Dual Battery Setups! Let's see them! Multiple Batteries Thread!

I don't think that is what Alex is saying.

The way I read this and the way I did it is to add a wire from the alt to the battery, leaving the original wires in place to power the fuse box like it always has. A higher gauge wire direct form the alt to the battery will ensure better amp carrying capacity for the HO alt.

 

Yes, this. However, because of my original isolator setup I actually removed the original alternator to fuse box wire altogether from the wire loom/harness. That one is very easy to get to with just a nut and bolt easily accessible in the fuse box. I replaced that wire with a 1/0 cable from the positive terminal of the battery to the alternator output. I left the small wire that was the original wire from the battery to fuse box.

You could leave that original alternator to fuse panel wire and just add another cable from alt to battery if you choose to take that route. However, with a high output upgraded alternator, I dont think this would be the route to take because I think there is a 130A fuse in the fuse panel and you might exceed that with your HO alt. I have the 130A alternator, but the reason that I removed that wire is that my original isolator (diode type) did not allow that option without it bypassing the isolator.

I apologize if I'm being confusing. I'm trying to explain the best I can. Here's a crappy drawing of what I'm trying to say.

 

Copy. It's just that abarber said twice the eight gauge wire from fuse box to battery was not part of the charging system. It seems to me that wire charges the battery. What Digiratus said about adding a wire from the alt to the battery makes sense (and barber11's diagram). Also, I don't think a HO alt affects the fuse because it appears to me the alt-fusebox and fusebox-battery wires are on the same end of the fuse - the other end going to the circuits. I will confirm this when I disassemble the fuse box. Thanks for your prompt responses.

 

Sorry about that. I didn't mean to give you incorrect info. I forgot that the original alternator wire went into the fuse panel. In my picture of the "upgrade" with a cable run from alternator to positive terminal, there are 2 wires that are from the original stock wiring harness that are not be part of the charging system (starter and battery to fuse panel). That's how my system is set up now and it's been like that for several years.

Let us know if both of those wires are on the same side of the fuse. I'd like to know for curiosity's sake.

 

Pre-wired my dual battery setup. Now I just need two batteries.

 

Chuy- If you don't mind, can you share a pic of the battery mount that is a wider angle view to show most of the passenger side engine bay? I think you might have more doohickeys in your truck on that side, near the firewall, than what I have in my 2005 DCSB V6 engine bay. I wanna put the battery on that side, but don't feel comfortable removing the air box duct and keeping it off. The metal battery tray appears to be sturdy. I'm liking the $13 price tag. Will it fit a 27F Optima?
Thanks Man!

 

@docloco - where are you putting the 2nd battery? I think two batteries in the original battery space seems too cramped and too heavy for that side.

 

I'll be going with optima batteries in the original space.

 

Sure thing. This weekend.
WirthCo #21087 is for group 27 batteries. On Amazon for $15. Tray comes without hold down kit, which I already had. Jegs sells a tray kit with the same tray. $20 plus shipping. The 27 tray will not fit in my truck without having to relocate either the ABS module or the windshield washer reservoir. The 24 tray fits perfectly in between, but after removing the air ducting. The main purpose of the air duct is to bring in cooler air into the engine. I will later look into after market air ducts to route one down and into the area below the washer reservoir. Spectre and Speedi-products make some. If you look further into the past threads, there is a link to a kit to relocate the PS reservoir and fit a 24/27 tray in it's place, but it requires longer PS hoses and mounting the reservoir directly to their battery tray, without the rubber grommets. I didn't like any of that.

 

I think I have more room on the firewall side. I don't have that gizmo that you have on the right side of your pic. I'll do a mock up piece of cardboard the size of that 27F WirthCo Battery Tray to make sure. I think this will work for me without moving my air duct.

 

I guessed wrong. The fusebox-battery wire is connected to the 140 fuse on one end (lg arrow, below) the other end goes to the alt wire (small arrow).



Since I had the fuse box apart, I replaced the fusebox-battery wire with a two gauge 18-inch piece I had laying around. It's huge compared to the OEM wire. I had to enlarge the opening where the OEM wire comes out of the fusebox. I'm going back in there to shorten the wire; OEM is 13 inch long. Also, the bolt in the fuse box is 6mm. The 2-gauge wire has a 3/8" opening. I'm going to replace the lug with 1/4 inch lug.

 

My install in a 2014 TRD OR manual. Relay on a plastic board mounted to studs that are used for abs on other models. Fuse block screwed to inner fender. Beside the relay there is a 40 amp circuit breaker that feeds the fuse block. Second battery is in the bed and has a single 200 fuse on the positive terminal. Control switch is on the cup holder between the seats.

 

Nice looking arrangement. What size wire are you running to the house battery in the bed? It looks pretty beefy.

 

How'd you get the cover off the factory fuse/relay box? I really need to replace that cable on mine too.

 

I still have these kits if you're interested?
https://www.tacomaworld.com/threads/2nd-gen-or-second-battery-mount.419262/

 

Aux battery installed in bed. 10-AWG wire from starting battery to CTEK Dual 250S unit.

I carry 75 watt solar panels. The solar panels are wired to a CTEK Dual 250S unit.

The CTEK is connected to both batteries. All charging, either by vehicle alternator or solar, is fully automatic due to the CTEK.

My charging system has operated flawlessly and has remained maintenance free for over three years now.

Solar panels.


CTEK Dual 250S unit.


My aux battery on bottom, and a cheap tool box where the CTEK lives along with a blue sea 6-circuit fuse block.


For any details, please see build thread.

 

I hate you guys that don't have that ABS module over the pass fender.

 

I can refine this when I re-visit the fuse box this weekend to shorten that wire.
Off top of my head:
1. Remove battery; remove fusebox cover
2. Remove nut on alt-fusebox cable, and disconnect the three harnesses - push wiring out of the way.
3. Use pliers to pull out the small plastic cover covering the cable and harness wiring
4. Open the two wire harness plastic 'brackets' that hold harness to chassis, on either side of fuse box (to give you more play on the harness when you open the fusebox
4b. There is s a wire zip tied to the bottom of the fuse box; you'll get more room to move the fuse tray if you clip the zip tie.
5. Use small screwdrivers to hold open the six tabs that clip the fuse 'tray' to the fusebox. Use pliers to gently pull up the tray. It will slide on grooves straight up; don't pull on the tray until the tray clears the grooves or you may damage the grooves as they are thin.
6. If replacing the fusebox to battery wire, the lugs on your new cable may not fit properly on the power strip until you press down the two tiny tabs that I believe are there to keep the power wire from rotating as you tighten the M6 screw.

To re-position the tray, you may have to loosen, but not remove, the three hold-down fusebox screws. The tray slides into the box on grooves and loosening the box screws makes it easier to position the tray over the grooves.

 

Awesome! Thanks Chuy! At one point I was trying to get it apart and I could not figure it out. Replaced my battery with one that has normal terminals and that wire is too short!