Does the charger always start to decrease current when it is almost fully charged?

[TerryWoo]

One of my lithium batteries has a small capacity. The 16 series iron lithium 58.4V5A charger can charge up to 58V or 5A, but most of the cells still have a protection of 3.65 when charged up to just over 3.4V. I hope there is a more obvious process of constant flow and pressure, for example, starting from 56V and then turning to 58V and dropping to 0.5 or 1A for slow charging. With the help of an equalizer, it can be fully charged.
Are all the lithium batteries the same?

 

[slaphappygamer]

Mine always does this. I have a 48v battery (Samsung 35E) and a 48v 2a charger. When the battery, including 4v voltage sag, goes is about 47v, I charge. I monitor the charging current each time. With a watt meter at the mains, I connect the charger to it. Before I plug in the battery, current sits at .033a. When i connect the battery, charging starts at about 1.54a. Charging eventually slows to around .244a, The led, on the charger, goes from red to green. Charging current gradually slows to .085a, then falls back to .033a. I believe (from what I’ve read) this is the cells balancing at low current and is normal if your BMS supports it.

 

[TerryWoo]

Mine always does this. I have a 48v battery (Samsung 35E) and a 48v 2a charger. When the battery, including 4v voltage sag, goes is about 47v, I charge. I monitor the charging current each time. With a watt meter at the mains, I connect the charger to it. Before I plug in the battery, current sits at .033a. When i connect the battery, charging starts at about 1.54a. Charging eventually slows to around .244a, The led, on the charger, goes from red to green. Charging current gradually slows to .085a, then falls back to .033a. I believe (from what I’ve read) this is the cells balancing at low current and is normal if your BMS supports it.

Thank you for your answer. I won't worry anymore if it's normal.

 

[slaphappygamer]

I also have a 54.6v 3a charger. Acts a similar way but begins charging slightly higher at 2.5a. I don’t use that charger as much.

 

[Wedy]

Yes, most modern battery chargers are designed to reduce the charging current as the battery approaches full charge. This is especially true for chargers designed for lithium-ion battery(Li-ion) and lithium polymer (LiPo) batteries, which require precise charging protocols to ensure safety and longevity.

 

[E-HP]

It’s the CV stage

Why are There Three Charging Stages in Lithium Battery? - Lithium ion Battery Manufacturer and Supplier in China-DNK Power

Why are There Three Charging Stages in Lithium Battery? Lithium-ion batteries are the most common choice for cash portable electronic products. Compared with other types of batteries, lithium-ion batteries are light in weight and have no memory effect. Compared with nickel-metal hydride...

www.dnkpower.com

 

[scianiac]

Yes the chargers are not really "designed" to do this, they are just simple CC/CV power supplies and when they are in CV the current will decrease because ohms law.