I recently had the opportunity to purchase 4@ Headway 38120 LiFePO4 batteries. My goal for these batteries is to build an 8AH 12v battery pack for emergency/ field power.

LiFePO4 batteries are very interesting and nothing like other lithium batteries. These batteries have several advantages over common lead acid batteries for emergency power applications including:

1. Life span (charge/discharge cycles) up to 10x lead acid
2. Lower internal resistance, thus a faster recharge
3. Better capacity for similar weight and volume
4. Much flatter discharge curve i.e. voltage doesn’t degrade during operation

LiFePO4 are much safer than other lithium batteries and are a flame retardant technology.

There is much to learn regarding proper configuring parallel/ serial configuration as well as proper charging/discharging for optimum life. The nominal battery voltage is 3.2 volts with a maximum charge voltage of 3.65 volts. A battery management system (BMS) is recommended to ensure that no cell is over charged or discharged. These batteries have a short circuit capacity of 200 AMPS!!! It is high recommended that an inline fuse be used between the batteries and load.

For the battery pack shown in the pictures below I used the following products:

1. Batteries https://batteryhookup.com/products/4-headway-38120-hp-3-2v-8ah-lifepo4-lithium-batteries-25c-200a-super-cells
2. Battery holder & buss bar (enough for 2@ 4S) https://www.ebay.com/itm/Headway-38120-connector-and-holder-2p4s-for-8-cells-US-Seller-USPS-First-Class/202877111391?hash=item2f3c6b0c5f:g:jqIAAOSwjONd9U5R
3. Battery management system https://www.batteryspace.com/PCM-for-4-cells-12.8V-LiFePO4-Battery-Pack-at-12A-limited.aspx
4. Case (remove individual parts bins) https://www.harborfreight.com/15-bin-portable-parts-storage-case-93929.html

 

                             Cover closed                                                      Cover open