Product description

1.1 Introduction EJ LiFePO4 batteries

Regarding this manual first before use of the E&J lithium battery is very IMPORTANT!!

We want you to have a battery that can last for a long time.

Using the batteries according to this manual helps to achieve this.

Dependent on the application this type of battery could have a typical lifetime of 10~20 years.

The wrong usage of lithium batteries in general can lead to unsafe situations or permanently defect batteries.

This manual explains clearly how to use the EJ lithium batteries in the right way.

1.2 General

EJ lithium batteries are designed and manufactured in China and are built with LiFePO4 or LFP cells.

The cells have a 3.2V nominal voltage

In contrast with Lithium NMC, LMO and LCO cells these LiFePO4 cells are inherently safe.

NMC, LMO and LCO cells are used in electric cars, phones, tables, bicycles, tools, toys and RC-models.

LFP cells do not contain Cobalt and Manganese and do not catch spontaneously fire or can expode.

These batteries are the best replacement for lead acid batteries.

Compared to Lead-acid, EJ LiFePO4  batteries offer a much longer life and will accept much easier high charge currents, which is a big advantage for solar panels. Charging is possible at any moment.

They have a smaller volume and up to 4 times lower weight.

Where a lead acid battery has about 60% capacity left at 1C discharge, the EJ lithium battery has still 97%.

The EJ lithium batteries are expected to have a lifespan of 10~20 years and more than 3000cycles before the capacity reaches 80%.

Whereas AGM lead-acid batteries have 2~w5 years and about 300~500 cycles to 70%.

The Built-in battery management system protects the battery against fault conditions.

1.3 Product features

  • Bluetooth functionality; the App is available from our website
  • Monitoring battery state via Bluetooth APP for iOS and Android
  • LFP(LiFePO4) chemistry using cells with high power density
  • Most safe lithium technology
  • Can be connected in parallel or in series up to 4 batteries
  • Integrated BMS ( Battery Management System)
  • Electronic short circuit protection and integrated fuse
  • Overload protection
  • Except for high charge currents
  • Can be fast charged in about 1 hour
  • Can be charged at all charge levels without shortening battery life
  • Failsafe BMS protection functions
  • Strong ABS case with handgrips
  • Broad range of EJ charges available for these batteries

1.4 Battery Management System (BMS)

The BMS will protect the battery against faults. See table below or a listing of BMS protections.

This guarantees the best safety and best functionality of the battery.

The BMS balances the cells, so the battery will always keep its maximum capacitance during life.

Protection Code Proteciton description
OVP Over voltage pack protection
OCP Overvoltage cell protection
UVP Under voltage pack protection
UCP Under voltage cell protection
 SCP Short circuit protection active
 OCC  Over current charge protection
 OCD Over current discharge protection
 OTD  Over temperature discharge protection
 OTC  Over temperature charge protection
 UTC  Under temperature charge protection (Below zero)
 UTD  Under temperature discharge protection

1.5 EJ APP installation and connection

Step1. Install the EJ APP “EJBMS” or “EJBMS PRO” via Google play store or Apple store on your Smart phone

Or you scan the QR code via our website

Android or iOS download link can be found on our webstie

Step2. Make sure the Bluetooth and location on your smartphone are activated

Open the APP n your smartphone

Step 3. You will see a list now with one or more Bluetooth connections.

Chose the model and serial number of your battery and you will be connected to the battery.

Step 4. Let the Apps learn the battery by 1~3 cycles full charge and discharge

Charging the battery fully and keep connected for more 3 hours, then discharge until BMS cut-off is the 1st cycle.

Functions on the main screen Description
SOC State of charge; % of capacity left in the battery
Voltage Actual battery voltage
Capacity Battery capacity in AH on label
Current Actual battery current
Power Watt
Temperature Temperature of the battery
Cycles Shows the number of charge cycles
Remaining time Time for Charging or discharging
Battery status Standby/ discharge/ charge/OVP/UVP…
Cell status Cell voltage

1.6 EJBMS PRO Android and iOS App example screens

2 Safety guidelines

2.1 General rules for safety

These batteries shall only be serviced by authorized personnel

Batteries opened by non-authorized personnel can have potential hazards and EJ can not grant warranty on the product anymore.

