When purchasing from our company, the process of charging lithium batteries becomes an everyday part of the routine, and we understand that there’s a lot of information about our products. Whether it’s about how the technology accepts a charge or best charging practices, we’re here to outline the basics. Whether it’s best charging practices about lithium batteries, to more information about how they cycle and can be charged in order to keep your battery system running efficiently, our team is here to help.
How can I charge a LiFePO4 battery?
Our team gets this question daily, and we have a blog post on charging LiFePO4 batteries that helps address that topic. There are three main ways to charge a system: solar, alternator, and shore.
Battle Born Batteries only sells accessories from brands we know to produce quality products. One such company is Victron Energy. Battle Born is a master dealer of Victron components because they are reliable and well-built. They even offer the Victron Connect phone app where you can view all the details of your Bluetooth-capable devices.
One component we often recommend is the Victron Energy SmartSolar MPPT charge controllers for systems equipped with solar. With Solar Charge Controllers we recommend the following settings:
- bulk and absorption: 14.2-14.6 volts (aiming for a sweet spot of 14.4 is recommended)
- float: 13.6
We also frequently suggest Victron’s IP-65 Blue Smart Charger because it’s waterproof, Bluetooth compatible, and has a charging profile for lithium batteries and other battery chemistries. This device connects directly to the battery and is meant for single-battery charging. It’s great for those with trolling motor applications or those with battery systems connected in series.
For alternator charging, we often recommend using a DC-to-DC charger or battery-to-battery charger. The Victron Orion-TR Smart DC-DC isolated charger is an adaptive, three-stage charger with algorithms for bulk, absorption, and float options.
You also can mix battery chemistries safely with this device, such as your AGM starting battery to your lithium house bank. Aim for a range between 14.2V and 14.6V with bulk and absorption stages and for the float stage, 13.6V is best.
While lithium batteries technically don’t need to be floated, a good majority of the devices out there still have a float charge mode. The batteries naturally float at 13.6V but reaching 14.6V is ideal and needs to happen in order to engage its balancing mechanisms.
Do I have to buy a special charger for LiFePO4 batteries?
Addressing this question, our COO, Sean, highlights how a retrofit kit from Progressive Dynamics with a converter system has lithium battery charging options. Another charger we recommend is a Progressive Dynamics Inteli-Power 9100 because of how easy they are to incorporate and install into your system, in addition to any Victron component.
Can I Charge My Lithium Batteries Using The Alternator?
Alternator charging is a common method to recharge lithium batteries. Charging from your alternator is a great option, however, you will need some extra equipment, like a battery isolation manager (BIM).
A well-known industry tool, this component is programmed specifically to run with our batteries. It helps with simultaneously monitoring the house and starter bank and has high internal resistance. It can certainly take more power from the alternator when compared to lead-acid batteries.
The BIM provides an extra layer of safety to make sure you don’t damage your system of three or more lithium batteries when charging from the alternator during a long drive. If you have less than three of our batteries in your system, a BIM isn’t exactly required, and instead, you can use a standard isolator. They can regulate the current up to 220 amps and prevent damaging the alternator during a long drive.
Sterling Alternator Protection devices (APD) are also available in our store to prevent damage from surges. These devices turn on with a small resistive load of milli-amp hours to reduce a possible increase in voltage due to cables breaking or any other issues. If the increase is excessively rough, it can lead to serious APD damage, but your alternator, batteries, and regulators have been protected.
The Lithium Battery Charging Cycle: to float or not to float?
Our lithium batteries don’t need to be float-charged.
When it comes to the charging cycle and our batteries, they do not need to float. When you’re charging lithium batteries up fully, you can disconnect your charger and leave them in storage. Please note that batteries will lose a bit of charge over time, but it won’t damage the battery. They might need to be topped off when bringing them out of storage. There is no need to trickle charge your Battle Born Batteries.
However, if you have an RV with a battery bank plugged into shore, you should avoid running your appliances off the battery bank. Unless you are utilizing a cutoff switch in your system, you do not have a choice to where the 12v comes from. Our team recommends that if you have a fixed voltage output converter, it’s best to use a disconnect switch to remove the batteries from the circuit and allow them to rest.
