Are my new lifepo4 batteries good or not?

[sdnomad]

I just received these three new Hamassi 100Ah batteries with Bluetooth that I plan to run in series. They arrived at 0% state of charge. I charged them to 100% on their own independent 10amp charging banks and below are the specs the Bluetooth app shows me after charging to 100% and sitting for 5 hours.

Battery 1's Bluetooth is stating a real capacity of 97.7Ah, which is concerning. How accurate is the Bluetooth real capacity reading?
When it was fully charged and the charger was still connected it showed high cell at 3700mV and low cell at 3435mV with a deviation of .265V. Since stopping the charge those two cells have settled to 3495mV and 3373mV with a deviation of .122V.
Also, the state of charge on battery 1 fell to 99% within 6 hours after charging, while the other two batteries remain at 100%.

Does anyone see anything that I should be concerned about? Should I check anything else, run any other tests, or do anything further? How will these batteries perform in series with these differences in specs between the 3?

I have a capacity load tester ordered but it won't arrive for a couple of weeks.


Battery (1)




Battery (2)




Battery (3)

 

[sdnomad]

Here are the BMS settings for each battery. Is the full capacity under BMS settings entered manually or is it an actual reading? If the "full capacity" is a setting why would this 100Ah battery be set to 97Ah?

Battery (1)


Battery (2)


Battery (3)

 

[timselectric]

If you plan to put them in series (I wouldn't), make sure that the manufacturer says that they can be.
And you must balance them completely before doing so. Also 3 in series is 36v. I guess that is the voltage that you want?

 

[sdnomad]

If you plan to put them in series (I wouldn't), make sure that the manufacturer says that they can be.
And you must balance them completely before doing so. Also 3 in series is 36v. I guess that is the voltage that you want?

The manufacturer states you can place 4 in series. And 36V is what I'm after.
How do you balance with the BMS? Everything I find is on balancing individual cells before assembling the battery.
I'm using a 3 bank NOCO Genius Pro 10A lithium charger. Do you leave it charging for a set length of time to balance? When do you know when it has finished balancing? I don't know if my NOCO Genius charger will work for balancing or if I need a DC power supply of some kind. It seems like the NOCO charger stops the charging amps when it senses it's charged. I don't know if it goes into some kind of float mode on lithium setting. The BMS app shows 0.0 amps at 14.625V with the NOCO charger connected.

 

[timselectric]

Put them in parallel and allow them to balance their own cells and balance with each other.

 

[sdnomad]

Put them in parallel and allow them to balance their own cells and balance with each other.

I found this thread describing balancing individual cells. I'm having a tough time finding instructions on balancing 12V battery packs with their own BMS's.

When using a 10A varible power supply, I imagine you use the same principle below but instead of starting at 3.4V as described in step 4, you start at 13.6V (3.4V x 4) at 8A. Then move to 14.0V at 8A. Then to 14.4V at 8A. This is just me guessing???

How to Parallel Balancing. (YEP 99% of us is doing it wrong)(PART#1)

So my boss who has a PhD in Chemical Engineering went to China on business about a month ago and visited one of the largest LiFePO4 battery manufacturers in the world that we use. They gave him a very good tour and today we reciprocated their hospitality by hosting their Lead Design Engineer who...

diysolarforum.com

How to Parallel Balancing. (YEP 99% of us is doing it wrong)

So we have all heard the instruction that by just wiring the cells in parallel they will somehow all get themselves magically in balance. This is NOT entirely true unless you have several days-weeks to waste. Now let me caveat something first. 95% of all the LiFePO4 (LFP) cells coming out of China now are made in batches and shipped in batches. This means that if you order four 100aH batteries that the odds are they are going to all be charged at 3.2v at the factory and by the time you get it ALL the cells are probably within a 0.1V variance. SO simply paralleling those four batteries for the next 24 hours will probably do the trick.

BUT if you get batteries that are 0.25v or more out of whack - or you don't want to wait 24 hours - here's how the Manufacturing Design engineers recommend. Remember - Balancing requires a voltage differential to move current between or from/to the cells. That’s why just putting them together in parallel and leaving them does NOT do much.

So to QUICKLY achieve a PERFECT balance.

1. If possible - top each of the cells up to the voltage of the highest cell prior to wiring them in parallel.
2. Wire the cells in parallel
3. Set the power supply to 3.40V and the amperage to about 80% of the max it can do. (Setting it at 80% is only to prolong the life of the Power Supply)
4. Turn on power supply and charge to 3.40V
5. When the current has dropped to 0.0A at 3.40V turn off the power supply & set it to 3.50V
6. Turn on power supply and charge cells to 3.50V
7. When current has dropped to 0.0A at 3.50V turn off the power supply & set to 3.60V
8. Allow current to drop to 0.0A at 3.60V
9. Disconnect Power.
10. The Battery pack is now perfectly balanced.

NOTE: Due to LFP characteristics, It will take about 70% of the time to get from 3.2 to 3.4V. Then about 25% of the time to get 3.4 to 3.5V... then 3.5 to 3.6 will be very short ...

NOTE: Measure the input voltage right at the cells - do not trust the voltmeter on the power supply.

NOTE: You have to do each step as described – you CAN'T simply set it at 3.6V and walk away.

 

[timselectric]

When using a 10A varible power supply, I imagine you use the same principle below but instead of starting at 3.4V as described in step 4, you start at 13.6V (3.4V x 4) at 8A. Then move to 14.0V at 8A. Then to 14.4V at 8A. This is just me guessing???

Exactly

 

[HRTKD]

With the cells out of balance by .2 volts, you may have to cycle the battery quite a few times to get the cells to balance. You don't need to cycle it 100% (100% down to 0%, back to 100%). Cycling it from 95% to 80% (for example) would be enough to take the cell voltages down far enough that you can then charge the battery and have it perform cell balancing.

I would be concerned about receiving batteries at 0% state of charge.