DIY 12v Lifepo4 Battery Pack (Rechargeable Lithium Ion)

02 Nov, 2022

By hqt

DIY 12v Lifepo4 Battery Pack
DIY 12v Lifepo4 Battery Pack

Lifepo4 is a newer, more cost-effective and safer Lithium Ion battery technology. It is commonly used in solar panels, medical devices and electric cars. Lifepo4 batteries are also known as LiFP or LFP batteries. They are great for DIY battery packs because they are safer than regular Li-ion batteries and cheaper than other types of Lithium Ion batteries such as NCRS or NGAF. Making your own Lifepo4 battery pack is not very difficult and is much cheaper than buying them readymade from suppliers like Amazon at around $40 per battery pack.

What is a Lifepo4 Battery?

A LiFePO4 battery or Lifepo4 battery is a type of Lithium Ion battery. It has high energy density, low self-discharge rate, high safety and longer lifespan compared to other types of Li-ion batteries. It is commonly used in solar panels, medical devices and electric cars. A Lifepo4 battery is made from a Lithium iron phosphate cathode, a phosphate based electrolyte and a graphite anode. The cathode in LiFePO4 batteries is different from Li-ion batteries, where the cathode is made of LiCoO2. It is safer than the latter because LiCoO2 batteries use cobalt in the negative electrode material which is a toxic metal.

Lifepo4 battery pack tutorial and guide

A Lifepo4 battery pack is made from a few LiFePO4 cells wired in series. You can find these cells as accessories or used batteries on websites like eBay, Craigslist and Amazon. They are used batteries so make sure you test them before you buy them. LiFePO4 cells are safer than Li-ion batteries and have a lower self-discharge rate. If you want to make your own Lifepo4 battery pack, here is a step by step guide.

Step 1: Find the right cells and make sure they are in good condition

A lithium iron phosphate battery pack consists of a few LiFePO4 cells. A single cell has a voltage of 3.2V, so a 3S pack will have a voltage of 12V and a 6S pack will have a voltage of 24V. You need to find the right cells and make sure they are in good condition. The cells should be in their original packaging or inside a foil or plastic bags. Here are a few things you can look for while buying used LiFePO4 cells. - The cells need to be in a good condition. If they are bent or cracked, they are damaged and need to be thrown away. - The electrolyte inside the cell should be pink or red. If it is black or yellow, the cell is aged and should be thrown away. - The label on the battery pack should be intact, readable and have a lot of information like voltage, charge and discharge rate, capacity in mAh and more.

Step 2: Test the cells with a battery tester

Once you have found the right cells, you need to test them to make sure they are in good condition. A battery tester is a handheld device that you can use to test the cells before wiring them together in series. The tester will show the voltage of each cell in the pack and whether they are good or damaged. While testing the cells, make sure you follow the instructions for your battery tester because every model is different. The voltage of the cells should be around 3.2V per cell. If a cell has a lower or higher voltage, it may be damaged or old. If the voltage of a cell is less than 2V, it is damaged and needs to be thrown away. A damaged cell can catch fire and explode while wiring it in series, so be very careful when testing and using damaged batteries. If a cell has a high voltage, you can discharge it by connecting a resistor to it.

Step 3: Connect the cells in series using AWG wire

LiFePO4 cells are 3.2V each. If you want to make a 12V Lifepo4 battery pack, you need to connect the cells in series. To connect the cells, use 18 or 16 AWG wire. A 12V Lifepo4 battery pack can have 4 to 8 cells in series, depending on the capacity and voltage you want. For example, a 12V, 5Ah battery pack will have four 3.2V cells wired in series in a 12V Lifepo4 battery pack. First, peel off the insulation from the wires, and then connect the positive end of the first cell with the positive end of the second cell and so on. Now connect the negative end of the first cell with the negative end of the second cell and so on. Now connect the positive end of the last cell with the negative end of the first cell to complete the wiring.

Step 4: Put a voltage regulator and fuse in the Lifepo4 pack

Once you have wired the cells, you need to put a voltage regulator in the Lifepo4 battery pack and add a fuse. A voltage regulator will take care of the voltage in your battery pack and protect it from over-charging. A 12V Lifepo4 battery pack will have two 6V batteries connected in series. They will have an output voltage of 12V, but the charge current will be 6A. Next, you need to add a fuse in the Lifepo4 battery pack. The fuse will protect the battery pack from short circuiting, over-heating and a current surge. A good fuse for a 12V Lifepo4 battery pack will be a 5A or 10A fuse. After adding a voltage regulator and a fuse, your battery pack is ready to use.

Important safety tips when working with LiPo batteries

- Make sure the cells are in good condition. The electrolyte inside the cells should be red or pink and not black or yellow. - Do not buy damaged cells and do not use a damaged cell in your battery pack. - Use a battery tester to test the cells before you use them in a battery pack. - Discharge the cells before wiring them together in a battery pack. - Do not charge a Lifepo4 battery pack when it is below 10V because it can overheat and catch fire. - Disconnect the battery pack from the power source when it is not in use. - Store the battery pack in a safe place in a fireproof container. - Keep your battery packs away from children and pets. - While working with LiPo batteries, always work in a well-ventilated area. - Wear safety goggles and protective clothing while working with LiPo batteries. - Charge Lifepo4 batteries in a LiPo charging bag and follow all safety precautions while charging them. - Charge the battery when it drops below 50% and do not discharge it completely. - Dispose of the battery when it has reached the end of its lifespan. You can find recycling centers near you that take LiPo batteries.

Wrap up

Lifepo4 batteries are a newer, more cost-effective and safer Lithium Ion battery technology. They are commonly used in solar panels, medical devices and electric cars. Lifepo4 batteries are also known as LiFP or LFP batteries. They are great for DIY battery packs because they are safer than regular Li-ion batteries and cheaper than other types of Lithium Ion batteries such as NCRS or NGAF. Making your own Lifepo4 battery pack is not very difficult and is much cheaper than buying them readymade from suppliers like Amazon at around $40 per battery pack.