I bought a
TekPower TP1540E for $189 USD to charge Cells, top balancing & charging up to 12V battery assembly.
I've used it quite a bit for Top Charging cells starting at 3.4V/45A CV till the cells hit 3.65V and are taking only 1.5-2.0A.
I had a problem with it when I first got it.... A Connector inside got loose (I guess during shipping, reconnected connectors and all was good.
Takes roughly 13 hours to take an EVE 280AH Cell from 2.60V to fully topped 3.65V drawing only 1.9A.
* Quirk. As most model with "dial" setting for voltage & current, you have to babysit the voltage as the cell fill. Once the amperage starts to drop below 25A the increase in voltage accelerates. Cells will absorb voltage quite quickly past 3.500V so you MUST eagle eye on the cells, check the terminal voltage on the Bench Supply against the cell voltage as you will have to fine-tune it at this stage. KEEP watching as the amperage declines, the voltage will increase to the cell and at the cell. Eventually, you will find the sweet spot for 3.600 or 3.650 where the amperage will slowly decrease to below 2.0A by which point the cell will be reaching "saturation". That can sit there but the amps dropping will slow as it continues from this point with little gain for the energy expended.
A note on Saturation.
Take a cell to 3.65V and just disconnect that "that voltage" and it will settle to 3.4?? something within an 1.5 hrs, 24 hours later it will be very low 3.400 to high 3.38+
Take a cell and fully top it "saturate" it at 3.65V and in 1 hour it will be 3.600, 2 hours 3.59?, 24 hours later 3.55?
This is consistent across the cells I have done.
TekPower also has this TP3030E 0-30V / 0-30A for $299 USD
TP3030E , Tekpower supply, DC Variable power supply, Adjustable Power supply, DC Power supply