LiFePO4 Battery Packs

Lithium Iron Phosphate, LiFePO4 is changing the face of battery technology. LiFePO4 cells offer high rates of discharge, long life cycles and are the safest lithium battery chemistry available.

Why would you buy LiFePO4?

  • 1/3 of the weight of Lead Acid batteries.
  • Non Toxic to the Environment.
  • 95% Energy efficient.
  • Can be recharged over 1,500 times*

Browse the LiFePO4 Battery Packs we sell

LiFePO4 has many advantages over other types of lithium-ion batteries. The abundance of Iron available makes this material relatively low cost. It is non-toxic making the batteries safer to use as well as better for the environment when producing and recycling them. They have a longer life span both in terms of shelf life and cycle life. They are more stable than other chemistry's and far less likely to suffer from thermal runaway.

Most LiFePO4 cells operate within a normal or 'nominal' voltage of 3.0 to 3.3 volts, have a maximum operating voltage of around 4.1 to 4.2 volts and a minimum operating voltage of 2.1 to 2.5 volts. Typically a LiFePO4 cell is fully charged at 3.65 - 3.7 volts. In order to get the proper voltage to charge your LiFePO4 battery pack you would multiply 3.65 x the number cells in series. So a 12V nominal pack (3.0V x 4 cells) would have a charging voltage of 14.6V.

Cells may be wired in series (multiply the voltage) or in parrallel (multiply the capacity). Cells are wired in series by connecting the positive(+) terminal of one cell to the negative(-) terminal of another. Cells are wired in parrallel by connecting positive to positive and negative to negative terminals. Wiring in parrallel can be used to increase the discharge rate of the battery (usually refered to as a 'C' rating). Multiplying the C rating by the capacity of the battery will give you its discharge rate. Higher voltages are achieved by wiring either individual cells or parrallel blocks in series.

Battery Management System - Given the sensitive charge and discharge characteristics of these cells it is important to have a battery management system (BMS) to regulate them, especially when constructing them into packs. Overdischarging a cell below 2.1 volts can cause irrevocable damage to a battery that would otherwise last you for several years. A well designed battery management system includes a low voltage cutoff circuit (LVC) for each cell to keep the cell from discharging beyond the safe operating voltage. It will also have a system to balance the cells in order to utilize the energy more efficiently and to allow all the cells in a pack to recieve a full charge.

The proper charger is also very important. Overcharging cells will damage them and can still be potentially dangerous even with the inherent safety of the LiFePO4 chemistry. A good LiFePO4 charger will simply cut off once the pack has reached the desired voltage. Most standard sealed lead acid chargers will not cut off automatically and should not be used. Also make sure that your charger is intended for LiFePO4 and not simply lithium-ion or LiPO (Lipo, Li-poly, Li-Po) which is a common mistake. Most Li-po (lithium polymer) cells have a charge cutoff voltage of 3.2 or 3.3 volts so a 12V nominal pack would have a charging voltage of around 13.2 volts, well below the 14.6 you need for your LiFePO's to become fully charged.

Uses: There are an endless number of things you can build with these awesome batteries! Here at greenskate.co.nz we use them in our electric skateboards to provide unparalled range, performance and did I mention the weight saving! We also have many satisfied electric bike customers.

Essentially, you can use these cells in anything that requires a long lasting and powerful battery.