Author Topic: MidNite Guru Needed!, Kid Charging LifePO4 issue's  (Read 1234 times)

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 3344
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #15 on: September 21, 2022, 01:26:06 PM »
So check something for me, Well after sundown when the kid should be resting please look and see if it still says float not resting. A phenomena on the kid I have seen is if the float voltage is lower than its resting voltage or another source holds the battery voltage up the kid will not go to resting thus it never sees a new day.

if this is the case take note of the battery voltage at this time (I would say like 8pm just for a good consistent time) and try setting float just above that.

Also can you share the Absorb and float settings and brand of battery.

I will talk to the Customer Service tech as well as they should have had you check this first to save the hassle of swapping the kid

Ryan

  Hi Ryan,
   I had checked the voltage a few times at night, the batteries usually sat around 13.2 iish with the display reading "resting"
Settings are 13.4 float 14.2 absorb for 20 min and 5 amp end amps (set to the whiz bang Jr)  my Battery, 4x280 amp/hr cells with a 200 amp JBD BMS with blue tooth.

   Not only would the Kids not start a new day.....but many days they just switched to float without ever hitting the absorb voltage.

  I had spoken to you a few times via email, And did try moving all of the setting up and down several points as per your suggestion... But it didn't help

Sadly,  I was so frustrated after weeks on the road having to re-boot the unit every morning and sometimes again mid day that I stopped and bought a Victron 100/50.  I hooked this charge controller up with all the same wiring and settings and have never had an issue since.

  It's really to bad as I do prefer the MidNite product.  (and well now I have a spare charge controller sitting in the garage)

Chris - I only skimmed over your posts on this topic. I was having an issue with my Classic going into resting after Absorb and just sitting there for a long time. I finally figured out that my PV voltage was too low for some reason - even though well above the Float setpoint. I used Tweaks to adjust the PV voltage that the Classic saw up about 4 volts ( on a 48v battery system) and that was what was wrong - it needed that for some reason and now all the transitions from wakeup, to absorb, to float work okay.
I don't remember all the settings on the Kid - or if it has the Tweaks for compensating the PV voltage  , but if you ever dig out your Kid again you might want to try turning it up . I forget what your setup was like type of PV and battery , etc - but something to consider trying to see if it makes any difference. I know the Kid is different than the Classic but that is what worked for me if your PV voltage isn't a lot higher than your charging voltage .
Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

chris

  • Jr. Member
  • **
  • Posts: 82
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #16 on: September 22, 2022, 11:06:40 AM »
So check something for me, Well after sundown when the kid should be resting please look and see if it still says float not resting. A phenomena on the kid I have seen is if the float voltage is lower than its resting voltage or another source holds the battery voltage up the kid will not go to resting thus it never sees a new day.

if this is the case take note of the battery voltage at this time (I would say like 8pm just for a good consistent time) and try setting float just above that.

Also can you share the Absorb and float settings and brand of battery.

I will talk to the Customer Service tech as well as they should have had you check this first to save the hassle of swapping the kid

Ryan

  Hi Ryan,
   I had checked the voltage a few times at night, the batteries usually sat around 13.2 iish with the display reading "resting"
Settings are 13.4 float 14.2 absorb for 20 min and 5 amp end amps (set to the whiz bang Jr)  my Battery, 4x280 amp/hr cells with a 200 amp JBD BMS with blue tooth.

   Not only would the Kids not start a new day.....but many days they just switched to float without ever hitting the absorb voltage.

  I had spoken to you a few times via email, And did try moving all of the setting up and down several points as per your suggestion... But it didn't help

Sadly,  I was so frustrated after weeks on the road having to re-boot the unit every morning and sometimes again mid day that I stopped and bought a Victron 100/50.  I hooked this charge controller up with all the same wiring and settings and have never had an issue since.

  It's really to bad as I do prefer the MidNite product.  (and well now I have a spare charge controller sitting in the garage)

Chris - I only skimmed over your posts on this topic. I was having an issue with my Classic going into resting after Absorb and just sitting there for a long time. I finally figured out that my PV voltage was too low for some reason - even though well above the Float setpoint. I used Tweaks to adjust the PV voltage that the Classic saw up about 4 volts ( on a 48v battery system) and that was what was wrong - it needed that for some reason and now all the transitions from wakeup, to absorb, to float work okay.
I don't remember all the settings on the Kid - or if it has the Tweaks for compensating the PV voltage  , but if you ever dig out your Kid again you might want to try turning it up . I forget what your setup was like type of PV and battery , etc - but something to consider trying to see if it makes any difference. I know the Kid is different than the Classic but that is what worked for me if your PV voltage isn't a lot higher than your charging voltage .
Larry

Hi Larry,
  I appreciate your suggestion.  At some point here I'm going to put together a ground deploy array for shady campsites. If I can get the kid to function properly I would love to make use of it.
 
    So my current array that I took the kid off (i experiment with 2 & 4 panels)  all in parallel.

195watt
Vmp 38.3
Imp 5.09
Voc 45
Isc 5.45

   I could try putting 2 of my panels in series and see if that makes a difference
 
System 1
12 volt system,
280 AH DIY LifePO4 with 200amp JBD BMS
4x200 Watt 36volt panels 4P
MidNite Kid, WBjr
2000 watt Kisae SW inverter

System 2
Off Grid RV (parked and used as a cabin)
12 volt system,
4 X T-105+
6X100 watt array wired as 3 strings
MidNite Kid, WBjr & MNBTS
1500 watt Cotek SW

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 3344
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #17 on: September 22, 2022, 06:26:15 PM »
Chris -
Well I doubt my suggestion would help since it looks like your PV voltage is well above the 12v battery charging voltages.
But maybe it will work for some other reason .
Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 3344
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #18 on: December 03, 2022, 07:53:25 PM »
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
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

littleharbor2

  • Jr. Member
  • **
  • Posts: 90
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #19 on: December 04, 2022, 08:00:40 AM »
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
« Last Edit: December 04, 2022, 08:04:54 AM by littleharbor2 »
12 Suntech 175's
   Classic 200
   Bogart Tri Metric
   Trace SW 4024 (brand new, sort of, first energized Feb. 2015)
  460 Ah. 24 volt LiFePo4  Battery bank

boB

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 4014
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #20 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
K7IQ 🌛  He/She/Me

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 3344
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #21 on: December 04, 2022, 11:21:00 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

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


system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

FNG

  • Administrator
  • Sr. Member
  • *****
  • Posts: 431
Re: MidNite Guru Needed!, Kid Charging LifePO4 issue's
« Reply #22 on: Today at 11:55:54 AM »
We recently found a bug in the kid that causes this. Mario should have new code this week to test that fixes this issue.