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Auxiliary battery charging (Lightp1.gif)
The Low Voltage Cut-Out 1 controls charging of the Auxiliary Battery. A detailed description is covered with
the cut out circuit diagram. Input to the cutout is taken from the accessory circuit. This prevents the batteries
being connected when the vehicle is unattended. The cut out senses the Alternator output via the connection to
the solenoid R1. The cutout supplies an earth connection to the solenoid. When the voltage falls below a preset
level (Typically 13.2V) the connection to ground is removed causing the charge to the auxiliary battery to be removed.
The solenoid is typically reactivated when the voltage returns to 13.8V indicating a full charge in the main battery.
This allows the starting battery to recover before the auxiliary battery is given charge. This protects the ability
to start the vehicle at all times. While disconnected Lamps and other accessory item will run from the auxiliary
battery. D4 is lit when the auxiliary battery is connected to the main battery and therefor receiving charge. I
have also added a third battery to my vehicle by adding a second aux battery and solenoid in parallel with the
first. This battery is used exclusively for the HF (2mhz) radio, Sat Phone, UHF CB radio and 27MHz CB Radio. The
winch, Lights, and all other accessories wire to the first aux battery. The main battery now only operates the
starter. The OEM accessories have been reconnected to the aux battery.
Auxiliary Battery Discharge protection (Lightp1.gif)
This is controlled by the second Low Voltage Cut Out Unit. This voltage cutout is set to turn on above 12.5Volts
and switch off below 11.8Volts. This stops the battery fully discharging and therefore not being capable of recharging.
When the battery voltage is ok D8 is lit indicating the battery is in good condition. The output from the cutout
supply an earth connection to accessory relays.
Driving Lamps (Lightp1.gif)
The circuit provides low voltage protection and as the lights are intended for off road use only (mounted on
roll bar) will operate off the 4wd circuit. The lamps require the vehicle to be in 4wd and the high beam to be
activated before the lamps will turn on. A bypass has also been incorporated to allow the lamps to be operate din
2wd. This was added as a legal requirement. Most laws prevent light mounted above eye level. My local laws prevent
any lamp above the headlamps. As the vehicle is part time 4wd. Preventing the lamps operation in 2wd (on Road)
is sufficient to make the lamps legal on the road. I use the power antenna output from the radio to control this
function. If ever pulled over for a vehicle check I can turn off the radio and the lamps return to a Legal installation.
Using the power antenna output also prevents having a hidden switch which can be found. The dotted area of the
diagram is repeated for each driving lamp. I have 4 lamps on the roll bar therefor it is repeated 4 times. This
is a typical wiring of driving lamp. When power from the high beam circuit is applied R3 is triggered. R3 supplies
power to the driving lamp. R3 will be disabled by R2 if the battery condition is below minimum levels. The 4wd
detect circuit provides an earth for the driving lamp relay R3. The 4wd bypass relay R4 is provides an earth to
R3 if the car radio is on. D9 is provided so as to prevent the bypass relay R4 triggering the function of the 4wd
circuit (Dash lamp and ADD if fitted). This brings us to the LED status lamps. When High beam is applied D6 is
lit. If the 4wd circuit is bypassed D5 is lit. D8 shows that the battery condition is OK. D1 Shows the fuse to
the driving lamp is ok. D2 show that power is applied to the driving lamp. D7 Shows that the lamps are enabled.
Providing the LED status lamps allows quick detection of any wiring faults. IE is a lamp does not operate and D2
is lit indicating power is going to the lamp you will know that the bulb is blown. Missing from the diagram is
a disable switch for the lamps. This is inserted between the high beam harness and the diode. Sorry for the fault..
Parts Details for Second Battery Control and Driving Lamps Circuit
B1 Standard Vehicle Battery
B2 Auxiliary Battery
R1 Battery Solenoid
R2 Automotive Relay
R3 Automotive Relay
R4 Automotive Relay
D1 LED Diode
D2 LED Diode
D3 LED Diode
D4 LED Diode
D5 LED Diode
D6 LED Diode
D7 LED Diode
D8 LED Diode
D9 Power Diode IN4004
L1 Driving Light
F1 10A (1 x Driving Lamp)
F2 5A (Power control Relays and Status LED's)
LED Functions
D1 Driving Light Fuse OK
D2 Driving Lamp On
D3 Fuse 2 OK
D4 Aux Battery Charging
D5 Driving Lamps Operating in 2WD
D6 High Beam On
D7 Driving Lamp On
D8 Driving Lamp Voltage OK
High Output High Beam (Lightp3.gif)
The standard harness for the headlamps is not much chop. The wires are thin and therefor the light become
dull due to the loss in the wiring. Another problem is that the lamps are wired with a positive earth which while
saving a relay for Toyota, is not optimal for accessory lighting. I have included a copy of the standard headlamp
harness for comparison to the modified unit (Lightp2.gif). You will find that your engine bay fuse box has 2 spare
relay sockets (diesel models). The entire modified harness can therefor be housed in the fuse box. I have included
the wiring codes on the diagram so the stock harness can be easily rewired. Additionally I replace the OEM wiring
from the fuse box to the headlamps with heavy duty. This provides far less voltage drop and brighter headlamp result.
