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

Thanks. Used that one ages ago. Looking for one under the hood. Guess I'll check them all out and use the add a line tap.

 

I have my battery in the bed. Ran my wires down the drivers side, on top of the frame. Secured them with wire ties, there are other wires and lines already there, wire tied to those. Used Heat Shroud, from Design Engineering, https://www.designengineering.com//...ineering-inc/line-hose-protection/heat-shroud ,where the wires were anywhere close to the exhaust. Hope that helps.
Are you talking about the brown wire? I still can't find where to hook that up.

 

Thanks, the brown wire is kicking my ass.

 

The small brown cable will connect to the fuse box, where you removed the alternator cable from. Also in the same spot is where you connect the small cable that was removed from the original positive post that is talked about in step 13. Once both these cables are mounted on the stud in the fuse box you can bolt them down.

See where the silver nut attached to the stud in the upper left corner of the fuse box, that is where the brown wire attaches to.

 

I have a Blue Sea set up. Does this apply. I need a "hot when the key is on" spot for the brown wire, in the fuse block under the hood.

 

No, That is my on anytime fog light mod.

 

OEM set up has two wires on the battery + post. The thicker one goes to the starter; the smaller one goes to the fuse box - lower bottom engine side. That wire attaches to a fuse and the wire comes out behind the fuse-box to battery wire and goes to the alternator. So, easiest place to tap to the alternator is at the battery post. However, that wire is 5 gauge and should you ever attempt to draw more amps than the fuse rating, you will blow that fuse.

You can consider tapping into the wire coming out the top of the fuse box (pre fuse) but you need a special connector because of the angle, and you still have that smallish 5 gauge wire headed to the alternator. You can try connecting directly to the alternator but you'll find out the bolt is not long enough to attach two battery wire connectors.

Best solution I found was to run a wire (I used 1/0 with 1/4" hole on the lug connector) from alternator to a junction block, then from there attach the alternator-to-fuse box wire and solenoid wire connections. BTW, I upgraded the alt to fusebox and fusebox to battery wires to 2AWG. It was not easy but I will not have to worry about the wiring ever getting too hot.

Edit: corrected description of wire coming out of the fuse box to the alternator. I thought it came out near the top but it comes out near the fuse box to battery wire. Both are black with blue tracer line. The starter wire is black with, either, a red or green tracer line. I got rid of it - if I recall, OEM size was between 2-4AWG; I replaced it with 1/0.

 

This is the type of junction/power block I'm using. Mine is a 3/8 post Fastronix. Blue Sea offers a greater variety. It doesn't matter what color you use; just make sure you use a boot or wire loom to cover the top for protection.

 

Got a question I need answered

The brown wire on the blue sea 7622 ml acr seems to be an issue of some debate and has me confused

I read in another post that the brown wire really doesn't need to be hooked up at all.

https://www.tacomaworld.com/threads/dual-battery-setup-help.396094/page-2

Posts 35 and 36

My question then-
1) is it necessary?

2) what are the advantages or disadvantages?

If it's better to have it hooked up, am I just looking for a source under the hood that is only hot when the key is on?

My setup is all under the hood
-1/0 cable throughout except 4 awg supplying blue sea fuse block off 2nd battery
-blue sea 7622 ml acr
-high output alternator
-big 3 upgrade
-2 odyssey pic 1200mjt, 1 in stock location, 1 close to firewall on passenger inner fender

Really appreciate a clear answer

 

I believe you are referring to battery terminals; I am referring to a power distribution block. They are useful if you run out of room when making multiple battery wire connections, which are rather thick and take up space quickly. I run my 1/0AWG alternator wire to the block. From there, a 2AWG wire goes to the fuse box and another 2AWG wire (with 200-amp fuse) goes to the solenoid isolator.

 

No, I'm referring the brown wire coming off the blue sea ml acr and my question has nothing to do with yours

 

I was talking to inv3ctiv3. No harm done.

 

Ahh shit, stress, sorry man

 

Sweet, thanks

 

I have the same problem, I don't know where to hook it up. Some say you don't need it at all. Others say theirs doesn't work without it being hooked up. I want the option of hooking it up if needed, just can't find a place.

 

You guys don't need the brown wire. Never hooked mine up and it works perfectly. When I fire up the truck the ML-ACR will link about 30 seconds later and charge both batteries. When I turn the truck off, the time it takes to de-link the batteries varries on how much is being drawn at that moment. For example, turn truck off with no auxiliary devices running on either battery and they'll eventually de-link once it senses the a difference in voltage between the two. Sometimes 5 minutes, sometimes 30+ minutes.

Now if I turn truck off and leave the radio/headlights on, it'll be pulling from juice from the main battery so the voltage varrience will come sooner therefore delinking the batteries within seconds. Same goes if you're running LED lights or fridge off secondary battery. It'll sense the voltage difference and delink sooner. Hope that helps.

 

How do you know when it de-links? I'm still trying this out. I'll give it a try this weekend.

 

I hear the magnetic latch delink. It's a pretty obvious sound. It's like a loud click.

 

Thanks, may PM you if I have other questions, if it's OK.