DUAL BATTERY WIRING

[WINGO]

What's the correct wiring to use two(2) 12 volt batteries at the same time?

I want to be able to use the power from both and charge at the same time also.

Thanks!



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WINGO
Vineland, NJ
USA
1984 GW 360

[Bernie]

You wire them positive to positive, negative to negative.

[fulmetal]

If you are going to just run two Batt. to crank you might be better off getting a higher CCA (cold cranking amp) Batt for your replacement. The only time you should need a dual system is iff you need to power a winch,a whole lot of lights or you frequently visit sub zero weather. If you still need to do this I would suggest that you not run them in series but add a selonoid(sp) and run it off keyed power.

[Narnian]

You can also get a manual switch. I know guys who used to power major sound systems would switch the batteries together to charge, then just use one battery when they wanted to play noise with the engine off.

[Ralph]

There used to be a system called the Good Samaritan Dual Battery System, which allowed several variations of battery use. It was expensive. Leon Rosser sold it, but I don't know if it's still available.

[scotty]

the easiest way is to goto a boat store,and buy a dual battery marine switch.it lets you pic betweenmbatt A,batt B,A+B,and has on off position to completely disconnect both systems.you can rig it with starter solenoids,but they are not really designed to be used in a continuous on situation,and we had trouble with them not lasting long. i highly reccomend the marine switch. they range in price from $25 to $45. the problem with wiring them simply in parallel is that they both drain,both charge.you cant drain one and have a fully charged backup.unless you install a handy on/off type terminal on one or both of them. b the time you buy 2 of those,tho,youve almost bought the dual batt switch,as they are usually $10-$15 each. it is also important that the batteries be the same CCA,and be in equal condition.if one is older and more worn out,the newer one will discharge into it.

you can also buy battery isolators at any auto parts store that send the charge to whichever bstt needs it,and keeps one from draining,but they are usually in the $40 range.

dual batteries give you alot of peace of ind in the woods,especially with an auto that you cant pull start.now if ya wear one down trying to restart it,you just flip the switch.this can be a real lifesaver if youre stalled ina mudhole,or on a hill,and it is literally impossible for someone to get around and give ya a jump.

also if your alt goes out,2 completely seperate battries will let you drive lot further than 1 big cca battery.
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scott
85 grand wagoneer
258 with motorcraft 2bbl/904/twin stick dana 300/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

T18/dana 20 swap very soon
searching for dana 18 to replace the 20...

[This message has been edited by scotty (edited November 06, 2000).]

[Juice]

Scotty,

[Juice]

Scotty...where would you mount the marine battery switch? Those things are pretty big. Also where is a good place to mount the 2nd battery without too many mods to the rig?

[River Beast]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Juice:
Scotty...where would you mount the marine battery switch? Those things are pretty big. Also where is a good place to mount the 2nd battery without too many mods to the rig?<HR></BLOCKQUOTE>

Fulmetal has his just the way I am going to do mine...his setup in QWESOME... side to side with a fabbed battery tray that is perpendicualar to to the front end now. removing a little bit of the fenderwell is all that is required. You can see it in his photos http://albums.photopoint.com/j/View?u=187566&a=7042531&p=23789900&Sequence=0&res=high




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Todd
78 Wagoneer, "River Beast"
360/TH400/QT
Dana 44's locked w/ 4.89's
39.50x15x15 Super Swamper TSL's
7" SOA in front-7" Rear Shackle Inversion Mods
4" Skyjacker Softride
3" Trailmaster Bodylift
My FSJ site: http://www.geocities.com/~spazz4life (http://www.geocities.com/~spazz4life)
My E-mail: monster_fsj@hotmail.com
"If you can't stop...SMILE as you go under!"

'93 3/4 ton 4x4 Suburban...a.k.a. "FSJ Hauler"

[WINGO]

Riverbeast & Fulmetal:

Correct me if I am wrong, but in looking at the photo, it seems that the two batteries are wired + to + and - to -.

What's that metal box attached to the inner fender wall?

Did Fulmetal install an "A" "B" switch?

Are those batteries the new Optima 1000 cca solid or gel batteries?

