BMS Parameter Concern (SOK, Jakiper, etc)

[power.esrl3]

I have a concern with the BMS parameter of these batteries. IMHO, these mentioned batteries in the title has the same BMS and firmware, based on their videos using PBMS Tools.

I have other brand of batteries using the same BMS as theirs, so parameters are the same.

Im satisfied because it really does balance the cells after a few cycles, around 20-30 cycles in my case.

My main concern is that, this BMS has 57.6v charging parameter wherein if you use loop communication with the inverter, it really does 57.6v. It also tapers current during balance usually at 56v.

However, it also floats at 57.6v. My other inverter is Deye with communication to the battery. My setting is grid charge to 100% regardless of sunlight.

So 100% is almost always guaranteed daily. Usually at 12noon, the batteries are already full. And my setting is to only discharge at 5PM onwards.

So, daily, it is floating at 57.6v for around 4-5 hours.

My concern is whether this is healthy or not for the cells. 3.6vpc is quite high for floating where 3.45vpc is full based on readings, and most of the other batteries recommend floating at 3.4vpc.

What I expect in loop communication should be to stop charging/floating if 57.6v is reached, as I understand LiFePO4 doesn't need floating.

Im quite tempted to switch to manual settings if this will mean prolonging battery life. On the other hand, loop communication is a plus with these batteries, its just that, Im quite hesitant with my observation.

I wonder what @HighTechLab @Zhoulun would say.

 

[sunshine_eggo]

"LFP doesn't need floating" if you're charging the battery and then taking it out of service.

In off-grid PV applications, LFP needs a float voltage to force the PV to power the loads by not letting the battery voltage to drop below that floor.

3.45V usually falls a little short of true 100%.

3.40V is definitely a preferable float voltage. Can you not change it?

The BMS may influence it. As an example, Battleborns don't balance below 14.2V. Ever.

 

[power.esrl3]

"LFP doesn't need floating" if you're charging the battery and then taking it out of service.

In off-grid PV applications, LFP needs a float voltage to force the PV to power the loads by not letting the battery voltage to drop below that floor.

3.45V usually falls a little short of true 100%.

3.40V is definitely a preferable float voltage. Can you not change it?

The BMS may influence it. As an example, Battleborns don't balance below 14.2V. Ever.

No, I can't change it if set to communicate with the battery. Unless I change the mode to Voltage Mode, which certainly would ditch the added feature of close loop communication.

Unless Im wrong and its fine for the cells, I would leave it as is. Its just that, I dont feel it healthy to float at 57.6v for 5hrs a day.

 

[sunshine_eggo]

No, I can't change it if set to communicate with the battery. Unless I change the mode to Voltage Mode, which certainly would ditch the added feature of close loop communication.

Unless Im wrong and its fine for the cells, I would leave it as is. Its just that, I dont feel it healthy to float at 57.6v for 5hrs a day.

I share those concerns.

 

[power.esrl3]

I share those concerns.

Welp... Custom setting it is. Unless someone could modify the firmware. I believe even though one knows the password of the software, its just for protection parameters and such, no way the software could change the charging profile based on what I see.

Bulk/Absorption: 56.7v (I still need it to reach 3.5v in order for the BMS to start balancing)
Float: 54.4v

What would you say with my planned settings?

 

[sunshine_eggo]

Like.

 

[HighTechLab]

The alarm parameters (set via PC programming software) are effectively when the BMS sends the commands to the inverter. You could certainly dial back charging through control of these parameters.

 

[power.esrl3]

The alarm parameters (set via PC programming software) are effectively when the BMS sends the commands to the inverter. You could certainly dial back charging through control of these parameters.

Oh yes, yes! Whats in my mind is that I expect there should be a literal settings on the software that says Charging Voltage/Bulk/Absorption/Float or something like that. What I see that is interesting though is the Full Pack Voltage which is set to 56v, and the amps below that settings which I believe is something similar to "tail current". I wish some documentation with this bms and its software be published, that would be cool.

