Help on some Lifepo4 Understanding pls

[hur3r]

Hi all i had a Broken Sony ij1001M Akku Pack with 128 Sony 26650 3000mah 25A Cells in so long so good.

I get Cheap K2 Energy Cells with 3800mah the white ones NEW and on the Datasheet they should work with 4C so around 12A

Ok more Space is allways welcome says may Brain

But now i am Confused here is why and i need a rly good Answer pls The Akku pack is a 16S8P Pack around 51.2 to 56.2 on loading max.

My Main problem is this Cells habe huge Energy Jumps on Charge and Discharge and i want to know what was my mistake or is it necessary to load them with 0.2C the first time?

Ok i was done had 4 Energy packs and all i needet to build the Battery as Sony want to a High Voltage System

So each pak Serial to the next so i get around 200V-230V

The Controller say all is ok all work well the Inverter say the Same and start Charging all is fine but when i check the Cell Voltages i get Confused.

All 3800 mah Cells had 3,3V Precharged i testet every one.

But on Charging the Cells jumps from 3,3V to 3,45V and that with around 1A with 3A it Jump to 3,55V ....... but then the BMS says Overload... the old bms go from 2,8V to maximum 3,55V

And the same on the Discharge it Break fast down to around 3V

The Sony Cells go on Charge from 3.3V to 3,42V BUT ON 16A!!!

I think this 3800 Cells are not 12A maybe 1C or is it possible i do a big mistake on build the 8 packs? I have no idea what was my mistake and i am rly frustratet now 128 Cells for the Trash and no i dont do it again................. Cut all out and Weld again all in........

 

[OffGridInTheCity]

I found this at this doc - https://www.manualslib.com/manual/1058455/Sony-Ij1001m.html?page=20#manual

Hi all i had a Broken Sony ij1001M Akku Pack with 128 Sony 26650 3000mah 25A Cells in so long so good.

Looks like 25a total for charging, not 25a/cell. 25a/cell would be 25a * 8p = 200a.

Based on the chart above it shows 57.6v @ 24a for CC. 57.6v / 16cells in series = 3.6v/cell for CC and 24a / 16 cells = 1.5a/cell. Perhaps the BMS is tripping at anything above this.

I get Cheap K2 Energy Cells with 3800mah the white ones NEW and on the Datasheet they should work with 4C so around 12A

Ok more Space is allways welcome says may Brain

But now i am Confused here is why and i need a rly good Answer pls The Akku pack is a 16S8P Pack around 51.2 to 56.2 on loading max.

My Main problem is this Cells habe huge Energy Jumps on Charge and Discharge and i want to know what was my mistake or is it necessary to load them with 0.2C the first time?

Well, charging will raise the voltage higher than the rest voltage of the cell to allow charging current to flow to the cells.

Ok i was done had 4 Energy packs and all i needet to build the Battery as Sony want to a High Voltage System

So each pak Serial to the next so i get around 200V-230V

The Controller say all is ok all work well the Inverter say the Same and start Charging all is fine but when i check the Cell Voltages i get Confused.

All 3800 mah Cells had 3,3V Precharged i testet every one.
But on Charging the Cells jumps from 3,3V to 3,45V and that with around 1A with 3A it Jump to 3,55V ......

Not sure what you mean "1A with 3A"..... 3a/cell would be too much.

. but then the BMS says Overload... the old bms go from 2,8V to maximum 3,55V

Perhaps you're charging too aggressively? - should be <= 1.5a/cell or 24a max charging current - and you're tripping the BMS.

And the same on the Discharge it Break fast down to around 3V

A large load (too large for the cells) can pull down voltages dramatically. At 1a/cell = 8a * 52v = 416w load would be reasonable. At 3a/cell = 24a * 52v = 1248w load would be pretty significant and pull down the voltage. How large is you're load?

The Sony Cells go on Charge from 3.3V to 3,42V BUT ON 16A!!!

I think this 3800 Cells are not 12A maybe 1C or is it possible i do a big mistake on build the 8 packs? I have no idea what was my mistake and i am rly frustratet now

Not sure where you get 12a / cell. Even if you find a specification that says 12a/cell max discharge - this doesn't mean you can operate at that level sustained loads. For example, a typical laptop 18650 cell will say 4a max discharge / cell but that would pull the voltage down so far as to be unusable more than a couple of minutes. 0.5a (0.2C) is pretty much the practical max in practice.

128 Cells for the Trash and no i dont do it again................. Cut all out and Weld again all in........

 

[hur3r]

You missunderstand me on some Points.

The Original paks with the Original Sony Cells can be Charged at 300-400A at 48V when they are 8 in Parallel.

But you can build this paks also as High Voltage in Series.
I try it Again.

I have the Original ones with Sony Cells Produced from Sony in 8 paks Serial to around 430V Max +-

And my Repaired Pack the one with brand New Cells in it 3800mah from 2K Energy the White ones with 12,10wh per Cell ratet at 4C so around 12a Max Discharge dont know the Charge (Ampere) A is always Ampere.

The Battery in Original can do 16A Constant Discharge and Charge 200V at 16A 300v at 16A or 400-430V at 16A is the Max from Sony for permanent and Maximal Use as Solar Battery this work frine no Issues.

But here comes what i cant understand the new pack with the 3800mah cells Kick the Cells Up as hell on Charging from 3,3V to 3,5V on 360V at only 2A with 1000W

And the Sony Cells jump on this low Ampere only from 3,3V to Max 3,35V on the same Load!

So what was my Mistake by replacing the Cells?

When the Datasheet is Correct and each Cell can handle max 12C why when i give them 2A with 1000W and 360V but the 360V comes from 6 Paks in Serial! every pak take what it want and run only on 50-56,2V not higher!

Why in the Hell Spike the cells in 8packs as 16S8P so 8 Parallel and 16x8 in Serial = 128 Cells in 1 Pack.

Is it the Cells? maybe i do a bad jop on welding? but on 16 Packs? Impossible or cant the Cells Handle this Type of Charging i am rly rly frustratet at this..... because i cant understand WHY

And Yes the Sony cells are Ratet at 20A

Technische Daten:
System:	LiFePO4
Spannung:	3,2 Volt
mAh:	3000 mAh
VPE:	Bulk
Stecksystem:	Flattop
Ummantelung:	Schrumpfschlauch
Zellentyp:	Industrie
Höhe (netto):	65,4 mm
Durchmesser (netto):	26 mm
Nettogewicht:	88 g
max. Ladestrom:	2,85 A
max. Entladestrom:	20 A
Geeignet für:	Starter-Akkus
Geeignet für:	E-Bike/Pedelec-Akkus
Geeignet für:	Werkzeug-Akkus
Gefahrgutklasse:	UN3480
Gefahrgutklasse:	SV188 ADR
Hersteller:	Sony
Hersteller- Art. Nr.:	US26650FTC1

 

[OffGridInTheCity]

It sounds like the battery of concern is one you're created and is 'in series' with others? and is not behaving as you expected?
I see no one else has posted so I'll just offer this.....

Get equipment or setup a process where you can test one of the 'good batteries' and then test the 'new DIY battery' in isolation of each other. This may bring to light what's different/wrong with the 'new DIY battery'.

 

[hur3r]

I cant Test it without the Others the minimal Configuration is 3 Battery Packs in Series so minimum 150-170V