Lithium Battery Basics
What is LiFePO₄?
LiFePO₄ stands for lithium iron phosphate, the lithium battery chemistry used across Dakota Lithium’s current battery lineup.
LiFePO₄ is known for long cycle life, stable performance, high energy density, and relatively low maintenance. Those characteristics make it well suited for applications that need reliable rechargeable power, including marine, RV, overland, golf cart, off-grid, and portable-power systems.
What are the benefits of lithium compared with lead-acid?
LiFePO₄ batteries offer several advantages over traditional lead-acid batteries.
They are generally lighter, maintain a more consistent voltage through much of the discharge cycle, recharge efficiently, require little routine maintenance, and can provide significantly longer cycle life when properly used.
Lithium batteries also provide more usable capacity than a similarly rated lead-acid battery because they can typically be discharged more deeply without the same impact on battery life.
Actual weight, runtime, charge time, and cycle life vary by battery model and application.
Are lithium batteries safe?
LiFePO₄ is known for its thermal and chemical stability and is widely used in applications where durability and long cycle life are important.
Dakota Lithium batteries include a Battery Management System that helps protect against conditions such as overcharge, over-discharge, excessive current, short circuits, and unsafe temperatures.
Like any battery, LiFePO₄ batteries should be installed, charged, and used correctly. Use a compatible charger, protect the battery from physical damage, keep terminals from shorting, and stay within the operating limits published for your specific battery.
What does “deep cycle” mean?
A deep-cycle battery is designed to provide sustained power over an extended period and to be repeatedly discharged and recharged.
That makes deep-cycle batteries well suited for applications such as trolling motors, RV house power, solar storage, electronics, camping, and other equipment that draws energy over time.
This is different from a traditional starting battery, which is designed primarily to deliver a short burst of very high current to start an engine.
What is the difference between voltage, amp-hours, and watt-hours?
Voltage (V) describes the electrical potential of the battery and needs to match the system or equipment being powered.
Amp-hours (Ah) describe the battery’s charge capacity. When comparing batteries at the same voltage, a higher Ah rating generally means more available energy and longer potential runtime.
Watt-hours (Wh) provide a better measure of total stored energy because they account for both voltage and capacity.
To estimate watt-hours:
Voltage × Amp-Hours = Watt-Hours
For example:
12.8V × 100Ah = 1,280Wh
How do I know what size battery I need?
Start with the requirements of the equipment you are powering.
Consider:
- Required system voltage
- Desired runtime
- Equipment current draw
- Maximum continuous current
- Peak or cranking current, if applicable
- Available installation space
- Charging method
Once you know how much energy your application uses, you can estimate the battery capacity needed to achieve your desired runtime.
For applications with high-current loads such as inverters, trolling motors, engines, or electric vehicles, make sure the battery’s current ratings are also sufficient. Capacity alone does not determine whether a battery is appropriate.
What is a Battery Management System (BMS)?
A Battery Management System, or BMS, is the built-in electronic control system that monitors and protects a lithium battery.
The BMS helps protect the battery against conditions such as overcharging, over-discharging, excessive current, short circuits, and unsafe temperatures. It also helps keep the individual cells balanced so they charge and discharge more evenly.
If a lithium battery suddenly shuts off or appears to have no output, the BMS may have entered a protection mode. That does not necessarily mean the battery has failed. A load, charger, temperature condition, or low state of charge may have triggered the protection.
Charging
How do I charge a lithium battery?
Use a charger that is compatible with LiFePO₄ batteries and matches the voltage of your battery or battery bank.
A compatible charger should provide the appropriate charging voltage and stay within the battery’s allowable charging-current range.
For example, a 12V battery requires a charger intended for a 12V LiFePO₄ system. The same principle applies to 24V, 36V, and 48V systems.
Lithium batteries may also be charged from alternators, solar systems, and other charging sources when those systems are properly configured for LiFePO₄ batteries.
How do I know when my battery is fully charged?
The easiest method is to use a compatible LiFePO₄ charger with a charge-status indicator. The charger will indicate when its charging cycle is complete.
