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Dual Battery Hook Up

Discussion in 'The Garage' started by K5er4Life, Mar 13, 2006.

  1. K5er4Life

    K5er4Life 1/2 ton status

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    http://www.westmarine.com/webapp/wcs/stores/servlet/product/10001/-1/10001/91533/10001/297/207/9

    So i picked up one of these heavy duty marine selector switches, i have a bunch of 1/0 cable that im gonna use to hook it up, i plan on running dual optimas and i have TWO QUESTIONS:

    1. To which battery should i hook the alternator wire to, or does it matter??

    2. Should I buy two red tops or a red top and a yellow top, basicly what im getting at should i keep the batteries the same or can i run a deep cycle and a cranking battery??

    SUPER SNAZZY!
     
  2. blazindorito

    blazindorito 1/2 ton status

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  3. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    well I was told to not put the same batteries together.. if you use an isolator then you can.... so if you hook one to #1 and another to #2 you should be fine....

    I have 2 - duralast gold 1000ca batteries.. dual posts too
    I have my duals just hooked together.... ground on each goto block (side posts)... and top post + on passenger side goes to drivers side + on side terminal... passenger side + to starter...... then both top posts on drivers side go to my winch..... 3/0 cable running from front of truck to the back... 20 feet of it!!!! per + and - :haha:
     
  4. K5er4Life

    K5er4Life 1/2 ton status

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    I am aware of those hellroarg battery isolators and a few other that they sell at the auto parts store, but I liked the simplicity and price of the marine switches. I have also heard its not good to run 2 different batteries together, which was why I was wondering about the red and yellow tops. Diesel trucks have atleast 2 or many more batteris hooked in parallel and never seem to have any problems. And the same with boats, they have run these switches for a long time. Nevertheless, I will have the negatives on the batteries hooked together and grounded very well. Thats one thing I am also going to do is rerun all new grounds with some heavy cable. Then on one battery the + side will go to terminal one, and the other battery the + side goes to terminal two. And then the "both" position on the switch goes to the starter. This is my understanding of what needs to be done. I just dont know to what battery the alternator wire should go to, along with my accessories. Or if it even matters for that matter. I am definitely no electrical guy that for sure so excuse my ignorance.
     
  5. MarcS

    MarcS 1/2 ton status

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    Just connect the grounds (Black) together.

    Red from one battery + to switch lug (1 or 2) the other Red to the switch (1 or 2), whichever one you didn't use.

    Connect the alternator and the main cable to the truck to the 3rd terminal on the switch. This should be the common lug.

    This way, if your on battery 1 or 2, the one your on will be charging. On Both- both will charge.

    It is a good idea to put on some kind of isolater, simple diodes to a Hellroaring.
    I wouldn't spend the money on the Hellroaring. See this link http://www.westmarine.com/webapp/wcs/stores/servlet/product/10001/-1/10001/97718/10001/208/207/9.

    There is also a 70 amp for less money.

    This link has other ways to combine batteries-their pros/cons etc....http://coloradok5.com/forums/showthread.php?t=139733
     
  6. Burt4x4

    Burt4x4 3/4 ton status

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    I put the Hellraoring in years ago and have never had it let me down and it automatically keeps both batts charged and I even know when my altenator craps out or is no longer charging and I can Combine the batts for double the power if needed. Technology is great...don't be affraid of it:D
     
  7. MTMike

    MTMike 1/2 ton status

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    [​IMG]

    Mine's in my garage just waiting to be put in....
     
  8. Leper

    Leper 1/2 ton status

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    I hope you mean to connect them together and then to a chassis ground.
     
  9. K5er4Life

    K5er4Life 1/2 ton status

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    I probably should run the isolator but what the real advantage versus the switch I have? Isnt the voltage regulator in the alternator suppossed to keep from overcharging the batteries anyways? I know with that isolator the relay thingy will switch to the battery that needs the charge, other than that whats the wondrful thing about them? I have read that some have had issues with running such a large cable to them only because the lugs will be too big and they will touch each other. I think Kidjethro had this problem iirc. The other downside is if I run off my sarting battery I wont be able to run my stereo until I switch over to the accessorie battery. Ohh and if I do run a red and a yellow and if I leave the switch in the both position its possible that batteries will drain themelves. These are all statements/questions that are just what I have gotten from searching and trying to interpret myself about what the pros and cons are of that switch.
     
  10. Burt4x4

    Burt4x4 3/4 ton status

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    Dual Batt info here www.hellroaring.com
    The site has alot of great info on dual batts and all the different was to use dual batts. Scematicas and all
    [​IMG]
    My setup I have it wired up so my second batt is 100% backup. I have nothing hooked up to it.
     
  11. chevyin

    chevyin 1/2 ton status

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    Its not 'bad' to run multiple batteries together, there are just certain issues you must be aware of. First and foremost, you need to understand all batteries have an internal resistance. This resistance will increase over time from useage of the battery (the plates oxidize due to the chemical processes) which affects the battery's charging efficiency. So placing two batteries together in a circuit with much different internal resistances (great age or design differences between the batteries) will result in them charging unevenly. So when running multiple batts you either want to buy two new batteries to start with (or however many you plan to run together), or you want to run an isolator.