The lithium batteries can provide extremely high currents, therefore be careful not to place any metal parts on the battery. Be careful when wearing metallic watches or armbands.

2.2 Transport guidelines

The battery must be transported in its original packing

Lithium batteries are classified as dangerous goods, and should be treated according to category UN3480, class 9 and should be packed according UN handbook.

For land and sea transport the batteries must be packed according to packing description P903

For aur-transport (IATA) the batteries must be packed according to P965.

The original packing is according to these rules.

2.3 End of life and disposal

EJ LiFePO4 batteries are considered EOL (End of life) when the usable capacity drops below 70% of the initial capacity. EOL or defect lithium batteries are not allowed to be put in private or industrial waste.

Therefore lithium batteries need to be disposed of separately according to EU STANDARD 2002/96/CE to official Recycling places. Lithium batteries or parts of I can be recycled.

3. Installation

3.1 Mounting and connection instructions

Check the battery for damages before installation. If the battery has been damaged contact EJ or your reseller.

A maximum of 4 *12.8v batteries can be connected in series.

The battery shall be mounted using special straps or clamps.

The battery shall be connected by using M5/6/8 screws and cable lugs ( torque of about 10-15 nm).

The battery shall be mounted on rubber foam or rubber blocks.

Fixing of the battery shall be strong and suitable for the application

The cable cross section shall be suitable for the maximum continuous current.

Finally, the cable connection shall be isolated by a suitable cable-boot, red for+ and black for -.

3.2 Series or parallel connection of the batteries

To increase the total voltage while maintaining the same capacity, up to four batteries can be connected in series. Be sure to only connect batteries of the same type, age and capacity in parallel. First full charge all the batteries individually!

To increase the total voltage while maintaining the same capacity, up to four batteries can be connected in series. Be sure to connect only batteries of the same type, age and capacity in parallel. First fully charge all the batteries individually!

When multiple E&J batteries are connected in parallel, the total capacity is increased while the voltage remains the same. This also results in correspondingly higher charging and discharging currents.

When multiple E&J batteries are connected in parallel, the total capacity is increased while the voltage remains the same. This also results in correspondingly higher charging and discharging currents.

Before Parallel or series connection follows the instructions below:

  • Make sure all the batteries are fully charged and have the same voltage
  • Use only batteries with the same capacity
  • The best is to use new batteries
  • Use only short cables suitable for the amount of current
  • The batteries have an electronic overcurrent protection

3.3 Short circuit prevention

The battery is electronically protected from short-circuit.  EJ LiFePO4 batteries with short circuit prevention will be auto active after short circuit protection.

3.4 Maintenance

No regular maintenance is needed for the battery

Check the connection to the battery poles regularly if the screw is fixed strongly.

Clean the battery poles when heavy corrosion is noticed

4. Use of the battery

4.1 Charge

  1. Use only appropriate CC/CV chargers with charge end-voltage and charge current within according to battery specification. For the longest cycle life use the recommended charge current.
  2. After finishing the charge to 100% the charge shall switch off or fall back to floating voltage.
  3. The battery can be charged at every SOC level without impact on the lifetime
  4. The battery will not accept charge current below 0°C, except EJ heated lithium series.
  5.  The battery can accept fast charging up to 1C. It is not recommended to do this always, because it will reduce cycle-life substantially.
  6. Switch on/off the charger first before connecting/disconnecting to the battery
  7. Always charge the battery to 100%. When the charger is ready it is recommended to keep the charger connected for at least 3 hours. During this time the battery will finish the internal cell balance process. When the cells are fully balanced each time, there will be no loss of capacity over a long time due to balance mismatch. 

