FAQ

Why Lithium-Iron Phosphate(LiFePO4 or LFP)?

Lithium-iron-phosphate (LiFePO4 or LFP) is the safest of the mainstream li-ion battery types.Lithium batteries offer many benefits over other battery chemistries. They are a safe and reliable battery solution, with no fear of thermal runaway and/or catastrophic meltdown, which is a significant possibility from other lithium battery types. These batteries offer extremely long cycle life, with some manufacturers even warranting batteries for up to 10,000 cycles. With high discharge and recharge rates upwards of C/2 continuous and a round-trip efficiency of up to 98%, it's no wonder these batteries are gaining traction within the industry. Lithium Iron Phosphate (LiFePO4) is a perfect energy storage solution.

What is the Battery Management System (BMS) and the way will it work ?

BMS Protection options :
● Low Voltage Protection Switch – mechanically disconnects at ten.0V
● Over Voltage Protection Switch – mechanically disconnects at fourteen.8V
● Short Circuit Protection Switch – mechanically and safely disconnects battery
● Reverse Polarity Protection Switch – mechanically and safely disconnects battery
● Over temperature – mechanically shut-down battery till traditional temperature recovery
Balancing options :
● Internal cell reconciliation – mechanically balances Wisdom Power® cells throughout battery operation. reconciliation algorithmic rule has been developed to confirm excellent balance between cells throughout battery life.
● Charge reconciliation – for BLS® connected in parallel and/or nonparallel, the BMS can balance every BLS® severally, so as to produce a perpetually balanced battery system.

I Must Use The Battery Management System (BMS)?

Important facts:

An LFP cell will fail if the voltage over the cell falls to less than 2.5V (note: recovery by charging with a low current, less than 0.1C, is sometimes possible).

An LFP cell will fail if the voltage over the cell increases to more than 4.2V. Lead-acid batteries will eventually also be damaged when discharged too deeply or overcharged, but not immediately. A lead-acid battery will recover from total discharge even after it has been left in a discharged state during days or weeks (depending on battery type and brand).

The cells of an LFP battery do not auto-balance at the end of the charge cycle. The cells in a battery are not 100% identical. Therefore, when cycled, some cells will be fully charged or discharged earlier than others. The differences will increase if the cells are not balanced/equalized from time to time. In a lead-acid battery a small current will continue to flow even after one or more cells are fully charged (the main effect of this current is decomposition of water into hydrogen and oxygen). This current helps to fully charge other cells that are lagging behind, thus equalizing the charge state of all cells. The current through an LFP cell, however, when fully charged, is nearly zero, and lagging cells will therefore not be fully charged. Over time the differences between cells may become so extreme that, even though the overall battery voltage is within limits, some cells will fail due to over- or under-voltage. Cell balancing is therefore highly recommended.

In Addition To Cell Balancing, A BMS Will:

  • Prevent cell under voltage by timely disconnecting the load.
  • Prevent cell overvoltage by reducing charge current or stopping the charging process.
  • Shut down the system in case of over temperature.
  • A BMS is, therefore, indispensable to prevent damage to large Li-ion battery banks.

Are Lithium batteries safe?

The Lithium Iron Phosphate (LiFePO4) batteries are the safest type of Lithium batteries as they will not overheat, and even if punctured they will not catch on fire. The cathode material in LiFePO4 batteries is not hazardous, and so poses no negative health hazards or environmental hazards. Due to the oxygen being bonded tightly to the molecule, there is no danger of the battery erupting into flames like there is with Lithium-Ion. The chemistry is so stable that LiFePO4 batteries will accept a charge from a Lead- Acid configured charger.

What is the life expectancy of a Lithium battery?

The typical estimated life of the Lithium Iron Phosphate (LiFePO4) battery is 5-15 years, or 2000 to 8000 charge cycles. One charge cycle is a period of use from fully charged, to fully discharged, and fully recharged again.

If I want to solar charge LiFePO4/Lithium Ion battery, which already has PCB, would a normal SLA controller work fine?

For LiFePO4 / Lithium Ion battery, we always recommend to use LiFePO4/Lithium Ion solar controller. Especially if you are using the battery as UPS (back up power supply).  The Lead Acid solar controller will constantly provide pulse current to the battery, in the long run, it might damage the PCB. So the PCB won't be able to protect the battery when it should be. 
The LiFePO4 / Lithium Ion solar controller won't provide constant current when the battery is fully charged. So it is much safer and reliable.

I have a lead acid charger with high charging current; can I use it instead to charge LiFePO4 batteries?

Lead acid batteries charge at 2.30V to 2.45V per cell whereas LiFePO4 batteries require 3.65V per cell. Your battery would potentially be undercharged, so you will not get use of the full capacity of the LiFePO4 battery, nor will balancing be triggered in the LiFePO4 battery pack, both of which are not desired. Furthermore, the floating charge of the lead acid charger is not expected by the battery and can cause problems. We recommend purchasing the battery with the bundled charger.