WHILL Model A, User Manual, Page: 38 / 40

Model A User Manual
Page 38 of 40
Battery service or replacement
7.3
The batteries have a life of at least 400 charging cycles. To prevent problems, WHILL recommends battery
replacement once a year. A weak battery or unusually short range per charge may be indicators of battery end of
life. The batteries are designed to be serviced or replaced only by technicians qualified by WHILL. Please do not
attempt to replace the batteries on your own. If you feel that the battery needs replacement, please contact WHILL
customer support.
8. Electromagnetic Interference (EMI)
WHILL Model A may be susceptible to electromagnetic interference - a kind of interfering electromagnetic
energy that is emitted from sources such as radio stations, TV stations, amateur radio (HAM) transmitters, two-
way radios, and cellular phones. The interference from these radio wave sources can cause the wheelchair brakes
to release, or the chair to move by itself or move in unintended directions. It can also permanently damage the
chair’s electronics and controls.
WARNING
•
Electromagnetic Interference (EMI) from external sources can impact braking and control of
the Model A. Unintended brake release or Model A movement could result in serious injury.
To prevent this:
o
DO NOT operate hand-held transceivers (transmitters/receivers), such as citizens
band (CB) radios, or turn on personal communication devices, such as cellular
phones, while the Model A is turned ON;
o
Be aware of nearby transmitters, such as radio or TV stations, and try to avoid
coming close to them;
o
If unintended movement or brake release occurs, turn the powered chair OFF as soon
as it is safe;
o
Be aware that adding accessories or components, or modifying the powered chair
may make it more susceptible to EMI
o
Report all incidents of unintended movement or brake release to WHILL, and note
whether there is a source of EMI nearby.
EMI Sources 8.1
The sources of radiated EMI can be broadly classified into three types:
1. Hand-held compact transceivers (transmitters/receivers) with the antenna mounted directly on
the transmitting unit. Examples include: citizens band (CB) radios, “walkie talkies”, security,
fire and police transceivers, cellular telephones and other personal communication devices.
Note: Some cellular telephones and similar devices transmit signals while they are ON, even when not
being used.
2. Medium-Range mobile transceivers, such as those used in police cars, fire trucks, ambulances
and taxis. These usually have the antenna mounted on the outside of the vehicle.
3. Long-Range transmitters and transceivers, such as commercial broadcast transmitters (radio
and TV broadcast antenna towers) and amateur (HAM) radios.
Note: Other types of hand-held devices, such as cordless phones, laptop computers, AM/FM radios, TV
sets, CD players, cassette players and small appliances such as electric shavers and hair dryers, so far, as we
know, are not likely to cause problems.