I’m curious about BMS designs that gradually reduce the charge current based on State of Charge (SOC), rather than the normal tapering that naturally occurs as the battery voltage approaches its final value. ( like what iPhone battery controller do after 80%)

For example, some BMS limit the current to 20A during the last 15% of charge regardless of the voltage.

• Has anyone used such a BMS?

• What are the pros and cons?

• Does it affect cell balancing or battery performance?

15 hours ago, esmail-kassir said:

Has anyone used such a BMS?

On my 3 older LEOCH 48100TB the BMS calculates SOC by counting metered Ah in and out but neglect the internal losses. The result is their SOC readings are always to optimistic. When approaching full charge their BMS display 100% SOC while the batteries have not yet reached full charge voltage and continue charging. Therefor I prefer charge managing by the Inverter on the base of battery voltage without interference from the BMS via coms.

4 hours ago, Beat said:

On my 3 older LEOCH 48100TB the BMS calculates SOC by counting metered Ah in and out but neglect the internal losses. The result is their SOC readings are always to optimistic. When approaching full charge their BMS display 100% SOC while the batteries have not yet reached full charge voltage and continue charging. Therefor I prefer charge managing by the Inverter on the base of battery voltage without interference from the BMS via coms.

I see your point

In general, smartphones , EVs .., etc tend to decrease the charging rate in based in the SOC or the voltage,
And I have found that my BMS do the same , so I am wondering if this feature useful in home LFP case or it only applies to NMC , lithium polymer in phones or LFP but with 2C car super fast chargers

Never seen that. My EV starts tapering off at 85% - but this corresponds with reaching the target charge voltage, and entering CV phase (where current tapers of natually).

Most lithium chemistries hit this point at around 85%.

None of the BMSs I have used have tapered off current for any other reason, but I suppose it is possible (although I have also not found any cell manufacturer who recommends anything but straight CC-CV charge profiles).

My twingo ev starts reducing charging power already at 60%.... for example under 50% it charges full 22kW, above 60 it reduces already around 16kW, at 80% it is around 12kW and at 90% it is already below 10! and so on...

24 minutes ago, iveky3 said:

My twingo ev starts reducing charging power already at 60%.... for example under 50% it charges full 22kW, above 60 it reduces already around 16kW, at 80% it is around 12kW and at 90% it is already below 10! and so on...

Interesting

What about your home battery BMS

I talk about public AC Type2 chargers.

At home I can't charge more then 5kW.