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dual batteries: yes, i know i'm beating a dead horse!!!! just 2 more ?s

Discussion in 'The Garage' started by rick88blaze, Nov 8, 2003.

  1. rick88blaze

    rick88blaze 1/2 ton status

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    dual batteries: yes, i know i\'m beating a dead horse!!!! just 2 more ?s

    is this the correct wiring diagram for the sure power isolator with the SI series alternator in most of our trucks?

    [​IMG]
    Also, will the 95 amp isolator be able to handle the stock alternator, and do you think it will handle a 140 amp alternator? /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif
     
  2. rick88blaze

    rick88blaze 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    I did some more research on other websites, and made a couple of phone calls. This is the correct diagram for the SI alternators. I would still like opinions on the amp rating of the isolator, compared to the amps from the alternator. /forums/images/graemlins/1zhelp.gif /forums/images/graemlins/ears.gif

    Rick
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    1. It would be absolutely silly for anyone here to tell you that you could put 140 amps through a 95 amp amp isolator.

    2. I think it's a total waste of time and money to isolate your batteries. Quick disconnects are really cheap.
     
  4. ntsqd

    ntsqd 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    It's Dead, Jim.












    Ideally you want the Isolator to be rated a little higher in amp capacity than the alternator can put out. Never work anything to it's rated capacity by design, only by circumstance.

    Why do you want an isolator ? If you want one starting battery and one for the stereo (All night camping parties and such) etc., get the Cole-Hersee constant duty solenoid. About $30. Connects the batteries together only when the ign is on.
    Isolators have a voltage drop in them. The result is that unless you have an Alt shop tweak the regulator the batteries will never get fully charged. That's not only capacity you can never use, it plays a part in shortening the lifespan of the battery.
     
  5. rick88blaze

    rick88blaze 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    first of all, i'm not asking opinions on what type of setup to use. i just wanted to know what the ratings mean on an isolator. next, i don't want quick disconnects on my batteries. i just want them isolated. here is the isolator that i've got. isolator link it says that the isolator can handle 25 to 350 amps. what's the difference between the 95 amp rating and the 25 to 350 amp system rating?
     
  6. rick88blaze

    rick88blaze 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    i've talked to about 4-5 different places here about isolators, and none of them said anything bad about them, and they weren't just giving me a sales pitch. 3 of the places were just garages. i just can't get a straight answer about the ratings on the isolators.

    Rick
     
  7. rick88blaze

    rick88blaze 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    P.S. I don't mean to offend anybody with my remarks above. i've posted about dual batteries a couple of other times before. from what i've gotten on here and from shops around Vegas, the isolator seems to be the best choice for what i plan on doing with my truck later on. i was just trying to get some more facts about the isolator. /forums/images/graemlins/cool.gif /forums/images/graemlins/grin.gif
     
  8. SCJimmy

    SCJimmy 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    Did you check out the Sure Power Industries website?

    Looks like they make several units for the application, of different capacities.

    I plan on doing this soon, with a deep cycle for the winch, isolated from the start battery.

    I would definitely use a larger unit, to give yourself some extra capacity.

    To address to notion that isolators are un-nesessary, silly , or stupid, read the explanation below, from the Sure Power website.


    [ QUOTE ]
    WHY YOU NEED TO ISOLATE YOUR BATTERIES
    Many vehicles and other types of equipment have multiple batteries... one to start the engine, and others to power accessories. To understand the problem of multi-battery drain, and how a Sure Power Battery Isolator prevents it, think of electricity as water. Electrical current is equal to the flow of water, and voltage is equal to the pressure. The alternator pumps current (water) into the batteries.


    The current then flows through the wires (pipes) to the accessories. Its important to think of batteries as storage tanks. If a fully charged battery is connected directly parallel with a discharged or empty battery, the voltage pressure in the full battery will force its current into the empty battery until the current stored in both batteries reaches a common level. The discharged battery will always rob power from a charged battery. So, no matter how many batteries you have on your vehicle, the accessories connected to one will draw power from the other batteries in the circuit. This is the problem of multi-battery drain. If it's allowed to continue unchecked, it can leave you stuck with dead batteries and an engine that won't start... all when you least expect it.


    THE SOLUTION
    To eliminate the multi-battery drain problem, a Sure Power Isolator acts as a check valve between the batteries, preventing current from flowing from one battery to another. Each battery is isolated, and acts as an independent power source. So, no matter how drained your accessory batteries become, they will never drain power from the battery you are depending on to start your engine. When the current is used from battery #2, the check valve (diodes) stops current flow from battery #1. When the alternator is charging, current can only flow in one direction, from the alternator to the batteries.

    Each battery then determines the amount of current which flows into it by its own state of charge based on the voltage regulator setting. With this system, the alternator is protected, and the batteries are protected. The balanced electronic Isolator is absolutely the only way proper isolation and control can be accomplished and every multi battery problem solved.


    [/ QUOTE ]

    Just my .02, but I believe it would be a worthwhile investment.

    Is it possible that your unit is rated 95 amps continous, 25-250 amps intermittent duty?

    If so, so long as your battery contained a reasonable charge, I would think it would supply the majority of the current to the load, with the alternator making up the difference as the battery is drained.
    /forums/images/graemlins/thinking.gif

    Byron
     
  9. rick88blaze

    rick88blaze 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    the isolator I got from NAPA is a sure power. I think you are right when you said that the 25-350 amps is intermittent. i'm going to call sure power tomorrow or tuesday to double check what all of the amp ratings are about. i'm not too worried about the 95 amp rating. i do know that is the max amps it will take from the alternator. for what i have right now that should be plenty. a 95 amp alternator will only be putting about 1/2 to 3/4 of that to the batteries at one time, depending on what accessories you have running. I'll post up sure power says after i talk to them. /forums/images/graemlins/thumb.gif

    Rick

    P.S. thanks for backing me up on the use of battery isolators /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  10. ntsqd

    ntsqd 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    [ QUOTE ]
    i've talked to about 4-5 different places here about isolators, and none of them said anything bad about them, and they weren't just giving me a sales pitch. 3 of the places were just garages. i just can't get a straight answer about the ratings on the isolators.

