Can I leave my ego battery on the charger over the winter?

Leaving an ego battery on the charger all winter is generally not recommended. However, with proper precautions, it may be okay in some circumstances. Here are some quick answers to common questions about storing ego batteries over winter:

Quick Answers

  • It’s best to remove ego batteries from the charger and store around 50% charge.
  • Storing at full charge all winter can degrade the battery over time.
  • Store ego batteries around room temperature if possible.
  • Completely draining the battery for months of storage is not recommended.
  • Occasionally check the charge over winter and top up around 50% if needed.
  • Fully recharge the battery before using again after winter.

Is It Okay to Leave an Ego Battery on the Charger?

Generally, it is not recommended to leave an ego battery connected to the charger all winter long. Most manufacturers advise removing the battery from the charger if it will not be used for an extended period of time.

When left on the charger at full charge for weeks or months, the battery can start to lose capacity over time. This is because being stored at maximum charge puts strain on the battery’s internal components.

However, there are some exceptions where leaving the ego battery plugged in may be acceptable:

  • If you live in a warm climate and will use the ebike semi-regularly, leaving it on the charger when not in use should be fine.
  • If temperatures remain moderate, around 15°C to 25°C, keeping it plugged in may not cause as much battery degradation.
  • Some chargers have a “maintenance mode” to hold the battery around 60% charge, which puts less strain on it.
  • Occasionally checking the charge and unplugging once it reaches full capacity can help.
  • Higher quality lithium-ion batteries may be more resilient to prolonged maximum charges.

So while it’s often recommended to unplug the battery for winter storage, there are some situations where you may be able to safely leave it on the charger if you monitor it periodically.

Why Should Ego Batteries Be Unplugged for Winter?

Removing your ego battery from the charger over winter provides optimal conditions for preserving battery health and capacity.

Here are some key reasons it’s advised to store your battery unplugged around 50% charge over the colder months:

  • Avoids capacity loss: Keeping an ego battery at full charge when it’s not being used puts strain on the internal battery cells and can cause permanent loss of capacity over time.
  • Prevents component degradation: The high voltage of a fully charged battery can degrade fragile internal materials and electronics in lithium-ion batteries.
  • Reduces aging: Storing around half charge reduces unwanted side reactions inside the battery, limiting premature age-related battery degradation.
  • Safety precaution: Avoiding full charges reduces the minor risk of overheating, fire or explosions from battery defects.
  • Saves energy: Keeping batteries at full charge when not needed wastes electricity.

Additionally, lithium-ion batteries slowly self-discharge when sitting idle for long periods. If left plugged in at full capacity, this self-discharge can drop the voltage too low for the charger to recharge it, rendering the battery unusable unless manually recovered.

What Is the Best Charge Level for Winter Storage?

Most experts recommend storing lithium-ion ego batteries around 40-60% charge for winter and long-term storage. This mid-range state-of-charge minimizes strain on the battery.

Here’s an overview of the optimal charge levels for winter storage:

  • 30-50%: This is the ideal charge range for storage lasting weeks or months. It provides a good balance, reducing age-related battery degradation while still keeping cells active.
  • 40%: If storing for 3-6 months, around 40% is optimal to prevent capacity loss. Manufacturers like Bosch recommend around this level.
  • 50-60%: For very long term storage of 6+ months, the upper range of 50-60% is suitable to account for self-discharge over time.
  • Avoid 0%: Fully depleting to 0% for months can deactivate cells and lead to permanent battery damage. Only discharge to 0% if storing under 30 days.
  • Avoid 100%: Maximum charge causes more stress. Only leave at 100% if storing for about a week.

If possible, use a voltmeter to precisely check the battery voltage to aim for ideal storage levels of around 3.7-3.9V per cell.

