Electrical System
358
Equalizer Troubleshooting
Equalizer Overload Condition
An overload condition exists when the 12 volt loads exceed the equalizer’s rated capacity. The overload
condition will not damage the equalizer but may cause damage to the batteries.
During the overload, the equalizer output is limited by internal protection circuits to its Rated Output
Amps. The 12 volt amps exceeding the equalizer output are drawn from Battery A, which will begin to
draw the batteries out of balance. The equalizer full Rated Output Amps are maintained as long as Bat
-
tery A and Battery B remain balanced within 0.10 volt. The internal protection circuits will reduce equal
-
izer output as the batteries become further out-of-balance. If Battery A voltage falls below approximately
8 volts the equalizer will shut itself OFF.
To correct the overload condition the 12 volt load must be reduced or the equalizer capacity must be
increased.
Engine No-Start Situation
Situation:
The coach has dead batteries and won’t start while jump starting. The coach has a moderate
12 volt load which cannot be turned OFF. The coach sits for several days and the batteries run com-
pletely dead. During jump starting the engine cranks but does not start due to low voltage on the 12 volt
supply. Electrical testing reveals there is no 12 volt output from the equalizer while jump starting even
though the equalizer separately tests OK.
Cause:
The 12 volt load which could not be turned OFF first ran both batteries down until the equalizer
shut itself OFF due to low voltage. (The equalizer will shut OFF if system voltage falls below 16 volts
or if voltage on either battery falls below 8 volts.) Then Battery A alone was drained to near zero volts.
As the bus is being jumped, 12 volt loads hold Battery A voltage too low for the equalizer to turn ON
and Battery A is too weak to support the 12 volt electronic engine control.
Solution:
Turn OFF all 12 volt loads (turning the Battery Disconnect switch OFF may accomplish this).
Voltage Comparison
Equalizer Status
Indicator
Light
battery A is lower than battery b
but within 0.05 volt.
stand-by mode
the equalizer will not turn oN until battery A
is lower than battery b by more than 0.05 volts.
battery A is lower than battery b
by 0.05 volt to 0.10 volts.
battery A is lower than battery b
by more than 0.10 volts.
battery A is lower than battery b
by more than 0.10 volts.
battery A is
higher
than battery b.
off
off
off
off
oN
oN
oN
oN
Normal operating mode
self-protection mode due to overload
condition. see below.
the equalizer is not functioning properly.
Abnormal condition. suspect battery b is defective
or a 12 volt load is connected to battery b.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...