FAQs

General LFP FAQs

Short Answer

Parallel: No Limit.

Series: Four, up to 48Vdc.

Series and Parallel: Series string up to 48V. Parallel strings unlimited.

In-Depth Explanation -

Parallel – There is no limit to the number of batteries that can be connected in parallel provided the wiring and connections are properly sized to handle the resulting power. See wire gauge calculator. Our BMS will balance each battery in the bank, continually share energy to maintain pack unity Voltage.

Total battery capacity is added, Voltage remains the same.

Example: 2 x 12.8V 100Ah batteries connected in parallel yield a 12.8V 200Ah bank.

Series – Up to four batteries can be connected in series or until a maximum of 48Vdc is reached. Example: 4 x 12V = 48V battery bank or 2 x 24V = 48V battery bank.

Total Battery Voltage is added, capacity remains the same.

Example: 2 x 12.8V 100Ah batteries connected in series yields a 25.6V 100Ah bank.

Extra battery balancing (balancers or equalizers) may be required to ensure that each battery pack stays at equal Voltage with the other batteries in the Series connected string. This depends mainly on the type of charging system being used.

If 2 x 12.8V batteries connected in series to create a 25.6V bank, there are three ways of charging.

A single 25.6V charger - connected across both batteries. Show diagram.

Balancers needed!

A 2 bank 12.8V charger – connected to each battery. Show diagram.

Balancers not necessary. The batteries will align once charged full. Each battery is essentially charged separately while remaining connected to the system.

Single 12.8V charger- connected to each battery individually. Show diagram.

Balancers not necessary

Batteries must be disconnected from each other and charged separately.

Series and Parallel:

Combination of Series and Parallel connected batteries. The same rules apply as above.

Example: Connect 2 x 12.8V 100Ah batteries in series to effectively produce a 25.6V 100Ah bank (or string). Now connect 2 of these 25.6V 100Ah banks (or strings) in parallel – you have created a 25.6V 200Ah bank. Series/ parallel connected bank.

Can LFP Batteries be used in low temperatures?

Yes, they can be but do not charge LFP batteries under 0 degrees Celcius.

Discharging: LFP batteries can be discharged at Temperatures down to -20 Celsius (-4 F) but will temporarily lose usable capacity once the internal temperature of the battery falls below 0 Celsius (32 F) and will continue to discharge more quickly as the temperature drops. See graph.

Charging: LFP batteries should not be charged below a Temperature of 0 Celsius. We recommend charging at above 5 Celsius. Internal Temperature.

Current must be reduced to.

0.1C max from -7⁰C to 3⁰C

0.05C max from -15⁰C to -7⁰C

Do your batteries have a battery managment system (BMS)?

Yes.

All of our batteries come stocked with oversized management systems capable of handling usage above and beyond standard ratings. The BMS provides internal cell balancing, thermal cut off, charge and discharge Voltage limit cut out, charge and discharge limit Current cut out, and short circuit protection. This is just the baseline! Safety - Reliability - Performance are front and center in our units.

All batteries over 100Ah boast Low-Temperature charge protection with options for in-battery heating, direct monitoring and communications, and adjustable setpoints to suit your project.

Can i connect my LFP batteries with other battery chemistries?

Can i charge LFP batteries from an alternator?

Yes.

You will need either a Voltage Regulator or DC-DC Converter Charger with the proper charging profile. Charging directly from an alternator, with no regulation, can damage the alternator and LFP batteries quickly. LFP batteries can take in high a amount of power when charging, enough to overburden the alternator and cause failures. While the output voltage of the alternator may be correct for LFP charging, the profile and current tapering needed to properly charge is not inherent.

A proper regulator or DC-DC converter charger will limit current flow from the alternator, protecting it and the batteries, as well as provide safe and effective charging capability.

EXCEPTION: Our Crank Series and Moto Sport Series are made specifically to charge off of an alternator.

Can i use LFP batteries to start my boat?

What type of charger do i need?

Below we will talk in-depth about how you can find the right charger, we also have the recommended chargers for each battery listed as "additional products" on each battery page.

Constant Current – Constant Voltage (CC-CV) charge profile.

A CC-CV charging profile is required to safely top up LFP batteries.

Most existing AGM or GEL battery chargers possess the proper charging profile LFP batteries.

