What is your voltage delta when your battery reaches 100%SOC?

[burgerking]

When I started, I do not have the equipment for top balancing, nor for capacity testing.
So my 32 cells were never Top Balanced nor matched.
I merely assembled the cells and BMS together and plugged them to a Deye Inverter.
And because I did not have enough solar panels, my 2 Batteries was charged up to 70~90% for 2 months.
Initially I set JK BMS to start balancing at 3.25v. then to 3.30v and now 3.40v
And OVP to 3.65, then to 3.55 and then 3.5V. Lastly Deye is set to push 56V.

So last week, I installed additional panels and is now fully charging my batteries to 56.0V (3.50V per cell) on a daily basis.

(Last week)


(Today)

The first few days my BMS were reporting OVP, exceeding 3.5V; so I increased
OVP to 3.55V to allow trickle charging as shown above.
Both batteries no longer report OVP and allow trickle charging.
I think I will leave OVP to 3.55V instead of 3.5v, but set Deye to 56V.
After a few more full charging, Voltage Delta seems getting smaller and smaller too.

Question: Should I be satisfied with voltage delta as shown?
Or should I push for a smaller delta perhaps ~5mv?

 

[Ampster]

I only charge to 3.45 volts per cell and the delta is 0.01 volt. Initially they might have been 0.05 but after connecting the JK active balancer the delta reduced.

 

[manjulabw]

my jk bms and deye inverter has voltage difference 1v less. please someone here explain me set it to same...

 

[robot_zombie]

I would be pretty happy myself, battery charging fully, no cell OVP events, happy days...
I did similar with a 16S CATL 302AH pack, but I am only charging to ~3.475-3.48 VPC, first full charge delta's hit ~110mV, after a few cycles down to ~50-60mV, hopefully lower after a few more. I may slighly boost charge voltage but am seeing 95+% capacity so will probably just leave it as is

 

[MisterSandals]

The first few days my BMS were reporting OVP, exceeding 3.5V; so I increased
OVP to 3.55V to allow trickle charging as shown above.
Both batteries no longer report OVP and allow trickle charging.
I think I will leave OVP to 3.55V instead of 3.5v, but set Deye to 56V.

You should NOT be using your BMS as a charge controller. The BMS is the battery protection device that should be set at (or just within) the safety limits (2.5V - 3.65V) of your battery.

Your charge controller should control the charging (that's why its called a charge controller).