V8 Dual Batt Set up. Tell me what I'm doing wrong...

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Jun 24, 2018
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Howdy!

So; getting ready to finally pull the trigger and order the parts for the dual battery set up in my V8'd FJ60, and want to make sure that I've got this right.

Spent many days reading about this, and wanted to make sure that I'm wiring/ordering it right way. Much of the info I know came from here.

My reasoning for the dual bat / Blue Sea 7622 system:
1) I run a winch (XD9500i) and want the ability to link the two batteries for serious amperage when needed.
2) I own and plan to run a Norcold 45 fridge in the rear of the 60' for longer jaunts.
3) I'd like insurance for operating a stereo / weather radio for longer periods.

My thinking is that I run 1 AWG wire between ACR and batteries, with 200a fuses in housings, and 2 AWG wire with another 100a fuse to the rear fuse box.
I'm going to put 2 individual volt meters into an A-Pillar pod so I can monitor the level of both batteries independently.
Lastly, since I don't plan on wiring 'sensitive' electronics, I think I can nix the isolator cables and run the remote switch with only the Red (remote) / Yellow (LED) / Black (Gnd) wires only.

Please take a look at my diagram and tell me if there's anything glaringly wrong.
Not in a rush, as this system'll probably cost a clean 1K after all is said and done (2 batteries included, x2 Yellow or Red tops, both the same battery) but... want to make 1000% sure I'm doing this right!

Thanks
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Joined
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I have pretty much the same dual battery setup. waytekwire website sells circuit breakers cheaper than blue sea. Eaton makes the circuit breakers for blue sea systems.

I also installed a manual marine switch between my winch and batteries so that I can keep voltage away from the winch in case of an accident. You dont want the winch to short and start a fire if you rear end something.

They sell the circuit breakers in flush mount or standard bolt on top style. I elected for the fancier ones that have a manual switch which allows you to turn off a circuit if you're working on it.


I winch using two standard car batteries and a warn M12000 using the blue sea 7622 to manage their charging. I have had zero issues and I winch a lot of people in my club when we are going through rougher terrain or snow.

Feel free to pm me if you want more details.

*The blue sea 7622 switch is a rebadged carling switch and you can buy the carling connector base and make your own harnesses that plug into the switch.
 

60Works

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I would highly recommend using your main battery as the house battery. This will leave your aux as a true back up. The only wires going to the spare should be the main connecting cable to the acr.

They way you've drawn it up will risk both batteries getting low at the same time.
 
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On my V8 FJ60 , I ran all accessories off the aux battery. I used a smart solenoid that took care of keeping both batteries charged.

I think 1AWG is overkill. 4AWG is great for the install and easier to work with .


National Luna makes a good system with everything you need for the install. I put one in my 200 Series.

 
Joined
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East Bay Area, CA
I also installed a manual marine switch between my winch and batteries so that I can keep voltage away from the winch in case of an accident. You dont want the winch to short and start a fire if you rear end something.
This is an excellent idea. Just an "On/Off" position, yea?

...They sell the circuit breakers in flush mount or standard bolt on top style. I elected for the fancier ones that have a manual switch which allows you to turn off a circuit if you're working on it...
I'm certainly in agreement here too. I see the models you suggested via Waytek. I'm thinking at least this for the "House" batt to the Acc. fuse box in the rear of the cabin. Any suggestions on amperage load size?

...I winch using two standard car batteries and a warn M12000 using the blue sea 7622 to manage their charging. I have had zero issues and I winch a lot of people in my club when we are going through rougher terrain or snow....
Thanks @Randy88FJ62! This is solid info.
Specifically, when you winch, do you 'link' (via remote or manual) the two batteries? Or, when winching, do you keep the 7622 isolating the draw from the *I presume* starting battery?


I would highly recommend using your main battery as the house battery. This will leave your aux as a true back up. The only wires going to the spare should be the main connecting cable to the acr.