4.2 Discharge

  1.  Care should be taken that the battery is not discharged with currents exceeding the specification
  2. If the battery is discharged with maximum currents at high ambient temperatures it is possible BMS thermal protection will switch off the battery
  3. Tt is recommended setting the Undervoltage protection level in the connected equipment to a level higher than the BMS UVP level. Advised for 12v battery 11, 24V battery 22V, for 48V battery 44V
  4. If during discharge the BMS Undervoltage protection level is exceeded, the battery will switch itself off. The battery will switch on again when a charger is connected.

4.3 Deep discharge

Deep discharge means that the battery is fully depleted and switched off the BMS UVP.

This is an unwanted situation because after longer period of UVP protection the cells can be completely deep discharged. Completely deep discharged cells mean the battery is permanently defective and cannot be repaired. Warranty is not granted when batteries are used like that.

Deep discharge with permeant damage can have the following reasons:

  1. During long time storage, connected equipment to the battery has still current draw and finally, the battery goes in UVP protection mode. Too long time in this protection mode can cause deep discharge.
  2. The battery is not charged before long, e.g.a winter stop, period
  3.  The battery poles are not disconnected before a long period of no usage.

Solution: Charge the battery to full before winter stop period and disconnect the poles.

Check by the APP the SOC condition of the battery regularly.

Important!! The battery shall be fully charged at least every 6 months to prevent deep discharge!!

5 Technical support

When the battery seems to be faulty first check the protection condition CODE on APP and check the monitoring values.

The following situations can apply:

Fault description Possible cause Solution
0V output voltage on poles BMS defect Remove the load, and use a regular DC charger to charge the battery. (Don’t use a smart charger)
Too low voltage on poles 1 BMS in protection UVP Charge the battery
Too low voltage on poles 2 BMS in protection OTP Wait until battery cools down
Too low voltage on poles 3 BMS in protection UTP Use the battery above -10°C
Too low voltage on poles 4 BMS in protection OCD Will recover within 1 minute after load disconnect
Too low voltage on poles 5 BMS in protection SCP Will recover within 1 minute after remove short circuit
Battery does not charge 1 BMS in protection UTC Use battery above zero ˚C
Battery does not charge 2 BMS in protection OTC Wait until battery cools down
Battery has too low AH Cells unbalanced Keep charger connected for
longer time until cells balanced
Bluetooth can not be found BLE module sleeping Use a inverter 1500W or 2000W
to wake up( inquiry us for details)
SOC of APP drops fast BMS save the wrong data Charging battery until full and keep connected
more 3 hours, Discharging until BMS Cut off

6. How To Store LiFePO4 Batteries

6.1 Summary of storage

How do I store my lithium battery? A question we receive from our customers on a daily  basis, especially in the Winter season. The answer depends on the temperature you are storing the batteries in and the period of time.

Here is a summary of how to store your LiFePO4 battery:

-Recommended storage temperature: -5 to 35°C ( 23 to 95 °F)

-Storage up to 1 month: -20 to +60 °C (4 to 140 °F)

-Storage up to 3 months: -10 to +35°C (14 to 95 °F)

-Extended storage time: +15 to 35°C (59 to 95 °F)

It is highly recommended to store lithium batteries indoors during the off-season. It is also recommended to store LiFePO4 batteries at about a 50% state of charge (SOC ) or higher. If batteries are stored for long periods of time, cycle the batteries at least once every 6 months. Do not store batteries that are discharged!!

6.2 Storage in cold weather

Lithium cells are not affected by extreme temperatures if the battery pack is not being used. We do not recommend storing lithium batteries in very cold temperatures for extended periods of time because that could cause the ABS casing of the battery pack to potentially crack. In addition to this, hot temperatures beyond 60°C(140°F) can cause damage to other components in the battery pack, therefore it’s best to always avoid high temperatures for long periods of time. It is always recommended to store lithium batteries indoors and at room temperature.