Following your decision to purchase LiFePO4 batteries, the logical next step is determining what other components your system will need. Among other accessories, having a charger that is compatible with your batteries is essential. Understanding how to determine the right charger for your Battle Born LiFePO4 batteries can be a daunting task. To tackle this challenge, we will dive into the basics of charging lithium batteries.
What Happens When You Charge a LiFePO4 Battery?
When you charge a LiFePO4 battery, you are applying an external voltage to drive current from the anode to the cathode of the battery. The lithium battery charger acts as a pump, pumping current upstream, opposite the normal direction of current flow when the battery discharges.
When the charger’s applied voltage is higher than the open-circuit battery voltage, the charging current flows. During this process, the battery’s open-circuit voltage increases, approaching the applied voltage of the charger.
The Difference Between Bulk and Float Charging
Lithium battery chargers can behave in several different ways during the charging process. First, the charger can steadily increase its voltage in order to keep the current flow constant. This is the first stage of the charging process – typically called the “bulk” charging stage. During this stage, the charger adjusts its applied voltage to deliver the maximum current to the battery.
For example, a 10-amp charger will deliver its maximum of 10 amps during this bulk charging stage, and the applied voltage will increase up to a maximum voltage, or “bulk voltage.”
Once the bulk voltage is reached, the charger enters a second stage, called the “absorption” charging stage. During absorption, the charger applies a constant voltage called the “absorption voltage.” As the battery’s open-circuit voltage approaches the absorption voltage, the current flow steadily decreases down to zero.
At this point, the battery is fully charged. However, a lead-acid battery will rapidly lose charge when the charger is disconnected. So, instead of turning off, the battery charger enters a third stage called the “float” stage, in which the charger drops to a lower voltage and holds at that voltage. The point of this stage is to keep the battery topped off and account for the fact that lead-acid batteries tend to drain, even when there is no load connected. Float charging is not necessary for Battle Born LiFePO4 batteries.
What is the Charging Algorithm for a Battery?
The bulk, absorption, and float stages combined sequentially form what is commonly called the “charging algorithm.” A battery charger may generally be classified by a charging current (i.e., the max charging current) and a target battery voltage (12 V, 24 V, 36 V, 48 V, etc.). But battery chargers may also include multiple charging algorithms (typically classified as “AGM,” “SLA,” “Gel,” “Wet,” etc.). A closer look reveals that each algorithm has its own unique parameters, including:
- Bulk voltage
- Absorption voltage
- Absorption time
- Float Voltage
There is a wide variation among values for charging algorithms for lead-acid batteries. The bulk and absorption voltages typically vary between 14.0 and 14.8 V, and the float can vary between 13.2 and 13.8 V.
The 12V Battle Born Batteries sit comfortably right in the middle of these ranges. We recommend a bulk and absorption voltage of 14.4 V. A float is unnecessary since lithium-ion batteries do not leak charge, but a floating voltage under 13.6 V is fine.
Frequently Asked Questions About Charging Lithium Batteries
How can I charge a LiFePO4 battery?
When choosing a device to charge your LiFePO4 battery, it is essential that it is compatible. Determining a charger's compatibility comes down to ensuring your charger's parameters match that of your battery. For Battle Born lithium batteries, you want to ensure that your charger offers between 14.2-14.6 Bulk/Absorb and 13.6 Float. If these specific parameters are offered, a variety of chargers will work with your lithium batteries.
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Although you don’t need to purchase a specific charger for Battle Born LiFePO4 batteries, it is essential that you check that your charger has compatible parameters. When evaluating the compatibility of your charger, check that it allows for between 14.2-14.6 Bulk/Absorb and 13.6 Float. While our batteries do not require float charging, many devices used to charge other types of batteries that have these parameters will work for a Battle Born Battery as well.
Do I have to buy a special charger for LiFePO4 batteries?
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How long do Battle Born Batteries last?
Through extensive cycle testing, we have determined that, after 3,000 full discharge cycles in extreme conditions, our lithium batteries will have 75%-80% battery life left. For the average user not operating their battery in extreme conditions, they will have 75%-80% battery capacity after 5,000 cycles. If you were to fully charge and discharge your Battle Born Batteries every day, they would last you between 10 and 15 years. With a 10-year warranty, our lithium batteries will keep you powered for years to come.
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Charging LiFePO4 Batteries in Cold Weather
After you’ve selected a compatible charger for your LiFePO4 battery, it’s important to prepare your electrical system for the variable conditions it may face. While some campers prefer to follow the 70-degree line, others want to experience a range of seasons. If it’s possible that you will encounter below-freezing temperatures while using your Battle Born lithium batteries, be sure to prepare your system ahead of time to avoid any loss of power or low voltage disconnect.
Cold weather can impact a battery’s ability to store and release energy. Without heated battery kits, a reduced energy transfer affects the battery’s efficiency by lowering its capacity, performance, and lifespan. Protecting your battery from the cold is necessary to prevent freezing, cracking, and long-term damage and to ensure reliable performance.
To protect your Battle Born LiFePO4 battery in cold weather, its temperature needs to remain above 35°F. With our heated battery kits, you can have peace of mind knowing that the internal temperature of your batteries will never drop below freezing. Our deep cycle LiFePO4 heated batteries use a proprietary, low-draw technology to keep batteries at an optimal temperature and ready to charge. This ensures your adventures won’t stop, no matter what weather you encounter.
Want To Learn More About Electrical Systems and Lithium Batteries
We know that building or upgrading an electrical system can be overwhelming, so we’re here to help. Our Reno, Nevada-based sales and customer service team is standing by to answer your questions! Reach them at (855) 292-2831 (M-F 8:00 am – 4:30 pm (PST)) or email info@battlebornbatteries.com.
Also, join us on Facebook, Instagram, and YouTube to learn more about how lithium battery systems can power your lifestyle, see how others have built their systems, and gain the confidence to get out there and stay out there.
