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NINTHCIT Grade A 3.2V 120Ah LiFePO4 cells - Out for Delivery

OnTheRoadAgain

Solar Enthusiast
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So within the next few hours my new 120Ah NINTHCIT cells arrive.
Of course, they will undergo rigorous scrutiny.

Few people have tried these yet and information on them has been slow to trickle in. I hope to change that.
I'll check them thoroughly, weigh each cell, test their arrival voltages and resistances. Then top balance and afterwards run a full capacity test with my DL24P

I like these because originally I went with an Off The Shelf 100Ah sealed LiFePO4 but ran into a small problem with one cell
running away at 3.4v resulting in a battery that wouldn't reach full charge state. Probably could have easily been resolved but
changing ANY settings resulted in voided warranty so I had no choice but to send it back.

After that I decided to stick with DIY batteries since I would have complete control over everything.

I like the fact that these are 120Ah batteries vs 100Ah batteries. That will allow me a good "cushion" while still having a full
100Ah that I can safely use.

Hoping these cells live up to the challenge. I'll report it either way, good bad or ugly.
As long as I don't blow them on the top balance procedure :whistle:

If you have any interest in these batteries, you'll get a lot of information on them here.

Hoping for the best.
 
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OK, here are some initial UnBoxing Photos

Click on any photo for larger view.

Box is very sturdy and well taped
1280_LiFePO4_1_20210503_133902.jpg

Blurry end view (only blurry pic, sry)
1280_LiFePO4_2_20210503_133914.jpg

Close Up of top of box. VERY well packed and sealed
1280_LiFePO4_3_20210503_133932.jpg

Open the top. Greeted by lots of foam packing.
1280_LiFePO4_4_20210503_134009.jpg

As you can see, the cells are well protected. Busbars in the center
1280_LiFePO4_5_20210503_134034.jpg

Foam packing all around the cells.
1280_LiFePO4_6_20210503_134106.jpg
 
Continued......

Click any photo for larger view


Individual cells removed from the master carton
1280_LiFePO4_7_20210503_134150.jpg

Included Busbars and hardware
Personally, I wish the terminals were beefier.
1280_LiFePO4_8_20210503_134426.jpg

Close up to show the thickness (thinness) of Busbars.
Not sure I will use these.
1280_LiFePO4_9_20210503_134438.jpg

Again, well packed and protected, even in the individual cell cartons
1280_LiFePO4_10_20210503_134751.jpg

Finally, the cells
1280_LiFePO4_11_20210503_134759.jpg
 
Each cell comes individually wrapped in a mylar pouch. but the mylar pouches themselves were not sealed.
1280_LiFePO4_12_20210503_134817.jpg

And finally the cells themselves. They look really good
A close inspection revealed no defects or problems.
They do look like Grade A cells.
1280_LiFePO4_13_20210503_135028.jpg


All very flat with no noticeable pillowing
1280_LiFePO4_14_20210503_135211.jpg

1280_LiFePO4_15_20210503_135230.jpg

The only thing I've found so far that I'm not crazy about is the small terminals.
All have QR code labels that look authentic to me. What do you think?
1280_LiFePO4_17_20210503_135322.jpg
 
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Initial Voltage Check passed with flying colors.....

All 4 cells exactly spot on 3.300v

3.300v
3.300v
3.300v
3.300v

SFSG

initialVoltageCheck.jpg
 
Make sure you do a thorough cleaning of the cell terminals .... that tape will leave a residue .... so something that will cut that residue.
I used goo gone ... then cleaned with alcohol ... then used emery cloth to remove oxidation .... then cleaned with alcohol again and then applied a very thin coat of noalox.

Don't underestimate the importance of clean ... and flat ... bus bars and terminals.
 
Quick IR test with SM8124 IR tester -

Cell 1 - 16 milliohms
Cell 2 - 17 milliohms
Cell 3 - 20 milliohms
Cell 4 - 14 milliohms

If these values were correct they would be considerably out of spec.

3.2V 120AH Product Specification
Product Name: Lithium iron phosphate cell Shell
Material:Aluminium
Rated capacity:120Ah
Minimum capacity:120Ah
Internal impedance:0.2~0.3mΩ
Nominal voltage:3.2V
Dimensions(L*W*H):174*48*171mm
Weight:2.86±0.10kg
Recommend Constant Current:120A(1C)
End-of-Discharge Voltage:2.5V
Recommend Constant Current:60A(0.5C)
Charge Voltage:3.65V
Maximum Pulse Discharging Current:200A(3min)
Maximum Pulse Discharging Current:240A(30S)
Charge Voltage:3.65V
Max Continuous Discharge Current:120A(1C)
Cycle life (80%DOD):4000 cycles
Charging Temperature:-5~60°C
Discharging Temperature:-30~60°C


I need to do a real test. I'm not sure I can trust these numbers from this SM8124A device.
 
