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Battery Isolator

Discussion in 'The Garage' started by drofdar, Oct 8, 2005.

  1. drofdar

    drofdar 1/2 ton status

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    I plan to use an Optima Red top for my charging system and the Yellow top for winch and onboard 12v air. They have different charging rates with the Yellow being a deep cycle. If I use a battery isolator, which would seperate the two batterys, but charge them with the same alternator, could that cause problems?
     
  2. Leper

    Leper 1/2 ton status

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    I run a group 31 yellow top as my only battery. It is big and tall but it is sooo strong. It is hooked up like a regular battery. I don't think you will run into any problems unless you use the blue top. Blue is the real deep cycle, yellow is kinda in the middle.
     
  3. Dallin

    Dallin 1/2 ton status

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    No, you will not have any problems using an isolator with different battery types.
     
  4. 4xcrazy

    4xcrazy 3/4 ton status

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    I was told by someone in the car electronics bizz, (a professional installer) that the isolators are not really all that great, as i was going to hook up dual batteries in the Burb, he mentioned some problems with them, he asked WHY there is usually a big heat sink on them? it's because they use some of the enegry they are transferring or something like that, so full power is not getting to the batteries, the other thing is he mentioned that the isolators don't usually allow for complete full charge of the batteries, not sure what exactly he was explaining to me, cause i was kinda in a hurry to get home, but maybe someone else on here can kinda fill in the blanks as to what i/he was referring to?

    i am still considering it though, as i have WAAAAAY too much running off the single and stock alternator.
     
  5. Leper

    Leper 1/2 ton status

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    What do you mean by this? Examples. I have never had the need for 2 alternators. Not with a 5000 watt stereo or winch or lighting. A high reserve capacity on the battery will take care of almost anything. If your stereo is at full volume and all of your lights are on at night while winching someone or welding I could see a brief need for more juice. Other than that, just run a good battery.
     
  6. txfiremank5

    txfiremank5 1/2 ton status

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    I think he's saying "single" as in single batt, and a stock (probably 100 amp) alternator.
     
  7. 4xcrazy

    4xcrazy 3/4 ton status

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    yup, sorry and thank you for clarifying that for me.

    The light rack i currently have on the roof, WILL kill the battery in about 5 minutes if i run with most of them on, not to mention the mild 1900 watt stereo system, and power everything in the truck, just too much work for the stock alt and single battery in my opinion.

    The other reason i was thinkin about the dual batt setup was to run all the add-on stuff, amps, add-on lights and whatnot, off of the secondary battery, so as not to kill the main starting battery and hopefully not leave me stranded somewhere.
     
  8. drofdar

    drofdar 1/2 ton status

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    If the isolators cause problems, or rob juice, perhaps two batteries of same type, ie: Optima Red tops, run in series could give the power needed. Then when using winch, or onboard air, perhaps a switch could isolate one battery, so that the other would not be drained, and leave you stranded. Does anyone have a diagram or experience with this type of dual batt setup?
     
  9. rick88blaze

    rick88blaze 1/2 ton status

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    I've been using an isolator from NAPA for a few years now and haven't had any problems. I still use my stock alternator too. HERE is the isolator I use. :D

    I have a pic of the wiring diagram too if you would like. :D

    Rick
     
  10. opfor2

    opfor2 1/2 ton status

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    I found this maybe it may help Found here: http://www.bcae1.com/battiso.htm


    Battery Isolators:
    Many people listen to their stereo without the engine running. This often leads to dead batteries and a vehicle that won't start. A battery isolator will let you completely discharge one battery without discharging the starting battery.

    Different Types of Isolators:
    There are 2 main types of battery isolators. The diode based type and the relay (solenoid) type.

    Diode Based Isolator:
    This type of isolator is basically two very high current diodes in a heat sink. The diode based isolator has the advantage of long life and trouble free operation but many of the diode based isolators cause a .4 to .6 volt loss which means that the batteries will not charge to as high a voltage as when they are connected directly to the alternator. The diagram below shows the connection for the diode based isolator. Some diode type isolators have a fourth terminal which controls the current flow through the device.




