LiFePO4 Batteries and The KID Charging Set Points

[A J Coop]

Hello fellow users, I just recently purchased two 12V, 175Ah LiFePO4 batteries and seeking some reassurance on how I should be programming The KIDs set points. The KID has Temp sensor and Whizbang Jr.

They supplied the Batts with NO documentation, just that they need to be charged "firstly by a AC Li charger (not done out of stock)"  then for use with DCDC and Solar chargers;
Bulk  14.4 - 14.7 Volts
Float 13.6 - 13.8 Volts

I will be having the Batteries in parallel, 350Ah 12 Volt system.

When I reset to Factory do I choose Lithium or Custom? - Is Lithium for all types of Li Chem types or...

My main concern is Temperature Compensation - That would be ZERO because of the BMS?

No "Balancing" or Equalization - BMS?
Then the
Battery Efficiency, ? ~98%.
Battery Temp Ref, @25 Celsius is standard.
Battery Change, Have no idea what that would be!

Any pointers would be muchly appreciated

Thank you

A.J.

[ClassicCrazy]

What you want is for battery to get up to it's recommended charge point .
At that point it should also be where the bms is doing cell balancing - or and it might start balancing some before that.
Some Lithium batteries these days might have a bms with bluetooth that an app can connect to and give some information.
But guessing that yours doesn't .
Anyway the question might be how long is absorb time ?  Depends - some say 5 minutes, some may say longer depending on battery manufacturer .
I wouldn't go higher than the low end of what they say 14.4v for absorb.
What you want with float is for it to supply power to loads without charging the battery any longer.
On my new lithium battery I found that point to be 13.65 ( converted from my 48v settings ) . You will have to watch what is going on based on the Whizbang readings.
No temp compensation - so disable or turn that off.
You could probably go to 99% efficiency.
I didn't know the Kid has a lithium setting ?
One important thing to do is use a good digital meter and take the voltage at the battery, then make it match the voltage the Kid is seeing.
I know the Classic has a way to compensate that in a setting menu - I don't remember if the Kid does.
You would do that at the top of the charge so when it is at 14.4v at battery you want that to be what the Kid is reading too.
I am just getting used to how lithiums work.
You might see that when it goes from Absorb to Float there might be a bit of a delay in that the voltage at the lithiums might stay high enough for a bit until the loads bring it down to Float value.
That will depend on your load.
Also take a look at this
http://www.midniteftp.com/support/kb/faq.php?id=87
Larry

[A J Coop]

Thank you Larry;
Yes I agree to get the Battery up to its recommended charge point, 14.7 I thought was a bit high, I am a little familiar with how Li's work, but my first with The KID and LiFe, I thought asking no matter how stupid the questions may get!
No Bluetooth, there was that option but I have no Phone and the extra cost, have a raspberry Pi, could of figured out a way to hack it via that and incorporate it in to the Serial Stack, oh well.
Cell Balancing, Yea the glory text said "Advanced BMS" ?? Active Cell Balancing, Management? No idea?
Absorb time I kind of had a thought about that I was going to use End Amps in the Battery menu, that from what I have read is about 1A, but my paranoia, I would set it at 2 End Amps and start the trial and error for the time starting at your 5 Min to start with.
The Battery manufacturer is unknown to my research, Global Power Solutions "Atlas" supplied throughout the US and Australia, if you look good luck...
14.4v for absorb, low end, Thank you.
Loads, yes and no loads, when the input is low, low power loads like LED lights or Laptop, travel fridge or none ..., when good that can vary from 100 - 250 Watts. I monitor that closely anyway.
13.6 Float, good thank you, I will watch what is going on with Whizbang. I have Serial Stack active to a RPi, so I will be able to record results every 59 something seconds and make a decision based on that.
No temp compensation â€" Ok, ZERO the BMS takes care of that, thought so, Thank you.
99% efficiency, Good starting point.
The Kid has a lithium setting, yes it does, only from factory boot, or Reset factory defaults. Select Lithium then, I am still unsure it means Li ion, Li Poly types of Lithium or all types??
Use a good digital meter - I have 3 good DMMs and all of them read different readings on the same Battery, I have a Specialist Clamp meter I heavily rely on, I will use that.
Absorb to Float, Ok thank you, yes Lithium is denser than the old AGMs so that makes sense.
Had a look at the FAQ “How do I set the KID to charge Lithium batteries?”
I understand what is said (means), I will have to be very very observant to what’s going on at absorb to float and in float, might increase  End Amps and your 5 Min to 1 as a start, Rebulk voltage to 0.1, 0.2V?  So the Lithium setting is nothing to go by, LUCKY I asked would have been a little troubling if things went belly up.
Thank you again Larry helped heaps.

