Husqvarna Automower 420 Technical Manual page 57

5. REPAIR INSTRUCTIONS
5.1.4 Magnets for sensors
There are 4 magnets in the body, one for each
collision sensor and one for each lift sensor. The
magnets have a south and a north pole. It is im-
portant that the magnets are fitted correctly. If they
are not fitted correctly the collision or lift sensor
will transmit a constant signal.
The magnets only need to be removed in ex-
ceptional cases and if this is necessary it is very
important to mark them so that they are refitted
correctly.
5.1.5 Cabling
The various electrical components (e.g. circuit
boards, sensors and motors) are connected to
each other by various types of cables. The con-
nectors on the circuit boards are marked with text
in English that describes which cable is to be con-
nected.
There are a number of points on the chassis to
which the cables can be attached with cable ties.
We recommend that these fixing points are used
at all times. It produces a safer installation and
reinforces the intuitive feel for where the cable
should be connected.
5.1.6 Battery
The robotic lawnmower is equipped with special
Li-Ion batteries. The battery is maintenance-free,
but has a limited life span. The battery is expected
to last for 3,000-4,000 charging cycles.
The battery is specially adapted to minimize dis-
turbance to the loop sensors and is equipped with
additional overload protection. Use only original
batteries from Husqvarna. The battery must not be
mixed up with similar batteries used for instance
with other GARDENA lawn care products.
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