9
♦
Disable the ignition; crank the engine for 15 seconds.
Check the Min. reading. If this reads less than 9.60 V at 21ºC, the battery is
weak. Recharge or replace before further testing.
F-1860 Minimum reading
Ambience temperature
10.0 V
33ºC
9.8 V
27ºC
9.6 V
21ºC
9.4 V
16ºC
9.2 V
10ºC
9.0 V
4º C
8.8 V
-1ºC
8.6 V
-7ºC
NOTE:
For each 6ºC above or below 21ºC, add or subtract 0.2 V.
Voltage Drop Testing
Resistance; what is it?
Resistance is an opposing force to the flow of electrical current, created by a
circuit or component.
A small amount of natural resistance is encountered when voltage flows through
wires, switches, grounds, or connections. This resistance increases beyond
acceptable limits if corrosion develops, fittings become loose or wires fray.
Resistance increases every time that something is added to the circuit, such as
wire, switches, connections, ground, etc.
Voltage Drop; what is it?
Voltage drop is the difference in voltage potential when measured across a
circuit or component creating resistance.
The resistance decreases the amount of voltage available. Bulbs will not light
up nor will the engine turn over if the voltage is too low.
Maximum Voltage Drop
Maximum voltage drop should not be more than 0.1 V per wire, ground,
connection or solenoid.
What should be tested?
Each wire, ground, connection or solenoid as well as the complete circuit should
be tested. Each connection point is a potential source of increased resistance.
Voltage Drop Testing
(1)
Negative (-) Engine Ground
