settings FYI:
Absorb: 13.8V, time: 0
Float: 13.2V
I have tested the output of the KID in float mode and (after a factory reset) bulk mode... both seem to be about the same output. I was under the impression that bulk mode takes advantage of MPPT, while float is more akin to PWM. With the output almost identical in both bulk and float, I'm not sure if this is the case.
It looks like everything is working ok, I'm not sure. Can anyone offer any guidance on this?
There is a lot of info on charging lithium batteries in this thread .
I think some of your setpoints depends on if you are top or bottom balancing them.
Take a look here
http://kb1uas.com/mnsforum/index.php?topic=962.0
Larry
I know this is a really old post. I'm having the same trouble did you ever resolve this issue?
Thanks,
James
What qwety steve described is pretty much how my Classic behaves with my calb lithium batteries.
Begins the day in Bulk and when it hits the setpoint of absorb voltage and then ending amps it changes very quickly from Bulk to Float.
It is going to stay in Float the rest of the day unless it goes below rebulk which it probably won't .
Any loads while in Float the charge controller will give all the available PV current to the loads but still say in Float .
Steve did not say if he had an ending amps setting .
And since this was two years old I hope he has done a firmware update by now since there were some issues that were fixed for some things.
Larry
I guess I misunderstood his problem. I would be perfectly happy with what you describe, but what I see is that it starts the day in float and stays in float, so my system is rarely reaching a full charge. Battery is reading 13.2 with the solar off, and by my ammeter I'm down about 40ah so I would expect it to be in bulk for sure.
Absorb 14.0 time 1 min
Float 13.8
EndAmps 8
Rebulk 13.1
I have played with every combination I can think of and can't get it to start the day in bulk. The problem is that it's my rv in the woods so I generally only get to play on the weekends.
Any thoughts would be appreciated.
James
might this have something to do with the Li voltage curve being much "flatter" than lead acid, and there is only a small difference in voltage if you are wanting to cycle 20%-80% without hitting the "knees" at either end ?
I thought it would bulk until it hit the absorb voltage. It couldn't have hit the absorb voltage with my batteries down the way they are. Please correct me if I'm wrong.
James
Quote from: jamesb on June 18, 2017, 01:09:30 PM
I guess I misunderstood his problem. I would be perfectly happy with what you describe, but what I see is that it starts the day in float and stays in float, so my system is rarely reaching a full charge. Battery is reading 13.2 with the solar off, and by my ammeter I'm down about 40ah so I would expect it to be in bulk for sure.
Absorb 14.0 time 1 min
Float 13.8
EndAmps 8
Rebulk 13.1
I have played with every combination I can think of and can't get it to start the day in bulk. The problem is that it's my rv in the woods so I generally only get to play on the weekends.
Any thoughts would be appreciated.
James
Why do you have Absorb Time at only one minute ?
I am wondering if it climbs to Absorb voltage really fast and then with one minute on timer you just don't notice it changing over ?
With only one minute Absorb time it may never use the 8 amp ending amps point.
Are you using the Whizbang SOC to determine that you are -40 amps ?
If so what do you have setup for the capacity and efficiency of the Battery SOC setup ?
Have you tried forcing it into Absorb and watch closely what happens ?
Larry
I felt that once it reaches absorb voltage it's essentially full, but that seems like fine tuning. If I reached absorb voltage then my voltage would be at least 13.4, since I have very little load 1.5 A in the morning. Plus, the float would really ensure it was full, but I'm seeing the voltage at 13.2 and the ammeter indicates it's still down. I don't have a wizbang jr, I have a shunt and an ammeter that has been working well for a couple of years. I bought the new controller because my cheap controller was tripping my BMS.
How would I force it into absorb mode?
Quote from: jamesb on June 18, 2017, 07:42:50 PM
I felt that once it reaches absorb voltage it's essentially full, but that seems like fine tuning. If I reached absorb voltage then my voltage would be at least 13.4, since I have very little load 1.5 A in the morning. Plus, the float would really ensure it was full, but I'm seeing the voltage at 13.2 and the ammeter indicates it's still down. I don't have a wizbang jr, I have a shunt and an ammeter that has been working well for a couple of years. I bought the new controller because my cheap controller was tripping my BMS.
