New lithium installation - float always on?

[ClassicCrazy]

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

[Westbranch]

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

[jamesb]

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

[ClassicCrazy]

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

[CDN-VT]

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

[jamesb]

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)

[ClassicCrazy]

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

[jamesb]

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

[ClassicCrazy]

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