Frequently Asked Questions

You can find most of our BWB LiFePO4 Battery models on this page BWB LiFePO4 Batteries.

Below is our complete list.  Some of the bigger capacity batteries requires assembly upon orders.  This will normally take around 2-3 days turn around time to complete the order for bigger capacities.  Please call us or chat with us for enquiries if you can’t find the LiFePO4 model in our website.

50A Cells      
Battery SizeModel no. Watt Hour Description Price WeightDimensions (cm)
12V 50AHSS1250             640SS Regular $ 390.00      6.9018.8 x 16.4 x 14.8
12V 50AHSS1250B640SS Regular + Bluetooth $ 460.00      6.9018.8 x 16.4 x 14.8
100A Cells      
Battery SizeModel no. Watt Hour Description Price WeightDimensions (cm)
12V 100AHSS12100a21  1,280SS + New Accessories $ 790.00  14.5032.3 x 19 x 19.5
 SS12100  1,280SS Regular  $ 690.00  13.8027.4 x 19 x 19.5
 SS12100A  1,280SS + accessories $ 790.00  14.5034 × 25 × 26
 P12100  1,280Plastic Regular $ 690.00  11.5035 x 18 x 19
 P12100A  1,280Plastic + accessories $ 790.00  12.0033 x 23 x 26.5
 SS12100S  1,280Slim $ 790.00  12.8037 x 12 x 19.2
12V 200AHSS12200A 2,560Long SS + accessories $ 1,490.00  25.3552 × 19.5 × 19
 P12200 2,560Plastic $ 1,390.00  23.0052.5 × 23 × 21.8 
24v 100AHSS24100A 2,560SS + 100AH $ 1,490.00  25.3552 × 19.5 × 19
 P24100 2,560Plastic $ 1,390.00  25.3552 × 19.5 × 19
48V 100AHSS48V100A21  5,120SS + accessories $2,990.00    4848 x 39 x 19.5
200A Cells      
Battery SizeModel no. Watt Hour Description Price WeightDimensions (cm)
12V 200AHSS12200A212,560SS + accessories $ 1,590.0025.535 x 19.5 x 27
12V 200AHSS122002,560SS Short $ 1,490.00 26.7033 x 20 x 24.5
12V 400AHSS12400 5,120SS Long $2,990.00 47.8057 × 20 × 25
24V 200AHSS24200 5,120SS Long $2,990.00 47.8057 × 20 × 25
12V 800AHSS1280010,240SS Big Box $5,980.00 89.6056 × 41 × 24.8
24V 400AHSS2440010,240SS Big Box $5,980.00 89.6057 × 41 × 24.8
48V 200AHSS48200 10,240SS Big Box $5,980.00 89.6058 × 41 × 24.8



Big Wei Battery warrants BWB LiFePO4 Battery to be free of defects in material and workmanship for the applicable 3-year warranty period.  Warranty is only given to the original purchaser of this product.  The warranty does not extend to subsequent purchasers or users. The 3-year warranty period starts from the date of the original purchase of the product.

The maximum liability of Big Wei Battery under this limited warranty shall not exceed the actual purchase price of the product.


We provide a warranty against defects for the period and application as detailed in this manual.  If you are experiencing any problems with your LiFePO4 Battery unit, you may call (07) 3090-3637 or visit us at our shop address located at Unit 4, 17 Moss St., Slacks Creek, QLD 4127 before returning the product to our business office.  The battery will be tested as per our test procedure. Proof of purchase is required during the claim.  Big Wei Battery will repair or replace any of the battery parts free of charge if found valid. The warranty excludes defects from after-sale damage, abuse, incorrect installation, or neglect. The benefits of this warranty are in addition to any other rights and remedies available at law. Costs of transportation to and from the Big Wei Battery shop will be shouldered by you. Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.


This warranty does not cover damage or defects resulting from normal wear and tear including scratches, abrasions, chips, dents caused by mishandling, accidents, damage during shipping to our business office, unauthorized use or repair, continued use of battery even after it has stopped operating or malfunctioned, alterations, neglect, abuse, misuse, failure to follow recommended proper care and maintenance, acts of god, fire and flood. The natural capacity decrease is not supported within the 3-year warranty period.


We offer Free Lifetime Service. So, whether it’s still under warranty or beyond the warranty period, our service is Free.  You will only have to pay for the parts or materials that need to be replaced when the product is beyond warranty.


Write us an email to and include the following:

  1. Full details of alleged defect or fault and the circumstances surrounding the defect or fault
  2. Provide relevant evidence of the claim, including photographs of the product installed and associated system wiring
  3. Provide proof of purchase and payment


Please DO NOT OPEN the battery box for whatever reason without our authorization as it will VOID the warranty and we are not responsible for any DAMAGE/s it may cause.  These batteries are NOT designed for, nor should be fitted into an engine bay due to high heat.  Damage may occur and is not covered by BWB LiFePO4 Battery Warranty.