How would I force it into absorb mode?
No on your idea of Absorb. It reaches Absorb setpoint and then stays there until it either reaches Absorb Time or Ending amps whichever is first. Then it goes to Float.
I think your Absorb Voltage is more like the point it is at 80% to 90 % full for Calb batteries. That is what I use for the top of my bottom balancing which is not a 100% full battery .
I guess I was thinking of the Classic which you can force into Absorb. I don't believe you can do that with the Kid.
What amp meter are you using ? You would have to have one that counts amp hours from full t know what your batteries use. It would use an external shunt that has only one connection from the battery negative to shunt and all other negatives go to the other side of the shunt. Without using a Whizbang which knows exactly what is going into the battery and what is going into loads it is not very easy to use an Ending Amps setting unless you know exactly what your load is and compensate for that .
A Whizbang is a very good and relatively inexpensive investment in knowing exactly what your battery state of charge is.
Look at the charts for your Calb batteries here
http://evwest.com/support/CALB-CA100Ah.pdf
I don't remember exactly how many cells you had and how you had them configured - I think it was in your other post where you said what you had.
Larry
Okay, based on your statement about absorb, I'm confused, how does the kid know when to do bulk and when to do absorb? You described when it goes to float.
Your description of the shunt installation is correct
Ammeter: http://www.electriccarpartscompany.com/ECPC404-Ammeter-and-Voltmeter-Intelligent-Digital-EV-Battery-Pack-Monitor
Shunt: http://www.electriccarpartscompany.com/400A-75MV-Shunt_p_608.html
I have 12 100 ah cells configured for 12 v @ 300 ah.
I looked at the WhizBang Jr and see that my shunt won't work, not a huge deal, but it does say, ". To use the Whizbang Jr (MNWBjr) with any of the Classic Lites, you will either need the local app or an MNGP." I don't know if the KID is included in that classic lite group or not, do you? The KID doesn't have a local app but it does have a graphics panel.
YES, the Kid and WBjr are fully compatible... if you go through the menu pages on the Kid graphics panel, you will see a WBjr Yes or No tick box IIRC ...
They are highly recommended for any battery type if you truly want a full charge, without one it is a guessing game,....
Quote from: jamesb on June 18, 2017, 10:44:21 PM
Okay, based on your statement about absorb, I'm confused, how does the kid know when to do bulk and when to do absorb? You described when it goes to float.
Your description of the shunt installation is correct
Ammeter: http://www.electriccarpartscompany.com/ECPC404-Ammeter-and-Voltmeter-Intelligent-Digital-EV-Battery-Pack-Monitor
Shunt: http://www.electriccarpartscompany.com/400A-75MV-Shunt_p_608.html
I have 12 100 ah cells configured for 12 v @ 300 ah.
Oh - too bad they use that shunt for your amp meter. If it was 500 amp 50mv shunt like Midnite uses you could have hooked up the Whizbang on it and also still used your existing meter both at same time.
https://www.solar-electric.com/mkb-500-50.html
As Westbranch said - you just enable Whizbang on the Kid and set it up on the screen and it will display all the data there.
Yes I do believe it should be in Bulk at the beginning of day if the voltage is lower than your Absorb Setpoint and up until it gets to the Absorb setpoint. Not sure why yours may not be doing that. You may want to run some big loads for awhile - and watch the voltage so you don't go below the critical 10v point ( your BMS should cut off the batteries before that happens) . Anyway run the batteries down some night and see what happens in the morning when the solar starts charging again. You will also be load testing your batteries . You should check each cell to make sure they are pretty close in balance too.
Larry
I think I can likely use my ammeter with the MN shunt with some programming changes. I'll consider getting a whizbang jr if I can ever get this working.
The batteries are well balanced, I had the pack apart over the winter to balance them. My batteries were down weeks ago and it made no difference, they still sat in float. I'm really at a loss where to go from here.
