Frequently Asked Questions

Answers to the most commonly asked questions regarding lithium-ion battery technology and Flux Power.


Lithium-Ion Technology Frequently Asked Questions

Powering The Future
General Information
What is the Flux Power LiFT Pack Battery made from?
A Flux Power battery pack is made using large format prismatic lithium-ion cells. The cells are constrained against shock and vibration in a steel enclosure.  Battery interconnections are made with flexible busbars and high strand cabling. 
What does the State of Charge (SOC) Gauge tell me?

The State of Charge Gauge is a string of LEDs which display the following:

  1. When the lights are static the LEDs act as a battery discharge indicator (BDI).
  2. If there is a single light flashing it is displaying a Device Trouble Code (DTC).
  3. If the lights are turning on in series it is confirming the pack is charging.
Is there a Battery Discharge Indicator (BDI) on the pack?
Yes, there is a State of Charge (SOC) gauge on the pack.  A series of LEDs indicate the batteries state of charge from 0-100%.
What are Device Trouble Codes (DTC)?
If the pack is trying to operate outside of its limits, the Battery Management System (BMS) will alert the user through a series of alarms.  Each model has their own DTCs which are described in the battery pack’s user manual.
Temperature Performance
Temperature Performance
At what temperatures can I charge and discharged a Flux Power LiFT Pack?
Flux Power LiFT Packs should only be charged from 0°C to 45°C (32°F to 113°F) and discharged from -20 °C to 55° C ( -4°F to 131 °F).
What are the effects of temperature on capacity and operation for both high 55 °C (131 F°) and low temperatures 0 °C and -20 °C (32 °F and -4°F)?
The supported discharge temperature range is -20 °C to 55 °C (-4 °F to 131 °F) and supported charge range is 0 °C to 45 °C (32 °F & 131 °F).  At 55 °C (131 °F) the available capacity is 100%, at 0° C (32 °F) there is 75% available capacity, and at -20 °C (-4 °F) there is 41% available capacity.  Constant operation at 55 °C (131 °F) will reduce the battery cycle lifetime by >20%.
Is the temperature range of -20 °C to 55 °C (-4 °F to 131 °F) the operating internal temperature of the pack or the ambient temperature?
This is the internal temperature.  There are temperature sensors inside the pack which monitor the operating temperature.  If the temperature range is exceeded, the buzzer will sound and the pack will automatically shut off until the pack is allowed to cool/heat to within operational parameters. 
What is the temperature increase during the use of Flux Power LiFT Packs compared to lead acid?
Flux Power LiFT Packs experience almost no temperature increase during charging and discharging.  Tests run by Flux Power indicate flooded lead acid temperatures increase 27% more and AGM increase 47% more than Flux Power LiFT packs during a 1 hour (1C) discharge.  This is due to the lower internal resistance of lithium-ion vs. lead acid, and means the battery wastes less energy when charging and discharging.
Charging Information
Charging Information
Can Flux Power LiFT Packs be opportunity charged?
Yes, Flux Power LiFT Packs can be plugged in at any state of charge with absolutely no negative effects.  In fact, opportunity charging can actually increase the lifetime amp-hour output of the battery.  The battery pack does need periodic balancing and should be plugged in overnight or over the weekend once per week.
What happens when the pack runs out of charge?
When the battery reaches 15% SOC a beeper will sound notifying the operator that the battery must be charged.  Once the battery reaches 2-3% SOC red LED will flash notifying the operator that the battery is about to go dead.  We recommend plugging the pack in as soon as the initial buzzer sounds to prolong the life of the battery.  If the pack is not plugged in and left sitting in an uncharged state, it is possible the lithium-ion cells will be permanently damaged and no longer function which will void the packs' warranty.
Do I need to disconnect the LiFT Power Pack from the truck to charge it?
Flux Power batteries include drive away protection which does not allow the user to use the truck while charging.  The battery does not need to be disconnected from the truck when charging.
If the pack is plugged in for charging, is the truck jack operational?
No, the battery cuts power to the truck when charging.  Once the charger is unplugged the power is re-enabled to the truck.
Is it OK to leave the LiFT Pack plugged in?
Yes, the Battery Management System (BMS) monitors charging so the battery will never overcharge.  Flux Power recommends leaving the charger plugged in when not in use.
Can you overcharge or over discharge the packs?

Flux Power’s patented Battery Management System (BMS) monitors charging so that the pack cannot be over charged or over discharged.  The only risk is if someone fully discharges the battery pack and then does not plug it in.  In this case, because of the small parasitic draw from the electronics, it is possible to completely kill the pack.  Therefore, we recommend the packs remain plugged in whenever not in use for more than a few days.  There is no harm in leaving the packs plugged in, but great harm if they are left discharged for extended periods of time. 