How to Store an Ego Battery for Winter

Follow these steps to properly winterize your ego battery for storage:

  1. Charge or discharge the battery to 40-60% capacity before storage.
  2. Remove the battery from the ebike or charger and store it indoors, protected from rain, snow and moisture.
  3. Aim to store the battery around room temperature, between 15°C to 25°C if possible.
  4. Place the battery in a safe storage area away from flammable objects.
  5. Periodically check the voltage every 1-2 months and recharge to around 50% if needed.
  6. At the end of winter, do a full recharge cycle before installing and using the battery.
  7. Consider using a smart charger or maintainer with storage mode to automate optimal voltage.

Also be sure your storage area is free of dust, debris or metal objects that could penetrate the casing and cause damage or short circuiting.

What Temperature Is Best for Storing Ego Batteries?

Ideally, ego batteries should be stored around room temperature for winter. Temperatures between 15°C to 20°C or 60°F to 70°F are optimal.

Here are the effects of various storage temperatures on battery health:

  • 10°C to 25°C (50°F to 77°F): This is the recommended range for storage. Capacity retention is very good.
  • Less than 0°C (32°F): Storing below freezing can damage the battery and reduce performance.
  • 0°C to 10°C (32°F to 50°F): Colder temperatures increase risk of lithium plating that can permanently reduce capacity.
  • 25°C to 40°C (77°F to 104°F): Warmer temperatures accelerate degradation but may be acceptable short term.
  • Above 40°C (104°F): High heat causes rapid battery aging. Avoid storing above this temperature.

If you don’t have a heated space and need to store batteries in a cold garage or shed, it’s recommended to keep the charge around 50-60% rather than a lower level. The slightly higher voltage helps mitigate effects of the cold.

Can Ego Batteries Stay in an Unheated Garage?

You can leave an ego battery in an unheated garage over winter, but it is not ideal for the battery’s lifespan and performance.

Here are some tips for storing in unheated conditions:

  • Keep the battery around 50-60% charge rather than a lower voltage.
  • Choose a spot protected from wind, moisture and freezing rain or snow.
  • Place on concrete floor rather than directly on cold ground.
  • Wrap battery in insulating material such as a towel to prevent surface frost.
  • Bring battery indoors on extremely cold nights below -10°C/15°F if possible.
  • Frequently check voltage and recharge to 50% if needed.

The battery may see greater capacity loss than if stored at room temperature, but these precautions can minimize winter effects.

Should Ego Batteries Be Conditioned Before Winter Storage?

It’s not necessary to condition an ego battery before winter storage, but it can be beneficial.

Some tips for conditioning before storage:

  • Run one or two full discharge/charge cycles to balance cell voltages.
  • Charge to 100%, let rest 24 hours, then discharge to 40-50% for storage.
  • For long-term storage, discharge to 30% and recharge to 60% 1-2 times.
  • Avoid draining to 0% unless recharging immediately.

Conditioning helps calibrate the battery management system and prevents imbalances between cells. It provides an extra bit of preparation to maximize battery lifespan.

How Should I Maintain an Ego Battery in Winter Storage?

During winter storage, occasional maintenance is recommended to keep the battery healthy.

  • Check the voltage monthly and recharge to around 50% if needed.
  • Inspect the battery casing for any signs of damage or leakage.
  • Store indoors and bring to room temperature at least once a month.
  • Charge to 100% and discharge to 40% once every 2-3 months to keep cells active.

Avoid leaving the battery discharged below 20% for more than a month during storage. Top it up to around half charge if it drops too low.


Leaving an ego battery on the charger all winter is generally not the best idea for longevity. Removing it from the charger and storing around 40-60% charge in a room temperature environment provides ideal conditions to preserve battery capacity and performance.

Occasionally monitoring voltage and topping up the charge during winter can keep the battery in good health. With proper precautions, an ego battery can safely withstand a winter of storage and be ready for spring riding.

Storage Duration Recommended Charge Level
1 week 80-100%
2 weeks to 2 months 50-70%
3-12 months 40-60%

This table summarizes the optimal charge levels based on expected storage duration.

Storing your battery correctly over winter can extend its overall lifespan by years. While leaving it on the charger seems more convenient, taking the proper long-term storage precautions will ensure your ebike battery lasts many seasons.

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