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Why It's Not Recommend to Build a Golf Cart Battery with 18650 Batteries

David Lee
David Lee
18/12/2024

18650 battery is a kind of ternary lithium battery that is easily available. Some people may want to use this battery to make golf cart batteries. However, the professional opinion is that we do not recommend doing so, the risk is very high. This is a very dangerous and troublesome thing.

Next, let's take a look at what you need to go through if you really use 18650 batteries to make golf cart batteries.

Part 1: Full Understanding of an 18650 Battery

An 18650 battery is a type of cylindrical lithium-ion rechargeable battery named after its dimensions: 18mm in diameter and 65mm in length—slightly larger than an AA battery. With a nominal voltage of 3.7V and a typical capacity ranging from 2600mAh to 3500mAh, these batteries are popular for their high energy density and long lifespan.

what is an 18650 battery

Commonly used in flashlights, laptops, electronics, and even electric vehicles, 18650 batteries are valued for their reliability and ability to endure hundreds of recharge cycles. They are considered "high-drain" batteries, designed to provide consistent high output voltage and current to meet the power demands of energy-intensive devices.

Another notable feature of 18650 batteries is their high depth of discharge, meaning they can be drained to nearly 0% and still be fully recharged. However, frequent deep discharges can reduce the battery’s lifespan over time, so maintaining a moderate charge level is recommended for optimal performance.

1.1 Specifications and Design

  • Voltage: Operates at a nominal 3.7 volts.
  • Capacity: Ranges from 1500mAh to 3500mAh for long-lasting power.
  • Chemistry: Uses lithium-ion for high energy density and low self-discharge.
  • Protection Circuit: Many models have built-in safeguards against overcharging, over-discharging, and short circuits.
  • Rechargeable: Supports multiple recharge cycles, reducing waste and environmental impact.

Its thoughtful design and robust specifications make the 18650 battery ideal for a range of applications.

1.2 Advantages of the 18650 Battery

  1. High Energy Density: Delivers long-lasting power for demanding devices.
  2. Long Cycle Life: Can handle hundreds of charge cycles with proper care.
  3. Wide Availability: Found globally from various manufacturers.
  4. Compact Size: Fits easily into portable gadgets due to its slim cylindrical design.
  5. High Discharge Rate: Supplies bursts of power when needed, ideal for high-demand electronics.

1.3 Disadvantages of the 18650 Battery

  1. Limited Shape Options: Its cylindrical form may not fit devices needing other shapes.
  2. Higher Cost: Premium models can be pricey, especially at higher capacities.
  3. Safety Risks: Mishandling can cause overheating, fires, or explosions. Follow safety guidelines carefully.
  4. Self-Discharge: Slowly loses charge over time, even when not in use.

 Bescause of these cons, it's not recommended to use 18650 battery to diy the golf cart battery. Becasue safety comes to the first. Compared to 18650 battery, LiFePO4 lithium battery is much safer.

Part 2: Build the Golf Cart Battery with 18650 Battery - What a Troublesome Thing

Constructing a golf cart battery using 18650 lithium-ion cells may seem like a fun DIY project, but it’s far from easy. The process requires extensive technical knowledge, precision, and patience. Here’s why building such a battery can be challenging:

1. Determine Voltage and Capacity

Decide your golf cart’s voltage and battery capacity. Most golf carts run on 36V and 48V systems.

For example:

  • Voltage: Connect 13 cells in series for 48V (3.7V x 13 = 48.1V).
  • Capacity (Ah): Add more parallel rows to increase capacity. For a 100Ah battery, and 2.5Ah cells, use 40 cells in parallel (100Ah ÷ 2.5Ah = 40).

2. Plan the Battery Configuration

Use a series-parallel configuration:

  • Series: Increases voltage (e.g., 13 cells for 48V). 
  • Parallel: Increases capacity (e.g., 40 cells per row for 100Ah).

3. Gather Essential Components

  1. 18650 Cells: Choose high-quality, high-discharge cells.
  2. Battery Management System (BMS): Protects the pack from overcharging and ensures balance.
  3. Nickel Strips: Connect cells securely.
  4. Spot Welder: Weld strips to cells without overheating.
  5. Bus Bars/Wires: For connecting the pack to the cart.
  6. Insulation and Enclosure: Prevents short circuits and secures cells.