Note:  Allowing the battery to over discharge due to extended use or storage after the low SOC alarm goes off will results in an “over discharge” condition and the battery will no longer charge.  Failure to properly maintain the batter will void the batteries warranty

What type of charger and charging profile is used in the LiFT Pack?
Batteries with on-board charger have a high frequency BMS controlled device.  It will charge at constant current until the desired pack voltage is reached.  Once the voltage is reached, the charger will hold a constant voltage to finish charging and balancing.
Can a lead acid charger be used to charge the Flux Power battery?
Flux Power LiFT Packs require a higher charging voltage than lead acid batteries.  It is recommended to use a Flux Power approved charger to charge the battery.  Charging with a non-approved charge will void the battery’s warranty.  Contact Flux Power for more information on approved chargers.
Is the charger CEC (California Energy Commission) approved/rated?
Yes.  Flux Power approved chargers are CEC compliant.
How much current does the S-Series LiFT Pack on-board charger draw?
It is a 775W charger, so the current draw is dependent on the supplied voltage.  If the socket supplies 130V, the charger will draw 6A.  If the wall socket supplies 110V, the charger will draw approximately 7A.  Standard US electrical outlets supply a range of voltages depending on the distance from the transformer.  Note:  Applies to S-Series models only.
What type of cord is used for charging?
Batteries with on-board chargers us a regular 120VAC extension cord for charging.  Batteries with external chargers typically use 4 AWG welding cable.
At what depth of discharge (DOD) does the battery experience 1 cycle?

There is no point at which a discharge counts as 1 cycle.  Each cycle puts wear on the battery proportional to its depth of discharge.  If the battery is discharged to 80% every cycle, it will last ~ 2000 cycles.  If the battery is cycled at 70% DOD, the battery will last ~3,000 cycles. 

This has a nonlinear effect on the total amp-hour throughput of the battery over its lifetime.  The smaller the DOD is, the larger the total Ah output of the battery is.  Comparing the lifetime output of two 100 Ah batteries at 80% and 70% DOD, the total Ah output can be idealized by the following:


100Ah*0.8DOD*2000=160,000Ah total output.

100Ah*0.7DOD*3000=210,000Ah total output.


In reality, the total lifetime output numbers will be closer together, as factors such as battery aging are not being considered, however the 70% DOD battery will still output more Ah over its lifetime.  This is the main reason why opportunity charging is a perfect fit for LiFT Packs.

Cell Chemistry Information
Cell Chemistry Information
What types of lithium-ion chemistries are available, and why do we use LiFePO4?

There are several different chemistries available.  Flux Power uses LiFePO4 due to its long cycle life, low cost of ownership, thermal stability, and high-power output.  Below is a chart which provides some information on alternative lithium-ion chemistries.

Specifications Li-cobalt LiCoO2 (LCO) Li-manganese LiMn2O4 (LMO) Li-phosphate LiFePO4 (LFP) NMC1 LiNiMnCoO2
Voltage 3.60V 3.80V 3.30V 3.60/3.70V
Charge Limit 4.20V 4.20V 3.60V 4.20V
Cycle Life 500 500 2,000 2,000

Operating Temperature

Average Average Good Good
Specific Energy 150–190Wh/kg 100–135Wh/kg 90–120Wh/kg 140-180Wh/kg
Loading 1C 10C, 40C pulse 35C continuous 10C
Safety Average Average Very Safe Safer than Li- Cobalt
Thermal Runway 150°C (302°F) 250°C (482°F) 270°C (518°F) 210°C (410°F)
What “wears out” in lithium-ion batteries?

As lithium iron phosphate cells cycle, the charge is carried between the anode and cathode using lithium-ions.  As the pack cycles a very small percentage of the mobile lithium-ions are caught in irreversible side reactions.  This reduces the amount of charge transfer possible between the electrodes. 

In lead acid this is somewhat analogous to sulfation, where the sulfur becomes locked in stable lead sulfite crystals and can no longer intercalate into the lead plates.  Sulfation is worse however as it occurs during use and during storage, the crystals can grow and crack the plates, and block electrolyte access to the plates.

What is the electrolyte in these batteries?
Flux Power lithium-ion batteries use an electrolytic salt dissolved in organic solvents.
What is the specific gravity of Flux Power lithium-ion batteries?
Specific gravity is not relevant for lithium-ion batteries.  Generally, specific gravity is used to measure the density of lead acid electrolyte against water.  Lithium-ion batteries are sealed and maintenance free, so there is no way to measure the electrolyte and no water is used.
What are the positive and negative active materials?
The cathode (positive electrode) is lithium iron phosphate with a copper charge collector, and the anode (negative electrode) is graphite with intercalated metallic lithium, and an aluminum charge collector.
What does Intercalate mean?
Intercalation is the insertion of lithium ions into the anode and cathode material.
What are the chemical reactions occurring within a Flux lithium-ion battery?