I was considering mounting my second battery behind my drivers side inner fender (inside the truck). What do you think about that location?

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WINGO
Vineland, NJ
USA
1984 GW 360

[River Beast]

Wingo,
Fulmetal can explain it better, what I can recall:

Bat1- to gound
bat1+ to solenoid1
solenoid1 to solenoid2
solenoid2 to bat2+(?)

The solenoids work as a one way switch to allow both batts to charge but one runs the rig the way it was designed and the other is strictly for his accesories like winch, lights, compressor and welder. Since the pic was taken he has added circuits and relays in as well...

They are gel batts, too. Fulmetal can explain it better.

Location is personal preference...
The closer the batts are to each other, the less wiring you will need to make things work.. plus it would probably cleaner is they were closer....


------------------
Todd
78 Wagoneer, "River Beast"
360/TH400/QT
Dana 44's locked w/ 4.89's
39.50x15x15 Super Swamper TSL's
7" SOA in front-7" Rear Shackle Inversion Mods
4" Skyjacker Softride
3" Trailmaster Bodylift
My FSJ site: http://www.geocities.com/~spazz4life (http://www.geocities.com/~spazz4life)
My E-mail: monster_fsj@hotmail.com
"If you can't stop...SMILE as you go under!"

'93 3/4 ton 4x4 Suburban...a.k.a. "FSJ Hauler"

[fulmetal]

Alright I will try and exolain the wirring on the dualls.
Solenoid 1(your starting solenoid) (+) to Batt#1, (+) 1 Batt to solenoid #2 Hot side or inlet, #2 solenoid out to + #2 Batt. All grounds to frame. The No 2 solenoid is wired to keyed power so it will activate when the key is on but engine not running.
No there is no A or B switch. Did not feel I needed it. The solenoid act as a one way regulator that allows current to flow to the batt. in one direction only. Be carefull when wirring them because they are directional on a 3 pole solenoid.
The metal box on the fender is the fusable link to my weldind machine and the associated regulator. So is all of the exterior wiring
The Batt. are the 850 cca spiral wound gell cell. If you are going to install the batt in another location remember the optima gel can be stored in any position and there is no leak off. They are twice as expensive but worth it if you beat the rig off road.
I would try to get the Batt Great Googley MoogleyGreat Googley MoogleyGreat Googley Moogley close together unless you are running #1 or #2 cable. I used #3 welding cable due to is flexability and toughness. Just changing all of the cables over made the starter scream like it was on steriods. Well maybee not that fast , but there was almost no amperage loss due to the cables. Good luck.

[WINGO]

Fulmetal:

One more question (I doubt it)?

What's the best connection point for the keyed power?

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WINGO
Vineland, NJ
USA
1984 GW 360

[scotty]

how many solenoids have you burned up? a friend and i have both had them wired that way,and weve both been thru a couple.are you using starter solenoids or something else? ive got my solenoid wired to a toggle switch so i can choose A only,or A+B.

the marine battery switch is big,but should not be too hard to fit on the fenderwell.i have been too lazy to modify the other side of the fenderwell,so my 2nd batt sits currently on the floor on the passender side.makes a nice foot rest for the passenger. since being in the engine compt will require me to get out and open the hood,i plan to install my switch on the dash infron of the passenger.all il have to do is lean over,or tell passenger "hey,move that big dial to B". http://www.ifsja.org/ubb/biggrin.gif



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scott
85 grand wagoneer
258 with motorcraft 2bbl/904/twin stick dana 300/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

T18/dana 20 swap very soon
searching for dana 18 to replace the 20...

[fulmetal]

I dont remember exactly where the keyed power is from. I believe I tapped to a source from the fuse block and ran the wire in some loom over to it. i will double check it tommorrow.
I bought the solenoid at an RV shop for around 15$ or so (it has been a while). I have not burned the solenoid up yet. I have about 2-21/2 years w/ my dual set up. Then again all it does is charge the batt. No real load on the solenoid. because power only travel in one direction. Maybee you have a bad set up somewhere. I also have a high out put alt 120 amp for the welder. Hope this helps