Electric footpath scooters (sometimes called Gophers, buggies or motorised scooters in Australia) are powered by batteries. They are a simple vehicle with few working parts, requiring a relatively low level of maintenance. Mobility scooters come in three or four wheel versions and are primarily designed for use on footpaths or the golf course.
In general, electric scooters have a maximum speed of less than 10 kph (the most common maximum speed allowed by Sate government regulations for a mobility scooter). They are activated by a simple throttle, operated by the fingers, which controls both speed and braking. Steering is via a variety of types of handlebars that operate in a similar fashion to push bikes or motor bikes. They come with varying equipment levels, from twin headlights, blinkers, “bull bars”, even independent suspension, down to basic machines with simple controls.
Batteries in mobility scooters are not like car batteries in that they are a deep cycle battery. These batteries are rated in Amp Hours - ie how many hours a battery will run when one amp is drawn in power. This rating will determine (along with the efficiency of the motor) the range an electric mobility scooter will travel between charges. The higher the rating, the longer the scooter will run, given similar conditions. Hills and weight load, as well as the surface and the age of the batteries will have an effect on range.
Dry cell batteries come in two basic types: Sealed Lead Acid (SLA’s) and Gel Acid. Both types are maintenance free. SLA’s are cheaper than Gel batteries, but Gel batteries have a longer life.
Almost all mobility scooters use either 12 volt or 24 volt motor. Usually if there are two motors, they are 12 volt in series; if there is one motor it will be 24 volts. There are different ways of rating the power of a motor. Most manufacturers rate their motors in continuous watts - usually over a period of 30 minutes. A few manufacturers use a different method, sometimes called “stalled” or "maximum" power. This usually gives a power rating of about 2 - 2.5 times the method using a continuous rating. Comparing one scooter’s power with another is therefore not easy if you don’t know whether the watts are quoted as a continuous rating or not. In general, most scooters draw between 300 and 600 watts of continuous power. One horsepower is 745 watts. The more watts drawn - ie power used - the less distance the scooter will travel on a given battery rating. There is a growing trend, however, for manufacturers to rate electric scooters with the "maximum" rating rather than the continuous method becuase it looks better on the specifications sheets.
To give you a basic idea of power, a large electric golf cart (that weighs 350 kg unladen and takes a payload of two people + golf clubs, and travels on grass at 20 kph) has between 2 and 3 horsepower - continuous. A mobility scooter weighs between 55 - 80kg.
Most importantly, the actual pulling power of a mobility scooter is determined by both the power of the motor and the type and power of the electronic controller (see section on electronics below). It a little like cars: a big engine is not the only thing that determines power - the fuel delivery system is also important and a turbo will deliver a lot more power to the same size motor. The more brushes a motor has, the more current that can be delivered at any one instant. So 4 brushes is better than 2.
1. Gear box differentials
In general, differential drives are expensive to produce and are mostly available in higher volume scooters or because a manufacturer has outsourced the component. These are the most reliable drive, and most resemble a motor car. Mobility scooters with these types of transmission are the most common. Mobility scooter brands such as Merits, Monarch, Afikim, Shoprider, Pride, ActiveCare, Invacare, CTM, all use this type of transmission
2. Chain and belt drives
These are less popular than when scooters were first developed (eg the earlier Australian made Gopher mobility scooter) - sometimes they require more maintenance than gear boxes, especially in adjustments caused by stretching or breaking. Very few modern scooters use chain drives. The Walkabout scooter, now no longer made, uses belts to drive the two rear wheels.
3. Other gear systems
Several scooter manufacturers who cannot afford a differential gear box (similar to motor cars) may opt for two motors. They use various methods of getting the power to the wheels like chain or belts, but mostly two gear boxes that use either helical gears (stronger but noisier) or worm gears (quieter but not as strong). In addition, a few mobility scooter manufacturers use front wheel drive for their drive system, but generally traction is not good enough for anything but flat areas and indoors – eg Afikim Superlight and some other lightweight mobility scooters. Some golf buggies use worm drive gearboxes.
In the early days of scooters braking was done manually - the early Gophers worked this way. However, all modern mobility scooters use regenerative braking as their main method of slowing down or holding a speed on a downhill slope. Here, the motor simply turns into a generator and recharges the batteries (at about 20% of the rate it uses when on a flat), and this generating function turns the motor into a brake at the same time. This is what most mobility scooter manufacturers refer to as “automatic braking”.
This refers to the parking brake that is automatically engaged when the scooter is either stopped or nearly stopped. It works by preventing the motor from turning. To free wheel a scooter, either this brake must be disengaged - usually by activating a switch, or by putting the scooter into the neutral gear (if it has a gear box). You can hear the electromagnetic brake disengage just after you start to activate the throttle as the electronic controller sends the signal to disengage the park brake.
Although not necessary, some scooters have a third braking system - some kind of manually operated brake. Sometimes this is simply a “billy cart” style brake that rubs on the tyre (eg the older Gopher scooters), but more common is a more sophisticated system that works on the axle - eg drum brakes or disc brakes - activated by a brake handle on the handle bars. Scooters sold in Europe are required to have some kind of manual "emergency" brake to comply with the tough European standards. Scooters like the Merits Cruizer or the Royales already have this option fitted.
Electric Mobility Scooters are battery powered. To charge the two batteries, the scooters either have an inbuilt charger or a separate charger. These two methods have different advantages. “On board” chargers allow the owner to take the scooter on holidays without having to take a separate charger with them. Separate chargers however, have the advantage of keeping the weight of the scooter down, are less likely to break down because they are not subject to vibration, and if they do fail, the scooter doesn’t have to be immobilised while the charger is repaired - a new charger can be quickly substituted without disruption.