When the battery charges, the lithium ions are in the carbon/graphite anode, and when discharging the lithium ions move to the cathode. The chemical reactions are as follows:

 Charge : LixC6 = 6C + xLi + xe
 Discharge : Li(1-x)FePO4 + xLi+ xe = LiFePO4

Does the lithium-ion battery pack have a positive and negative grid like lead acid batteries?
Lead acid uses a lead plate, and a lead dioxide paste that must be supported by a structural grid as their anode and cathode.  Flux Power lithium-ion batteries have an anode and cathode, but no grid is used as there is no lead dioxide paste.
What is Ahe vs. Ah?

It is difficult to compare a lithium-ion and lead acid battery when only looking at amp hours.  Flux Power uses amp hour equivalent to give a better estimate of the run-times you should expect.  The voltage is higher and stays higher, meaning there's more energy (kWh) in the battery pack, for a given amp hour rating. 

In addition the pack is lighter, and the chemistry is more efficient, so you save energy charging and discharging, and use less while running the equipment.  You can also drain more of the energy from the battery without serious effects, meaning for identical amp-hour ratings, lithium-ion will run longer.  This is why we call our 100Ah lithium-ion pack a 135.  It will run as long (or longer) than a 135Ah lead acid.

Shipping & Recycling
Shipping & Recycling
What do I need to know to ship a LiFT Pack?
Similar to lead acid, there are packaging instructions which must be followed when shipping.  A LiFT Pack must be shipped in accordance with UN3480, Hazard Class 9, packaging group II, instruction 965.  If the pack is shipped in equipment, use packaging instructions 967.  If you need further assistance, please contact your Flux Power representative.
What do you do with the batteries at the end of their life? Is there a recycling program?

Recycling methods are currently being developed, with reports of 60% recyclability at the cell level.  Lithium-ion batteries are the future of energy storage, and recycling efficiencies are predicted to climb to >90% as the markets scale and additional recycling methods are developed.  Until a mature recycling program is available, Flux Power agrees to take back any battery at the end of its usable life for either recycling or repurposing. 

Also note, because lithium-ion batteries have a much longer life-time vs. lead acid, there will be dramatically fewer batteries subject to recycling over time.  If you require more detailed information regarding recycling, please contact your Flux Power representative.

Maintenance & Watering
Maintenance & Watering
Do the packs require watering?
No, lithium-ion batteries do not require watering. They are completely sealed and produce no gas when charging. In addition, the electrolyte is made of organic solvents, so water should not be used.
Do LiFT Packs require periodic maintenance?
No, but an annual inspection is recommended by an authorized dealer to ensure maximum battery health and life.
Safety Information
Safety Information
What have you done to verify the pack will physically last 5 to 10 years?
The pack has been through extensive abuse testing for UL 2271, UN 38.3 and OEM testing and approval.  It is protected by our full 5 or 10 year warranty (depending on the pack).
Are Flux Power lithium-ion batteries safe?

There are several factors responsible for the remarkable safety of Flux Power lithium-ion batteries.

  1. The selection of battery chemistry is important. There are several lithium-ion chemistries to choose from, and each has unique properties.  Flux Power has chosen lithium iron phosphate (LiFePO4) for several reasons.  Most importantly LiFePO4 is chemically stable and has the highest thermal runaway temperature of any lithium-ion chemistry at 270 °C (518F).  The news stories of cell phone and laptop batteries catching fire were a cobalt based chemistry that is less chemically stable.  These batteries are also in a small cylindrical cell format.
  2. The lithium-ion cells used are in the form of large pouch and prismatic cell technology versus cylindrical cell. The pouch and prismatic cells contain >20Ah versus the 2.5Ah in cylindrical, meaning LiFT Pack batteries have up to 10 times fewer power connections.  In addition, the cells are connected with flexible busbars, meaning they are extremely vibration resistant.
  3. The use of Large Format Cells means there are far fewer cell taps and temperature sensors. This system is less complex and inherently safer.
  4. The BMS monitors the cell temperature and current and shuts the system down if it detects anything which may cause harm to the battery. This is to maintain battery performance and expected lifetime.
What happens if the pack is breached, what leaks out and is it dangerous?

The lithium-ion cells are first encased in hard plastic, and then an industrial 10-gauge powder coated steel case.  If a user punctures through all these materials and exposes the lithium-ion cell electrodes and electrolyte, be cautious when handling.  The electrolyte consists of organic solvents (EC, PC, DEC) and a dissolved electrolytic salt (LiPF6).  They are skin and eye irritants, and fumes can cause mucus membrane irritation. 

