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ELECTRIC BIKE BATTERY GUIDE
Electric bike battery is without doubt the single most expensive part on your electric bike. And unlike other expensive components such as motor, batteries have a life cycle. Therefore, you must be very careful when purchasing an electric bike or a replacement e-bike battery.
After you read this article, you will know as much as an ebike store owner about your electric bike battery.
What is the difference between Volt and Amp of an ebike battery?
I will try to simplify them here. I will use a watermill analogy. If water flowing in a pipe is electricity, then voltage will be the water pressure. Amp is the amount of water flowing through the pipe.
If you multiply both you will find watts which is the power applied to turn the watermill.
If we take two identical electric bikes, one of which has a higher battery voltage, that one will go faster.
And if one has higher amp will have a better acceleration.
Amp Hours: This is different than amps. It shows basically how many amps your battery can supply for one hour.
C rate: This is something related to the chemistry of your battery cell. It shows how much “max amps” your battery can supply without any problem. So if your battery is 20 amp hour and has C rate: 4. Then your battery can supply 20x4=80 amps in a safe way.
Battery suppliers such as Samsung or Panasonic produce different 18650 battery cells for different purposes. Batteries used in electric vehicles need to have a high C value so that when needed, they can provide higher amps. And these cells are generally more expensive. And they have some cells designed for electronic cigarettes, which don’t need such high amp consumption, and they have lower C-rate.
Ask your e-bike battery supplier or e-bike seller what is C-rate of the battery is. Because there can be two identical batteries, both with 48V 14Ah values. If one battery pack has C rate 1 cells and the other has C rate 4 cells, your e-bike will perform very differently. One e-bike battery can provide up to 14 amps. Another e-bike battery can supply 56 amps if needed(Most probably your controller will limit this).
Watt Hour: This is your battery voltage x amp hour, which shows your battery capacity. Basically, it tells how much energy can be stored in your ebike battery pack.
If you have a 1500 Wh (watt-hour) battery pack, it can deliver 500 watts of power for 3 hours.
Ah vs Amp: Don’t confuse them. Amp value is generally not advertised on batteries. If someone mentions about 13 amp battery, they mean 13Ah battery.
Ah vs Wh: Ah is a parameter about capacity but without Volt it means nothing. Important parameter is Watt hour (Wh). 10ah battery can have a larger capacity than a 12ah, if 12ah one is 36V and 10ah one is 48 e-bike batteries.
36x12= 432 wh and 10 ah. One has 48x10=480 wh capacity. So please check battery wh value.
Does a Larger Battery Pack Mean Better?
If you’re referring to size in terms of volume or weight, the answer is no. The key factor to consider is the watt-hour rating of your battery, along with other specifications. If one e-bike is larger but has similar watt-hour values, it likely uses older technology cells.
Older generation batteries have a lower capacity, requiring the use of more units to achieve the same overall power.
But this extra volume or weight comes with issues too, such as;
- Your ebike becomes heavier. Heavier e-bike means slower and lower range e-bike.
- Harder to lift your e-bike
- Higher chance of damaging your battery if it falls.
- Affects the balance of your e-bike.
- Larger packs generally don’t look that nice.
- Large volume ones may affect your riding style
How to Store Your Ebike Battery?
Charging and discharging by using your e-bike battery is the best way to store your ebike battery. This is the shortest answer I can give.
If an e-bike battery remains unused for an extended period, its internal chemistry can change, leading to a significant decrease in capacity. Additionally, if the battery management system (BMS) is not advanced enough, the battery may not recharge at all. At Ariel Rider, we utilize a highly sophisticated BMS to help prevent these issues. However, our best advice is to use your e-bike regularly, even if just occasionally.
Why do e-bike batteries deteriorate over time?
Your battery charge does not only go down when you use your e-bike. It also decreases when you store it. On average, you will see a 1% drop in stored energy of your battery pack.
As mentioned before, each battery cell has a safe range of capacity, which is 3.0V to 4.2V. A single battery cell’s nominal capacity is 3.6V. If you combine 10in series, it will be 36V, and if you combine 13 in series, you will have your 48V battery pack.
Your battery management system is programmed to keep your battery pack within this range. If your cells reach 4.2V, then it stops them charging, and if charge drops below 3.0V, it shuts them down to prevent further damage.
If your electric bike battery shows “empty” on the display, it means it is close to 3.0 V per cell. For a 48V battery, this is about 39V.
Each month, your e-bike battery will lose about 1% of its capacity. If you store your battery for a long time and let its charge drop too low, it can get damaged. This occurs when the battery's internal chemistry changes, leading to what is known as a "lazy cell" situation. Once this happens, your battery may hold little to no charge, depending on the extent of the chemical change.
