Inverter peak power and inrush current

A 48V LiFePO4 battery contains either 15 or 16 groups of cells connected in series to give a total nominal voltage of 48V or 51.2V. You may be asking why the nominal voltage for some batteries sit at 51.2V and not 48V. Well, it’s very hard to vary the voltage in a cell. For example, LiFePO4 cells have a voltage of 3.2V because of their internal makeup, and this voltage can’t be changed. Therefore, the closest to a 12V battery that you can form with these cells is 12.8V (four, 3.2V cells in series). If we then scale this to a 48V battery, we have 16, 3.2V cells in series for a nominal voltage of 51.2V.

For brands such as TN power and RELiON whose batteries come in 12V, 24V, and 48V variants, it’s important that four 12V batteries or two 24V batteries in series give the same output voltage as a single 48V battery. Therefore, in this case, a 48V battery needs a nominal voltage of 51.2V and a 16 cell configuration is suitable. For 48V battery models that don’t come in lower voltages, such as the Pylontech US5000, this doesn’t pose an issue. So, the battery can contain 15 cells in series at exactly 48V.

You can either purchase a prebuilt 48V battery or easily make your own 48V battery bank by connecting multiple smaller, 12V or 24V batteries in series. There aren’t loads of benefits either way, but making your own allows you to select the specific batteries that you want to use and can offer some flexibility in terms of capacity and form factor. On the other hand, opting for a pre-built rack mounted battery can offer significant savings in certain cases. Read on for a further look at this.