4. Assemble the Battery Pack

  1. Layout: Arrange cells in the planned configuration. For 48V 100Ah, use 13 cells in series and 40 rows in parallel (520 cells total).
  2. Spot Weld: Connect cells in series first (positive to negative).
  3. Parallel Groups: Connect each series group in parallel for added capacity.
  4. Install BMS: Wire the BMS as specified for safe charging and operation.

5. Charge and Test

  • Use a lithium-compatible charger to fully charge the pack.
  • Measure voltage and check for balanced cells.
  • Perform a capacity test to ensure the pack works correctly.

Suggest reading: How to Test a Battery with a Multimeter

6. Install in Golf Cart

  • Connect the battery pack to the motor controller.
  • Use proper wiring and connectors.
  • Secure the pack within a sturdy enclosure.

Safety Considerations when DIY Golf Cart Battery

  • Fire Risk: Prevent overheating by using proper insulation. 
  • BMS Protection: Never skip the BMS; it ensures safe operation. 
  • Cooling: Allow proper ventilation to avoid heat buildup.

Improper assembly increases the risk of thermal runaway, overheating, or even fire. Insulating the battery and ensuring proper cooling mechanisms are vital but challenging without professional tools.

Example Configurations

  • 48V 100Ah Pack: 13 cells in series, 40 rows in parallel (520 cells total).
  • 36V 100Ah Pack: 10 cells in series, 40 rows in parallel (400 cells total).

Imagine connecting 400 to 520 individual cells by spot-welding nickel strips, ensuring each connection is precise and secure. This task alone could take hours, even for experienced builders with the right tools.

2.1 Hidden Costs of DIY

DIY may seem affordable at first, but hidden costs stack up fast:

Specialized Tools: You’ll need a spot welder, multimeter, thermal sensors, and custom enclosures. These tools aren’t cheap.

Quality Materials: Skimping on batteries or components risks overheating, short circuits, or even fire. Safety comes at a price.

Time Investment: Assembling, testing, and fixing mistakes can take weeks or months, especially if you're new to battery building.

In the end, DIY can drain both your wallet and time while posing serious safety risks. Choosing a pre-built lithium golf cart battery saves effort and ensures reliable performance.

Part 3: Is DIY Worth the Effort? Consider Better Alternatives

Building a golf cart battery with 18650 cells can be overwhelming due to the sheer number of cells needed. For example, constructing a 48V 100Ah battery pack requires 520 individual cells. Managing so many components can be time-consuming, challenging, and risky without proper tools and expertise.

Why Consider Lithium Golf Cart Batteries?

Instead of assembling hundreds of 18650 batteries, consider using pre-built lithium golf cart batteries. These batteries are designed specifically for golf carts, offering:

  • Higher Capacity: More power storage with fewer cells.
  • Longer Lifespan: Thousands of charge cycles, ensuring years of use.
  • Simplified Installation: Ready-to-install units with built-in protection.
  • Enhanced Safety: Professional construction with robust BMS systems.

Why Choose LiTime Lithium Golf Cart Batteries?

LiTime lithium golf cart batteries use advanced Grade A LiFePO4 cells, a superior alternative to 18650 cells. Here’s why they stand out:

lithium golf cart battery cells

  1. Fewer, Larger Cells: Each LiTime LiFePO4 lithium cell has much higher capacity than an 18650, reducing the number of cells needed for the same power output.
  2. Superior Lifespan: LiFePO4 chemistry ensures up to 4,000+ charging cycles, far outlasting traditional lead-acid batteries.
  3. Built-In Protection: Every LiTime battery includes a smart BMS that prevents high temperatures, short circuit, over-voltage, under-voltage, and over-current.
  4. Eco-Friendly: LiFePO4 cells are non-toxic, offering a safer and greener energy solution.
  5. Plug-and-Play: Our batteries are pre-assembled and designed for easy installation, eliminating complex DIY setups.
48v 100ah lithium golf cart battery kit
LiTime 48V (51.2V) 100Ah Lithium Golf Cart Battery Kits $1,199.99 Click to View

Part 4: The Smarter Choice for Golf Cart Power

Why struggle with assembling hundreds of 18650 cells when you can choose a ready-made, powerful, and reliable LiTime lithium golf cart battery? Our batteries simplify your golf cart upgrade while delivering maximum performance and long-term value.

Upgrade to LiTime and experience efficient, worry-free power on the course!

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David Lee
David Lee is a renewable energy consultant with global experience in off-grid systems and battery applications, especially in golf carts. A graduate of the University of Sydney, he shares insights on sustainability through his writing.