Wet cell batteries are less fussy and therefore can be charged with a cheap charger - usually 12 volt in series. Dry cell batteries need a more accurate charger and usually come in a 24 volt 4 amp configuration. When higher amp hour batteries are used it is advisable to use a 6-8 amp charger. Most “smart” chargers are automatic and either cut out altogether when the battery is charged, or drop to a “trickle” or “float” charge (about 200-300 milli-amps). The second method is preferable as this will keep the battery at 100% until the scooter is used.
Charging the batteries properly produces a longer life and better range. Whenever an electric scooter is used it is important to charge the scooter within 12 hours. Leaving scooter batteries in a discharged or partially charged state diminishes the life of the battery. “Smart” chargers can be left on for extended periods, even after the batteries are charged. In fact it is better to leave the charger on for at least 2 hours after the “charged” light comes on. It is also important that once the charger is turned off it is disconnected from the scooter, otherwise some current drainage may occur, leaving the batteries at less than 100%.
Charging scooters overseas
Most mobility scooter chargers use switch mode, which means that they can be used in the USA and on cruise liners (where voltage is only 110 volts). Some chargers automatically detect the voltage and adjust themselves, while others have a switch where you can choose the appropriate voltage. Most countries are either 220 or 240 volt and the charger will work normally. If in doubt, take your charger to your nearest dealer to have it checked.
Most electric gophers or electric scooters (sometimes called electric buggies), use dry cell cyclic batteries. These are either Sealed Lead Acid (SLA), or Gell based sealed batteries. It is important that only cyclic batteries are used. Some battery sellers try to pass off general use batteries as suitable for electric scooters, but they will have a very short life span as they are not designed for electric vehicle use. Poor battery selection can lead to plenty of problems down the track, especially if they are at the budget end of the market.
SLA batteries are cheaper than Gel batteries. There are also some new batteries slowly entering the market that are phosphorous based, and some Gel batteries are really a hybrid battery somewhere between the SLA and true Gel battery. There is also experimentation with new types of terminals that seem to extend the life of the battery. It is also important to match the batteries with the correct charger to achieve a long battery life.
Please note that any quoted "range" is an estimate only. Like car manufacturers who quote ideal fuel consumption figures, scooter range is quoted in ideal situations which may not be replicated in the field. Battery performance, and hence scooter range, is determined by many factors and we make no guarantee as to the ability of the battery to perform to expectations.
If your batteries do not allow for a range that you are expecting or need, please talk to our representatives who may be able to suggest alternatives.
All modern mobility scooters have a “black box” - ie a sophisticated electronic controller. These control the speed of the scooter (no matter how heavy the payload), the acceleration and braking rates, and apply the parking brake. They also have a major impact on the power of the scooter, depending on the ampere rating of the controller and the amount of current the controller feeds to the motor.
Two identical motors can perform very differently when controlled by different electronic controllers. The controller is like a fuel delivery system on a car - a turbo produces more power than a carburettor for the same size motor. The scooter's electronic controller delivers the fuel (current) to the motor. The bigger the amp rating of the controller, the more current can be delivered to the motor - and the more power the motor delivers to the wheels. So always check the rating on the controller as this will give a better indicatioin of power.
There are a small number of major controller manufacturers in the world - Curtis (made in U.S.A.), Dynamic (made in N.Z.), P&G (UK) are three of the more well known. Some mobility scooter manufacturers use their own controller or a locally made one. When a controller malfunctions it is expensive to repair and is usually discarded for a new one (it is usually cheaper if the controller is one of the more common ones). Some controllers are programmable to alter speed, acceleration and deceleration rates and other variables. Some controllers also turn the scooter off when it is left unattended for a period of time (“sleep” mode). Care must be taken when connecting batteries or plugs so that no electrical short is caused, thus damaging the controller.
Motorised scooters for the elderly have some sort of finger accelerator to activate the electronics and consequently the motor and brakes. These controls work a potentiometer that gives an infinitely variable speed. These are either of the Wig-Wag style (Merits, Monarch, ActiveCare, Pride, Shoprider, Invacare, CTM, etc)- where the forward and reverse function is operated by the one lever that is operated by either hand - or by using a switch to determine forward and reverse and operating the accelerator with the same action by the same hand (eg Afikim, Walkabout, and Monarch mobility scooters). Some accelerators are operated by the thumbs, others by the fingers (eg Plega, Merits, Avanti, Pride, and some Shoprider scooters). A few operate with either.
There is usually some sort of “cruise control” that sets the maximum speed that the accelerator can activate. This may be in the form of a knob or a switch, or some form of touch button system. There may be indicator and light switches and a brake lever for manual emergency brakes. The Monarch Royales have a sophisticated dash board that gives accurate speed and distance measurements and other information such as battery life, indicator and light status, even the time and the temperature!
Lots of claims are made about suspension. But there is a huge variation in the quality. Some claim that the scooter has suspension "all round", but in many cases, the front suspensions on some four wheelers is fake - it's not really suspension at all. Some scooters merely have two springs inserted into each side of the swinging arm axle. This provides no more suspension than if the springs weren't even there! Only independent suspension on the front of a four wheeler is true suspension and gives a softer ride. Telescopic forks are the only true suspension for a three wheeler's front wheel.
On the rear, some scooters merely have a spring on each side with no shock absorber. Again, while it is a form of suspension, it's a bit of a cheap shortcut and is inferior to suspension with shock absorbers. Some shock absorbers are adjustable to cater for the different weights of the user. Ask your supplier to show you the actual shock absorbers inside the springs - it's easy for you to see.
Some scooters have double springs at the rear and some have a single mono shock absorber. Both will do the job. But the real test is how much "travel" the springs have - the more the spring compresses the more the shock will be absorbed.