We use Class A prismatic cells with 100% charge & discharge currents.  

Cell Specs:   3.2V (50AH, 100AH, 200AH).  Cycle Life:  3,000 for Electric Vehicles & 8,000 for Deep Cycle use.  To read more about our LiFePO4 prismatic cells, please click here

With BWB LiFePO4 Battery, the usable power is 90%.  Unlike AGM, you can only draw up to 50%.

These LiFePO4 cells come from one of the top three largest and most reputable lithium manufacturer’s in China – GANFENG Lithium.

Ganfeng Lithium Group covers a wide swath of the lithium battery supply chain, from lithium resource development, refining and processing to battery manufacturing to battery recycling. it’s the Company’s products are widely used in electric vehicles, energy storage, 3C products, chemicals and pharmaceuticals. The Group’s lithium resources are located across the globe and it is the only Company in the lithium industry that has the commercial scale technologies to extract lithium from brine, ore and recycled materials. The Groups lithium compound capacity ranks third worldwide and first in China, and is the worlds largest lithium metal producer. The Group has complete battery manufacturing and recycling technology, providing sustainable value-added solutions to battery manufacturers and electric vehicle manufacturers.

Read more about GANFENG LITHIUM by visiting their website Lithium Metals|Lithium Compounds–Ganfeng Lithium Co.,Ltd

Use only a lithium specific charger. Our BWB LiFePO4 Battery requires constant charging. Before you use your LiFePO4 battery, please charge it up until it gets full. First time charging may take longer but succeeding charges will be faster. Note that different voltage requires different max input/charge voltage.

  • Voltage 12V – Standard Voltage 12.8V
    • Max Input Voltage 14.6V
    • Discharge Cut-Off 10V
  • Voltage 24V – Standard Voltage 25.6V
    • Max Input Voltage 29.2V
    • Discharge Cut-Off 20V
  • Voltage 36V – Standard Voltage 38.4V
    • Max Input Voltage 43.8V
    • Discharge Cut-Off 30V
  • Voltage 48V – Standard Voltage 51.2V
    • Max Input Voltage 58.4V
    • Discharge Cut-Off 40V
Fully charge the battery before use. (e.g., 12V battery max charge is 14.6V)

       Charge up to Maximum charge voltage. Check below for model type:

Voltage/ Battery Model


Input Voltage

Cut-Off Voltage

















A smart charger will indicate a green light once battery has been fully charged.


üBattery cells are brand new and only has 25% power.  First time charging will take longer to fully charge up to maximum charge voltage as indicated above (Maximum charge voltage details).  Succeeding charges will be faster.
üUsing a battery charger with a specific Lithium charge algorithm is the best option for maximum performance and lifespan of any lithium battery.
üBattery can be charged using AC/DC, DC/DC and/or Solar Charger.
üAnderson plugs are 50A max capacity.  Both Anderson plugs can be used for input/output.  For current of more than 50A, please use the regular +/- terminals.
üCigarette lighter socket has 10A maximum input & output.
üWhen storing for a long period, you may only charge the battery to 50%.  No need to fully charge it.
üIf charging the battery using solar panel, it may take longer to fully charge it depending on the size of the solar panel. To give you an idea, a 200W solar panel may only charge a maximum of 10A per hour for 5 hours (50A/Day) on a good sunny day.
Please do not use the battery once it cuts-off.  If battery goes flat, kindly unplug any equipment and recharge the battery until it fully charges before using.

Warranty: This battery comes with 24 months warranty.  Please DO NOT OPEN the battery box for whatever reason as it will VOID the warranty and we are not responsible for any DAMAGE/s it may cause.


  • Alternator: Most factory alternators can sufficiently charge our LiFePO4 Battery. You can use our Lithium Relay or a DC/DC charger with Lithium option. Learn more about our LITHIUM RELAY.
  • Inverter: Most inverters have a battery type switch that can either be selected to AGM for the closest setting to lithium or have a custom voltage setting that can be programmed to optimize your lithium battery.
  • AC/DC or Solar Charger: You can set your chargers voltage to lithium. Please take note of your battery voltage type to manually set the voltage. Like for a 12V system, the max charge voltage is 14.6V.  Learn more about our LITHIUM CHARGERS

charge curve· When the voltage of each cell gets around 3.5V, means the battery charge capacity is nearly full, then the cells would charge much faster towards full capacity, and the cell voltage rise rapidly. This is normal and is a characteristic of LiFePO4 cells. One cell may charge quicker than the rest, and will reach 3.65V earlier than others.