Thanks,
James
Quote from: jamesb on June 19, 2017, 08:28:15 AM
I think I can likely use my ammeter with the MN shunt with some programming changes. I'll consider getting a whizbang jr if I can ever get this working.
The batteries are well balanced, I had the pack apart over the winter to balance them. My batteries were down weeks ago and it made no difference, they still sat in float. I'm really at a loss where to go from here.
Thanks,
James
First - I don't remember if you updated your firmware for Kid to newest ? If not do that .
I wrote the steps below I would try - and after writing it I just thought of a quicker test I would make. I wonder if having the Absorb time set to 1 and ending amps set without having a Whizbang on it is messing something up.
Try disabling ending amps - set it to Zero
Set the Absorb time to 1 hour.
Make sure you save settings
disconnect PV and then disconnect battery and wait 5 minutes or so .
Then turn the battery back on and let it boot and check to make sure that all the settings are as you just set them up.
Turn PV back on - the Kid should think it is a new day and go into Bulk as long as the battery voltage is below Absorb Voltage setpoint.
If it goes to Bulk then you know there is some problem with either having it set to only 1 minute Absorb time or 8 amps ending amps with no Whizbang . So you would have to experiment to find out where the problem is and then figure out a way to make it work without overcharging the batteries.
If it doesn't go to Bulk you could try steps below or just open up online service ticket with Midnite and see what they say .
This is the other thing I wrote ....
Here is what I would try when you can monitor it closely .
Run batteries down to around 40% of capacity .
Turn ending amps off - set it to zero.
Set your Absorb time to 1 hour .
Set your Float
Set the Equalize to the same as the Absorb voltage but do not enable it.
Make sure you save all those settings in the Kid.
Then disconnect both the PV and the battery and give it a few minutes and restart because I believe that way it will think it is a new day .
Reconnect up the battery , then check and make sure you have all the settings the same as above. - they should be.
Turn on the PV and watch what it does closely.
If the battery voltage is well below the Absorb voltage it should be in Bulk and charging with all available PV power to batteries.
If it is not in Bulk then there has to be some problem with the Kid.
If it goes to Bulk and starts charging with all available current and the voltage should probably stay around 54 volts I think . It should stay in Bulk and keep charging with little change in current. When the amp meter counts up to 80 to 90 % full there would be a point when the voltage quickly rises to 56v Absorb voltage and the current quickly drops down to 5 amps. That would be the point when you would want to stop absorb and go to Float .
A lot of this would depend on if your amp meter is really in sync with what state the batteries are.
It would also take some close monitoring .
I wouldn't leave these settings they are just to test.
If after you tried this it just starts out in Float like before then you should open a service ticket with Midnite and see what they say.
Larry
Have you checked the MODE it is in...?
I just spoke with a friend that recently installed new AGMs and it was not charging as it should have been, very short bulk and Absorb... I asked if he had written down all the Settings..NO!
so he went and checked all settings...
Found that it was not in Solar but in Observe?Perturb mode....
changed it to Solar, SAVED setting, and off it went, charging happily...
hth
Larry,
Thanks, that sounds like a reasonable test. I am away from the installation for the week now, but I'm on vacation after that so I should have some good time to run through the tests. I had started with a support ticket and they directed me to the forum for settings.
I haven't updated to the newest firmware I'm on 1811, I tried, but was having trouble with my windows (7) detecting the KID (windows is a virtual machine because I run on a mac). I will give it another shot next weekend with a new usb cable.
I think the lowest for the ending amps is .1 isn't it?
@Westbranch, I know it's on Solar, I did try the O&P mode when I saw that helped someone in a post, but other than that little test on Sunday, it has been in Solar all along. I am also very careful to save and double check the values.
Thank you
Something was messed up with ending amps in that old firmware that they fixed in the newest firmware.
So yeah I think you should figure out a way to update before you do anything else.
The newest firmware will let ending amps go down to zero.