When charging a lead–acid battery, the three main stages are bulk, absorption, and float. Occasionally, there are equalization and maintenance stages for lead–acid batteries as well. This differs significantly from charging lithium batteries and their constant current stage and constant voltage stage. In the constant current stage, it will keep it steady while the battery takes the bulk of its charge. Once the maximum voltage is reached then the charger will hold that voltage and the current will begin to drop as the battery is topped off.
For a lead–acid battery, that constant voltage stage is typically called absorption, and because the lead-acid has a higher resistance, the charger will hit the higher absorption stage halfway through the charging cycle. You could be bulk charging at the maximum current for a couple of hours and then you’d have to wait another 2-3 hours in absorption while the battery is being topped off. By contrast, our batteries will stay in the constant current or bulk stage for almost the entire charge cycle.
Once it hits the maximum voltage, 14.4V, then the battery is basically charged. Now we request that you hold that voltage for 15-20 minutes per battery. It’s not necessarily for the battery to get topped off but it helps the battery balance. Cell voltage starts to separate at maximum voltage. Once that voltage separation happens, we can tell which cell is more charged than the others.
Once we know that, then the battery management system (BMS) can initiate a balancing cycle where the highest charged batteries are bled through a resistor, and then all of them can come back down to the same state of charge. Although there is no required absorption for our battery, we use the absorption stage in conventional chargers to balance the cells.
All About Multi-bank Charging:
Multi-bank charging is a great way to balance series-connected battery systems. Connected positive–to–negative to create a 24V system, it’s important to make sure that the batteries are kept in balance. The first battery to deplete will enter low voltage disconnect mode, triggering the other battery as well. You’ll end up with a lower capacity system than you think.
This also applies when your system experiences high voltage disconnects, so taking these steps will protect your system in either of these extreme situations. If you keep them charged up frequently, they will be more likely to stay in balance because the BMS will internally balance the system. With this multibank charger, output leads are isolated electrically and are still able to connect each individual lead to each battery without disrupting the charge. They will both be ready for discharge and at a full state of charge.
If you want to purchase a multi-bank charger of your own, we suggest the Dual Pro Professional Series Battery charger for your system. It’s also a popular choice among the bass fishing community. It has a specific algorithm for our batteries and is offered in 2 or 4 output options.
What are the proper charging voltages for the 12V, 24V, and 48V lithium batteries?
Our Battle Born Battery charging parameters consist of the following:
- Bulk/absorb = 14.2V–14.6V.
- Float = 13.6V or lower.
- No equalization (or set it to 14.4V if possible).
- No temperature compensation.
- Absorption time is approximately 20 minutes per battery, if possible.
For a 12V system, we really want to emphasize reaching 14.2V – 14.6V for bulk and absorption and float to be 13.6V or lower.
For a 24V system, we suggest a bulk and absorption rate of 28.4V– 29.2V and float to 27.2V or lower. No equalization is required, but if it’s possible we suggest 28.8V. No temperature compensation is required either, and absorption time is approximately 20 minutes per battery if that is an option.
For a 48V system, we recommend a bulk and absorption rate of 57.4V and floating it at 56.5V to 57V. Sometimes, one of the batteries may trigger a high voltage disconnect in your system. The battery’s internal BMS will help handle a high voltage disconnect. Our team wants to emphasize that, overall, there’s no harm in playing around with charge rates to optimize your system.
How long does it take to charge lithium batteries?
One of our most frequently asked questions is “how long does it take to charge lithium batteries?”
Our experts note charging time depends on the specific charger in your system. Lithium-ion batteries have low internal resistance, so they will take all the current delivered from the current charge cycle. For example, if you have a 50-amp charger and a single 100-amp hour battery, divide the 100 amps by 50 amps to come up with a 2-hour charging time.
Another example is if you had five 100Ah (amp-hour) batteries for a total of 500Ah and a 100-amp charger. It would take about 5 hours of charging from empty to 100 percent while factoring in enough time to balance the charging cycle. We don’t recommend you exceed this charge rate as it can lead to a shortened battery cycle life. In an emergency, the battery can be charged at a quicker rate if needed, but we don’t recommend you make a habit of emergency charging your battery.
If you have any additional questions on charging lithium batteries, our YouTube channel and frequently asked questions section on our website offers a wealth of information. Need more help? Please direct your questions to our sales and tech team by giving them a call at 855-292-2831 or sending an email to [email protected].
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 at (855) 292-2831 to take your questions!
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.