Lithium-Ion Battery Information

The battery pack supplied with your wheelchair contains a set of maintenance-free, rechargeable lithium-ion cells with very high energy density. The electronics integrated into the battery pack allows you to use it safely and ensures a long battery life. As lithium-ion batteries have a higher energy density than conventional batteries, they offer a more extended range while being compact and lightweight

The life of a lithium-ion battery pack depends on its age and how much demand is placed on it as well as the number of charge/discharge cycles. The very high energy density of the battery gives your wheelchair a more extended range. The battery continues to age even when it is not in use. Partially charging and discharging the battery will not damage it. However, you should not allow the battery to become fully discharged! To look after your battery pack, charge it regularly.

Charging

First, plug the battery charger’s plug into a power socket. Then connect the charger to the battery pack. Once the batteries have been fully charged, the charge algorithm automatically switches to charge conservation mode. This prevents the cells from being overcharged. The battery pack should be charged at a temperature of around 20 °C. Charging is not possible at temperatures below 0 °C or above 40 °C.

Storage

If you intend to store a battery pack for an extended period, you should first charge or discharge it to a level of at least 60 % and a maximum of 80 %.

Charge the battery pack if necessary before putting it into storage and check the charge level once a month. Recharge it when the charge level falls below 60 %

Store in a dry, cool and well-ventilated place
Do not store a battery pack where it is exposed to direct sunlight or rain
Store in the original packaging
The optimum charge level is 60 – 80 %

What affects the range?

According to the ISO 7176-4 standard, the range is the distance that an electric wheelchair can cover on even ground under constant travel conditions and with a fully charged battery at around 20 °C. Normally, these ideal conditions do not apply to everyday life. Uneven roads, unfavourable wind conditions, hilly terrain etc. cause the wheelchair to consume more power, which consequently reduces its range. The stated range may also be affected by frequent acceleration, braking, steering corrections, the actual topography and other factors. 

Roll Resistance

Roll resistance is a very important factor. For example, if the roll resistance is 6 % instead of 3 %, the range is reduced by half.

The roll resistance can be optimised by the correct tyre pressure. Tip: To maximise the range, use the maximum permissible tyre pressure. 

Slopes

The range is also reduced by half if the wheelchair is climbing a 3 % slope instead of travelling on even terrain. On a 12 % slope, the range is only 1⁄5 of the range which is possible on level terrain. In reality, of course, a journey will always include a combination of upward slopes, downward slopes and level stretches. When going downhill, only some of the generated energy can be fed back to the battery. The maximum possible range can only be achieved with full batteries and full capacity. As a user, you can also increase the range by adapting your driving style.

Weight

The range is affected by the total weight of the wheelchair, baggage and user. Excess weight on the wheelchair, such as backpacks, should be avoided as much as possible. 

Wheelchair geometry and dimensions

The l camber incline, wheelbase, diameter of the front castor wheels, front/rear load distribution and left/right wheel alignment also have a significant effect on a wheelchair’s roll resistance.

Ideal conditions:
0° wheel camber incline
Front/rear load distribution of 20:80
Symmetrical wheel alignment Long wheelbase
Front wheels as large as possible with solid rubber tyre

Temperature

The battery performance decreases as the temperature falls because the electrical resistance is increased. Therefore in winter, the usual range is likely to be reduced.

Starting and Braking

As with a car, frequent start and stop, steering and braking are less economical than continually driving at the same speed.