View Full Version : Electrical Upgrade Questions - 85 4Runner

08-07-2006, 09:35 AM
Good Morning Neverland!

I had a couple of questions that hopefully some folks may know the answer to. I'm planning on upgrading my electrical system to a higher output alternator (thank you Bill) and a dual battery system. The previous owners had definately hacked the electrical system with multiple alarm systems and who knows what else, so this improvement is definately needed. Anyway, here's the first:

On the 85 4Runner (22RE) where is the fusable link located? The manual is not very clear on this (and it sort of indicates the fuse(s) in the fuse box located in the engine compartment. Odd. I'm enclosing a picture of something I don't recognize, which looks more like an in-line fuse coming from the alternator.

The second question is about the power going from the battery to the main fuse box. Has anyone taken apart this fuse box? It doesn't look too difficult, but I wanted to see if anyone had a procedure so I didn't mess it up. Hence the second picture. (Oh, and if someone has an image of the fuse assignments for this box, I would be much obliged if you could post it.)

The last question, for this morning, is about battery relocation. I was toying with the idea of relocating the spare tire inside the truck and placing one or both batteries in it's place. (Along with an air tank.) It seems like most people just bolt the batteries together, but I am inclined to put them in a box. I realize the batteries are sealed, but I think a bit of protection might be a good thing.

Thanks for your help.

the Other Matt

08-07-2006, 01:44 PM
Beyond the PMs and our correspondence on the alternator upgrade... I elected to do what you are planning, putting both batts where the spare goes. This frees up engine compartment room, even allowing you to shorten the intake and draw colder air a shorter distance. You would have to splice the AFM wiring to do this; not terribly difficult (hint: use soldered connections, meltable shrink tubing, and an overwrap of normal shrink tube, and you'll have no worries ever).

It also evens out the weight somewhat, and lowers it somewhat.

I used Yellowtop Optimas mounted on their sides, with Unistrut bolted on to the rear deck. I learned to love Unistrut doing electrical work. This allowed me to place threaded rod where I wanted. I made a bottom pan to spread the load of the batteries' weight evenly, probably overkill but it also holds them securely. I used neoprene sheet to cushion and insulate this pan.

For isolating the batteries, I'd either go whole hog and use a PerfectSwitch PowerGate rectifier (www.perfectswitch.com, the Mobi-Arc folks), or a simple golf cart solenoid that only picks on ignition = 'ON', and that via a switch. I would NOT go with a battery isolator that uses a large heat sink; it's more expensive than the solenoid and generates a lot of losses via heat. There are other reasons; PM me and I'll explain. You will want to isolate loads between the main/ignition battery and the aux battery (not absolutely necessary with just the solenoid, but way preferable with some scheme of solid state isolation).

Even if you go with solid state isolation, a solenoid is not a bad thing to have for self-jumping. So, you can do it in stages, installing the solenoid first and upgrading to the PerfectSwitch later.

I get absolutely nothing from this. I am doing an article on a PowerGate, and will be installing one to replace my solenoid isolation I currently use. The design, form factor, and 'no thermal losses' function of the rectifier is really amazing. A 250 amp unit is extremely small. A 1200 amp unit could be built in the same form factor. It may be overkill for the 4x4 world, but the major consumers of this have been military communications vehicle fabrication, and power industry communications vehicles. Prior to these, the military ended up with obscene thermal losses, adn the power company lost several vehicles to fire caused by same. I'd say hybrid technology is about to pop bigtime from this type of design. You may or may not find it a crucial mod to your vehicle, but I would use no other solid state solution personally.

08-07-2006, 02:52 PM
Thanks for the info Bill.

It looks I will need some serious cable in order to run cable from the rear of the truck to the engine compartment. Depending on my wiring topology, I will probably need to run power and ground for each battery (and tie the grounds somewhere in the engine compartment. No loops. Part of the need to do this is for specific high current applications (such as welding) or a winch. If you were to have a Warn XD9000 winch, for example, and were actually able to pull 9000 pounds, according to Warn you would draw approximately 400A! Thats some serious current. (Not that it would normally occur. A more realistic number might be 4000 pounds at 230A.) Normally the winch would be directly connected to the battery (at least that's what I did on my Taco). Roger Brown (4Crawler) (http://www.4crawler.com/4Runner.shtml) used 0/00 welding cable and some Wrangler NW connectors to join them. That could be interesting. (The connectors he used were rated for 350A. The current for winching was split.) I would also wonder what sort of buss bars to use to tie in my other electrical components. What did you use Bill?


