E Bike Battery Life: How to get the most out of your ebike battery
Like traditional bicycles, e bikes need routine maintenance to keep them running smoothly. However, e bikes also have motors and batteries. While many motors are almost maintenance free, batteries need some care if you want to maintain the capacity and e bike battery life..
Lithium-ion batteries can be expensive, but they are great for e bikes because they have a high energy density, no memory effect and low self-discharge. Batteries start at about $400 and can go more than $1,000. It can be the most expensive part of an e bike or e bike conversion kit, so it makes sense to try to extend your e bike battery life.
Stress factors can prematurely age lithium-ion batteries and shorten their useful e bike battery life, which is typically three to five years, or 800 full discharge cycles, if well maintained. These factors include charging, discharging, initialstate of charge, temperature and more. While some battery stress cannot be avoided, you can do a few simple things to extend your e bike battery life.
Charging
As with your cellphone, tablet and laptop, overcharging the battery puts stress on it. While high charge levels may give extra performance for a few cycles, it will lead to a drop in performance and reduce the e bike battery life.
According to Grin Technologies, charging to 80 per cent of capacity can triple the number of charge cycles a lithium-ion battery can go through, compared with full charging.
Many batteries only need four to six hours to fully charge, so you could set a timer on your charger.
Smart chargers can be set to the desired amount of charge. However, make sure your charger’s maximum voltage matches the battery’s maximum. If it isn’t, you not only risk the longevity of your pack, you also risk a fire hazard.
Charging to 100 per cent is OK if done periodically. When you first get your lithium-ion battery, it’s only partially charged, so it’s good to fully charge it to ensure all of the battery cells are balanced. If you find your battery isn’t running as long as it used to, a full charge for an extended period of 10 hours could rebalance the cells. Never charge for more than 24 hours.
Batteries from reputable manufacturers all have battery management systems (BMS), which handles the rebalancing. When a battery has reached its peak charge, the individual battery cells will slowly be balanced, so each parallel string of cells has the same voltage. This not only extends the range of your battery but also extends its life expectancy.
Discharging
While overcharging a battery is harmful to your e bike battery life, so too is completely discharging it. The BMS will prevent battery cells from dropping too low. When the controller registers the battery as being “flat,” the BMS will cut off the battery. While the ebike motor won’t work, lights and other low-power components may.
Similar to how charging to 80 per cent is ideal, discharging to 20 per cent is also preferred.
Charge state
If you don’t ride your ebike in the winter or won’t be riding it for a couple of weeks, you will need to store it. Rechargeable batteries need to be used regularly, so sitting idle is not ideal. However, you will not always be able to avoid it.
As mentioned, batteries don’t like to be completely charged nor completely drained. Lithium-ion batteries are often shipped about half charged, which is an ideal percentage when storing. That’s because they slowly discharge on their own over time. If the voltage drops too low, the cells can be damaged.
Over the winter months, check the battery periodically to ensure it’s OK. If it’s below 40 per cent, give it a half-hour charge to keep it happy. Follow us on Facebook for regular reminders in the winter. You’ll also find events, e bike news and cycling safety tips.
Temperature
Heat hurts batteries. It’s that simple.
Avoid leaving a lithium battery in direct sunlight or in hot places, like in a car on a bright, sunny summer day.
While supercharging at high rates is convenient for getting you back on the road quickly, it heats the battery and shortens its life. It is better to slowly charge your ebike battery.
Batteries also don’t like extreme cold. While it’s OK to ride your ebike in the winter, it’s best not to store the battery with your ebike outside or in an unheated garage or shed. Remove the battery and bring it inside with you.
Ensure the battery is above freezing before charging it to avoid damaging the cells.
Last thoughts
While most decent batteries will be water resistant, if not waterproof, keep them dry and clean. If you are riding in wet weather, be sure to wipe your battery clean and dry at the end of your ride.
Perhaps needless to say (but I will anyway), try not to drop the battery or your ebike, as that could cause damage. For mre information on batteries, how they work and how to maintain them you can read our article on Volt, Amps & Watts.