Hey guys!
Just wanted to put a warning out there for OYE Store on AliExpress. I know other people on here have purchased from this store and many of their products might be fine but I wanted to share my experience as a warning to others.
First, I tried ordering from more reputable sellers on AliExpress but, since I live in Hawaii, many of them were not willing to ship items here. Even though Hawaii is much closer to China, packages must first be sent to the mainland US before coming here... but that's another story.
Anyway, I ended up giving OYE Store a try since they were very responsive to my questions and willing to work with me to ship to Hawaii. For that part, I'll give them a little +. They are responsive.
I purchased 16x 200Ah lifepo4 CALB cells to make a 48v battery. The item description stated that the cells were brand new but also listed that the minimum capacity of the cells was 180 to 190 Ah. It did not mention the grade but did state that all cells would be matched and balanced.
The cells arrived in good shape and packaged well. I top balanced them all, connected them in series, and then ran a capacity test using a shunt-based battery monitor. After discharging from 3.65v to 2.5v at about 40A (0.2C), I got only 156Ah! I found the weak cell and retested it using a stand-alone capacity tester running at about 23A. This test confirmed the cell capacity at 156Ah. As for the rest of the battery, a couple other cells were around 3.0v when that one cell hit the 2.5v cutoff voltage so they may not have been far behind. Because the capacity tests take so long and I'm using the battery for an off-grid setup, I have not tested any other cells.
I did try reaching out to OYE Store again to let them know about the problem. They asked me some questions about it and asked for photos of the capacity test. Ultimately, though, they were unwilling to do anything about the problem (not a big surprise to me).
The end result is that I have a 7.5KWh battery when it should have been much closer to 10KWh. I am disappointed but not too surprised. I was expecting some cells to be around the 180Ah mark but didn't expect them to be this low! Of course, even one cell limits the capacity of all the rest.
Buyer beware!
Just wanted to put a warning out there for OYE Store on AliExpress. I know other people on here have purchased from this store and many of their products might be fine but I wanted to share my experience as a warning to others.
First, I tried ordering from more reputable sellers on AliExpress but, since I live in Hawaii, many of them were not willing to ship items here. Even though Hawaii is much closer to China, packages must first be sent to the mainland US before coming here... but that's another story.
Anyway, I ended up giving OYE Store a try since they were very responsive to my questions and willing to work with me to ship to Hawaii. For that part, I'll give them a little +. They are responsive.
I purchased 16x 200Ah lifepo4 CALB cells to make a 48v battery. The item description stated that the cells were brand new but also listed that the minimum capacity of the cells was 180 to 190 Ah. It did not mention the grade but did state that all cells would be matched and balanced.
The cells arrived in good shape and packaged well. I top balanced them all, connected them in series, and then ran a capacity test using a shunt-based battery monitor. After discharging from 3.65v to 2.5v at about 40A (0.2C), I got only 156Ah! I found the weak cell and retested it using a stand-alone capacity tester running at about 23A. This test confirmed the cell capacity at 156Ah. As for the rest of the battery, a couple other cells were around 3.0v when that one cell hit the 2.5v cutoff voltage so they may not have been far behind. Because the capacity tests take so long and I'm using the battery for an off-grid setup, I have not tested any other cells.
I did try reaching out to OYE Store again to let them know about the problem. They asked me some questions about it and asked for photos of the capacity test. Ultimately, though, they were unwilling to do anything about the problem (not a big surprise to me).
The end result is that I have a 7.5KWh battery when it should have been much closer to 10KWh. I am disappointed but not too surprised. I was expecting some cells to be around the 180Ah mark but didn't expect them to be this low! Of course, even one cell limits the capacity of all the rest.
Buyer beware!