Overview
The electric bike battery is one of the highest cost components of any electric bike and is often a major cause of anxiety for customers. The concern for many is twofold, how long will it last, and how much will it cost me to replace? To further complicate matters, it can be hard to calculate battery life as it can vary drastically from customer to customer.
For second hand ebike riders, or riders with older ebike models it can become a major source of frustration when a battery model is not known. This can lead to endless calls to try and locate a compatible battery model, which may not fit, and in most cases no ability to try before buying. Knowing what battery will be compatible is a minefield when purchasing from a third-party supplier and an expensive exercise if the incorrect model is purchased.
So, is it worth the extra upfront cost of buying a second-hand battery? The answer will depend on your individual circumstances and your desired outcome from riding. Before we dive into this question it is important to first understand what sort of range you currently achieve.
Calculating your ebike range
The terrain, travelling speed, pedal assist setting, tyre pressure, weight, and most most importantly the model of both bike and battery are all factors in determining your range. Other factors like the age of the battery and outside temperature can also have an impact. It's not uncommon for riders with the same bike and battery to get different ranges from their bikes.
With so many variables, you will always be working off a rough guide rather than an exact range, but how can you make that educated guess?
How to estimate your ebike range
First you need to calculate the battery capacity. This is expressed in Watt hours (Wh). This is calculated by multiplying the volts by the amp hours. i.e., 48V 10Ah battery would equal 480-Watt hours.
Next you need to calculate the efficiency range by dividing the watt hour capacity by the average efficiency number. This is where the key battery draining factors come into play but for simplicity, we will base the range on 3 general efficiencies.
Full power range would be for hilly terrain using high pedal assist settings which will drain the battery quickly, mid-range would be using pedal-assist on medium setting and low power range would be pushing it to the extreme with no more than the lowest pedal assist setting with less hills and more downhill flat terrain.
Estimated range chart
Here is a guide to estimated range based on average speed of 18km/h for 250W motor. Note that most riders will tend to operate in the medium power range. Most ranges are based on lighter riders (around 70kg). If you weigh closer to 90-100kg you would need to reduce the range by 20%. Conversely if you are lighter say 45-50kg then you could extend the range by around 20%.
Estimated battery range*
|
Battery capacity (V x Ah) = Wh |
Full power range 15Wh/km |
Medium power range 10Wh/km |
Low power range 5Kwh/km |
|
360-Watt hours |
360/15 = 24km |
360/10 = 36km |
360/5 = 72km |
|
400-Watt hours |
400/15 = 26.6km |
400/10 = 40km |
400/5 = 80km |
|
480-Watt hours |
480/15 = 32km |
480/10 = 48km |
480/5 = 96km |
|
600-Watt hours |
600/15 = 40km |
600/10 = 60km |
600/5 = 120km |
*These ranges are estimates and should be used as a guide only
Is pedalling an option when you run out of battery power?
We are looking for a best of both worlds option here. Yes, an ebike is a bike first and foremost albeit with a battery and motor that provides power and assistance. Well, depending on the weight of the ebike and the level of resistance you face when pedalling without pedal assistance on it is possible but for most models over 25kg it is extremely difficult when riding uphill. Put another way it is best to try and understand the range of your bike by running some tests based on how you normally ride and then try and not find out how difficult it is to ride without the motor over any great distance.
I have ridden a 25kg ebike over 10km without pedal assistance including hill climbs and whilst it was possible it is fair to say it wasn’t all that pleasurable. Sure, I got a great workout, but I probably wouldn’t recommend it as a fun way to get exercise!
So then is it worth buying a second battery?
If most of your riding is done locally and you don't have a huge distance to cover to get home, then it might make sense to just run off one battery and accept a little extra effort to get home should you miscalculate your range. If riding takes you further and you have a long commute, or you're ambitious with your day rides, a second battery is a good idea.
So if you're calculating whether carrying another battery is a good solution, you need to look at the current battery range against how you currently rider you ebike. Also, consider whether you're likely to carry on riding in the same way, or add more distance or ride harder terrain in the future. If things are likely to change, it might make sense to get an extra battery early so you can take full advantage of it.
Open new riding possibilities by extending your bike range
Another thing to consider is what possibilities longer battery life can create for you. As ebikes become more popular, their potential is starting to be understood. There are people using them for a wide range of purposes, including a replacement for cars for commuting, errands, and even couriers and food delivery services.
With a greater range comes greater opportunities to ride. Long bike trials, adventure holidays, scenic rides through the forest or along bike tracks all become less restrictive when you don’t have to be concerned with a limited range. With the additional riding distance comes the added enjoyment and improvement to your fitness and ultimately your riding ability.
Is it better to upgrade your battery or have a second battery?
Instead of buying a second battery, there is an option to simply replace your existing one with a model with extra range. There are however a few things to consider.
All batteries will lose the capacity to retain their power based on how many times they have been charged. A lot of brands specify around 60% retention of charge after 500 charges. If you have a second battery, you can alternate between them and extend the life by double. This wouldn't be the case with just one.
Another benefit of switching batteries is if there is an issue with one, you will always have a spare. You can also charge one battery while using the other. You can even leave on at another location, like the office, or a friend's house, to be swapped over when the need arises.
Just remember that if you carry the second battery this will have to be stored safely somewhere. Some bikes allow 2 batteries to be mounted to the bike, but this will increase the bikes weight (reducing battery range). Most batteries weigh anywhere from 1-4kg depending on the brand and model.
Another consideration is that batteries can be a popular target for thieves. If you are storing them in a bag or front or rear basket it is best not to leave them with the bike for any extended period as the likelihood of them being stolen is greatly increased. With ebike’s that allow a second battery this can be locked. For any bike left for an extended period it is probably safest to carry the battery with you in a bag rather than leave it unattended.
A couple of warnings with battery backpacks
Whilst it is tempting to repurpose your own backpack you should remember what is contained in an ebike battery. Lithium-ion batteries are classified as dangerous goods so should be treated with the utmost respect. It is important that the bag is waterproof and provides adequate protection and comfort to ensure a comfortable and safe ride. Also, remember that not every battery fits in every backpack. Some batteries are extremely big and may not fit in smaller backpacks. If the backpack comes with a battery compartment, make sure you understand your battery dimensions and that if the bag you choose to buy.
The key things to look out for are:
Correct fit – centre of gravity is as close to the body as possible; this is the most crucial element of your backpack as you don’t want it sliding up and down or inhibiting you riding
- Compartments – places to separate hydration from sharp objects from batteries, this is to ensure a neat and tidy space
- Durability – It must be able to withstand sweat, dust, mud, moisture, sun, and the occasional crash at times.
- Comfort – Good padding, shoulder, hip, and chest straps are vital to reduce strain and ensure the backpack is secure to your body.
Conclusion
A second battery can be a great option if you want to branch out and start expanding your ebike riding adventures. Yes, it isn’t cheap but even if you just own a second battery as a spare you can at least have the option of extending your range as and when you need to open another world of riding adventures. Sometimes we don’t know the fun we can have until we open our minds, take a risk and step into the unknown.