Larry
Quote from: jamesb on June 19, 2017, 08:28:15 AM
I'll consider getting a whizbang jr if I can ever get this working.
James
Thats the only way James
Do it Right ONCE
Your wasting cells & time !!
VT
I was able to install the 1856 firmware today and it is behaving much better. Larry, I followed your instructions except for the setting the equalize voltage, because I couldn't figure out how to do that. When I go into the equalize menu there isn't a setting for voltage, just start.
So after a full restart (waiting 5 min or so) this is what I see. It's quite cloudy today and the system came up in bulk mppt 13.4/13.5 V solar and stayed that way until full sun came out. When the full sun came out, the solar voltage quickly jumped up which moved the system into absorb. I turned off the solar and the voltage read 13.2 on the KID. I then set rebulk at 13.3 and I turned solar back on and it started in bulk mppt mode again until the sun came back out, the voltage climbed and it switched back to absorb at 7.5A. I would be okay with that if I absorb was at 15A but I'm really getting less than 1/2 of what the panels will put out in full sun. BTW when all of this was going on I was drawing 30A so there was no way the system was going to keep up.
To me, it seems like the KID is registering the voltage it is giving the battery, instead of the actual battery voltage, because every time in this test, if I shut the solar off the voltage registered by the KID is down at 13.2 V, but full sun it jumps up and switches to Absorb.
What am I missing here.
Absorb 14.0 Time 60 min
Float 13.9
End Amps 0
Rebulk 13.3 (currently)
First - you can set the equalize by going to the equalize where you saw start but when you are there push the top left up/Setup button and you will get the other part of the menu.
I am not quite following you .
You had a 30 amp load on your system and the batteries were charging at 7.5 amps ?
That means you panels were putting out 37.5 amps or 37.5 x 13.2 = 495 watts .
If you turn off the load what happens ? What are the batteries charging at then ?
I don't remember if you had a Whizbang or not - is that where you got the charging and load currents from ?
On my system if I want to see the full capacity of the PV output at the time I will turn on enough loads until the charge into the batteries goes negative - taking power out of the batteries. Then I look at the PV and it will be giving it's maximum.
Also remember unless you know your batteries SOC you don't know how much they need to take in to full - or with the voltage you have to not quite full since 14v is not 100% full .
Also I don't understand why you have rebulk set where you do ?
Larry
With my panels off I started 30A worth of load. I was looking at the KID when I saw the 7.5A on the display. I have an ammeter which I have been using for a couple of years and has always been pretty accurate. No whizbang.
I know that the battery is down over 100 ah, but it continues to go into absorb. With the full sun the voltage on the KID quickly climbs to 14 and then switches to absorb. The voltage on the battery is not 14 at this point, in fact in 1 test I switched off the solar and the voltage was reading 13.1 on the KID. It just doesn't seem right to me. I set the rebulk at 13.3 because I was trying to see the different behaviours with different settings.
Can I ask you how long would your system be in bulk before switching to absorb if you are down to 50%?
Thanks,
James
Here is screen shot of a day charging when they filled up
Keep in mind my batteries are set up for bottom balancing - drained and balanced each cell to 2.5v , then top of charge is 56v total ( 48v system)
The vertical line at 1 is what the data at right is showing at that time .
Soon after 1 location it went from Bulk to Absorb but very quickly to Float because when it got to Absorb the system amps dropped down to 5 amps which is my ending amps . I have a Whizbang so the controller knows when it gets to that 5 amps point and takes it out of absorb.
So at number 2 that shows where it dropped to Float Voltage but you see SOC is at 100 % or close to that there.
But for my bottom balance system 100% is not 100 AH , I have it set to 80 AH because I am bottom balancing so the batteries are never up at their top voltage which would be higher than the 56v Absorb I have it set for . Top would be 57.6v and at that point it better have a BMS to balance the cells. Also at that point is where most chargers would go from constant current to constant voltage ( think I have that right ) so the chargers cut their current down so the BMS bleed resistors can balance the cells .
I don't have and BMS on my system.
Hope this makes sense .
Larry