A.J.

[ClassicCrazy]

You shouldn't need rebulk.
If you have loads and sun then  your loads will get powered when system is in float with  pv power and some from battery if not enough pv available.
Lithiums don't get temperature compensated like lead acid - which raises the voltage setpoint as the batteries get colder.
Lithiums sometimes have temperature sensors in them that will tell the BMS to shut off if the battery gets too cold ( below freezing ) since not good to charge lithiums that cold.
But if you look up Will Prowse on youtube , or there is also another guy but forget his name now - they get all types of those 12v lithium batteries by various manufacturers and then they cut them open . They look at the build quality but also look to see if there are temperature sensors connected the bms that will shut off the charging . Some don't have the cold sensors .
Yeah I read that Kid knowledge base about the lithium setting and it said those are basically just suggestions. Different lithium chemistries have different charge setpoints so they were just trying to make sure people didn't mess up their batteries right away if they didn't know what they are doing.
Regarding the Android - you can usually pick up an outdated android phone for free or next to nothing and then use it just with wifi without having to pay for phone service.
They are handy to use for the gps, camera, and other apps you can get for it.
Larry

[A J Coop]

Shouldn’t need rebulk ok.

Loads at the moment are adjusted accordingly to the AGMs I have at the moment I sort of don’t like them being used when in float! Just my thing I’ve developed over the years SoC, DoD in case I need it..., I don’t think I am going to be too concerned about it with these Batts!

Temperature compensated, Ha, I don’t know where I got that from, might have been some BS I was reading, watching or confused it somehow… I know about the cut offs, hum, ok. It pays to cross reference and ask questions...

I have watched a lot of Will’s vids, lost touch with him, I was/am on his Forum but the attitude of the users steered me away from it so…

The Lithium setting sucked me in to what’s it about, again lucky I asked, I don’t know either!

Regarding the Android - Too late, something to think about though for the future as many people said they won't go back.

Thank you AGAIN Larry

A.J.

[boB]

Shouldn’t need rebulk ok.

Loads at the moment are adjusted accordingly to the AGMs I have at the moment I sort of don’t like them being used when in float! Just my thing I’ve developed over the years SoC, DoD in case I need it..., I don’t think I am going to be too concerned about it with these Batts!

Temperature compensated, Ha, I don’t know where I got that from, might have been some BS I was reading, watching or confused it somehow… I know about the cut offs, hum, ok. It pays to cross reference and ask questions...

I have watched a lot of Will’s vids, lost touch with him, I was/am on his Forum but the attitude of the users steered me away from it so…

The Lithium setting sucked me in to what’s it about, again lucky I asked, I don’t know either!

Regarding the Android - Too late, something to think about though for the future as many people said they won't go back.

Thank you AGAIN Larry

A.J.

A J, glad you are here !   We don't know it all and are learning too of course.

As for Re-Bulk, you "shouldn't" need it...  Amp-Hours can be put back into the battery at the float voltage too.

FLA batteries need to be Bulk/Absorbed once in a while but not necessarily every day.

But definitely use the available energy/power so you don't discharge the batteries more than needed before the sun goes down, if solar is the main source.

boB

[A J Coop]

Hi boB;
I've been on this Forum since 2016, glad I'm here too.. I keep low key, I'm more at home! I've been learning for over 20 years with electronics, about half that with solar and I still know nothing! So yea we can only keep on learning  .
Thank you, I have noticed that the amps get replaced, then settles down once the batts top up.
My AGMs get 10 to 20% DoD 80-90% SoC every week or so, the most the time without a charge has been two weeks because I was away in another state, they are treated like babies, I will be using the LiFe batteries for going bush (Camping) and when the AC mains power goes out, when our power goes out it's out for hours, on the camping trips they will be put to the test and I get a good idea on their capability, I will let the forum know how it goes, wont be for a while yet.
Solar is the only charging source, been like that since 2016, NO, years before that! That's when I found The KID, the Chinese controllers X3 didn't have it in them! The load out function stopped working after a while powering a LED strip light, 1.3A of power, the shop tried telling me I was shorting it? Well I let them have it  .
I'm in the process of trying to make/build a Battery/KID combo box for camping so I can eat those Ah right up and still have lots of power for when the sun goes down, still stuck at phase 1! In my head...
Thanks boB

A.J.