Buying an electric bike battery (also known as an E-Bike) is never as easy as it looks. There are many battery types and on top of that, some electric bikes cant even use specific types of batteries! Before starting your shopping process, you should be aware of a few things. This includes, but not limited to, understanding the battery’s voltage rating, charge capacity, maximum range, as well as replacement cost and, most importantly, the battery system itself.
Basic Bicycle Battery Information – Crash Course
Before shopping for an electric bicycle battery, here is a crash course on what you should look out for:
In the E-Bike world, voltage rating in electric bicycles is equivalent to horsepower in automobiles. The higher the voltage, the faster the bicycle could go. Most electric bike batteries fall between the range of 24V, 36V, 48V, and 72V. Occasionally there may be batteries with a higher voltage than 72V, but those are not very common and significantly more expensive. The general range is between 24V and 48V, with 36V being the most common.
When shopping around, make sure to look at the power output rating (in Watts) of your battery. In the United States, anything above 750 Watts and capable of going faster than 20 mph (roughly 32 km/h) is considered a moped and will require additional registration, insurance, and a license plate. It is a burden, but who doesn’t like speed right?
Protip: When installing electric bike batteries, be careful to never touch the tip of the connectors. Your fingers are conductive, and electric shocks can (and do) occur. If your battery is strong enough, a shock of 20 mA (milliamperes) through the heart can be extremely dangerous, if not lethal.
Another thing to pay special attention to is the electronic controller. The electronic controller is fed with sensor input, and in turn dictate functions to regulate the power of the motor as well as speed.
If regenerative braking is installed, the controller also provides assistance to that. The electronic controller is important because the controller’s commands directly correlate with the performance of your electric bike.
When it comes to range, the ampere hour (Ah) rating of your battery is usually the first to look at. In automobile terms again, the ampere hour (Ah) rating of the battery is equivalent to the gas tank size of your car. The more Ah you got (and the bigger the gas tank), the more miles you can run. Because there are many other things to consider when it comes to mpg (miles per gallon – miles per Ah?), solely looking at the Ah rating may not always be the best choice. In addition to the fact that same numbers from different manufactures can mean different things, it is best to consult customer reviews before deciding for yourself.
Electric Bike Range and Influences
The range of electric bicycles is affected by a variety of factors, including:
- Ampere-Hour rating
- Battery system type
- Power assist settings and throttle variations
- Motor efficiency
- Terrain slope
- Weight load
- Tire pressure
- Lubrication of chains (never use WD-40 on your roller chains!)
There are many types of battery systems available for electric bicycles. Sealed lead-acid (SLA), lithium-ion polymer (Li-ion), and nickel-metal hydride (NiMH) are the most common, followed by lithium-iron phosphate (LiFePO4) and nickel-cadmium (NiCad). Each has their own characteristics and advantages, as well as weaknesses and disadvantages.
If you are looking for better range though, high capacity batteries like lithium-ion is what you need. Among the types, lithium-ion offers the most range and recharge cycles, but is also the most expensive. Sealed lead acid (SLA) batteries, on the other hand, are the cheapest and most common. They are quite heavy, however, and are generally lower quality.
The rest of the list is slightly more self-explanatory. The bigger the slope, the harder the motor will be running at. Same goes for weight. If tire pressure is lower than normal, there will be more friction (but more traction) and thus lower range.
Electric Bike Battery Life, Costs, and Other Factors
When it comes to cost and pricing, lithium batteries like mentioned earlier are the most expensive. Be ready to shell out anything between $1000 to $2500 if you are shopping for them. On the good side, lithium-ion batteries have the longest battery life and due to their extended recharge cycles, may eventually even cost you less in the long run.
In our experience when buying bicycle batteries, we noticed that different brands can vary greatly in quality against others. A 30 miles range for one manufacture could mean 20 miles for another. Thus, we only recommend buying from brand names or from those with exceptionally high reviews. In the case of lithium ion batteries, please know that there is always the extreme possibility of overheating and fire for the battery. Standard plastic casings will not contain the fire, and you will be better of with metal enclosures. However, we have personally not seen a fire outbreak before, so we cannot really guarantee that metal enclosures will help contain the fire. What we do know is that metal casings provide better protection than standard plastic casings, and would thus do a better job at preventing deformation and penetrations.
A last pointer to mention is that at the current time of writing, there are no testing specifications or standards for an electric bike battery. Without reading third party reviews, comparing manufacturer battery specifications might not be very helpful at all.
If you have any questions, please comment on the comments section below!