JWLV
-.-. --.-
- Joined
- May 27, 2020
- Messages
- 551
I just noticed a very disturbing trend. Some 48V 100Ah batteries that are sold on Amazon actually contain 15 cells instead of 16.
What does this mean? In general, when we talk about 12V batteries, we mean 12.8V. When we talk about 48V batteries, we mean 12.8v x 4 = 51.2V. That is the commonly accepted language when it comes to batteries. A typical 48V (51.2V) LiFePo4 battery has 16 cells in series, with each cell voltage at 3.2V nominal. So 3.2V x 16 = 51.2V. And 3.2V x 15 = 48.0V. This is where some manufacturers sneak in a "48V" battery that only has 15 cells. They save a few bucks by removing one cell. One cell is probably about $30, I estimate?
What happens when you get a "48V" 15-cell battery? Your solar charge controller's settings are going to be all wrong. A typical 16-cell battery should be charged at 54-56V. If you do that on a 15-cell battery, you'll likely cause the BMS to a over-voltage fault and disconnect. I'm not even sure if any charge controllers can be used on a 15-cell battery.
Here are a few that I saw on Amazon that look like they have 15 cells instead of 16.
Some of them even state "15pcs Grade A Prismatic Lifepo4 Cells".
Another thing is these "48V" batteries are usually mixed in with their 12V 100Ah, 12V 200Ah, and other varieties of batteries so their reviews and ratings are pretty high.
What does this mean? In general, when we talk about 12V batteries, we mean 12.8V. When we talk about 48V batteries, we mean 12.8v x 4 = 51.2V. That is the commonly accepted language when it comes to batteries. A typical 48V (51.2V) LiFePo4 battery has 16 cells in series, with each cell voltage at 3.2V nominal. So 3.2V x 16 = 51.2V. And 3.2V x 15 = 48.0V. This is where some manufacturers sneak in a "48V" battery that only has 15 cells. They save a few bucks by removing one cell. One cell is probably about $30, I estimate?
What happens when you get a "48V" 15-cell battery? Your solar charge controller's settings are going to be all wrong. A typical 16-cell battery should be charged at 54-56V. If you do that on a 15-cell battery, you'll likely cause the BMS to a over-voltage fault and disconnect. I'm not even sure if any charge controllers can be used on a 15-cell battery.
Here are a few that I saw on Amazon that look like they have 15 cells instead of 16.
Some of them even state "15pcs Grade A Prismatic Lifepo4 Cells".
Another thing is these "48V" batteries are usually mixed in with their 12V 100Ah, 12V 200Ah, and other varieties of batteries so their reviews and ratings are pretty high.
