The 101 for Ebike Batteries

What you need to know & what you can ignore (like this very simplified article if you are an ebike battery expert).

Looking for the ultimate ebike or eMTB experience? We understand the desire for a hassle-free conversion kit that seamlessly integrates with your bike frame without the complexity of navigating through the intricate technical details or an expert-level understanding of mechanics and electronics.

Although you can do this for a lot of motors out there, the same can't be said when it comes to batteries. You need to be able to make an informed decision because if you don't, this could happen to you:

• Emptying your battery in the middle of your ride

• Overloading yourself with huge and unnecessary load

• Not maximizing the full power of the motor's rated power

The aim is to find a balance between the distance and power output you want to achieve while ensuring the size and weight of your ebike battery are suitable for you at the same time.

So, how do we reach this perfect balance? There are some technical specifications from ebike battery suppliers you'll need to look at.

Your battery's specifications probably look like this (if not even more detailed):

52v 21ah 14s6p

1100 watt hours

50amp continuous BMS

There are 4 aspects that you need to consider here

- the voltage (52V)

- the capacity (21ah)

- the watt hour (1100)

- the continuous current drawn (50amp)

Don't worry about the "14s6p" for now.

It's important to have an idea of how each aspect will affect your ebike conversion kit's performance. So, let's have a look.

What's the mileage looking like?

Your range will mainly depend on 2 factors: the capacity (ah) and the watt hours (wh). But here's the tricky part, there is no fixed formula to calculate your range since no 2 riders are the same, no 2 bikes are the same, no 2 setups are the same, and no 2 trails are the same.

The rule of thumb >> higher capacity means longer range!

But what does "watt hour" have to do with anything then? When you multiply your voltage by your capacity, you get watt hours. Watt hours are what we use to determine your range. Since there is no fixed calculation here's an idea:

A 36V battery, for example, may or may not have a very long range. If this battery has a capacity of 8ah, then 36V x 8ah = 288wh. This is not much. On the other hand, if this battery had a capacity of 21ah, which gives you 756wh, then you're looking at decent mileage.

This only tells us how to read the numbers though. It doesn't give us any idea of how far we can go. Luckily, based on our experience and user feedback, you can expect the following from our high-powered motors:

15wh per mile or 9wh per km using pedal assist only 30wh per mile or 18wh per km using throttle only

It's obvious to assume that the less power you use, the more range you can expect. If you're riding according to your region's legal limits (usually 250W only) then you can expect at least double the range.

So in our example, if you are only using pedal assist, the 36V 8ah (288wh) battery will give us approx. 19 miles or 31km. Whereas the 36V 21ah (756wh) battery will give us approx. 50 miles or 81km.

Don't hold us to this number though. Like we said before, this will differ significantly for each rider. If your kit has a throttle or if you have a good relationship with that turbo button, then you might want to consider keeping a spare battery for those cross-country rides. At least you can still pedal with a dead battery but that's not a point any of us wants to reach.

OK, so we got the distance down. What about the power?

Higher voltage means more POWER! Right? Not necessarily but it does mean a higher top end.

A higher battery voltage will give you a higher top speed because the higher the voltage, the higher the maximum motor RPM. The important thing to note here is that just because 2 batteries have the same voltage & can go up to the same speed, doesn't mean that they output the same power. It might take one 52V battery 5 seconds to reach 25km/h yet for another 52V, it might take 30 seconds to reach 25km/h.

To put this into perspective, you can have a 72V battery that can output only 2200W or you can have a 72V battery that can output 5800W. The difference? The continuous current rating. The former battery is rated at 30A continuous, while the latter is rated at 80A continuous. Note that your continuous current can be limited by your ebike kit's controller. It doesn't help you get an 80A continuous current battery when your kit's controller is limited to only 50A. This, in most cases, won't do any damage to your kit, but it means that your battery is bigger (& heavier) than it needs to be.

Our advice: Look at your kit's controller 1st. What is the continuous current rating? Then, look at the motor's rated power. Now, work out the specs you need by multiplying the continuous current with the voltage. Does it give you your motor's rated power?

Now what's the catch?

The catch is that there is usually a trade-off between these factors. This is where the size & weight of your battery comes in.

It's very important to consider how much physical space you have available to mount your battery as well as how much weight you want to add because the battery nowadays weighs more than the motor! Take the CYC A-52 Battery for example. The A-52 has the following specifications:

52v 10ah 14s2p

520 watt hours

50 amp continuous BMS

The A-52 battery is capable of delivering a continuous output of up to 2600W, a very good battery for our CYC high-powered motors like the X1 Pro Gen 4. That said, as it has 520Wh which is good enough for most uses, it may fall short for longer journeys like an 80km trip.

The reason for this is that if the battery capacity was higher, it would mean the physical size of the battery would need to be bigger- making it unable to fit inside the bike triangle in most full-suspension bikes.

On the other hand, if your goal is to increase the range while maintaining your current physical size, you will need to decrease the continuous current rating. This would ultimately mean decreasing the kit's overall power to accelerate. This is why it's crucial to have a clear understanding of your power requirements, and desired range, and consider the available space on your bike frame.

By considering these factors, you can make an informed decision that aligns with your specific needs and achieve your desired riding style.

There's a whole more when it comes to batteries than this article but we're not going to go dive deeper into specific things like cell types, BMS, chargers, or battery health here. You can read about it in our other battery blogs.

So, there you have it! An idea of how to understand the main numbers of ebike batteries' technical specifications and get a ballpark of what battery specifications you need for your brand new ebike conversion kit.

Purchase our newly launched A-Series ebike battery packs here.