If your FavoriteBikes e-bike shows battery remaining, such as around 20%, but suddenly gives a low-battery warning, reduces power, or shuts off during riding, this can be normal behavior in many situations.

This usually happens because the battery percentage shown on the display is estimated from battery voltage, and voltage can temporarily drop when the bike is under heavy load.

Why the Display Can Still Show Battery Remaining

The battery percentage shown on your display is not a direct measurement like a fuel gauge in a car. Instead, the system estimates the battery level mainly based on battery voltage.

When the bike is resting or riding gently, the voltage may be high enough for the display to show remaining battery.

However, when the motor needs a large amount of power, the voltage can temporarily drop. This temporary drop is called voltage sag.

What Causes Voltage Sag?

Voltage sag is more likely to happen when the battery is already low and the bike is working hard, such as:

• Using full throttle
• Climbing a hill
• Riding in a high assist level
• Carrying a heavy rider or cargo
• Riding against strong wind
• Riding with low tire pressure
• Riding in cold weather
• Accelerating hard from a stop

In these conditions, the motor asks the battery for a large amount of current. The battery voltage may briefly fall below the system’s protection threshold.

Why the Bike Shuts Off

FavoriteBikes e-bikes include low-voltage protection to help protect the battery from being over-discharged.

If the voltage drops too low, the system may automatically:

• Show a low-battery warning
• Reduce motor power
• Shut off temporarily

This is a protection feature. It helps protect the battery cells and prevent long-term battery damage.

Is My Battery Damaged?

Not necessarily.

If this happens when the battery is already low, especially during full-throttle riding, hill climbing, cold weather, or heavy load, it is usually normal low-voltage protection.

After the bike rests for a few minutes, the battery voltage may recover slightly and the display may turn back on. However, the battery is still low and should be charged before continuing normal riding.

What Should I Do When This Happens?

If your bike gives a low-battery warning or shuts off when the battery is low:

1. Stop riding in a safe location.
2. Turn off the bike.
3. Let the battery rest for a few minutes.
4. Avoid using full throttle or high assist if you need to ride a short distance.
5. Charge the battery as soon as possible.

For best battery health, we recommend charging when the battery drops below about 20–30% instead of regularly riding until the bike shuts off.

How to Reduce the Chance of Early Low-Battery Protection

To reduce voltage sag and early shutdowns:

• Charge before long rides.
• Avoid full throttle when the battery is below 30%.
• Use a lower assist level when the battery is low.
• Pedal more actively when climbing hills.
• Keep tires properly inflated.
• Avoid storing or riding the battery in very cold temperatures when possible.
• Let the battery warm to room temperature before charging in winter.

When to Contact FavoriteBikes Support

Please contact us if:

• The bike shuts off at a high battery level, such as 50% or more.
• The battery percentage drops suddenly from high to very low.
• The bike shuts off repeatedly on flat ground under light use.
• The battery will not charge afterward.
• The charger light behaves abnormally.
• You see an error code on the display.
• The battery is swollen, hot, leaking, smoking, damaged, or has an unusual smell.

When contacting support, please include:

• Your bike model
• Order number or proof of purchase
• Battery percentage before the shutdown
• Riding condition when it happened, such as hill, throttle, assist level, or temperature
• Charger light behavior
• Any error code shown on the display
• A short video of the issue if possible