08-08-2006, 07:58 AM
I used 1/0 welding cable. I ran it in irrigation hose for armor, and routed it carefully. I also bought a crimper and crimp connections (you may borrow the crimper, though they are not too expensive. It's hammer driven.:zilla: 5-pounder works great). I ran each neg. to the frame near the batts in the rear, then ran a ground cable from that location up to a tcase crossover bolt in the middle/front of the truck. From there I ran another cable to the block, and another to the body (smaller than 1/0; more like 2AWG).

Good grounds be mitey important...:cool: Electric motors, such as starters and winches, really do NOT like seeing less than rated voltage. EFI likes its ground to be really ground too, no floaty action for him, please. With 1/0, and with a 1/0 ground wire commoning the two ground points in addition to the frame, loops are not a concern.

I ran the positives to the engine compartment, landing them on my isolation solenoid. On one side of the solenoid I landed the truck's positive feed, and ran a fat cable to the starter motor. On the other side of the solenoid I landed my backup battery and auxiliary circuits, including winch. I 'pick' the relay via a toggle in the cab, which in turn is fed off of ignition hot (only hot with the key on). I leave the toggle 'on', and when I turn on the key I hear the 'poink' of the solenoid, paralleling the batteries. Turn off the key, and I can run aux things till the aux batt is dead, and the main batt is good to go. Should the aux batt really be flat, I would turn off the solenoid toggle and start it up. Then, I'd turn on the solenoid. Or, I could self-jump I suppose. Could be a lot of current I guess. It's never happened.

My solenoid is a little on the 'light' side for full warp factor; hence, my redesign for the PowerGate soon. With a rectifying device, only charge current can flow through the isolation. Load current flows from the battery to the load, and each battery only sees it's own portion of the load, preserving the main. In my current configuration though, my winch only draws down one battery in a non-charging state, and the current never flows through the isolation device (only the 1/0). No real current worries with this setup. The max current for the winch is the stall current; the winch motor would not dissipate enough heat to keep that up for very long. Most winch pulls are a LOT less than your figures. Good to keep worst-case in mind though.:thumb:

I bought the eye connectors, meltable shrink tube, and normal shrink tube from http://www.columbineautoproducts.com/. Shoot her a call; she is very helpful. VERY much cheaper than Wrangler NW. I would get the welding cable from General Air on S. Santa Fe, talk to Dave Rios and tell him I sent you. He will take care of you.

08-08-2006, 10:20 AM
If "Unistrut" is 2" right angle stock full of holes (some threaded), I've got a bunch of it, and you could have as much as you need. I was also thinking of using some for a dual batt system in the 40, but that's 3 or 4 projects down the road on that guy.. all just speculation at this point.

The Red Chili dual batt system is sweet, but the only thing I don't like is how the batteries are exposed under the truck. Sometimes it's wet down there, or snowy.. occasional pokey things, etc. Granted they're like 4' in the air and 2' above the axles, but I'd sleep better if they were in a box or something. I'm sure if was a serious issue it would have been dealt with long ago, but if installing batteries under the vehicle I'd box 'em up. :twocents:

08-09-2006, 10:04 PM
I agree, I think I'd like a box for the batteries. Of course, I wonder if I'll have to fabricate one.

On a seperate note, has anyone opened up the fuse box? And is the first picture of the fusable link?


08-23-2006, 05:39 PM
On the 85 4Runner (22RE) where is the fusable link located? The manual is not very clear on this (and it sort of indicates the fuse(s) in the fuse box located in the engine compartment. Odd. I'm enclosing a picture of something I don't recognize, which looks more like an in-line fuse coming from the alternator.

The Fuseable link is under the fuse box in the second picture you posted. My 85 EFI has one link and my 84 4Runner 22R carb has two links. They were both white and ran into the bottom of the fuse box. Hope that helps.

08-24-2006, 04:40 PM
Have you ever taken the box apart? If so, how do I do it without mangling it? The PO cut the line in from the battery (and did a poor job of patching it), since I am upgrading the wiring, I wanted to replace it.

the Other Matt