    [/ QUOTE ]

    In and of themselves isolators aren't a bad thing. There are just some things about them that you need to know. I looked at that page too and what I get is that it will withstand 95 amps continuous. Exactly what they're trying to say with the 6-48 volts - 25-350 amps mumbo jumbo I don't get either. If they are saying 350 amps at 6 volts ranging up/down to 25 amps at 48 volts, their wattage calcs are off. By a lot.


    [ QUOTE ]
    [ QUOTE ]
    ....... When the current is used from battery #2, the check valve (diodes) stops current flow from battery #1. When the alternator is charging, current can only flow in one direction, from the alternator to the batteries.

    Each battery then determines the amount of current which flows into it by its own state of charge based on the voltage regulator setting. With this system, the alternator is protected, and the batteries are protected. The balanced electronic Isolator is absolutely the only way proper isolation and control can be accomplished and every multi battery problem solved.


    [/ QUOTE ]

    [/ QUOTE ]

    All of this is true, but what they aren't telling you is that those check valves come at a cost beyond out of your wallet. To get them to open requires what's called a "cracking voltage", they have a voltage drop of almost one volt across them in the 'right' direction. How this matters is that the voltage regulator in the Alt is set to let the Alt produce ~14.4 VDC so it will have enough more voltage to bring the battery(ies) up to 13.6 VDC w/o over-voltaging them which would cause them to boil - a bad thing. So you come along and put an isolator in the circut. The diodes in the isolator 'consume' nearly one volt in order to allow current to pass from the Alt to the battery. So now that ~14.4 VDC is cut down to ~13.4 VDC, which isn't enough to completely charge the battery. The simple cure is to take your Alt to a real Alt/Starter/Generator shop and tell them what you're trying to do. They can tune a regulator to allow the Alt to put out enough volts to get a full charge thru the diodes. This is a common thing, if they don't know what you're talking about you're in the wrong shop.
     
  11. Batmanjr

    Batmanjr 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    Just to let the average user know... Isolators are not a bad thing and they are the correct way to isolate your batteries! I use one and do not have a voltage drop! I have dual yelow tops ran parallel to each other that are wired to the starter only and another RV battery on the other fender that runs the rest of the truck and the stereo.... I did this so that my diesel could use the yellow tops and have maximum cranking speed and amps! Before I isolated my batteries, the stock setup would drain the batteries and leave the truck without enough power to crank the diesel engine... With three batteries, two acting like one, I always haad them at a constant 13V and never cooked a battery liked mentioned before! I simply hooked the RV battery up to the alteranator and let it drive the power draw... Knowing that the yellow tops would never be drawn lower than the RV battery and that the RV battery was in constant use while the truck was on, the yellow tops were always kept at full charge! I don't know the technical terms for it, but with it hooked this way, you really can't over charge the yellow tops.... The current will always go to the battery with the most demand! Therefor, Since there is less resistance with the RV battery once the yellow tops reach max capacity, the current overflows into the RV battery and charges it alone! Once the RV battery is full or practically full, it cuts down the Alternator draw and therefor keep the alternator from cooking anything! Since the RV battery controls the alternator! I have never experianced a downside to wiring my batteries this way and have done so for over a year now! The only thing I need from the RV battery to start the vehichle is enough power to throw the starter solinoid! Once that happens, all the cranking amps come from the yellow tops! If I ever run the RV battery down all the way(leave the lights on), I simply jump myself with a single jumper cable and it works great!!!! I Highly suggest this setup for whoever looks at using there power supplies to their fullest extent! I have messed and researched many differnt setups and this has worked by far the best I have ever seen! Switches work, but aren't convenient, Solinoids and relays are nice, but expensive and fail... They also enduse drain while the vehichle is running... There are many ways to doing this, pick whichever best suits you and go for it! /forums/images/graemlins/thumb.gif
     
  12. rick88blaze

    rick88blaze 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    I called Sure Power today. They said that the 95 amp isolator is perfect for the 94 amp SI series GM alternator. They told me that it is the one most recommended for that alternator. The 25 to 350 amp ratings are for the vehicle's electrical system overall. Like if the vehicle has a rated amp capacity of 200 amps, but the alternator is 95, then you can use the 95 amp isolator. He also said that if an SI alternator is working properly it will self adjust the voltage output to make up for the voltage drop from the isolator. He exlpained how to check it. If any body else wants to hear it you can either call sure power at 503-692-5360 or you can PM me and i will give you my home phone.

    Rick
     
  13. ntsqd

    ntsqd 1/2 ton status

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    Re: dual batteries: yes, i know i\'m beating a dead horse!!!! just 1 more ??

    [ QUOTE ]
    ....I use one and do not have a voltage drop!.....

    [/ QUOTE ]

    If you use an isolator you have a voltage drop across the diodes. If there is no voltage drop you don't have diodes, you have relays. It's that simple.

    I never said that an isolator is a bad thing. I did say that their vendor isn't saying everything there is to know about them. Late model's require the 4 post isolator which allows the Alt to 'see' the actual voltage of one of the batteries. Prior to the 4 post isolator there was no way for the Alt to 'see' this and the regulator had to be adjusted to offset the drop. I was operating on the assumption, good or bad, that a 3 post isolator was intended.
     

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