If you bought a bike last year, chances are it was an electric-assist bike. Electric-assist bikes are currently the fastest growing model in the U.S. In 2021, they surpass road bikes in sales to become the third largest category of bicycles. There's a reason that electric-assist bikes are outselling electric bikes. The lightweight motors on electric-assist bikes provide powerful power for a variety of riding trails, especially for uses like commuting and running errands.
At the heart of electric assist is a powerful lithium battery. Taking proper care of the battery is key to getting the best range and extending its life.
Here's how to charge an electric-assist bike best for your battery.

The basics of safe charging

Kunal Kapoor, manager for quality at Bosch, a leading supplier of electric-assist bicycle motors, says, "The battery should be charged indoors with a suitable charger while the electric-assist system is turned off. While electric-assist bikes have weatherproof engines, batteries and wiring, the chargers are not suitable for outdoor use".
With modern lithium batteries, when the battery signals to accept a charge, the battery monitoring system in the charger ensures that the internal temperature of the battery is in optimal condition to begin charging and disconnects power when needed. An unbranded charger does not have all the features of a battery management system even if it is rated at the same output, so even if the temperature rises, current will flow to the battery, which carries the risk of a short-circuit fire.
The chances of a battery shorting out and catching fire are low, but we are advised not to leave it unattended while charging. We can charge the battery mounted on the bike, or we can remove it, as long as it is not on or near a flammable object (such as a spare gasoline can in the garage). If you are looking for a cheaper electric assist bike with your own or unbranded motor and battery, make sure the battery and charger carry the Underwriters Laboratories UL 2849 seal of approval. Viribus electric bikes use high-tech lithium batteries and chargers that have been lab tested, so please feel free to use them. This is the full industry standard for safe electrical systems and battery charging for electric assist bicycles. Some bike stores refuse to maintain electric-assist bikes without this type, citing the fire risk of staying in the store overnight.

How to optimize battery life and longevity

Let's start with the principles. Range is essentially runtime: the amount of time a battery lasts on a single full charge, expressed in miles ridden. Even on the same bike, range can vary, and you can go farther on a flat commute with just a light backpack than you can on an uphill trip home from the supermarket after a full load. Most electric assist bikes now have a range of between 25-75 miles, depending on road conditions.
Life refers to the number of times a battery can be discharged and recharged before it starts to lose significant capacity. When capacity starts to drop, you won't notice less power, but you will feel the range start to shrink. The typical life benchmark for an electric bicycle battery is 500 "full" discharges/recharges (if you use half the capacity of the battery and then recharge it, that's half a cycle), and the battery capacity starts to drop significantly in about 3 to 5 years of normal use. Although battery life and battery life are not the same thing, they are linked, and the act of reducing the range over time will also shorten the life. One major reason, Kapoor said, is the increased use of boost, such as leaving it in Boost or Turbo mode all the time, which means the ride is increasingly dependent on the power of the motor rather than assisting with climbs or when it's in poor condition. This can cause the battery to be charged more often and shorten its life. A less obvious factor that can cause engine and battery stress is pedaling frequency. Most electric assist bike motors are efficient at around 70-90 revolutions per minute. Too fast a pedaling speed may reduce efficiency, but of course it is more common to use a large gear ratio and pedal too slowly resulting in poor efficiency. This is the same as "towing an engine" in a car, whether gasoline or electric, when the motor needs to "work harder". "Choose your gear ratios wisely and try to maintain an optimal pedaling frequency of 70-90 rpm. viribus' mountain bikes use

Battery Damage Mistakes

When you buy a new electric bicycle, you should charge the battery before you ride it, since it has been sitting around for a while.
In fact, it's best not to run the battery down. "If you let the battery drain completely, that could permanently damage it and it will never be able to recharge to its original capacity." , If you don't ride your bike for a few weeks or more, store the car or at least the battery in a dry, room temperature place where the battery stays between 30 and 60 percent of its full charge. This is the optimal level for long-term storage and reduces the chance of deep discharges, which can damage batteries. Do not leave the battery plugged into the charger for long periods of time. This is unnecessary and can cause a short discharge/charge cycle that will eventually reduce capacity.
If you don't ride your bike for a long time, you need to check the charge level once a month and recharge it when it falls below 30%. Lithium batteries are less affected by cold weather than other types of batteries, and you'll hardly feel a reduction in range during a ride unless it's really cold. But the U.S. Department of Energy (Department of Energy) researchers recently found that prolonged storage of lithium batteries below low temperatures can damage part of the battery's cathode, thereby reducing battery capacity. Lithium batteries also can't be charged effectively at low temperatures, says Kunal Kapoor, adding that if you store your bike outside or in an unheated area and live in temperatures below freezing, bring the battery back indoors when not in use. Also, protect the battery from extreme heat, such as by a sunny window or a hot car. Excess heat can raise the battery temperature enough to damage its components; in extreme cases, it can lead to what's called thermal runaway, where the battery enters an unstable, uncontrollable state of self-heating, which can lead to a fire.

Plus, you don't need to charge after every ride. Charging the battery early sounds smart, but it will reduce capacity more quickly over time. If you can get 50 miles on a charge and ride 10 miles a day, then you only need to charge every 3 to 4 days, and even if you take good care of the battery, it will lose capacity over time. Capacity is a major indicator of battery health, so if you notice your range dropping to 70% or less of what it was when your bike was new, that's a sign to plan a battery replacement. If your battery is less than two years old and has far less capacity than it originally had, it may require a warranty claim (terms vary by manufacturer). If it's not a warranty issue, when to replace it is a matter of personal preference. "If the battery range was 50 miles to begin with and now it's only 40 miles, and you can live with 40 miles of range, I wouldn't recommend replacing it." However, don't worry, a reduced capacity battery is still safe. Be sure to buy a regular brand of battery. Just like the battery and charger should be paired.
Also, never try to repair a damaged battery or have someone else do it, despite what some guides claim you can. While batteries for electric-assist bikes are almost always made from standard 18650 cells, which are widely used in a variety of products (even electric cars), these batteries have a variety of different chemistries, capacities and currents that can increase the risk of fire if you're not careful. If you need a new battery, buy one. The dealer who sells you the brand of bike can order that brand of bike battery or a replacement directly for you. Battery prices vary depending on the size and brand of the battery, but plan on $400- $800 for a new one. Dealers can also recycle your old batteries. a new program from Call 2 Recycle has partner stores in almost every major city and many smaller cities that can offer free electric assist bike battery recycling (paid for by bike and car brands). Why recycle? Even used batteries have raw materials that can be remanufactured into new batteries with lower energy costs and environmental damage than if the batteries were produced from virgin materials. Waste lithium batteries also pose a fire risk in landfills and can leach toxic metals and other chemicals into the soil and air.
In the event of a fire
Battery fires, while rare, are still a possibility. If your battery becomes overheated while charging, it needs to be unplugged from the charger immediately. If the situation permits, place the battery in a metal container, such as a bucket (preferably one filled with sand), away from any
flammable items.
If conditions do not permit operation, call the fire alarm promptly and tell the dispatcher that you have a lithium battery fire, which requires different firefighting methods than traditional fires. Do not pour water on a battery fire; water and lithium react to produce hydrogen, which is highly flammable, and a fire extinguisher
A fire extinguisher may be helpful.