They way you've drawn it up will risk both batteries getting low at the same time.
@60Works Thanks for looking at my *admittedly juvenile* diagram!
...This is the first I've ever heard of using the starting AS the house battery and leaving the Aux as a true back-up.
To my understanding, the ACR isolates the draw on both batteries IF it detects a draw, which I intend to monitor with individual/dedicated 2 1/4 pod style voltmeters (maybe Autometer, or whatever's cheapest), and I'm planning to run the 7622 ACR specifically because it can manually or remotely isolate the batteries in question IF a draw is detected or one is obviously overdrawn.


On my V8 FJ60 , I ran all accessories off the aux battery. I used a smart solenoid that took care of keeping both batteries charged.
@mep1811 Thanks for this. I wanted someone to sign off on a V8'd dual battery. I THINK @Elbert runs dual bat too, but I could be wrong.

I think 1AWG is overkill. 4AWG is great for the install and easier to work with .
Gotcha. I need to watch my amperage draw limits for the potential draw the winch, at max strain, could produce. I haven't consulted a AWG wire chart. I know my winch pulls 478a at maximum CHONK, so... that'd tell me that I need at least 1AWG? For non-continuous duty at MAX strain... or am I smoking something?

National Luna makes a good system with everything you need for the install. I put one in my 200 Series.
Saw that system. Like the battery monitor, but going to build my own system! Thanks for this suggestion.
 

Elbert

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i do have dual batteries but for now other projects have gotten in the way of further refinement. I'm still running a true "red-neck" setup on the dual batteries. I have a single cable that joins at the positive terminals. I pull loads off each battery and have my winch on the primary start battery (passenger side). Later on I do plan on some type of dual setup and likely with some of the Blue Sea "stuff", but as mentioned I'm still old school. I do have a winch and will have on-board air and hopefully a refrigerator too.

So not really awe inspiring....my engine is a 5.7 Vortec, I run a CS 144 ALT, with matching conventional batteries connected by 4 ga hot wire as I recall. Grounds run off each battery.

I plan to incorporate a HD switch where I can cut power to the winch if I want to, I plan to run some type of smart controls, not sure I'm sold on pulling loads just off the start battery...but I do follow the concept. I will power lights, winch, on board air, refrigerator at some point. My general thought has been the dual battery to add some reserve...not necessarily as having a 2nd battery in reserve, more so ...to have more overall capacity. Yes ...in my dream if I kill a battery its likely to kill both. I'm waiting to have time to think this through and get some of my other projects done, before I get back on the dual battery setup.

For now I can do some serious welding if I ground my watch on the 2nd battery... I've already tested this theory :)
 
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I have little to offer here but if you need cables made... I can help. I just bought a hydraulic crimper. Thing is awesome. Can crimp 1awg- all the way down to 16 gauge wire.

Also to anyone drawing in "napkin cad" like the above (which is great by the way). Here is a great FREE online drawing program. It's actually awesome for drawing wiring diagrams. I use this a lot.

 
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East Bay Area, CA
...I'm still running a true "red-neck" setup on the dual batteries. I have a single cable that joins at the positive terminals. I pull loads off each battery and have my winch on the primary start battery (passenger side)....

...engine is a 5.7 Vortec, I run a CS 144 ALT, with matching conventional batteries connected by 4 ga hot wire as I recall. Grounds run off each battery...
EXCELLENT 411. This is my exact engine (96' 5.7L Vortec MPFI). I believe I'm still stocker CS130 alt, as it's the Delco unit, but I haven't checked the P/N. So GLAD to hear that the ol' SBC can deal with the dual batts.

...I will power lights, winch, on board air, refrigerator at some point. My general thought has been the dual battery to add some reserve...not necessarily as having a 2nd battery in reserve, more so ...to have more overall capacity...
This is exactly my reasoning as well. Extra 'capacity' for a 'Fridge, the Winch, some camping/aux lights, and a proper stereo (e.g. with an amplifier). I'll supplement draw from the "house" battery with a 100w-200w Solar Panel eventually, but that's a horse of different colors.

For now I can do some serious welding if I ground my watch on the 2nd battery... I've already tested this theory :)
...Oh lawd. Don' do that. >.<

I have little to offer here but if you need cables made... I can help. I just bought a hydraulic crimper. Thing is awesome. Can crimp 1awg- all the way down to 16 gauge wire.
Thanks man. I'll definitely take you up on this when I pull the trigger (likely February 1st or so). I got the hammer-on cheap-o crimper tool for winch wiring when I made up some cables for the winch out of 1/0AWG that I got a Harbor Freight... so far so good... but, I'd wager that your tool is way better... plus; Oakland Cruiser party.

