The battery is generally the most expensive component on any ebike whether you’ve built it yourself or bought the bike online. Therefore it makes sense to know how to look after your battery to make it last longer.
Factors such as your weight, riding conditions and how you look after it all determine how long an ebike battery lasts. Even weather conditions can play a factor.
- Easy tips to follow include when you’re out riding use the throttle sparingly and where possible use the lowest level of assist.
- When you’re home charge the battery at room temperature.
- Slow charge the battery when you have the time
- Leave the battery for 30 minutes before charging in order to give it a chance to cool down first.
- Don’t let your battery run down to empty before charging.
- Charge your battery regularly. These simple tips will make your eBike battery last longer.
However the advanced method to increase your eBike battery life is by undercharging.
Under charging your lithium battery can extend its life by up to 8 times.
For a deeper explanation read on.
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How Long do eBike Batteries Last?
Today’s eBikes use lithium-ion (Li-ion) batteries, the same type as used in laptops and smartphones.The life expectancy of a lithium battery is measured in cycles.
A charge cycle happens when you use all of the battery’s power.
Using and recharging 100% of battery capacity equals one full charge cycle. A cycle involves discharging the battery by a certain amount eg 70%, 50% 100% and then recharging it to full.
The amount discharged from the battery is known as depth of discharge (DoD). This DoD determines the cycle count of the battery. The smaller the discharge, the longer the battery will last.
Undercharge To Extend eBike Battery Life
According to Battery University if you fully discharge your eBike battery and fully recharge to 100% ie 4.2v per cell, then the life expectancy of that battery is 300 – 500 cycles.
(The inside of an eBike battery is made up of a number of cells ie small 18650 lithium batteries that look like AA batteries each holding around 4.2v. The best brands of battery cells are made by Panasonic, LG and Samsung)
However if you charge your eBike battery to between 85% and 90% ie 4.10v per cell then the life expectancy doubles to between 600 and 1000 cycles.
Finally, if you charge your battery to between 60% and 65% ie 3.90v per cell then the life expectancy is multipled by 8 times to 2400 and 4000 cycles.
So how long do eBike batteries last? Anything from 300 cycles to a whopping 4000 cycles.
Please see table from Battery University below for full details.
This method of charging your battery to below 100% is known as under charging.
In order to make your eBike battery last longer using this method you need a special programmable battery charger like the Cycle Satiator from Grin Technologies.
It is highly flexible and will work with any type of battery including lead acid. You can program what charge rates you want and what percentage to charge to.
Check out the Grin Technologies quick video below which outlines the features of the Cycle Satiator
Now while undercharging your battery increases its life span the downside is that you will get less capacity out of the battery for each charge.
The other problem is that after a while the cells inside your eBike battery can become unbalanced. This means the individual cells start holding different levels of volts. The result is the battery will give you even less capacity.
To resolve this all you have to do is every once in a while fully charge up your battery to 100%. This puts all the cells back into balance.
This functionality is carried out by a circuit board within the eBike battery and is called the Battery Management System or BMS for short. It’s main function is to ensure all the cells are maintained at the same voltage.
Frequently Asked Battery Questions from Newbies
How Long Will an eBike Battery Take To Charge?
On average it takes between 3 to 5 hours for a battery to be fully charged. If the battery is already been used then it should take around 2 hours for it to become 80% full from flat.
How Many times Can I Recharge an eBike Battery?
Depending on the make and manufacturer of the battery it can be anything from about 300 times to 750 times. But we now know that this can be extended massively by undercharging the battery.
That means that the battery can be used for between 15000 and 50000 miles depending on how it is treated.
How Do I Recharge the Battery?
How far can I travel on one charge?
A typical battery should give you around 50 miles on one charge depending on the size of the battery so it can be significantly more or less.
Of course the length of the ride will also depend on what kind of assistance you’ve used with the motor so if you’ve use maximum assist for example you would get less of a range than if you used the minimum assist which is called eco on a lot of eBikes.
How Should I Store My Battery?
If you’re storing for longer than a few days your battery should be left between 30% and 60% of maximum charge. If you leave it at 100% the life expectancy will be reduced. According to Battery University the cells should be between 3.7v to 4.0v for maximum longevity.
So to increase your eBike battery life
- Undercharge your battery to extend it’s life for up to 4000 more cycles
- Avoid 100% discharging except when necessary
- Recharge often
- Use slow charging where possible
- Store your battery with between 50 -70% charge
- Avoid extreme temperatures
- Ride your eBike efficiently especially with a small battery
Last update on 2020-10-26 / Affiliate links / Images from Amazon Product Advertising API