To prevent this, make sure to charge your battery regularly. If you see that the charge is low or the battery is dead during your ride, charge it when you get home.
If you plan to leave your electric bike unused for a long time, whether due to travel or seasonal changes, check the charge level. If it’s too low, be sure to recharge it.
DON’T FORGET YOUR E-BIKE WILL LOSE 1% OF ITS CHARGE EVERY MONTH EVEN IF YOU DON’T USE IT.
The 1% figure is an average. It is affected by different factors. These include the type of cells used, the battery management system (BMS), and the outside temperature. In our tests, we looked at batteries from various suppliers. We discovered that inexpensive, generic batteries from China tend to lose around 3% of their capacity every month. This is both surprising and concerning. Like many low-cost components, these batteries require more maintenance. This highlights why some e-bikes may seem affordable at first glance, but can lead to numerous issues that you'll need to address.
SHALL I STORE MY EBIKE BATTERY FULLY CHARGED?
Keeping your battery fully charged for a long duration is also not advised. Because once your battery is fully charged, your batteries will have stress internally. And once they are subject to such stress for long duration of time, they can get damaged (Not a major one).
Based on our talks with Samsung executives and our tests, we see best rate to keep your batteries for long periods is 70%. Try to store them at this rate and try not to go below 30%. In this way, you can use your e-bike battery for longer periods without seeing major drops in your range.
DOES HEAT AFFECT THE BATTERY PERFORMANCE?
Batteries use electrochemical reactions. As we learned in high school, heat affects all chemical reactions. Certain reactions occur faster in hot conditions, and certain reactions stop happening in cold temperatures.
Safe temperature to keep your e-bike is between -10 Celsius and 40 Celsius.
This last February, Ariel Rider was invited to the Samsung battery cell factory. Samsung engineers taught us things related to our experience with e-bike batteries.
- If your battery gets hotter than 45 degrees Celsius for more than 5 hours, its capacity will drop. Don't leave your e-bike in the back of your van for too long. Also, avoid direct sunlight in summer for long periods.
- If your battery cells reach -20 Celcius for longer than 24 hours, then they may have irreversible damage too. If you have long, cold winters, keep your battery inside your home or garage. This will help prevent damage.
Humidity is also not a good friend of your battery. Try to keep it in a dry environment. At Ariel Rider, we spend a lot of effort to prevent humidity from penetrating inside your battery pack.
You can see our packing. After batteries are packed then they are covered with anti-static film, and on top of that, an anti-humidity film is applied. In this way, we can protect battery cells from humidity, dust, and other things that can damage your e-bike battery.
IS IT DANGEROUS TO LET MY BATTERY CONNECTED TO CHARGER OVERNIGHT?
Most of the electric bike batteries have smart and sophisticated BMS on them. This BMS will prevent your battery being overcharged or overdischarged. Besides that, most chargers also have a smart control system to prevent overcharging the battery.
In theory, you can leave your e-bike battery connected to the charger for an extended period without damaging its lifespan. However, once the battery is fully charged, keeping it plugged in will only waste electricity, costing you money and depleting our natural resources. To avoid this, disconnect the charger as soon as the green light indicates that your battery is fully charged.
When it comes to smart battery management systems (BMS) and chargers, it's difficult to make broad statements about every e-bike brand. Many companies cut costs by using basic BMS in their batteries, which can compromise the safety and longevity of your e-bike battery. Understanding the type of BMS an e-bike uses can be challenging unless you have expertise in the field. Therefore, it's essential to purchase an e-bike from a reputable company. Ensure they demonstrate knowledge and can answer your questions promptly. If they struggle to provide clear answers, it's wise to proceed with caution.
AFTER A LONG TIME OF STORING, CAN I IMMEDIATELY RIDE MY E-BIKE?
Yes, you can charge your e-bike battery at any time without worrying about damaging it. Lithium-ion batteries do not have a memory effect, so charging them at different points in their cycle won’t impact their lifespan.
However, if your e-bike battery has been sitting unused for more than three to four months, you may encounter some cell balancing issues. To address this, it’s a good idea to charge your battery for a short period. This will allow the battery management system (BMS) and charger to balance the cells, ensuring you get the best range on your first ride after a long storage period.
TRANSPORTING YOUR E-BIKE WITH BATTERY
For your safety, we recommend removing the battery from your e-bike. Here are some steps to follow:
- Place the battery in a shaded area inside your car to avoid direct sunlight.
- Remove the key from the battery to prevent it from breaking inside.
- Consider using terminal covers for added protection.
CAN I CLEAN MY E-BIKE WHEN THE BATTERY IS ON IT?
Absolutely! Our electric bike batteries are built to withstand humid and rainy conditions. Avoid using a steam pressure washer, pressure washer, or water jet to clean your e-bike battery or your ebike.