Lithium batteries maintain a relatively flat voltage through much of their discharge cycle, so voltage alone is not always an accurate way to estimate remaining capacity.
If your system requires a more precise state-of-charge reading, a battery monitor or shunt-based monitor can provide a better picture of how much energy has gone into and out of the battery.
Can I use my existing lead-acid charger?
Using a lead-acid charger is generally not recommended unless you have confirmed that its charging profile is compatible with LiFePO₄ batteries.
Lead-acid chargers are designed around a different battery chemistry and may use charging voltages, maintenance modes, or equalization stages that are not appropriate for lithium batteries. Even when a lead-acid charger appears to work, it may not bring a LiFePO₄ battery to a full state of charge or may not charge it as efficiently as a charger designed for lithium.
For the best performance and charging reliability, use a LiFePO₄-compatible charger that matches the voltage and charging specifications of your battery.
What charger should I use?
Use a LiFePO₄-compatible charger that matches your battery’s nominal voltage and recommended charging specifications.
Charging amperage affects how quickly the battery recharges. A higher-output charger can reduce charging time, but the charger should never exceed the battery’s maximum allowable charging current.
For multi-battery banks, size the charger for the voltage and capacity of the complete system rather than simply the rating of one battery.
Can I charge from an alternator?
Yes, many lithium battery systems can be charged from an alternator when the charging system is properly designed.
In many deep-cycle house-battery applications, a LiFePO₄-compatible DC-DC charger is recommended between the alternator or starting battery and the lithium battery bank. This helps control charging voltage and current and can protect both the lithium battery and the vehicle charging system.
Some batteries designed for starting or dual-purpose applications may support other charging configurations. Follow the specifications for the specific battery and vehicle charging system.
Can I charge with solar?
Yes. Dakota Lithium batteries can be charged from solar with a properly configured solar charging system.
Solar panels are typically connected to a solar charge controller, which regulates the voltage and current delivered to the battery. The controller should support a LiFePO₄ charging profile and be properly sized for both the solar array and battery bank.
How long will charging take?
A simple estimate is:
Battery Capacity (Ah) ÷ Charger Output (A) = Approximate Charging Time
For example:
100Ah ÷ 10A = approximately 10 hours
This is only a rough estimate. Actual charging time depends on the battery’s starting state of charge, charger output, battery temperature, system losses, and how the charger manages the final portion of the charging cycle.
Series, Parallel + Battery Banks
Can Dakota Lithium batteries be connected in series or parallel?
Many Dakota Lithium batteries can be connected in series, parallel, or both, but approved configurations vary by battery model.
Series wiring increases system voltage while keeping amp-hour capacity the same.
Parallel wiring keeps system voltage the same while increasing total amp-hour capacity and potential runtime.
Always confirm the approved series and parallel configuration for your specific battery before connecting multiple batteries.
Can I use two 12V batteries to make a 24V system?
Yes, if the battery model is approved for series operation.
Two 12V batteries connected in series create a 24V battery bank. The voltage adds together while the amp-hour capacity stays the same.
For example:
Two 12V 100Ah batteries in series = 24V 100Ah
Use matching batteries and begin with them at a similar state of charge.
What happens to voltage and amp-hours in series?
When batteries are connected in series, their voltage adds together while amp-hour capacity stays the same.
For example:
Two 12V 100Ah batteries = 24V 100Ah
Three 12V 100Ah batteries = 36V 100Ah
Four 12V 100Ah batteries = 48V 100Ah
Series wiring is used when your equipment requires a higher system voltage.
What happens in parallel?
When batteries are connected in parallel, voltage stays the same while amp-hour capacity adds together.
For example:
Two 12V 100Ah batteries = 12V 200Ah
Parallel wiring is commonly used when you want more energy storage and longer runtime without changing the system voltage.
Do batteries need to be the same model, age, and capacity?
For best performance, batteries connected in the same bank should be the same voltage, capacity, model, and preferably similar in age and usage history.
Mixing batteries with different capacities, internal resistance, states of charge, or levels of wear can cause them to charge and discharge unevenly.
