Safety first !
Without the protective resistors it would be hazardous to touch the measuring
leads, However, with the resistors the current will be limited to a save
Batscan was developed taking highest possible safety into
primary requirement for a Battery Monitoring System was safety. First,
the system could not pose any hazard to a person coming in touch with
any parts of it. Second, a short-circuit must not result in heat release
or spark formation. Batscan complies with these requirements due to the
fact that all connections to batteries are done through high value resistors
which limits short-circuit current to less than 1mA.
"Foolproof is not enough, it must be idiot-friendly."
There are several reasons for using a protective resistor:
- Rules and engineering practice states that electrical wires must be dimensioned
to support the highest possible short-circuit current derived from
the source they are connected to.
- In a room full of batteries the environment is corrosive. Sooner or
later this will affect connecting cables.
- It is unreasonable assuming any Battery Monitoring System is never
replaced or modified. Therefore it should never be hazardous to
touch any part of the system.
- Although small, there is always a risk that a cable is touched by a closing
link with a different potential. With the protective resistor there
is no hazard. However, without a protective resistor a short-circuit
will immediately burn up the cable. This could start the automatic
fire-control system or in worst-case lead to an explosion.
Of all requirements
one has on a Battery Monitoring System the protective resistor has to
be number one. After all, it is far more important that the system is
safe than anything else.