Dual Batt. Cable Specs

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Good Evening All. I am aquiring parts for a dual batt. setup similar to George's writeup in the tech section. I have decided on a 200 AMP solenoid, two relays, and a 300 AMP 4 postion marine batt. switch as others have done, with a 91-92 passenger side tray. I am considering having some cables made up by Wrangler products. Does anyone happen to know the specs of cables for similar setups (length, amperage rating, terminal ends etc.). I want to use military posts at least on the aux. batt. and probably the main batt. also as my negative cable is worn beyond belief. I am not planning to run any sort of interior switch, just the isolation under the hood, where both batteries charge when the truck is running but are isolated when the truck is off. Any suggestions other than the writeups in the tech section would be a great help. I have rough ideas but would like to know the cable specs others have used to make as clean an install as possible and avoid extra cable slack. Cheers!
 

ppc

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For what you will be charged for custom length cables you are better off buying a length of welding cable, a crimp tool and heat shrink tubing and make your own cables. You end up with exact measurements and a crimper afterwards. It will come in handy when you install the winch. I bought mine for $26 at Tractor supply. One good hit with a sludge hammer does the trick.
 
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I concure make your own. You can get welding cable localy(normaly on in balck however) 2 guage is fine for joining the batts, I think its around $1 a ft. Buy, borrow or rent the tool, most marine stores rent crimpers. Its hard to guess what length the cable need to be untill you start to run them. You will need a cable cutter, $15 will get you one.

get the selnoids and mil spec terms from Wranger, and some heat shrink in red and black

for winch cables I use 2/0 or 1/0 depending on winch.

John H
 

lx450landcruiser

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does anyone run a switch to the inside of there rig to switch on and off the dual batteries or at least from battery to battery. I was also wondering what's so great about running a switch when some isolators will switch from batt to batt automaticaly when the amp drops low an on and will charge the low batt when while running off the charged batt. why run a switch unless its for welding/winching?
 

Photoman

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Basically, there are two choices when it comes to charging the dual batteries. An isolator or a solenoid setup. I had bad luck with isolators and burned up two of them, so went with a solenoid setup. I did have a manual switch in the cab when I wanted to charge both batteries. There are many variations to setup how the second battery is charged. See Christo's site and I believe George has a writeup also. As usual there are pros and cons to anything you do. Instead of the manual switch you can use the so called alternator good wire (used for the alternator light in the dash to to let you know you are charging) to pull in the solenoid relay to charge the second bat. It can be picked up at the underhood fuse panel. One thing I heard and don't know if it's true is with an isolator or even with certain solenoid setups is if your main battery is flat (dead) and your trying to start the motor and you pull in the second very good battery that the sudden spike of higher voltage can fry the computer. :eek:
Bill
 
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I run the Wrangler battery manager switch in my fj80(and the same is being done to my 86 and 82) it works great.

Some isolators have a voltage drop of .5 or so. Selnoids do not. Selnoids are simple and and you can get them at any parts store. Cole Hersee(sp) makes em, West Marine or even my local auto parts store, so if you fry one(and I haven't) they would be easy to replace almost anywhere.

John H
 

Photoman

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John,
That reminded me. I did fry a solenoid. Or a better way to put it is it got so hot it would not hold in. I ended up using a continuous duty golf cart one from NAPA, part number ST552. A little pricey and the wiring takes a little thought as it is a reversing type, but it worked fine for two years. I'm got the one from Wrangler wired up now and will try that next, but am taking the NAPA spares with me as I know they work.
Bill
 
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Solenoids ??? That is so 1970's....
One name. Hellroaring. Isolator. Can be wired in many fashions.
-B- did you ever get yours?
I have had mine now for over a year and it has worked flawlessly. Fry your ECU?
Explain that one to me :slap: If you have one battery and you replace it, wouldn't that be the same as connecting a second good batt to your dead one.
My battery has been so dead before that the remote chirp was like one slow long chirp to unlock the doors, except there wasn't enough juice to actually unlock the doors. Good thing I remembered you could use a key like in the old days :rolleyes: Got in, flipped my switch and started up. I did this for two weeks before I bought a new primary battery.

Yomama
 
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Is 2 gauge welding wire sufficient as batt. cables or is 1/0 gauge more suitable. I am not running a winch yet, but plan to in the future. Just two batts, a 300 amp marine switch, 200 amp solenoid, relays, power dist. block. What cable specs are people using? Wire crimpers are expensive and the compression type connections and terminals are hard to find except at wrangler, which is also expensive. Any suggestions/opinions? Cheers
 
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I used 1/0 gauge, but I am running from the second battery where the spare tire used to be. I shorter run may not need quite so heavy a wire, then again I prefer over kill myself. Crimper? I used a vise to crimp my connectors and I purchsed my wire on the internet from a car audio source (don't recall which one). Spendy wire though...

Yomama
 
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go to the welding supply house I used to work for airgas adn they had copper pound on lugs from tweco for all tifferent sizes and a $15 tool to crimp them on worked great for welding leads cant imagine would be different for batteries once you heat shrinked.
Dave
 

Photoman

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I think I got my tool from NAPA. Don't remember the price, but Wrangler's is $37.25. They are called hammer style. I have in the past used a VERY dull cold chisel and hammer to crimp.
Bill
 
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Good ideas. I'll look into getting the crimper from wrnagler or tractor supply. For the cable I have a roll of 2 gauge welding cable rated to 200 amps at 50 feet. I would think this is sufficient but also like to overbuild things. If there is ay chance the 2 gauge will over heat or otherwise be unacceptable I will get the 1/0 gauge.

Bill, what gauge cables do you run? Did this have something to do with toasting an isolator and solenoid?
 