When building a new battery bank, start with matching batteries whenever possible.
How do I balance my batteries?
Balancing a battery bank means bringing each battery to a similar state of charge so the batteries work together more evenly.
This is especially useful when building a new bank, reconnecting batteries that have been used separately, or troubleshooting a system where one battery reaches protection before the others.
A simple approach is to:
- Disconnect the batteries from the bank.
- Charge each battery individually to full with an appropriate charger.
- Allow the batteries to rest.
- Confirm that their voltages are similar.
- Reconnect the bank.
Battery Life, Storage + Care
How do I get the longest life from my LiFePO₄ battery?
Use a compatible charger and operate the battery within its published charging, discharging, current, and temperature limits.
Avoid unnecessary exposure to extreme heat, and do not repeatedly push the battery into low-voltage protection when it is not necessary.
LiFePO₄ batteries do not need to be fully discharged before recharging. Partial discharge and recharge cycles are completely normal.
Properly sized wiring, clean connections, secure mounting, and appropriate storage will also help support long-term performance.
How should I store my battery?
For extended storage, disconnect the battery from loads and charging sources and keep it in a cool, dry location.
Protect the terminals from accidental short circuits and avoid storing the battery completely discharged.
Check the battery periodically during long storage periods, particularly if anything remains connected that could create a small parasitic load.
Can lithium batteries be stored partially charged?
Yes, but long-term storage recommendations can vary by battery model. Always follow the storage guidance provided for your specific Dakota Lithium battery.
Do not store a lithium battery fully depleted. Allowing a battery to remain at an excessively low state of charge can permanently damage the cells and may prevent the battery from recovering normally.
Before long-term storage, make sure the battery is adequately charged, disconnect loads that could slowly drain it, and store it in a cool, dry location. Check the battery periodically during extended storage to make sure it has not discharged too far.
How does temperature affect lithium batteries?
Temperature affects both battery performance and charging.
Cold temperatures can temporarily reduce available capacity and power output, while excessive heat can accelerate battery aging and reduce long-term service life.
Charging restrictions are especially important. LiFePO₄ cells should not be charged below their permitted charging temperature unless the specific battery includes a system designed to safely manage low-temperature charging.
Always follow the temperature limits published for your specific battery.
What maintenance is required?
LiFePO₄ batteries require very little routine maintenance compared with traditional flooded lead-acid batteries.
There is no water to add and no regular equalization cycle.
Periodically inspect:
- Battery terminals
- Cable connections
- Fuses and circuit breakers
- Mounting hardware
- Wiring for damage or corrosion
Keep terminals clean and connections tight, particularly in marine, vehicle, RV, and other high-vibration environments.
Starting + Dual Purpose
Can I use a lithium battery to start my car or boat?
Only if the specific battery is designed and rated for starting or cranking applications.
Dakota Lithium DL+ Dual Purpose batteries combine deep-cycle capability with high-current starting capability. Cranking performance varies by model, so compare the battery’s published cranking specifications with the requirements of your engine.
A standard deep-cycle battery should not automatically be assumed to be suitable for engine starting.
What is the difference between deep-cycle and dual-purpose batteries?
A deep-cycle battery is primarily designed to deliver sustained energy over longer periods and withstand repeated charging and discharging.
A dual-purpose battery is designed to provide both sustained deep-cycle power and the high-current output needed for engine starting.
Dual-purpose batteries are useful in applications such as boats, RVs, and vehicles where one battery may need to handle both starting and accessory loads.
What do CCA and peak current mean?
Cold Cranking Amps (CCA) is a standardized measurement of a battery’s ability to deliver starting current under cold conditions.
Peak current describes a battery’s ability to provide a very high amount of current for a short period.
These ratings are different from continuous discharge current, which describes how much current the battery can supply continuously.
When choosing a battery for engine starting, use the cranking specification relevant to the engine rather than selecting a battery based only on amp-hour capacity.
Which batteries are designed for engine starting?
Use Dakota Lithium batteries specifically identified as starting, cranking, powersports, or DL+ Dual Purpose batteries.
