Which battery position?

The battery of an e-bike supplies power to the motor. However, the battery also adds weight to the e-bike. Together with the motor and other items, the battery means that an e-bike is six kilos heavier on average than an ordinary bike. This extra weight affects the balance and the centre of gravity of the bike. Depending on the type of e-bike, the battery is fitted under the luggage or front carrier, around the bottom bracket or in/on the frame. Accordingly, it holds that: the lower the battery is positioned on the bike, the more stable the handling. You have a choice of four different positions.

Battery under the luggage carrier

Many e-bikes are equipped with a battery under the luggage carrier. It endows front-wheel motor e-bikes with optimum balance. In the other e-bikes it means that the centre of gravity is towards the rear of the bike.

Advantages

  • Easily concealed by fitting bike bags 
  • The centre of gravity is towards the rear end and on front-wheel motor bikes it is in the middle 
  • The battery is simple to fit and remove

Disadvantages

  • Not all types of bike bag can be fitted on the luggage carrier 
  • The centre of gravity is high, which can affect the stability of the luggage carrier 
 

Battery around the bottom bracket

An e-bike battery can be incorporated in the chain case. This makes the bike barely distinguishable from a 'normal' bike. If the battery is incorporated behind the bottom bracket, it will be quite visible. The centre of gravity is positioned centrally, which gives the bike stable handling.

Advantages

  • The bike is barely recognisable as an e-bike 
  • The centre of gravity is lower 
  • The e-bike boasts more stable handling

Disadvantages

  • Not all battery variants are removable 
  • The chain case does not have much space available, which means that battery capacity is very limited 
  • If the battery is fitted above or behind the bottom bracket, it will have a significant impact on the appearance of the bike

Battery in or on the frame

E-bikes with the battery in or on the frame have the centre of gravity in the middle of the bike. This gives the bike stable handling and due to the positioning of the motor is barely recognisable as an e-bike.

Advantages

  • The centre of gravity is lower 
  • The e-bike handles with greater stability 
  • In the frame: the bike is barely recognisable as an e-bike

Disadvantages

  • On the frame: the battery can be in the way 
  • Not all integrated batteries are removable, in which case charging can be an awkward operation
 

Battery under the front carrier

If the bike is fitted with a front carrier, the battery can be fitted under this carrier. This added weight is quite noticeable when steering.

Advantage

  • Easily concealed by fitting a bike crate or basket

Disadvantage

  • Steering feels heavier due to the extra weight over the front wheel

Fixed or removable battery?

An e-bike battery is rechargeable and needs to be recharged regularly in use. You have a choice of two options.

Removable battery

If you want flexibility when charging the battery, then your preference will be for a removable battery. The battery is actually supplied with a charger that can be plugged into any mains socket. You simply remove the battery from the e-bike and recharge it at the nearest mains socket. Do you take your bike on a bike carrier regularly? If so, a removable battery is desirable. An e-bike is quite a bit lighter without its battery and easier to lift onto the carrier.

Advantages

  • The battery is easy to remove, for charging or in extremely cold weather, for example 
  • The battery is easy to replace (on the go as well, with a spare battery) 
  • The battery can be recharged easily from any mains socket

Fixed battery

If you want your battery to be well protected, then your preference will be for a fixed battery. The bike will need to be close to a mains socket in order to be able to recharge the battery.

Advantage

  • The battery will be protected by the frame

Disadvantages

  • The battery can only be replaced by a specialist (bike repair technician) 
  • The bike must be capable of being positioned close to a mains socket in order to recharge the battery 
  • The bike needs to be protected against extremes of hot or cold weather

Which type of battery?

The battery powers the motor on an e-bike. The type of battery, like the range, will have an impact on the distance you can travel on your e-bike. There are five different types of battery, four of which are still available on new e-bikes. You will only come across the NiCad, short for nickel-cadmium, type on second-hand e-bikes.

NiMH (nickel metal hydride)

The NiMH battery is the successor to the NiCad battery and is the current standard in Europe. This type of battery requires regular charging, even if the e-bike is not being used (for an extended period). The battery must be left connected to the charger at all times. The charger thus ensures that the battery is kept in optimum condition. Allow 4 to 6 hours' charging time for this type of battery.

Advantage

  • These batteries are less expensive than other types of battery

Disadvantages

  • The useful life of these batteries is shorter than those using Lithium technology 
  • They have a relatively high rate of self-discharge 
  • They are larger and heavier than other types of battery 
  • They are less able to withstand temperature fluctuations 
  • They need to be left connected to the charger

Li-ion (lithium-ion)

Lithium-ion is known as the generic term for the many batteries containing lithium. This type of battery has a low self-discharge rate and a long(er) useful life. This is offset by the fact that the price of this type of battery is higher.

Advantages

  • These batteries are small in size 
  • They need just 2 to 3.5 hours to be fully recharged 
  • They are well able to withstand temperature fluctuations 
  • They have a relatively low rate of self-discharge 
  • They do not need to be connected to the charger continuously 
  • They offer the best value in terms of performance versus cost

Disadvantage

  • These batteries carry a higher price tag than a NiMH battery

LiPo (Lithium Polymer)

The LiPo battery is one of the better batteries in the Li-ion range. This battery is even smaller than the average Li-ion battery. If the e-bike is not being used for an extended period, it is recommended that this battery should be stored with a 40% charge (preferably in a cool environment).

Advantages

  • Rapid charging, a completely discharged battery can be recharged in 1 to 1.5 hours 
  • This battery is lightweight and boasts a long(er) useful life 
  • It has a relatively low rate of self-discharge

Disadvantage

  • This battery is priced higher than other types with limited advantages

LiFePO4 (lithium-iron-phosphate)

The latest generation of batteries bears the name LiFePO4 (or a derivative of it; LP4, LFP, LFP4). This battery is improved on all fronts which makes it the pick of the crop. However, it is priced accordingly. If you work it out, acquiring an e-bike fitted with a LiFePO4 battery is worth considering, given that the battery will last longer and is less likely to need replacing before the bike itself is due for replacement. There is only a limited range of e-bikes equipped with this type of battery at present. This range will be expanded in the future.


Advantages

  • This battery has a longer useful life that NiMH or Li-ion batteries 
  • Rapid charging 
  • This battery is light in weight 
  • It has a low rate of self-discharge

Disadvantage

  • This battery is priced considerably higher than other types of battery