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-H-
You would have to ride on the roof as he has only a driver's seat. He might let you sit on the ARB fridge mounted where the front passenger seat used to be.

And before you agree, don't forget Bill sleeps naked in the back of the truck.

:D

-B-
 

Photoman

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Hell, you can all come. Let's try to forget that naked thing please.

Basically, I ran 1 gauge wire for the dual battery setup. The ground for the aux battery is 2/0 wire. For the front winch I used 1 gauge. For the rear winch I used 2/0 if I remember correctly. One thing to keep in mind on the second battery setup is if you go to a larger alternator you need to upgrade the stock fuse link to the main battery. I cut out the stock stuff and wired from the alternator through a 200 amp fuse to the main bat. (size fuse to alt max. output) If you follow the wire charts for lengths/sixes etc. I'm sure you'll be fine. If you feel uncomfortable go to the next size larger.
I think my problems with batteries, isolators, and solenoids came from pulling a large amp load constantly from mostly the aux. battery which was mismatched with the main battery. Regular main vrs. deep cycle aux. Also, perhaps the location of the isolators/solenoids were on the side of the aux. battery box which is the hotter exhaust side of the motor. Also, I had a six gauge wire burn off at the alternator which ran to the solenoid. There may be better solutions out there now, but I am happy that the golf cart solenoid worked and will put in two Odessey 1700 batteries which will be matched for my next go round.
FWIW, here is a pic of the bracket and dual battery/dual winch switch setup I made. I can choose either battery to power either winch or choose both batterys to power either winch/winches.
Hope this is of some help.
Bill
 
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>> Let's try to forget that naked thing please. <<

Sure Bill.... you indelibly burn that image in our brains and expect us to simply *forget* all about it. Believe me, I wish I could but that haunting image will live with me for a looooong time.

-B-

(Haunting... get it? Halloween. Haunting. Hee hee.)
 
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I will be installing a dual battery setup in my truck, thus I have given a lot of consideration to the situation. Having installed and run dual batteries in a boat I also have some practical experience.

Ideally, wire size required is determined by the following three items:
A. Max amperage that will be required. If you are going to run a winch, the max amperage for a large winch is over 400 amps!
B. Total length of circuit.
C. The maximum voltage drop to be allowed. Voltage drop is bad, as it results in provided less power to the device (I.E. winch) which results in lower performance. 10% would be the max voltage drop that I would design for, and 5% certainly more desirable.

Once you run the calculations, or use the appropriate lookup tables, you will see the disadvantage of 12 volt, large amperage systems - the required cable sizes are very large, the cost can be fairly high, and the connections sometimes difficult do to the large size of the required connectors. I haven't yet measured the actual lengths of cable I will need, but I expect that 2/0 or 4/0 cable will be needed to minimize voltage drop when winching.

If you are going to charge batteries in parallel from a single voltage regulator, then the batteries should be identical in all respects including size, model, and age.

If the goal is to improve the overall reliability of your truck, then the design should be as simple as possible while still meeting all other objectives.

My objectives are a bit different than that addressed by designs posted by George and Christo. I want to be able to:

1) Power the entire vehicle from either battery or both batteries.
2) Totally shut off all power to all devices
3) Operate winch off either or both batteries
4) Disconnect winch from all power, independently of rest of vehicle
5) Automatically charge both batteries, regardless of which batteries are powering the truck
6) Automatically disconnect parallel charging when using winch.
7) Manually disconnect parallel charging when desired.


Objectives 1, 2, and 3 above are accomplished by using a 4 way marine battery switch. Switch 9002e (http://www.bluesea.com/Products/SW/SW.html) is what I will use. The four way switch allows me to choose from battery 1, battery 2, both, or all off. I will connect all of the wiring currently connected to the single battery positive cable to the output of the switch. This switch is the same or similar to what photoman has pictured. They are made by the same manufacturer. I believe photoman's are house branded West Marine and made by BlueSea.

Objective 4 is accomplished by using a on off marine switch. The input is connected to the output of the 4 way switch. The output is connected to the positive winch cable. This switch will normally be off and only turned on when winching is required. The switch that I will use is 9003e and is depicted on the page linked to above.

Objective 5 is accomplished by using a single solenoid. Model 9012, again depicted on the page linked to above, is the one that I will use. This solenoid will parallel the batteries when the engine is running.

Objective 6 is accomplished by using a relay to disable the solenoid when the winch switch is on. This is necessary to prevent the solenoid from paralleling the batteries when it is desired to power the winch from a single battery.

Objective 7 is accomplished by using a small switch to interrupt the coil power to the solenoid.

This scheme will let me operate electrical items in the truck, engine running or not, from either or both batteries. Neither battery is the master battery, and if either battery were to fail I can run the truck off of the other just by popping the hood and turning the switch. No overly expensive or complicated electronics are required. There is one risk that needs to be mentioned. If one were to disconnect both batteries while the engine is running, I would expect that the alternator diodes would burn out. You can eliminate this risk, but it requires modifying the alternator. The 4 way switch I specified above includes an integrated disconnect for the alternator field wire. When switching to off, before the batteries are disconnected, the field circuit is disconnected. Switching off the field circuit stops the alternator from charging and protects the diodes from burnout. The gotcha is that the voltage regulator and thus the field wire, is internal to the alternator on the 80 Land Cruiser. I have disassembled the alternator, and I believe it is feasible to modify the brush wiring to externalize the field wiring so that it can be routed through the 4 way switch.

Perhaps the above will be of interest to others considering installing dual batteries. The major difference between this and the designs posted by George and Christo is that this design enables one to run the entire truck off either battery and also be able to disconnect all power by a single switch.

Rich
 

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