Just completed the proper Internal resistance tests.
Again...they passed with flying colors.
Here's my little Internal Resistance cheat sheet

So my batteries are turning out to be perfect....so far.
Next comes top balance then capacity test.
If they hit 120Ah or better then these are golden.

BatteryResistanceWorksheet.jpg
 
120Ah cells in 4P configuration
Starting voltage 3.300v for each cell
PZEM-15 monitoring device
Power supply set to 3.60v (maximum current)
CC/CV Power Supply rated at 10 Amps
Batteries connected in Parallel
Average watts going into pack = 17watts


45 Hours into charge.......

Total Pack Voltage increase over 45 hours = .071v


Amp hours is saying 175Ah...but......only ~720watt hours (Pack capacity should be 1440Watt Hours)
Cell temperatures and terminal temperatures checked with laser thermometer. All are at room temp

I'm wondering if maybe I got 280Ah cells by accident :unsure: (lol)
 
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An oddity has surfaced....maybe......

Pack voltage seems to drop if I raise the current. In my past experience...that's indicative of a bad cell?

It's time to split the pack and charge cells individually.
 
An oddity has surfaced....maybe......

Pack voltage seems to drop if I raise the current. In my past experience...that's indicative of a bad cell?

It's time to split the pack and charge cells individually.
Why don't you set the voltage to 3.65 volts and the current at max? Of course before connecting the power supply to the cells.

Pack voltage seems to drop if I raise the current. In my past experience...that's indicative of a bad cell?
Do you mean raise the current because I thought you had the current set at the max 10 amps? Anyways, it does not mean you have a bad cell. Where did you get that experience from? It could be because your connections and cables are not optimal. Have you looked at any of the voltage drop calculators?
 
Why don't you set the voltage to 3.65 volts and the current at max? Of course before connecting the power supply to the cells.


Do you mean raise the current because I thought you had the current set at the max 10 amps? Anyways, it does not mean you have a bad cell. Where did you get that experience from? It could be because your connections and cables are not optimal. Have you looked at any of the voltage drop calculators?

Hello Gazoo,

I did set the voltage at 3.60 (safety margin)
What was happening is that the voltage began dropping, while charging.
So I stopped the process, disconnected all the bus bars and ran the same charge rate on the individual cells.
They all got to 3.377 then began slowly going the other way, losing voltage and would slowly drop from 3.377v and slowly keep dropping.

I only let them drop to 3.360v before shutting it off.

Since all 4 cells individually did the exact same thing, I'm discounting it as perfectly normal.
I read that the batteries are likely entering absorption phase and will eventually resume increasing voltage.

No I did not touch the current. The current is set at it's max (10Amps.) but it never uses that much. Only about 5amps
I made extra extra extra sure I did the connections correctly. And it does the exact same thing on the cells individually.

It's just aphase the batteries are going through as they begin to reach full SOC. I'm pretty sure of it now.
 
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The current is set at it's max (10Amps.) but it never uses that much. Only about 5amps
Are you using the cables that came with the power supply? It should be putting out 10 amps if you replaced the cables with at least 12AWG cables.
 
Using custom 12Gauge cables with ring terminals on all 4 ends.

If I set it to 3.65v then it does draw more amps.
 
Using custom 12Gauge cables with ring terminals on all 4 ends.

If I set it to 3.65v then it does draw more amps.
That's normal. Dealing with the small voltage is a pain. I found the same to be true with my Riden. I tried the step method and quickly made the decision to set it to 3.65 volts.
 
That's normal. Dealing with the small voltage is a pain. I found the same to be true with my Riden. I tried the step method and quickly made the decision to set it to 3.65 volts.

Have you ever observed the voltage at the battery terminals dropping, while the charger was connected with your LiFePO4?
 
Have you ever observed the voltage at the battery terminals dropping, while the charger was connected with your LiFePO4?
No and I do find that odd especially since you upgraded your PS cables and it's only putting out 6 amps or so. I am wondering if you got a bad PS? As far as I can recall no one has posted cells voltages dropping while charging. Mine didn't when I top balanced and they don't when charging in series.

Is the voltage displayed on the PS dropping? And on your meter too? I like that meter BTW, brings back memories.
 
The voltage doesn't drop but the current does a bit at the PSU.
But it does drop on the Meter directly at the battery terminals.

Only happens when it hits around 3.377v - 3.380v
then it'll just creep slowly back down to about 3.6v

BTW...the PZEM-15 says I've put 185Ah into the battery so far (it's a 120Ah battery). :unsure:

Now, I can get 10A flowing to the battery if I crank up the voltage. 4v or higher.
that's what gets so many people in trouble. Trying to expedite the charging by upping the voltage, to increase the amps.

But at 3.65v it only goes to about 6amps.

I'm sure there a mathematical way I could calculate what the amps delivery is supposed to be at this voltage.

Yeah, this meter is solid and still spot on. They don't make em like that anymore (y)
 
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