Maintenance, reconditioning and equalization modes should be avoided, they generally included high Voltage and Current pulsating spikes that are unnecessary for LFP battery chemistry and can be damaging with prolonged use.

When using standard AGM chargers with maintenance, equalization, or reconditioning stages, it is recommended the charger is disconnected or turned off before these stages activate. They will only activate once the battery is fully charged or after an extended period of time. Disconnect chargers with these phases once the battery is fully charged.

Floating profiles or Floating stages are acceptable, often beneficial in solar and constant battery cycling applications. 13.2V – 13.6Vdc

Note: LFP batteries do not need to remain fully charged and prefer to rest in a partially charged state. They are designed to cycle. The best practice is to charge before use. Leave resting at a 40% - 80% SOC.

Recommended charge settings.

Charge Current = Bulk Current = Constant Current Phase (CC) = 0.1C - 0.5C (C= Capacity Rate)

Capacity Rate Example: For a 12.8V 100Ah battery – total capacity is 100Ah

1.0C (100% of total battery capacity) = 100A

0.5C (50% of total battery capacity) = 50A

0.2C (20% of total battery capacity) = 20A

Charge Voltage – Absorption Voltage = 14V – 14.4V

Float Voltage – 13.2V - 13.6V

Equalization Voltage or Equalization Time = 0 = OFF

How to charge multiple batteries?

Are heated options available?

Can the heating option be adjusted?

What is the "Low-Temperature Protection Feature"?

Will a PWM solar controller work to charge LFP batteries or will I need an MPPT?

UN 38.3 Certification

Did you know the U.S. Department of Transportation and many international regulatory bodies require lithium batteries are certified to UN38.3 prior to transport?

Shipping Standards For Lithium Batteries

Lithium batteries must have safeguards built in to withstand the physical and environmental hazards encountered not only during shipping but throughout their lifetimes. UN38.3 is the prevailing United Nations standard that lithium batteries must meet to receive certification for safe transport. The U.S. Department of Transportation and many international regulatory bodies require lithium batteries are certified to UN38.3 prior to transport.

Lithium batteries must undergo a rigorous series of tests to meet UN38.3 performed by an approved independent testing laboratory. Batteries must not rupture, leak, disassemble, or catch fire to receive certification. There are eight tests that that must be passed for a lithium battery to receive the certification.

Testing For UN38.3 Certification

Altitude Simulation, which means that low-pressure testing simulates unpressurized airplane cargo space at 15,000 meters.
Thermal Testing, ensures the cell and battery remain sealed through rapid and extreme temperature changes.
Vibration Testing meaning it simulates vibration during transport, followed by Shock which assesses cells and battery's ability to withstand cumulative physical shock.
External Short Circuit, which assesses a battery's ability to withstand prolonged external short circuit conditions.
Impact & Crush. This simulates a battery's ability to withstand mechanical abuse that could create an internal short circuit.
Overcharge aka evaluating the battery's ability to withstand overcharge conditions, and finally, Forced Discharge, which tests the battery's ability to withstand its stated maximum discharge rating.

The responsibility to ensure that batteries meet the UN standard falls upon the seller and unfortunately, some products in the marketplace do not meet the standard. UN38.3 is an extremely important safeguard for you the customer. A lithium battery could see a 15 year or longer lifetime depending on how often it is discharged and UN38.3 certification should be a primary consideration in your lithium battery purchase.

Storage FAQs

Can i store my LFP batteries in low temperatures?

Storage is allowed in cold temperatures, to -20 Celsius, although not strongly recommended. It is important the proper SOC is maintained to avoid damage.
Storing at the improper state of charge levels has increased detrimental effects at temperatures below 0 Celsius. The battery cells can freeze below -25C, and although not necessarily detrimental to battery health, precautions must be taken to slowly thaw and then charge to full before using.

How should i store my LFP batteries?

70% State of Charge @ 13.2V - in a cool dry location.

Disconnect from all loads and charging sources. They exhibit very low self-discharge characteristics and can be stored for up to 1 year without any additional charge.

We recommend checking State of Charge (SOC) after the first month to ensure no unexpected discharge is taking place. It is detrimental to leave them in a fully charged or fully discharged state for any extended period of time. Roughly speaking – storage SOC can safely range from 40% – 80%.