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

It should be in constant current mode.


The battery is actually 480ah's. Because you have 4 120ah cells connected in parallel.


You need to verify that. Again it "could" be a faulty power supply. I doubt the cells are bad. Do you have anything else you could use to verify? Something like the variable voltage wall warts Radio Shack used to sell. If you do you could connect it to the cell and see if the voltage of the cell comes up.

The fact your power supply is not in constant current mode isn't good. Did it ever go into CC mode? I don't know how you have everything connected which is why I asked you to post a photo. Nevertheless, I suspect either bad connections, a bad power supply or both based on what you have said.


I get that. Please verify which direction the current is going when it does that using your clamp meter.

Ah! Forgot all about that. Thank you Gazoo !!

I can get it into CC mode by adjusting the current down from maximum.
But that does not change the current amount going to the battery.
But now the indicator light is next to the Current display so it's in Constant current mode.

I understand what you mean about constant voltage. But I have been sitting here next to it the entire time watching it carefully.

cellsinparallel_1.jpg
 
You are not using banana plugs and have the ring terminals connected to the power supply too right? Which power supply are you using? If you can verify which direction the current is going using your clamp meter that would help. Something about all of this is not making sense. Sounds to me like you are doing everything correctly.

Considering cells are generally shipped with a 50% SOC, and your power supply is putting apx. 6 amps into them, it would take apx 40 hours to top them up.

Here's a pic of mine when I parallel top balanced. Show and tell....lol. I used 12AWG copper stranded silicone insulated wire.
 

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No banana plugs. about 50 hours charging now and 202Ah, 684Wh.

Cheap Dr.Meter PSU.
5.5A is ALL I can get out of it unless I crank up the voltage.

DrMeter.jpg
 
The PS is in CC mode but I guess that's because you turned the current down as you said. I don't know why it's doing that. Everything looks good to me. I would just leave it as is and see what happens, but keep a close eye on it.

When the voltage of the power supply reaches 3.65 volts or so, it should then switch into CV mode. And then the amps will taper off.
 
I took a look at the voltage and current on my PS when I took that photo. Notice I have it set to 3.40 volts and it is in CV mode. And the amps is only 5.84 amps. That's because I was going to use the step method to parallel top balance. Once I turned the voltage up to 3.65 volts the PS did go into CC mode, and it was putting out very close to 12 amps. Just wanted to make that clear in case anyone questions it...lol.
 
Gazoo,
Thanks again for your assistance.

Let me ask you this......

If it was in fact a bad PSU......

How could the voltage rise, then begin to fall every time the battery pack reached 3.377 - 3.380v ?
All, while a clamp meter still shows full current flowing to the battery?

What problem in a PSU could cause that behavior?
 
Gazoo,
Thanks again for your assistance.

Let me ask you this......

If it was in fact a bad PSU......

How could the voltage rise, then begin to fall every time the battery pack reached 3.377 - 3.380v ?
All, while a clamp meter still shows full current flowing to the battery?

What problem in a PSU could cause that behavior?
Honestly I don't know. If your clamp meter is showing current going into the cells the voltage should be rising. You have a unique situation and I still suspect it's the power supply and not the cells but I could be wrong. There is a point during the process it will appear the voltage is not increasing due to the flat part of the curve. Has the voltage of the cells come up at all since yesterday. Even a millivolt or 2?
 
It's normal for the voltage to sit at these values for a very very very long time. Don't underestimate h ow long it takes to top balance using this method.

I saw my voltages at the cell terminals DECLINE while top-balancing. It was minor (millivolts) but I consider it normal - the internal resistance of the battery is changing as it's being charged and other factors will easily contribute to observing small voltage changes while charging in the flat part of the charge curve for this chemistry.
 
Gazoo.....

You were spot on correct.

This ended up totally being a faulty power supply issue. Dr. Meter, Black 10A unit. Brand new from Amazon.
So somehow, this bad PSU would get to 3.377v - 3.800v and then just go nuts and the voltage would begin dropping....even while the clamp meter still showed nearly the full amps indicated on the display going to the battery? This is an electronics issue.
I'm not even sure how this happened?

I have an older 5 Amp power supply on hand and connected it to the batteries......

Sure enough within one hour the battery pack reached 3.4 volts for the first time. I was surprised because I had more faith in the new PSU than the batteries. You were the one who correctly zeroed in on that. A BIG Thank you!

But VERY relieved to know it's not the batteries after all. I said no way I'm going to spend $200 on a PSU....may have to eat that.
Got the batteries fully charged, put them in series, hooked up the BMS and running a capacity test now.

How much was that Riden unit? :)
 
You can find the Riden on aliexpress and that's where I ordered it from. Other places might have it for a little less. I have the 12 amp model. Last I looked they are now up to 18 amps. I bought the complete kit including the case and the power supply. No regrets. It has come in handy for other things and I used it to balance one of my cells that was a bit weak on the top.
 
I love my Riden, too. But if you series-charge the cells through a BMS first and then parallel top-balance them, this process will go a lot faster (assuming you have a higher-power 12v source) and it's still perfectly safe and you don't need a fancy PS for the 3.65v stuff.
 
After being led astray by a bad brand new Dr. Meter 10A power supply (since returned), things have gone smoothly.

The 120Ah cells tested out at 124Ah.
Resistances were in specs.
Arrived flat as pancakes.
Price was about as good as I have found state side.
From all I can gather, they do appear to be new, grade A cells as advertised. At least my batch.

I would give these cells a top notch rating.

But always keep i mind, YMMV

By the way...I found out the power supply was seriously bad 4 days after the Amazon 30 day window closed.
They accepted the return....but I had to pay a 20% restocking fee.
Check and double check all those Amazon goods quickly after they arrive. It's ALWAYS possible to get something defective yet brand new.
 
You can find the Riden on aliexpress and that's where I ordered it from. Other places might have it for a little less. I have the 12 amp model. Last I looked they are now up to 18 amps. I bought the complete kit including the case and the power supply. No regrets. It has come in handy for other things and I used it to balance one of my cells that was a bit weak on the top.

Gazoo,
Just before I learned my new Dr.Meter PSU was bad, I had said I would not be spending $200 on a PSU.
Then after the failure of the new PSu I decided a good PSu was something I needed on hand.
I ordered the Riden 18Amp unit like what you have.

I hope it's not too difficult to learn to use. All the old ones I had just required a twist of a few knobs.
 
Gazoo,
Just before I learned my new Dr.Meter PSU was bad, I had said I would not be spending $200 on a PSU.
Then after the failure of the new PSu I decided a good PSu was something I needed on hand.
I ordered the Riden 18Amp unit like what you have.

I hope it's not too difficult to learn to use. All the old ones I had just required a twist of a few knobs.
It can be a little intimidating at first but once you play around with it it's not bad. Carefully read the manual. I downloaded it before I decided to order mine and became familiar with it. I am sure you will be happy with it.
 
It can be a little intimidating at first but once you play around with it it's not bad. Carefully read the manual. I downloaded it before I decided to order mine and became familiar with it. I am sure you will be happy with it.

Getting used to the Riden Power Supply. It's quite a step up from anything I've had before in terms of a power supply.
So far I really like it. (y)

Gotta get all the ropes ironed out cause I just ordered 8 more big cells that should arrive in about 45 days.

One thing......I bought just the head unit and my own AC-DC power supply. 480watt, 20Amp.

How often do you need more than that? I can't recall ever doing anything with a PSU above about 14v and 20A
Good PSU and thanks for the recommendation.
Thanks
 

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