Max charge per cell is set for 3.65V.  (You can find this on the BMS parameter). Once one cell get 3.65V, BMS will stop charging the battery unit, and start balancing the voltage of cells.

Sometimes, the BMS will show an alarm when it’s fully charged (“cell voltage level high”). But after several minutes, it will disappear as long as charger has been disconnected, and the voltage difference will be balanced gradually by the BMS.

When a battery is fully charged, a significant voltage difference of 0.2V-0.5V is normal. (However, is shouldn’t happen when you are discharging the battery). The more you use the battery and charge it, the more you will see it stabilizes.

· When you are discharging the LiFePO4 battery, the voltage will drop fast at the beginning(3.4V), and will stabilizes when it’s under 3.3V. However, when the voltage get around 3.1V, it will start dropping rapidly until the battery is cut off by the BMS. The voltage drop rate can be different depending on the DOD (depth of discharge).

No. The BMS cuts off the battery supply when 90% of its power has been used. When this happens, simply charge back the battery. It’s best recommended you use at least a minimum of 10A lithium charger so that it activates the BMS quicker. Always remember that BMS also protects your battery from over-discharge. Attempting to use the battery after it has cut-off may take longer time to reactivate when recharging. 


Our BWB lithium Iron LiFePO4 battery technology will provide you with up to 3000 cycles for Electric Vehicles & up to 8000 cycles for Electronic Storage Systems still provide over 80% of usable capacity.

We don’t recommend you lay it either sideways or upside down. The lithium cells have pressure release valve which helps protects the cells when extreme pressure is happening and/or any excess of electrolytes may need released. To keep the battery safe, healthy, lasts longer and away from possible damage, keep it standing upright for maximum performance.

We build our LiFePO4 batteries in Australia. Major battery components are sourced directly from only the best manufacturers with reputable background and experience. This means you will be buying the best quality product for your lithium battery needs.

We have been in the battery business in China for more than 30 years now. We know exactly where to source all of the best quality components, from Lithium cells to BMS including cables, etc. We partner directly with the best companies in the China. No Middle Man. Therefore, it makes our BWB LiFePO4 products more affordable and high quality.

Disclaimer: We would like to thank Blue Sea Systems for this article below.  You can find more of their electrical system frequently asked questions in their website.

Choosing the right wire size for your DC electrical project is important, since a wire that is too small can overheat and possibly start a fire. The American Boat and Yacht Council (ABYC) publishes charts with valuable detail to help experienced boatbuilders and installers determine what wire size they need. Although these charts are an excellent resource, they are a bit intimidating. This technical brief distills the information on these charts to a more manageable size for installers and boatowners alike.

Quality marine wire, as specified by ABYC standards, will always be stranded rather than solid, and always tin-plated copper. In addition, the DC Wire Selection Chart shown below assumes a wire insulation rating of 105°C. A lower rating will decrease the current-carrying capacity of the wire.

To use the chart included with this technical brief, follow the instructions below.

Choosing the correct wire

A  Locate the CURRENT IN AMPS of your appliance across the top of the chart. Most electrical products include a rating label, or you can find the amperage rating in the documentation that came with the product.

B  Find circuit LENGTH IN FEET along the left side of the chart. Note that the total length of the circuit is the roundtrip distance from power source (usually the battery) to the product and back.

C  Select the CIRCUIT TYPE. Allowable voltage drop is based on whether a circuit is critical or non-critical.

Critical circuits, with 3% allowable voltage drop, include

  • Panel main feeders
  • Bilge blowers
  • Electronics
  • Navigation lights

Non-critical circuits, with 10% allowable voltage drop, include

  • General lighting
  • Windlasses
  • Bait pumps
  • General appliances

Follow down the column until you find your circuit’s LENGTH IN FEET.

D  Intersect CURRENT IN AMPS with LENGTH IN FEET to identify the wire size.

Example: A windlass rated 80A is 25’ from the battery. Circuit length is 50’, circuit type is ‘non-critical’, and correct wire size is 4 AWG.

Click the image below to enlarge

Although this process uses information from ABYC E-11 to recommend wire size and circuit protection, it may not cover all of the unique characteristics that may exist on a boat. If you have specific questions about your installation please consult an ABYC certified installer.

The Circuit Wizard, at, is a resource for a more detailed treatment of wire size selection for DC circuits. It allows you to input detailed information including wire insulation temperature rating and other derating factors. The Circuit Wizard is easy to use, and is accessible from any computer with an Internet connection.

Look for additional articles on the topic of selecting circuit protection at

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