    --------------------------------------------------------------------------------


    Solenoid Based Isolators:
    This type of isolator uses large high current relays to control the flow of current. The diagram below shows two solenoids. Solenoid A determines whether the second battery is connected to the rest of the charging system or not. Solenoid B connects the second battery to the distribution block. The second solenoid allows a complete disconnect from the amplifiers for safety. The diodes connected in parallel to the solenoid's coils are used to protect switch A and switch B from inductive kickback when the solenoid's coils are de-energized. The advantage of the solenoid based isolator is that there is virtually no voltage loss across the contacts. The main disadvantage is that the reliability isn't quite as good as the diode based isolator.

    The coil of the solenoid will draw significantly more current than can safely be supplied by the remote/power antenna output of your head unit. You should NOT connect them directly to the head unit. You need to use a relay to buffer the remote/power antenna output of the head unit so that the head unit's switching transistor isn't damaged.

    In the demo below, click on the head unit to switch it on and off. Click on either side of the toggle switch to change its position. The round green dots are voltage indicators. They are dark when there is no voltage and bright when voltage is present. The arrows indicate current flow through the respective part of the circuit. Switch A allows you to disconnect the main starting battery from the rear battery and amplifiers. This allows you to play the amplifier without fear of draining the starting battery. When switch B is off, the solenoid B is off (disconnected) and you can work on the amplifier's main power wiring without fear of shorting battery power to ground.


    Click HERE to make this demo fill this window.

    NOTE:
    There are 2 types of solenoids. They look virtually identical but are designed for different uses.

    Ford Type Solenoid:
    If you're familiar with older Ford vehicles, you've no doubt seen the fender mounted solenoid. It's used to make/break the connection from the battery to the starter. This solenoid is designed to pass as much as 400 amps of current but only for a short period of time. The solenoid's magnetic coil has only 3-4 ohms of resistance. If used for continuous duty, the coil will overheat and fail. The low resistance provides higher the contact pressure that's needed to keep the contact resistance to a minimum.

    Continuous Duty Solenoids:
    For main power switching in car audio, you need a continuous duty solenoid. These solenoids will have approximately 15-30 ohms of resistance across the coil. As you can imagine, this will allow the coil to run much cooler than the starter solenoid mentioned above (although the solenoid will be quite warm after a while). The solenoid I've used is the White-Rogers 70-111224-5. It's available from Grainger or virtually any auto parts supplier. It's rated at 80 amps continuous and can take short periods of higher current flow. I've been using one on my test bench where I draw more than 100 amps through it for 20 minutes at a time and it hasn't failed yet.


    --------------------------------------------------------------------------------


    Adding a second battery without using an isolator:
    Some people have good results when they add a second battery to their system. Especially if the second battery is close to their amplifiers. If you want to add a second battery, there are a few things that you should know.

    If the battery is inside the passenger (in a hatchback vehicle or in a car with a back seat that folds down), you must use a sealed battery (i.e. Optima). If the battery is being used in the trunk of a vehicle you can use a standard battery but you will need put the battery in a battery box and you will need to provide proper ventillation. Proper ventillation would mean forced air (fan) ventilation from the battery box to the outside of the vehicle. When a standard lead acid battery charges, it produces flammable gases which must be removed from the vehicle to prevent a fire/explosion hazard.
    The second battery must be fused. The fuse must be as close to the battery as possible (just as you have on the main battery). All of the power for the system must flow through through the fuses (at the batteries) to protect against electrical fires. The diagram below shows the proper fusing and wiring. The fuse at the main battery must be properly rated to protect wire 'A'. The fuse at the second battery must be properly rated to protect wire 'B'.



    No matter what kind of battery you use, care must be taken to assure that nothing can come in contact with the battery's terminals. I would strongly recommend putting the battery into a plastic battery box with a cover that can be secured onto the box.
    The ground for the second battery should be grounded to the floor pan of the vehicle. The floor pan is the main piece of sheet metal that forms the largest portion of most new vehicles. This will provide the best return path for the second battery.
     
  11. MarcS

    MarcS 1/2 ton status

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    Nice website. Great info. Here is a link on the subject from a while ago from CK5 to give you ideas on the different ways to do this from simple to expensive.