With the OEM harness unfused wiring runs to the combination switch which in my opinion is not safe. The new harness
does not roue any headlamp power into the combination switch. This makes the wiring shorter and not subject to
burning out the harness if a short occurs as in the OEM unit. Also as a result of the shorter wiring less voltage
drop is present at the headlamps.
Fog Lamps (Lightp3.gif)
The operation of the foglamps is a bit tricky. The Lamps go on with the parking lamps. When the headlamps are turned
on the lights go off and go on again with the high beam. I usually use Hella Rally 1000 Wide cornering fog lamps.
Having the fogs come on with the high beam illuminates the road just ahead of the bulbar which is often dark on
high beam. I also operate my rock lamps, of which I have 6. All of the rock lamps are Hella Dual globe flood lamps.
I have 2 lamps on the front face of the bulbar pointing down at 45 deg. The other 4 lamps are mounted to the Tcase
crossmember and Centre bearing crossmember respectively. For the rocklamps I trigger the relays from the output
of the foglamp relay (prior to the fuse). I earth the relay through point A3 (Lightp1.gif) via a diode. This gives
low voltage protection and ensures that the rock lamp work only off road. This can be bypassed to operate on road
, see driving lamps (Lightp1.gif). The rock lights therefor function the same as the foglamps but also need 4wd.
So when on high beam or park lamps the rock lights are on, they are off for low beam. I have also provided a switch
to turn on the rock lights at any time this has proved good for winching operations. The fog lamp circuit is simple
in operation. The fog lamp relay is a SPDT type relay. The output to the lamps is connected to the NC terminal.
The relay is triggered by the Low beam circuit. This causes the power to the lamps to be interrupted turning them
off. As the low beam is disables when the park lamps or high beam is on, this provides the main function of the
circuit. To prevent the fog lamp turning on when the park lamps are off, power from the output of the tail lamp
relay is routed to the foglamp relay (Lightp3.gif).
Flood Lamps Over bed (Lightp4.gif)
For these lamps I use the Hella Dual beam Flood lamps. This harness relies on two relays to provide a legal
function. Local laws prevent the use of revering lamps above the height of the tail lamps. Additionally revering
lamps can not be greater than 21W and a maximum of two is allowed. So to get around the local laws the Floods are
treated as Work lamps. This means they must be operated by a switch outside the cabin. So a switch is placed in
the bed which operate the lamps. These have proved invaluable in wincing and breakdowns as I can illuminate the
immediate area or the bed, a torch just does not compare. The circuit is also wired into the 4wd circuit to further
prover to the police that they are not reverse lamp. The floods will function as reversing lamps only if the bypass
in operation (see driving lamps). The circuit also requires the headlamps to be on before the floods will light
and as in the other harness voltage protection is provided by the driving lamp harness via connection A3.
Cutout Circuit
I have attached the circuit diagram for the Low Voltage Cutout. I won't describe how this works , if you want
to know let me know. The whole thing fits on a circuit board about the size of a pack of matches.
Adjustments
RV1 adjust the cut out voltage. This is set to be anywhere from 10.9 to 11.9 volts. Regardless of where the cutout
is set the unit is set to re-establish power at 13V. I set the main cutout to 11.9V which controls the solenoid
to the aux battery. This causes the unit to trip upon engine startup and reconnect the aux battery once the starting
battery has recovered. I set the second cut out which controls the lights to cut at 11.5V. This ensures that the
aux battery will recover charge by not fully discharging the battery. I cant recall ever having the either cut
out disconnecting while the vehicle is running. This is probably more due the engine being a diesel an to the lights.
Late model diesel have a 120A alt standard, all three of my Hilux pickups are 96 and 97 models (two are factory
solid axle dual cabs and one is a factory solid standard cab). I have since raised the reconnection voltage of
the main cut out controlling the aux battery solenoid to 13.5V. To do this I changed R2 to a 500K trimpot. This
allows an adjustment of the turn on voltage from 10.2V to over 13.8V. The unit should never be set to over 13.5V
as the normal voltage of the alternator is 13.8V. I changed to 13.5V to give additional charge to the main battery
before recharging the auxiliary battery.
Operation.
SW1 when connected sets the cut out to Auto mode. When in auto mode the cut out will reconnect power when the voltage
rises to the turn on voltage. If SW1 is disconnected the unit is placed in manual mode. This requires you to press
SW2 to re-establish power. Pressing SW2 and not releasing it will cause the circuit to maintain power regardless
of the voltage. This brings me to the next change I made to the cut out. I added a second solenoid connected between
the starter battery an the starter motor. This allows me to force the batteries to connect but isolate the starter
battery. Instead of using a battery switch to start from the aux battery I do this with a single toggle switch
mounted on the dashboard. This is a lot more convenient and eliminates problems with the manual battery switch.
With manual battery switches you tend to forget to disconnect them. This allows the two batteries discharge angst
each other flattening both batteries. With the dashboard switch I can push it in to start from the aux battery
and the system returns to the starter battery after I release the switch. I have also included this mod in a second
diagram
That's about it. Hope this help you all out
James |
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