Electric Lawnmower Motor

• What it is: The maximum horsepower the motor can produce for a short duration (usually seconds to a few minutes).
• Use Case: Useful during acceleration, startup, or when extra torque is temporarily needed (like in go- karts, e-bikes, or heavy-duty machinery).
• Limitation: Not sustainable for long periods—pushing the motor at peak power for too long can overheat or damage it.

• What it is: The maximum horsepower the motor can safely produce continuously without overheating or degrading performance.
• Use Case: This is the reliable, everyday power the motor can deliver during extended operation—important for systems that run for long periods.
• Rated Conditions: Usually based on ambient temperature, cooling, and duty cycle assumptions (e.g., 40°C ambient, proper ventilation).

Think of it like your own strength:

• Peak HP is like lifting something heavy for a few seconds.
• Continuous HP is what you can lift repeatedly or hold for an hour without tiring or hurting yourself.

• For ourPeak HP rating, we use 335 Amp as the current draw amount when presenting the data.
• For ourContinuous HP rating, we use 100 Amp as the current draw amount when presenting the data.

If you're selecting a motor for an application (like your go-kart project), always size the motor based on the continuous horsepower for sustained performance—and ensure your controller and battery can handle the peak load for bursts when needed.

When converting a gas car to electric using 72, 96, 120, or 144 volts, the total amp-hour (Ah) capacity of the battery pack will vary depending on your goals for range, performance, weight, and budget.

🔋 Step 1: Assumptions and Inputs (Typical Battery Capacities)

⚡ Step 2: Energy Consumption (Wh/mile)

We'll base this on the following assumptions:

• Vehicle weight: 2000 lbs
• Gear ratio: 3:1
• Tire size: 19"

💡 For general-use estimation, use 300 Wh/mile as an average energy consumption value.

🚗 Estimated Range & Top Speed

Here’s your complete breakdown of estimated usable energy, range, and top speed for the D&D 170-015-0004 motor at 72V, 96V, 120V, and 144V, using both lead acid and lithium batteries:

Using power curves and wheel data:

• Motor Max RPM @ each voltage (from performance data)
• Gear Ratio: 3:1
• Tire Diameter: 19" → Circumference ≈ 59.7 in ≈ 1.516 m

Formula: Wheel speed (mph) = (Motor RPM / Gear Ratio) × Tire Circumference / 1609.34 × 60

🔍 Range & Speed Highlights

• 🔼 Top Speed increases slightly with voltage: from ~71 to ~73 mph
• 🔋 Range increases significantly with higher voltage & lithium batteries (due to better usable energy)

Note: These values are estimates based on test data and standard conditions. Real-world performance will vary with terrain, driving habits, regenerative braking, and payload.

When converting a gas car to electric using 72 volts, the total amp-hour (Ah) capacity of the battery pack will vary depending on your goals for range, performance, weight, and budget.

• Configuration: Usually made with 6x 12V deep-cycle batteries in series
• Typical battery types: Flooded lead-acid (FLA) or sealed AGM/gel
• Amp-Hour Range (per battery): Commonly 100–200 Ah (at 20-hour rate)
• Total Pack Rating: 72V @ 100–150 Ah is typical. That equals 7.2 to 10.8 kWh of usable energy (but lead-acid should only be discharged to ~50% to avoid damage)
• Example: 6 × 12V, 150Ah = 72V, 150Ah pack → Usable energy ≈ 5.4 kWh (at 50% DOD)

Pros/Cons:

• ✅ Inexpensive, widely available
• ❌ Heavy, low cycle life, limited range, low efficiency

• Configuration: Usually 20–24 cells of LiFePO₄ or NMC (nominal 3.2–3.6V per cell)
• Custom BMS and packaging: Required
• Amp-Hour Range: Typically 60–200 Ah, depending on goals
• Total Pack Rating: 72V @ 100–150 Ah is also common. But lithium has 80–90% usable capacity, so it’s more efficient
• Example: 24 × 3.2V, 100Ah LiFePO₄ = 76.8V, 100Ah → Usable energy ≈ 7.5–8 kWh

Pros/Cons:

• ✅ Lightweight, high efficiency, long lifespan
• ❌ Higher upfront cost, needs BMS and charger compatibility

Interpreting the Chart:

• Lead-Acid (72V 100Ah): ~10–14 miles
• Lead-Acid (72V 150Ah): ~15–22 miles
• Lithium (72V 100Ah): ~21–30 miles
• Lithium (72V 150Ah): ~31–44 miles

Energy Usage Context:

• 250 Wh/mile: Very efficient (lightweight car, flat terrain)
• 300 Wh/mile: Typical moderate driving (light acceleration)
• 350 Wh/mile: Heavier vehicle, hills, or aggressive driving

Assumptions for Estimating Range:

• Vehicle Weight: 800 lbs
• Gear Ratio: 3:1
• Tire Size: 19 inches

Based on these assumptions, we can estimate:

• Rolling resistance and aerodynamic drag
• Motor efficiency and power draw
• Vehicle speed at a given RPM (considering gear ratio and tire size)
• Estimated Wh/mile under normal driving conditions

Street-Legal EV Assumptions:

• Cruising Speeds: ~30–45 mph (typical), up to ~60 mph max
• Driving Style: Moderate acceleration, low-to-moderate aero drag

Key Calculations:

• Vehicle Speed vs. Motor RPM: Considering a 19" tire, 3:1 gear ratio, and motor RPM from test data
• Energy Consumption (Wh/mile): Based on rolling resistance, aerodynamic drag, and motor efficiency
• Real-World Range Estimation: For both lead-acid and lithium battery setups

Estimated Energy Use vs Speed:

• At 30–40 mph: Energy usage is around 250–300 Wh/mile, which is efficient for a street-legal EV.
• At 55–60 mph: Energy usage rises to 350+ Wh/mile due to aerodynamic drag becoming dominant.
• Motor Efficiency (~80%+): Helps maintain lower Wh/mile at midrange speeds.

Estimated Ranges (Recap):

Note: Variables such as hills, stop-start traffic, or regen braking will affect performance. These estimates provide a good understanding of approximate performance under typical conditions.