Do not assume every 12V lithium battery can start an engine simply because the voltage matches.
Check the individual product specifications for cranking output, continuous current, peak current, and recommended applications.
Marine + Trolling Motors
What trolling motor battery do I need?
Start with the voltage required by your trolling motor.
A 12V trolling motor requires a 12V battery system, while 24V and 36V trolling motors require matching system voltage.
Next, determine how much runtime you need. Higher amp-hour capacity generally provides more runtime, while the battery’s continuous-discharge rating must be sufficient for the trolling motor’s maximum current draw.
Boat weight, motor speed, wind, current, and operating conditions all affect actual runtime.
How do I size a battery for trolling motor runtime?
Find the trolling motor’s approximate current draw at the speed you expect to use most often.
A rough runtime estimate is:
Battery Capacity (Ah) ÷ Current Draw (A) = Approximate Runtime in Hours
For example:
100Ah ÷ 20A = approximately 5 hours
Actual runtime can vary significantly because trolling motors rarely draw the exact same current continuously. Higher speeds, heavier boats, wind, current, and other conditions increase energy use.
Can I run a 24V or 36V trolling motor with multiple 12V batteries?
Yes, when the batteries are approved for series operation.
Two 12V batteries connected in series create a 24V system.
Three 12V batteries connected in series create a 36V system.
Use matching batteries and confirm that the specific battery model supports the intended series configuration.
A single native 24V or 36V battery can also be used when its current rating, capacity, and physical size meet the requirements of the application.
Can Dakota Lithium batteries be used in saltwater environments?
Dakota Lithium batteries can be used in many saltwater marine applications when they are properly installed and protected.
Protect the battery, terminals, wiring, and electrical connections from direct saltwater exposure, salt spray, corrosion, and excessive moisture.
Secure the battery properly and use corrosion-resistant marine-grade wiring and connections where appropriate.
Environmental protection varies by battery model, so check the specifications for the specific battery being installed.
Solar + Off-Grid
Will my battery work with solar?
Yes. Dakota Lithium batteries can be charged from solar when paired with a properly configured charging system.
The solar array should feed a compatible solar charge controller, which regulates charging voltage and current before sending power to the battery.
The controller should be appropriate for LiFePO₄ batteries and for the voltage of your battery bank.
Do I need a solar charge controller?
In most solar battery systems, yes.
A solar panel’s voltage and current change with sunlight and operating conditions. A solar charge controller regulates that power so the battery receives an appropriate charging profile.
The controller also needs to be properly sized for the voltage, current, and wattage of the solar array.
MPPT vs. PWM: What is the difference?
MPPT and PWM are two types of solar charge controllers.
PWM controllers use a simpler method of regulating panel output to match the battery charging voltage. They can work well in smaller, straightforward systems where panel and battery voltages are closely matched.
MPPT controllers actively convert available panel voltage into usable charging power. They are generally more flexible and can capture more available energy, particularly with larger arrays, higher panel voltages, changing weather, or limited sunlight.
For many modern lithium solar systems, MPPT is the preferred choice.
How do I size my solar array?
Start by calculating how much energy you expect to use and how much of that energy needs to be replaced by solar each day.
Battery energy can be estimated as:
Battery Voltage × Capacity = Watt-Hours
Then consider:
- Daily energy consumption
- Desired recharge time
- Available peak-sun hours
- Solar-panel wattage
- Charge-controller limits
- Expected system losses
A larger array can recharge a battery faster, but panel voltage, current, and total wattage must remain within the limits of the charge controller and battery system.
How do I estimate runtime from a battery bank?
First calculate the battery bank’s approximate energy capacity:
Voltage × Amp-Hours = Watt-Hours
Then estimate how much power your equipment uses:
Watts × Hours = Watt-Hours Used
For example, a device drawing 200W for five hours would use approximately:
200W × 5 hours = 1,000Wh
Real-world runtime will usually be somewhat lower than the simple calculation because of inverter losses, wiring losses, temperature, equipment startup loads, and other system factors.
