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We recently found a bug in the kid that causes this. Mario should have new code this week to test that fixes this issue.
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  Larry, what kind of BMS is in this 12V system ?

  Since the source, a 24v battery, has a very low impedance, it could be that the current spiked up and the BMS disconnected ?

  I hear about a LOT of problems with BMS's for lithium batteries turning off.  Some can't even turn on an inverter connected to a Li battery
    without the BMS turning itself off.

  boB

It is an SOK 12v battery - not sure what kind of bms is in it. But it has a nice bluetooth app so I was watching the data from battery directly which shows voltage ,current, etc and it didn't look like it ever shut off or send any alarms.
I think the problem some of those batteries have with inverters is when they first hook up there is a huge inrush to charge the capacitors . Some of the newer 48v lithium batteries have precharge circuits in them to avoid that. But I also read about people using a pencil to precharge the capacitors in inverters first .
I didn't spend too much time messing around with the Kid since it was cold out in the shed where I had it.
I just got a Riden 60v 24 amp power supply that I am going to use to charge that 12v battery . I was working on hooking that up today - I got it without AC power supply and am going to power it with my 48v lithium battery system.
That has a special battery charging jack and features like CC and CV  that you can set however you want. But of course there is the learning curve so I got the power supply  hooked up to power but now have to figure out all the menus and option on how to use it ! 
Larry


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The "KID" charge controller / Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Last post by boB on December 04, 2022, 07:12:49 PM »

  Larry, what kind of BMS is in this 12V system ?

  Since the source, a 24v battery, has a very low impedance, it could be that the current spiked up and the BMS disconnected ?

  I hear about a LOT of problems with BMS's for lithium batteries turning off.  Some can't even turn on an inverter connected to a Li battery
    without the BMS turning itself off.

  boB
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Longshot here but worth checking.
 Check the clock in the controller. I was having the same Float in the am issue and one of the experts here pointed me toward the clock being off. He was right, problem solved. My controller is a Classic 200 but your controller may have a similar clock set up.

Here's the original thread.
http://midniteftp.com/forum/index.php?topic=5809.msg53077#msg53077
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I connected my Kid to a 12v lithium battery today . The Kid had it's input from 24v battery system.
The Kid initially started charging but went to absorb too fast. I had too much wire on the way to the battery ( temp setup) and then calibrated offset for the wire.
It still doesn't like to charge , goes to resting and won't go back to bulk even though well below the setpoint.
I have used the Kid like this in past to charge 12v lead acid batteries and no problems.
Something about  the lithium it just doesn't seem to want to charge properly.
I gave up - charging this new battery for a friend so will try a different approach tomorrow not using the Kid.

Larry
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Hawke's Bay / Re: Hawke's Bay testing in Texas
« Last post by boB on December 02, 2022, 06:15:23 PM »
Thanks for the clarification.  But it does show us the data available from Midnite stuff.  Very well defined and allows for good understanding when the Combox does arrive from Midnite.

I think that Jim has done a fine job on this !   Graphical and pretty nicely laid out too !

boB
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Hawke's Bay / Re: Hawke's Bay testing in Texas
« Last post by Highflyer on December 01, 2022, 03:03:18 PM »
Thanks for the clarification.  But it does show us the data available from Midnite stuff.  Very well defined and allows for good understanding when the Combox does arrive from Midnite.
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General Discussion / Re: Seeing strange things on my off grid system
« Last post by Wizbandit on December 01, 2022, 06:34:57 AM »
The solar panels are 5S 12v with many more paralleled into the five in series. In full mid day sun, I only get about 400watts.

My guess is the issue is here.   Incompatible arrangement of PV modules.  Will need a one-line drawing to see how they are hooked up...
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General Discussion / Re: Seeing strange things on my off grid system
« Last post by ClassicCrazy on November 30, 2022, 07:49:08 PM »
Its a 2S lifepo4 24v 300ah system (6 100 ah 12v batteries) The solar panels are 5S 12v with many more paralleled into the five in series. In full mid day sun, I only get about 400watts. I run only a big fridge and freezer off of the system 24/7.  So typically the batt ah might go down from 300 ah  fully charged to 60% in the morining when the panels start generating power.  In mid- morning on a sunny day, I check on it and its still about the same. But If I come back to it only an hour later, its showing 99% and its in float mode. And stranger still, its been in float mode over three hours and the bank charging rate is still at 15 amps.   This would be .5C, right? The inverter load as shown on Wizbang display is about 1.5 to 4.5 amps only.  I thought that once float mode started, the charging amps would drop down to a very low value.

Could you give some more info ?
What brand of batteries are they ? ( so I can look up the manufacturer specs)
What kind of panels do you have ?
What are the Absorb, Absorb time, Float setpoints you have programmed in to your controller ?  What kind of controller is it  - Classic or Kid ?
The correct terminology for your battery setup would be 2s 3p    ( 2 in series  and 3 parallel )
Have you put the panel specs into the Classic string calculator ( there is a different calculator for Kid)
https://www.midnitesolar.com/sizingTool/index.php

Some considerations - wiring is important to try and have all wiring resistances be the same . See this
http://www.smartgauge.co.uk/batt_con.html

In general lithium will charge at the same voltage for a long time, then quickly rise to absorb setpoint, and go to float  . You may not notice the transition from absorb to float depending on your setpoints.

The reason you may see it at 99% in Float is because depending on your settings and load  it will have to use a bit of the stored energy in battery before it drops to Float voltage .
You may see it charging in float depending on your settings.  And it could be your don't have the Absorb voltage high enough so the batteries continue to charge in Float - really depends on what you have set for them and how you have them wired.

Larry

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General Discussion / Re: Seeing strange things on my off grid system
« Last post by boB on November 30, 2022, 04:32:08 PM »

What stage is the charging when you see only 400 watts or less ?   In Absorb or Float, it would be expected to see a much lower power and current in anything but bulk MPPT charging.

Is your Absorb time set to a very short time ?  Sometimes lithium batteries have a longer Absorb time and sometimes they are very short times.

boB
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