I'll try that. Thank you!

I'll report back with the experience.

 

[HighTechLab]

I wish some documentation with this bms and its software be published

It's in progress. I have been working on the less-advanced documentation that helps the majority of users, once that's done I'll dig in very deep on the technical stuff.

 

[power.esrl3]

It's in progress. I have been working on the less-advanced documentation that helps the majority of users, once that's done I'll dig in very deep on the technical stuff.

Nice! I'll be waiting for that. Thank you!

 

[Zhoulun]

I have a concern with the BMS parameter of these batteries. IMHO, these mentioned batteries in the title has the same BMS and firmware, based on their videos using PBMS Tools.

I have other brand of batteries using the same BMS as theirs, so parameters are the same.

Im satisfied because it really does balance the cells after a few cycles, around 20-30 cycles in my case.

My main concern is that, this BMS has 57.6v charging parameter wherein if you use loop communication with the inverter, it really does 57.6v. It also tapers current during balance usually at 56v.

However, it also floats at 57.6v. My other inverter is Deye with communication to the battery. My setting is grid charge to 100% regardless of sunlight.

So 100% is almost always guaranteed daily. Usually at 12noon, the batteries are already full. And my setting is to only discharge at 5PM onwards.

So, daily, it is floating at 57.6v for around 4-5 hours.

My concern is whether this is healthy or not for the cells. 3.6vpc is quite high for floating where 3.45vpc is full based on readings, and most of the other batteries recommend floating at 3.4vpc.

What I expect in loop communication should be to stop charging/floating if 57.6v is reached, as I understand LiFePO4 doesn't need floating.

Im quite tempted to switch to manual settings if this will mean prolonging battery life. On the other hand, loop communication is a plus with these batteries, its just that, Im quite hesitant with my observation.

I wonder what @HighTechLab @Zhoulun would say.

BMS has a cut off function, if your battery voltage is >56V, and charge current is less than 2A, after certain delay, charge will cut off, and have OVP protection. If the OVP release is not set too high then the charging should not kick in so frequently.

 

[power.esrl3]

BMS has a cut off function, if your battery voltage is >56V, and charge current is less than 2A, after certain delay, charge will cut off, and have OVP protection. If the OVP release is not set too high then the charging should not kick in so frequently.

My concern is it tells (as far as I can observe) Deye inverter to float at 57.6V, when your settings to inverter is charge to 100% using Time of Use. The problem with that, for example, you reach 100% at 12:00PM, but your Time of Use setting is to discharge only at 5PM, hence, floats for 5 hours.

No, I dont experience OVP anymore since cells are balanced and no runners that triggers OVP, so it can reach 57.6V no problem, the problem is, it also floats at 57.6V.

The only solution I tried so far is to use Voltage Mode in the inverter and set my own bulk and float settings. I have not tried to tinker yet with alarm parameters as suggested by @HighTechLab , I dont have the time yet and the confidence, atleast not without proper documentation of the bms and software.

What I have in mind though is to try Pylon RS485 protocol, you know... Wishful thinking it might have effects. Because Pylon RS485 Protocol will show individual packs in the BMS info of the inverter (not yet tested, but I guess this is possible with protocol change via the software). But I must also sacrifice Solar Assistant monitoring via RS485. But I doubt it has any effect in charging profile, as I think 57.6v charging voltage is hard coded and no floating instructions set IMO or maybe it has, but also set to 57.6v?

Edit:
And oh, I'd like to thank @HighTechLab and @Zhoulun by the way for doing videos, releasing softwares and documentations that other brand of batteries fails to do so. A lousy manufacturer, that I had to rely from other brand that uses the same component (bms).

 

[shishagott2]

It's in progress. I have been working on the less-advanced documentation that helps the majority of users, once that's done I'll dig in very deep on the technical stuff.

its finished the documentation yet maybe?