My 1985 FJ60 Dual Battery Setup (Leaky gets Dual Batts) 
As part of my expedition build I wanted to install a dual battery system to power my Ham Radios, Laptop, Winch., ETC, as well has having backup starting power. I also wanted to find a way to tame all the “direct to battery” wire runs I had for my various accessory equipment and provide a method of placing a heavy duty fuse to protect the rest of vehicles wiring. There have been a few write-ups on this but I thought I would write my own to share. The system is designed to have all loads run off the optima yellow top deep cycle battery and have the red-top act only as backup with no loads attached to it other than the battery isolator.
After reading some posts here in IH8MUD I went with the Hell Roaring BIC-95300B system. It seemed very reliable and there were not too many reports of trouble.
Hellroaring Battery Isolator/Combiner notes for 4 Wheel Drive dual battery applications
I relocated the coolant overflow tank and built a bracket for it that utilized an existing bolt hole over the passenger side wheel well. I then installed the backup battery which is resting on a 4+Plus Battery Tray from Man-A-Fre. The negative side of the backup battery is fused with a 250A fuse to protect the entire wire run from the backup battery to the BIC-95300B. I struggled with the positive wire run from the backup battery to the BIC-95300B. I did not want to run it along the back of the fire wall due to the heat generated by the top of the motor so I chose to run it along the top of the radiator and wrap it in wire loom. Hopefully it will be cool enough and there is plenty of room between the hood and the radiator. The air inlet hose to the carb has to get squished between the backup battery and the headlamp washer tank.
MAF Dual Battery
The next photo(s) shows the heavy duty fuse 300A Fuse and 4 Point Power Dist. Bus all under plastic isolators to minimize the chance of and accidental short. (There is a bus for negative wires mounted close by) Again I made a bracket that took advantage of existing holes so I would not have to drill any holes in the body.
The fuse, power dist bus, heavy duty battery lugs and insulated covers can be found at:
VTE Inc. - 4 Point Power Distribution Block
VTE Inc. - T-Class Fuses & Holder
VTE - 3534, 3535 Heavy Duty Battery Terminal
I made another bracket utilizing existing bolt holes in the body to mount the HellRoaring BIC-95300B to the fire wall. The photo shows the unit with the 1/0 cables I made (wrapped in flexible wire loom) along with the wires for the control switch that is mounted in under the dash.
When the install was complete, I simulated a completely dead main battery by disconnecting it and using the unit to start my FJ60 which it did !
The BIC-95300B has three settings for use depending on the condition of the main battery. The settings are selected via the remote switch mounted under the dash. It can automatically sense when the voltage on the main battery goes low and will automatically combine both batteries in parallel for higher amperage. One can also manually combine the batteries when winching or turn the unit off. It will also provide an optimal charge rate to both batteries.
The instructions from Hell Roaring were good but I would recommend studying them well prior to doing the install. All things considered I am very happy with the product and the project as a whole.
I hope this helps soemone with thier dual battery setup plans. Feel Free PM me or post any ?s
Mark
PS: To see the rest of my build click here:
Edit: The battery cable from the BIC to the backup battery has been rerouted away from the top of the RAD.
https://forum.ih8mud.com/expedition-builds/189160-my-expidition-style-85-fj60.html
As part of my expedition build I wanted to install a dual battery system to power my Ham Radios, Laptop, Winch., ETC, as well has having backup starting power. I also wanted to find a way to tame all the “direct to battery” wire runs I had for my various accessory equipment and provide a method of placing a heavy duty fuse to protect the rest of vehicles wiring. There have been a few write-ups on this but I thought I would write my own to share. The system is designed to have all loads run off the optima yellow top deep cycle battery and have the red-top act only as backup with no loads attached to it other than the battery isolator.
After reading some posts here in IH8MUD I went with the Hell Roaring BIC-95300B system. It seemed very reliable and there were not too many reports of trouble.
Hellroaring Battery Isolator/Combiner notes for 4 Wheel Drive dual battery applications
I relocated the coolant overflow tank and built a bracket for it that utilized an existing bolt hole over the passenger side wheel well. I then installed the backup battery which is resting on a 4+Plus Battery Tray from Man-A-Fre. The negative side of the backup battery is fused with a 250A fuse to protect the entire wire run from the backup battery to the BIC-95300B. I struggled with the positive wire run from the backup battery to the BIC-95300B. I did not want to run it along the back of the fire wall due to the heat generated by the top of the motor so I chose to run it along the top of the radiator and wrap it in wire loom. Hopefully it will be cool enough and there is plenty of room between the hood and the radiator. The air inlet hose to the carb has to get squished between the backup battery and the headlamp washer tank.
MAF Dual Battery
The next photo(s) shows the heavy duty fuse 300A Fuse and 4 Point Power Dist. Bus all under plastic isolators to minimize the chance of and accidental short. (There is a bus for negative wires mounted close by) Again I made a bracket that took advantage of existing holes so I would not have to drill any holes in the body.
The fuse, power dist bus, heavy duty battery lugs and insulated covers can be found at:
VTE Inc. - 4 Point Power Distribution Block
VTE Inc. - T-Class Fuses & Holder
VTE - 3534, 3535 Heavy Duty Battery Terminal
I made another bracket utilizing existing bolt holes in the body to mount the HellRoaring BIC-95300B to the fire wall. The photo shows the unit with the 1/0 cables I made (wrapped in flexible wire loom) along with the wires for the control switch that is mounted in under the dash.
When the install was complete, I simulated a completely dead main battery by disconnecting it and using the unit to start my FJ60 which it did !
The BIC-95300B has three settings for use depending on the condition of the main battery. The settings are selected via the remote switch mounted under the dash. It can automatically sense when the voltage on the main battery goes low and will automatically combine both batteries in parallel for higher amperage. One can also manually combine the batteries when winching or turn the unit off. It will also provide an optimal charge rate to both batteries.
The instructions from Hell Roaring were good but I would recommend studying them well prior to doing the install. All things considered I am very happy with the product and the project as a whole.
I hope this helps soemone with thier dual battery setup plans. Feel Free PM me or post any ?s
Mark
PS: To see the rest of my build click here:
Edit: The battery cable from the BIC to the backup battery has been rerouted away from the top of the RAD.
https://forum.ih8mud.com/expedition-builds/189160-my-expidition-style-85-fj60.html
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