    Isolators do exactly what the name implies, it isolates two (or more) batteries from each other, 100% of the time. The batteries charge and discharge completely independant of each other.

    Switches like this marine switch usually just run the batteries in parallel when in the 'both' position, which is much like simply splicing the batteries together in parallel with the added advantage of controlling which batt is being used.

    Another simple and effective method is to run a relay (usually 200amp for this application.... about $50) which will allow you to run the batteries isolated from each other when the relay's contact's are disengaged, and run them paralleled for charging. With the engine off, the relay's contacts are disengaged and the batteries operate independantly which means you can run the secondary batt dead using stereo/winch/etc and still have a full batt to start the truck. With both the relay and the switch method, you must take battery resistances into consideration as I mentioned above (basically buy two new ones).

    Isolators generally cost more than switches or relays (2x-3x) and some do have problems with voltage loss through them, but they do not have any concerns about the age/condition of each battery they isolate. There are advantages and disadvantages to each setup.

    There are many ways to run multiple batteries that work just fine. But, there are also some ways to run them that will yield worse performance than a single batt alone. Understand what you are doing and it's easy to set up a large power reserve in your rig. :)

    Cheers.
     
  12. chevyin

    chevyin 1/2 ton status

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    As for red tops versus yellow tops, the main difference is in their design. The yellow top is a deep cycle which means it can be discharged (even fully) and recharged without any noticeable degredation in performance. Normal non-deep cycle batteries lose a little capacity every time they are discharged and recharged. The drawback to deep cycle's is they tend to not have the cold cranking amps of traditional non-deep cycles. Some people claim yellow tops wont work for a main battery for this reason, but Ive personally used a yellow top as my main batt for several years without problem. However this was on a 4.3 V6, I have never tried using one regularly for turning over a high-compression bigblock etc. ;) Id recommend either getting 2 yellow tops, or if you are concerned about the CCA's, one rep top for the main and one yellow top for the secondary. I highly recommend the secondary batt (at least) be a deep cycle so you can drain it with engine-off useage without worry of damaging it upon recharge.

    Hope I helped.
     
  13. K5er4Life

    K5er4Life 1/2 ton status

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    Great, thanks for the info. I will buy two new batteries, but I was unsure if I could run two different ones. Sounds like you answered my question, I am going to run the yellow on switch two, red top on number one. This way I can start the truck and if Im sitting listening to music or winching (soon I will have one) I can kill the yellow and switch over to the red. So far I think my plan for batteries setup should work out nicely. I am having a charging issue when I have my stereo up and the bass hits but I think that is a result of horrible grounds. My alt. is new and I dont want to rig up these batteries to mask the problem I have now.

    Lets say that I kill battery 2 (yellow top) and I start the truck on battery one (red top), will I have to switch over to both or battery 2 to get the yellow to charge? Will both batteries be charging all the time no matter switch position. I do know not to switch it to the off position while running, but I can switch it through the both position while running. The instructions in the box say I can do that. It does also say the in case by accident I do switch to the off position while running there is a fail safe to prevent the alt from going out. But I really dont want to find that out.
     
  14. chevyin

    chevyin 1/2 ton status

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    First, Im not familiar with that exact switch, so my comments are only based on assumptions of generic switches. Assuming its a standard setup, you will need to switch either to batt 2 (the one that needs charged) or both before it would charge, as it will also be isolated from the alternator otherwise.

    Your current charging problems could be from many things, bad grounds are only one possibility. How big is your amplifier(s)? How big is your alternator? A decent sized aftermarket stereo system can easily overpower even a brand new stock sized alternator. If you think the problem is elsewhere, Id start by upgrading the charging cables under the hood (alt and battery cables plus ground cable) as the stock system was not intended to pass so much current through it.

    Also keep in mind that adding auxilliary batts will actually place a larger load on your alternator. It certainly wont double the load, as each batt would take up some of the charge/discharge/storage needs, but over all you do have additional resistance in the charging circuit (more added internal resistances from the batts). Adding a second batt wont likely hurt anything assuming the charging system isn't riding the ragged edge of keeping up already, but it also wont help an under-powered charging system like so many people seem to think.

    Good luck and keep us posted.
     
  15. MarcS

    MarcS 1/2 ton status

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    Yes, thanks for catching that.

    I'm not. That's why I'm going to use this setup. Much simpler and cheaper than the others (For me).
    (6 million dollar man voice) I have the technology, I will built it.:rotfl:

    Like chevyin said, the disadvantage with this setup is it's not isolated and if one battery loses a cell it will kill the other when both are connected.

    And whichever way you go, LEAVE EXTRA CABLE, so if there is a failure you can just move the cable to the other post and jump out the system.
     

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