The solvents are flammable so do not expose to an open flame.  Use rubber gloves, eye protection, ventilation and positive pressure breathing protection when removing the damaged battery and electrolyte.  In addition, LiPF6 is hydrophilic and reacts with water releasing hydrogen fluoride, a corrosive flammable gas.  If a fire does occur, use a CO2 or chemical fire extinguisher.

Will the batteries catch fire?

Flux Power uses lithium iron phosphate (LFP) in its products as it is a very stable chemistry.  The burn temperature is over 500F, much higher than other chemistries such as lithium cobalt at 149C (300F).  The chemical stability also provides long cycle lifetimes (2000 at 80% DOD). In addition, there are safety measures built into the pack which prevent overcharging and rapid discharging.  Finally, the battery case is made of high-grade steel, protecting the cells from damage, and containing them should a cell breach occur. 

All these protections mean that under normal usage there is no danger of a fire.  The dangers of spills and explosive gas buildup from lead acid batteries are much more common than a LiFT Pack catching fire.

Warranty & Miscellaneous
Warranty & Miscellaneous
What is storage mode?
The LiFT Packs are shipped in storage mode, to activate the pack, close the circuit breaker by folding in the yellow tab, as shown in the guide included with to the battery.  If you wish to store your battery for a long period of time, fully charge the battery and then press the red button in the cable storage box.  This will allow the battery to be stored for up to 1 year before requiring a re-charged.
What happens when a single cell fails in a lead acid battery vs. a Flux Power lithium-ion battery?

Lead acid:

When a single cell fails, there is no BMS to manage the charging.  Therefore the failing cell will heat up, but not fully charge.  The failing cell will accelerate its decline as it is used improperly and cause the entire pack to drain rapidly when in use.  As an example, if a failing lead acid cell is at 50% capacity, the charger will not attempt to charge it to its full (diminished) capacity, this means that once the pack is used, the voltage drop will be significant in this cell, and the entire pack will see a drastic drop in run-time due to the low voltage in this cell.


Flux Power lithium-ion battery:

When a single cell begins to fail, the entire pack will experience a reduction of run-time proportional to the single failing cell’s reduction in run time.  The BMS will still charge and balance the cells, but the pack will cut off when the failing cell voltage drops to 2.8 Volts.  As an example, if the failing cell is at 50% capacity, the charger will still charge the cell to full (diminished) capacity and the cell will produce the expected voltage, just for 50% shorter run-time.  The pack will then run as if it has 50% capacity.  The BMS will protect the other cells from harm due to a low cell.  The BMS avoids the low voltage scenario which is problematic in lead acid.

How does a dealer diagnose a battery should an issue arise?
The State of Charge indicator lights also display Diagnostic Trouble Codes (DTCs) which are detailed in the Quick Start Guide and this FAQ.  If for some reason the problem cannot be determined using the DTCs, Flux Power will provide communication cables and software to connect to the pack for a more detailed inspection of the issue.  The on-board firmware provides detailed reports of all cell and pack behavior, making diagnosis of a problem quick and easy.
Why does the Flux Power product specification sheet show a voltage different than lead acid batterie

Lithium-ion cells have a higher nominal voltage than lead acid.  The Flux Power LiFT pack is comprised of an array of 8 lithium-ion cells connected in series or parallel, each with a nominal voltage of 3.2V.  The pack nominal voltage is therefore the summation of the number of cells in the battery.  There is minimal voltage drop as the pack discharges under normal use.  The pack will indicate it needs to be charged when it drops to 3.0 volts per cell.  See the table below for a summary of the different lithium-ion nominal voltage compared to lead acid nominal voltage.

Lead Acid (nominal)





Flux Power Lithium-ion (nominal)





How can we offer a 5 or 10 year warranty?
Based on average usage profiles and Flux Power lithium-ion battery packs lasting 2000 cycles, Flux Power expects the LiFT Packs to last 7 to 12 years (depending on the battery model) before they are at 80% of their original capacity.  If an end user is running the pack 24/7 and cycling the pack 3 times in a 24-hour period, there may be additional decreased capacity after the 5 to 10 year mark, but the pack will still function as intended.

Lithium-Ion vs Lead Acid Batteries

How does Lithium-ion battery technology compare to Lead-Acid battery technology?

Lithium-ion technology is transforming the material handling and ground transportation industries by offering:

  • 30% MORE Energy Efficient
  • 40% Lower Cost of Ownership
  • 2x Longer Life
  • 2.5x More Productivity

than lead-acid batteries. Download our free ebook to learn how you can increase your overall return on investment.

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