![]() ![]() In this range, you can expect to see the fuller capacity charging benefits of using a lithium battery. Additionally, the dead battery detector might interpret a lithium battery that has gone into protection mode as a dead battery, and may not be able to get the lithium battery out of protection.Īs mentioned in this blog, SLA charging profiles feature a voltage of 13.8 to 14.7. ![]() This de-sulfation mode can cause a lithium battery BMS to shut the battery down, or even damage the battery due to the high voltage pulse. ![]() For reference, the de-sulfation function on SLA chargers is to bring back an over-discharged SLA battery by using low amps and high voltage pulses. So, can you use lithium in an SLA charger? Yes, as long as that charger does not have a de-sulfation mode or a dead battery detector. As you can see in the chart below, this means the lithium battery still charges in less time than it would take for the equivalent SLA battery to charge on an SLA profile. The charge time will be increased when charging lithium on an SLA profile – from about 2.5 hours in the 20AH lithium battery charged on a lithium profile above to about 5 hours for the same battery on the SLA profile. If this lithium battery were charged on a 14.6V bulk charge (typical constant voltage for charging an AGM battery – chosen because lithium is usually a drop-in replacement for AGM batteries), it would have absorbed 99% capacity in 95% of the total charge time, meaning the last 1% of charge is absorbed in the last 5% of charge time. This means the last 5% of capacity is absorbed in 10% of float charging time. When charging a lithium battery on an SLA charger with a 13.8v bulk charge (the typical float voltage for SLA and a common voltage for simple chargers), it reaches 95% capacity in about 90% of the total charging time. Understanding how Lithium and SLA charging profiles work, you may have questions about what would happen during charge if you were to use a lithium battery as a drop-in replacement where an SLA battery charger was used? Would this damage the battery? Will the lithium battery tolerate the voltage differences and float charging? Lithium Absorption on an SLA Charging Profile In larger SLA batteries, the extended charging time may require extra batteries to be in use while some batteries charge. This is especially important in highly cyclic applications where a device will be out of service for charging. In this comparison, the lithium battery has been fully charged before the SLA battery even reaches the constant voltage stage of its charging cycle, and charges in 1/3 the time of the SLA battery. Additionally, lithium batteries do not need to be kept on float charges because the lower self-discharge rate of the battery. The constant voltage charge stage only provides an additional 1% to the capacity with only 4% of the charge time. This means in the 12.8V 20AH lithium battery example above, the battery reaches nearly 100% SOC in just under two hours. In the constant current/bulk charging stage, the battery can absorb 99% of it’s capacity (SOC of 99%) in 96% of the charge time. However, in a charging cycle for lithium, there are only two stages: constant current and constant voltage. Additionally, the battery should be kept on a float charge for most applications to prevent the battery from going into an over-discharged state due to self-discharging of the chemistry. The constant voltage charge, which can also be called the absorption charge, charges the remaining 20% of the battery but also takes approximately 50% of the total charge time. In the 20Ah deep cycle SLA battery charging example above, the SLA battery has reached a State of Charge (SOC) of 80% during this phase – which is just over half of the total charging time. In the constant current stage, the battery is getting its bulk charge. In a charging cycle for SLA, there are three stages: constant current, constant voltage, and float charging. Charge absorption of lithium versus charge absorption of SLA But, the 12.8-volt 20-amp hour lithium iron phosphate battery took just over 2.5 hours to reach 100% SOC. For example, in the chart below we charged a 12-volt 20-amp hour deep cycle SLA battery, which took about 6.5 hours to reach 100% State of Charge (SOC). If you’ve ever had to wait around for an SLA battery to finish charging before you can use it in a device, you know that this is incredibly time consuming. You may have heard time and time again that lithium batteries charge very quickly, but exactly how quickly, and how much faster than SLA? What does this mean for you, the end user? And, ultimately, can you charge a lithium battery with a normal sealed lead acid charger? Charging Absorption Differences between SLA and Lithium One of the biggest advantages to lithium batteries is their faster charging capabilities versus their sealed lead acid counterparts. Can I Charge a Lithium Battery with a Normal Charger?
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