    Dual Batteries
     
  12. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    Basically all a battery isolator is one or more Schottkey diodes. They're dirt simple inside. They can take around .6v out of the system. If you want to, you don't have to lose any voltage as long as your alternator has an internal voltage regulator.

    I have my truck set up so I run my truck off one battery and have one diode isolating my auxilary battery. I have non-critical stuff running off the auxilary battery like electric fans and the such.
     
  13. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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  14. Dallin

    Dallin 1/2 ton status

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    The .4 to .6 volt drop that is characteristic of battery isolators isn't that big of a deal. 3 wire alternators that are found stock on Chevys have a remote sense wire that compensates for the voltage drop. If the alternator is set to put out 14.1V and the isolator has a .5V drop the alternator will put out 14.6V so the batteris still charge at 14.1V. There is no incomplete charging to worry about. If the alternator is putting out 100 amps then the isolator will consume 50 Watts of power with a .5V drop. That really isn't too much power (about the same as 1 headlight). The power is turned into heat which is the reason for the heat sink. Isolators are used stock on police cars, fire trucks, ambulances and many other commercial vehicles. They are extremely reliable and don't require any thinking on the part of the user. I think their bad reputation is undeserved.

    Technically solenoids or relays should be called battery combiners or disconnectors. They don't really have any ability to isolate batteries.

    The Hellroaring setup has some interesting advantages and extremely low power consumption, but I still prefer an ordinary isolator for its simplicity.
     
  15. neverendingproject

    neverendingproject 1/2 ton status

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    The yellow top is a heavy duty deep cycle, and the blue is a marine battery, but also a deep cylce. something with material makes them different, but both work just as good. I have a yellow top and I will never go to a different battery.
     
  16. rick88blaze

    rick88blaze 1/2 ton status

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    Here is a diagram of how my batter isolator is setup. My K5 sat in storage for 8 months last year and my Red top optima went completely dead and had a dead cell in it. My backup batter was still charged enough that it fired my K5 up right away after it hadn't been started in 7 months. After seeing that, I'm a very firm believer in isolators now. I put it in originally because it was a cheaper setup. :thumb:

    Rick

    [​IMG]
     
  17. MarcS

    MarcS 1/2 ton status

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    Yes, the newer alts have a remote sense wire and should take care of the diode voltage drop.

    As for solenoids/relays/combiners and a simple switch, it's all in the way they are wired for isolation. See the link I posted for wiring diagrams.

    The Hellroaring setup seems to have the best of both worlds. It has diodes for isolation, then they are jumped out for full power while cranking the engine. The price is rediculous though.
     
  18. Dallin

    Dallin 1/2 ton status

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    I like the Hellroaring system, but the solid state switches used to jump the batteries together are a major weakness. The Hellroaring site says it can only handle 150 amps from the aux. battery. That isn't enough to power a starter and deffinitely not enough for a winch. This is why they suggest allowing a dead main battery to charge for 15 minutes from the aux. battery before trying to start the vehicle. If the solid state switch was burned out I guess you could always pop the hood and connect the batteries together with a short cable, but then why would you buy the Hellroaring setup.

    I've read the post you linked to and it's full of errors. There are a lot of different ways to control relays, and some of them work really well. But they still aren't isolators. Relays only have 2 modes connected and disconnected. That's just symantecs though, no big deal.
     
  19. az-k5

    az-k5 1/2 ton status

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    I have heard those isolators only put a trickle type charge to the second battery. I want to run a winch/lights battery and a start/truck battery but was afraid of an isolator not keeping up with the demand of one of them. I currently have 2 wired in parralel.
     
  20. Dallin

    Dallin 1/2 ton status

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    Diode isolators fully charge both batteries when properly setup. There is no reduced charging of either battery. This is a common misconception of diode isolators.

    Having said that, many people improperly install there isolator or try to use it with a 1 wire alternator. This can result in a reduced or weak charge. If this were true of all isolator installations isolators wouldn't be regularly used on critical equipment like ambulances, fire engines and military vehicles.
     

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