Lithium Iron Phosphate - LiFePO4 - Battery 

Lithium Iron batteries are to Sealed Lead Acid batteries what an old model ford is to a new  mercedes. They will both get you from A to B, its just that LifePO4 batteries do it BETTER IN EVERY WAY.  If you are serious about your ride, maybe want to take it to work, ride around town, shred up the off road scene recharge quickly and then do ot all over again, then LifePO4 is for YOU. With their extended run time, their increased torque, their increase abilty to give up power more quickly ( faster acceleration for longer) and extended long life (up 5 years & 2000 re charges), these are the tools of the profesisonal. Making a decision to purchase your skateboard initially with  a lithium Iron battery, or as an upgrade to your SLA battery, is an investment that you will be enjoying for years to come. It is a fact that when LifePO4 e-skaters purchase another board, it is nearly ALWAYS with LifePO4 batteries. Its hard to go backwards.

Comparison between Lithium and Lead-Acid Battery

I. Lighter and smaller
Compared to the lead-acid battery, the LiFePO4 battery is 1/3~1/4 in weight and volume but 5 times more efficient. On top of that, it is portable due to its light weight and has a lifetime 5-10 times longer than that of the lead-acid battery.

Battery

Lead-Acid

Lithium-ion

Capacity

10AH(36V)

10AH(36V)

volume

6.12dm3

1.66dm3

Mass

Approx. 13KG

Approx. 3.8KG

Capacity density

80-100 WH/L

350-400 WH/L

Mass density

30 WH/KG

150 WH/KG

 

II. Long life
A typical lithium cell can be charger more than 500 times (100%DOD) and retain more than 60% of the original cell capacity. A lead-acid cell, however, can only be charger 50 to 200 times before its capacity drops to 60% (100%DOD). We choose the Lithium battery mainly because of three reasons:

  • The material is superior but much more expensive. However, we expect that the cost shall be cut in half in three years. 
  • Each Lithium cell carries a higher voltage with greater consistency.
  • There is no loss of acidic steam.

III. Low internal resistance
The internal resistance of one LiFePO4 cell is less than 6mΩ and that of a whole battery set is less than 80mΩ. Therefore, the Lithium battery set can provide much more power when heavy power is needed, such as initiating and climbing. For a whole set of  lead-acid batteries, however, the internal resistance reaches, on average, 200mΩ upon 10A current discharge. On the other hand, a lithium battery can provide 12W with the same conditions, thus the lithium battery provides more power for quicker initiating, climbing and acceleration.


IV. High voltage

The working voltage of a LiFePO4 cell is 3.7V, but that of a lead-acid cell is 2V. There are several cells combined in a roll under tandem so as to better ensure consistency. Therefore, when a Lithium battery is being assembled, it has a greater capacity and a longer life cycle than that of a Lead Acid battery.

V. Low temperature resistance

Lithium-ion batteries can discharge soundly at -20℃ (According to tests, they can discharge over 95% of its capacity at -20℃ and even 90% at -40℃). Lead-acid batteries, however, can only discharge less than 60% at 0℃.

VI. Heavy Electric-Current discharge
A lithium battery can discharge up to 25A without affecting its life cycle, but a lead-acid battery can only discharge 15A. Most power boards in the market place nowadays take more than 30A to function well which potentially shortens their battery life. It only take around 8A or less to run our power boards on a flat surface.

VII. Low self-discharge
The self discharge of a lithium battery is 6-8% a month and that of a lead-acid battery is 15-20% a month. Therefore, after being fully charged, it can be stored longer than a lead-acid battery.

VIII. No memory
Lithium batteries can be charged any time, absolutely free of charge memory.

IX. Environmentally friendly
Lithium batteries are free of leakage, pollution and from harmful heavy metals, such as cadmium, lead and mercury. There is no contamination during the course of production and application. According to the Eco-Mark Authentication Center, the lithium battery is currently in position to be recognized as a green and ecologically friendly product. The lead-acid battery, however, is not recommended as an environmentally friendly battery product.  

X.
Quick charging rate (being developed- proposal of Xinri Company expected)

The newest lithium battery can be charged at 10A/Sec. Now, a quicker charger is under development, which could charge a Lithium battery in 2 hours or less.
Of course, Lithium is expensive nowadays, and in order to avoid excessive costs for the first stage power board rider, we designed an upgradeable batteries utility , which means that the lead-acid batteries in the old skateboards can be upgraded to Lithium  upon Client request.

For more technical information on LifePo4 - Lithium batteries
For more details on Lead Acid Batteries for Electric Skateboards

 

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