Also to anyone drawing in "napkin cad" like the above (which is great by the way). Here is a great FREE online drawing program. It's actually awesome for drawing wiring diagrams. I use this a lot.
YES! I'll definitely use this. Thanks for getting me slowly out of Napkin Cad. When I doodle, I like a tactile paper, but this will certainly help when I'm at my desk at work.
 
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The manual battery switch has Off, Bat 1, Bat 2, or both combined 1+2. I keep it in the off position and when I need to winch I open my hood and connect the batteries via the switch. You have to turn off the car when combining which some people may not like.


The size of the circuit breaker must be calculated based on load, wire size, and run length.


Batteries:
You want a two normal high CCA batteries for winching.
For fridge you want a deep cycle.
You need to choose what is more important to you.

I would recommend making things more complex. Run the fridge off a smaller lithium battery in the back that can be charged by the main two batteries and add a solar panel to charge the lithium battery too. $$$$

Depends what your needs are and what you want out of this.
 
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The manual battery switch has Off, Bat 1, Bat 2, or both combined 1+2. I keep it in the off position and when I need to winch I open my hood and connect the batteries via the switch. You have to turn off the car when combining which some people may not like.


The size of the circuit breaker must be calculated based on load, wire size, and run length.


Batteries:
You want a two normal high CCA batteries for winching.
For fridge you want a deep cycle.
You need to choose what is more important to you.

...Depends what your needs are and what you want out of this...
This is a valid question I've had too... RE: What TYPE of battery I'll need for my application, and how I can design my application best to meet the needs.

Realistically, I winch 1/20th of the time I'm off road. Lockers, and working solo a lot keep me from needing to pull others out often... I just want extra the extra amperage when I need it for such a task. In this way, I see the marine switch mentioned above as the absolute best way to get proper power when I need it, and a way to isolate it when I need to.

I'd intend to use the 'fridge/acc's more, and do intend to back up the system with a 100w-200w Solar panel feeding the house battery eventually...

From what I can tell, running TWO Yellow-Top Optima's (D34/78 variety as starting/house) will give me the power I need, and will make the system as 'simple' yet complex as I need, I THINK...
Related Specs:
CA
: 870
CCA: 750
C20: 55 Ah

I know I'm supposed to match internal specs, Manu. date, and usage of batteries I'm linking (even temporarily) in a dual batt system... so; this is the best battery I could find find so far that would do positively in the roles of (in order of importance)

1) Starting battery (DAILY need)
2) Acc. power (e.g. Fridge, stereo + amp, 1-2 LED light circuits) (Bi-Tri WEEKLY need)
3) Winching (4-6 times YEARLY need)

Any thoughts here?
Am I persisting in delusion to think that dealing with dual Optima bats of these specs will yield me a functional system for my needs.
 
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For all following / curious:

I finished this install during the CoV-19 B/S home-work extravaganza.

If anyone wants the 411, I'm happy to post more photos and/or PM details.
 

Elbert

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Yeah....post the full details, as noted above I'm gonna dig into this too at some point in greater detail. Always interested in what the magic details are along with the "fine print"...
 

FJ60Seth

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Blue Sea ACR is easy to hookup. One big cable from each battery and a splice to switched power going to the alternator. I omitted the remote switch & use the switch on top of the ACR to manually combine batteries.
 
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I saw this system at Equipt1 in person yesterday. Looks like an interesting system and fairly simple install for the extra battery install I am planning.
I have the National Luna system on my truck. I did an install with the entire system hidden in the passenger rear fender behind the trim panel. Good system. Really is an install it, and forget it type thing.
 
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I like the Blue Sea 7622 ACR as well. I like having the switch in my truck to control the isolate, auto, or manual join. I also like that when the motor shuts off I can hear the ACR clunk and isolate the batteries. Hearing that relay clunk gives me the auditory cue that the system is working properly.
 
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