Hello everyone,
I am new to the DIY Solar Power Forum and recently purchased some EVE 280K prismatic cells. I have been testing the cells and thought I should get some experienced opinions on my testing methods to make sure I am not missing something important before I building a battery.
As a starting point I read the LF280K (3.2V 280Ah) Product Specification guide and try to follow the test conditions in section 4 as closely as possible with my limited equipment.
The cells are stored and tested in a room that stays at 23-24C.
As a first step I check physical condition of the cells and then measure the voltage and IR.
A ZKETECK Battery Tester is next used to charge the cells to 3.65V at a rate of 40 Amps. The cut off amperage is 14 Amps (0.05C) to signify the cell is fully charged. While the cells are charging the temperature of the terminals is checked to see if they differ from the room temperature.
The cells then sit for 60-90 minutes. After the wait the cell voltage is checked and the discharge test begins. They are discharged at 35 Amp (0.125C) with a cut off voltage of 2.8 Volts.
The cells are then charged to 40% SOC where they wait until it is time to build a battery.
I know the EVE LF280K product specification says to use a cut off of 2.5V but I tested 3 of the cells and there was only 2.3-2.9 Ah additional capacity between 2.8V and 2.5V.
I am not sure of the absolute accuracy of the ZKETECK tester but it appears to give very repeatable results. Doing a discharge test on the same cell three times showed only a 0.5Ah difference between the three measured capacities.
Is there anything glaringly wrong with this procedure or anything else I should be checking?
I am new to the DIY Solar Power Forum and recently purchased some EVE 280K prismatic cells. I have been testing the cells and thought I should get some experienced opinions on my testing methods to make sure I am not missing something important before I building a battery.
As a starting point I read the LF280K (3.2V 280Ah) Product Specification guide and try to follow the test conditions in section 4 as closely as possible with my limited equipment.
The cells are stored and tested in a room that stays at 23-24C.
As a first step I check physical condition of the cells and then measure the voltage and IR.
A ZKETECK Battery Tester is next used to charge the cells to 3.65V at a rate of 40 Amps. The cut off amperage is 14 Amps (0.05C) to signify the cell is fully charged. While the cells are charging the temperature of the terminals is checked to see if they differ from the room temperature.
The cells then sit for 60-90 minutes. After the wait the cell voltage is checked and the discharge test begins. They are discharged at 35 Amp (0.125C) with a cut off voltage of 2.8 Volts.
The cells are then charged to 40% SOC where they wait until it is time to build a battery.
I know the EVE LF280K product specification says to use a cut off of 2.5V but I tested 3 of the cells and there was only 2.3-2.9 Ah additional capacity between 2.8V and 2.5V.
I am not sure of the absolute accuracy of the ZKETECK tester but it appears to give very repeatable results. Doing a discharge test on the same cell three times showed only a 0.5Ah difference between the three measured capacities.
Is there anything glaringly wrong with this procedure or anything else I should be checking?