In most cases, simply wiping the battery with a damp cloth is sufficient for cleaning.
WILL MY E-BIKE CHARGER GET HOT?
If you leave your charger plugged into your battery for an extended period, it can overheat. To prevent fire hazards, avoid placing your battery or charger in risky locations.
While our chargers and batteries come with temperature sensors, some models lack this feature. If you're unsure about the specifications of your charger or battery, it's best to err on the side of caution.
HOW TO CHARGE ELECTRIC BIKE BATTERY?
- Charge your battery in a dry location.
- Use a high-quality charger, preferably the OEM version; avoid cheap, low-end options.
- Only use fast chargers if the e-bike manufacturer explicitly states that they are safe to use.
- Ensure your battery is fully connected to the charger.
- If possible, use a wall-plug timer. This will automatically turn off the charger after a set time, usually 4 to 6 hours. This depends on your charger’s speed and battery size. This helps prevent overheating and can lower your electric bill.
- Charge your battery in an area equipped with a smoke detector.
- Keep a fire extinguisher nearby while charging your e-bike battery.
- Be prepared to handle a battery fire if it occurs. This video provides helpful tips for extinguishing a battery fire.
How long does an Electric Bike Battery Last?
Electric bike battery life is measured in charge cycles, not days or months. A quality battery typically lasts for 500 to 700 full charge cycles. With proper care, you can expect your e-bike battery to last between 3 to 5 years.
What happens when my e-bike battery reaches max. Number of charge cycles?
Your e-bike battery's life isn't over just because it has reached its maximum charge cycles. While you may notice a significant decrease in capacity and range, the decision to replace the battery is ultimately yours. If you don’t travel long distances, you can continue using your current battery. However, if the reduced range is affecting your daily commute, it might be time to invest in a replacement. You could also consider purchasing a battery with a larger capacity for added convenience.
Is it ok to leave my e-bike battery in the rain?
While it's possible to ride your e-bike in the rain or park it outside on a rainy day, it's not recommended. If you have the option, store your e-bike or its battery in a dry place. It's best to avoid taking unnecessary risks with your e-bike battery.
How many cells are in a 36-volt battery?
The battery capacity is measured in amp-hours (Ah). Typically, these batteries contain either 40 or 50 cells. They are configured in a series-parallel arrangement, usually with 10 cells in series and either 4 or 5 cells in parallel.
How much does it cost to charge an e-bike?
If your e-bike battery has a capacity of 500Wh, it requires 0.5 kWh to charge. In the United States, the average cost of electricity is $0.12 per kWh, which means it will cost you about $0.06 to fully charge your e-bike battery. For just 6 cents, you can expect to ride your e-bike for up to 40 miles.
Do electric bikes charge themselves?
Only direct drive hub motors can recharge themselves because they lack internal gears. This feature is known as regenerative charging. However, to utilize this function, you will need a specialized controller.
While the idea of self-charging may seem appealing, the reality is less promising. The amount of energy you can generate through self-charging is minimal. Additionally, direct drive motors tend to be heavier and less efficient, meaning the energy gained from self-charging is far outweighed by the extra energy consumed due to their inefficiency.
How much is a battery on an electric bike?
Typically, a new e-bike battery costs between $450 and $750. However, the price can vary based on the battery's capacity, the brand of the cells, and the e-bike manufacturer.
How long does a battery last on electric bike ?
The lifespan of a battery can vary significantly based on the brand of the battery cells, the battery management system (BMS), and how the battery is packaged. Typically, you can expect between 500 to 1,500 full charge cycles. After reaching this limit, the battery will still function, but you may notice a significant decline in performance and a reduced range.
The number of full charge cycles you achieve depends on how you maintain and use your battery.
Some users worry about charging their e-bikes when the battery level drops to 10-20%, fearing that this counts as a full charge cycle. The good news is that it does not. If you charge your battery from 20% five times, that would count as one full charge cycle. While the calculation is a bit more complex—where charging from 20% to full is roughly equivalent to 4.73 times for a full cycle—it's simpler to think of it as five times.
How often should you charge your electric bike battery?
You can charge your e-bike battery as often as you like. Unlike older batteries, e-bike batteries don’t have a memory effect, so you can recharge them after a short ride, even if it’s just five miles.
While it’s best to keep your battery charged, avoid leaving it at 100% for long periods.
Do you need to fully charge an Electric Bike Battery for the first time ?
If you have a NiCad e-bike battery, it's essential to fully discharge and recharge it regularly. In contrast, Lithium-Ion batteries do not require this practice. They lack charge memory, so you don't need to perform deep discharges or full charges when you purchase your e-bike battery.