[mrlocksmith]

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.



My Expidition Style '85 FJ60

[D'Animal]

Looks good!

[NocalFJ60]

Great job Mark. I want to add a additional battery too soon.

[Marc311]

I've been trying to figure out what setup I want to run. A lot of people seem to like the Hellroaring kit and it's nice to see it set up on a 60.

I was wondering how you came up withy your fuse sizes and locations. I see you have a 300 amp fuse to protect 1/0 wiring. But I am under the impression the max amps for 1/0 (depending which chart you read) is 245 amps at the most? Shouldn't you have something more along the lines of a 200 amp fuse?

I also don't understand the 250 amp fuse on the ground side. I saw the Hellroaring site showed a fuse there. Just wondering the logic behind that since I was always under the impression fuses should be near the power source. I am by no means an electrician - just curious since I will have to figure out how to protect my own set up.

Looks real clean!

[mrlocksmith]

I am not an expert either but I will try to explain things as I understand them. If there is one of those slide rule carrying engineer types on the board I am sure they can explain things better.

I also don't understand the 250 amp fuse on the ground side. I saw the Hellroaring site showed a fuse there.

According to Mike'e instructions from Hell Roaring, A fuse at the negative side of the backup battery will protect the entire length of the positive cable from the backup battery to the BIC.

I was wondering how you came up with your fuse sizes and locations. I see you have a 300 amp fuse to protect 1/0 wiring. But I am under the impression the max amps for 1/0 (depending which chart you read) is 245 amps at the most? Shouldn't you have something more along the lines of a 200 amp fuse?

The 300A fuse rating is a another story. My winch can draw 400 A under load with a full spool (not a good thing to try). So I mostly chose a fuse rating that wont allow my winch to burn up the wiring yet still function under most situations. As for the wire.... well... I'm not an expert but this is what I looked at when considering what size... The wire/gauge amp charts as rated by the Handbook of Electronic Tables and Formulas for American Wire Gauge as you might guess, the rated “amps” mostly a rule of thumb. The Maximum Amps for Chassis Wiring (1/0 Chassis Wire is 245A ) is also a conservative rating, but is meant for wiring in air, and not in a bundle. So with a short 18" 1/0 wire from the battery to the fuse, bundled and insulated, I'll bet that the wire is capable of handling more than 245 amps.


So I hope that helps and good luck with your system.

Mark

[Marc311]

Thanks - that all makes sense to me. I never realized a winch could put out that kind of draw. I don't have to deal with winch issues right now, but hopefully I will have that problem someday.

By the way, I'm originally from the Bay Area and my Dad used to live in RC on a boat near Pete's Harbor (Whipple Ave exit off 101 if I remember right).

[Dirty Toad]

So what did this cost you when all was said and done?

I guess I could check out all the links and total it all up, but that would leave out wiring and other misc. stuff.

[Marc311]

Here's a "complete" kit for $375 : EQUIPT Expedition Outfitters - Intelligent Split Charging Kit

Of course, you still need a second battery, a second tray, and to relocate your coolant resevoir.

[Dirty Toad]

Originally Posted by Marc311

Here's a "complete" kit for $375 : EQUIPT Expedition Outfitters - Intelligent Split Charging Kit

Of course, you still need a second battery, a second tray, and to relocate your coolant resevoir.

Thanks for that link.

I was told that the second battery tray from a diesel 60 had a mounting bracket on it to relocate the coolant reservoir. Is this not the case?

[mrlocksmith]

I think I spent about $400.00 for everyting... Just continuting my FJ60 Addiction...

About the battery tray, even the Man-A-Free battery tray has a place to mount the coolant tank. The trouble is there is all the smog cra-p-ola that is in the way. It is not hard to move it to the battery hold down in the main battery, but in my case it got in the way of my main wire run so I made a bracket.

Later

Mark

[mrlocksmith]

Note:

The wire going from the backup battery to the Hell Roaring unit has now been run in the u-channel in front of radiator and is now away from the heat at the top of the rad.


Mark

[Front Range 4x4]

Did you look at the kit offered by 12volt guy? Mud sponsor and iirc it's closer to $200 complete. Saw one installed and the owner was very happy with it.

[mrlocksmith]

Originally Posted by Front Range 4x4

Did you look at the kit offered by 12volt guy? Mud sponsor and iirc it's closer to $200 complete. Saw one installed and the owner was very happy with it.

I am sure it is a fine product but I had not heard of it at the time I bought my HellRoaring kit.

Mark