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Discussion Starter · #1 ·
I was thinking to run 2 batteries in my 64 fairlane. My problem is when I turn the fuel pump on and the fan I can hear the pump drop in volts and see it on my volts gauge, so I was thinking 2 batteries tied together and use one for my accessories, or is there an easier way?
 

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It's probably a weak alternator. One battery should be enough for that. However, lot's of people run dual batteries, mostly trunk mounted. My truck (F350 Power Stroke) came with dual batteries mounted up front. If you are going to run two make sure you hook them up properly or you'll end up with 24 volts and bad things will happen. :eek: Also some kind of switch to be able to isolate them.

I say get the right alternator and be done with it.

John
 

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I was thinking to run 2 batteries in my 64 fairlane. My problem is when I turn the fuel pump on and the fan I can hear the pump drop in volts and see it on my volts gauge, so I was thinking 2 batteries tied together and use one for my accessories, or is there an easier way?
cheaper in the long run to just get the right alternator.....the one u have now is most likely being overworked and will go out soon. this will continue until you get a beefier alternator. In my neck of the woods there is an electrical place that can beef up ur existing alternator for a very reasonable price. Probably somewhere like that in ur area also.
 

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Agreed - you are in a losing situation if your generator isn't providing enough power to maintain proper voltage. And, I assume it is the original 1964 generator setup, and not already converted to alternator?

Dual batteries are primarily for vehicles that will have a draw on the batteries when the engine is not running. This provides one battery to drain as you wish with the engine off, but have the other fully charged for engine starting. Even in this case the alternators are yet more powerful, as they must not only recharge the starting battery after cranking, but also recharge the partly or fully discharged accessory battery - all while powering the vehicle, lights, pumps, wipers, etc. Again, sufficient alternator amperage output is key to a solid system.

David
 

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Your going to have to add up ALL the accessories in your car that draw power....I mean EVERYTHING from the radio to the headlights. Once you break down and add up what everything draws in amps, the total should NOT exceed 80% of the output of the alternator.

I also agree with the 1-wire alternator setup suggestion. BTW, just out of curiousity, do you have a relay wired into your fan and fuel pump circuits? If you don't , you should have them because the sudden current demand, especially for that electric fan, is too much of a shock to ANY alternator to handle over a period of time.
 

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Dual batteries are a crutch and should only be used in diesel applications that have a ton of cranking pressure. They need torque...and usually one standard size automotive battery won't turn it fast enough in cold weather to start it.

On 99% of gasoline engines, dual batteries are a waste of time/money. Even those 15:1 alky burning race engines. One battery is plenty. 16v batteries are getting popular, even in some hot street car applications. But 12v is usually fine for most. 12v battery plus a GOOD alternator...none of the one-wire crap either. A good Ford 3G alternator will run circles around a typical one-wire. And the 4G is even more efficient, but also more expensive.
 

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Discussion Starter · #8 ·
It's a new alternator and regulator I'm running... But maybe it's not getting enough juice. It's so bad even when I have my blinkers on my volts gauge will bounce in pattern with the clicking of them.
 

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I run 2 batterys in my race car. I also have no alternator. I have one 6 volt on one side and a 8 volt on the other side. They give a few more amps to the car when I switch on fan, fuel pumps and motor to water pump rather rhan one 12 volt. I also charge them with a 18 volt charger between runs
 

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Take your alt to be tested to see how many volts it is putting out. Some local parts stores here does that for free. Alt good I would make sure ya got a good ground to motor to frame, maybe add a higher volt battery . There could be a positive wire maybe touching metal somewhere when you cut things on that draws more amps or a small short grounding out. Your voltage regulator maybe going bad. Does not take but a few minutes to check those things. If not one of those ya not no worse off than before the changes. Maybe you will get lucky on one of those things. I can call the speed shop. He thinks he knows everything but most times he is correct. When you are 72 years old and raced fords all ya life one should have ran into near anything about a ford and what it is doing.
 

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Two batteries are NOT a crutch!!! I run two batteries,have a 100 AMP alternator on the Comet.I use it on the street and drags,NEVER have had to worry about a low or dead situation!Plus when I finish a run I can run my water pump and fan,NO PROBLEMS!!! ALWAYS use a relay on any high amp draw accessories! ROY.
 

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It's a new alternator and regulator I'm running... But maybe it's not getting enough juice. It's so bad even when I have my blinkers on my volts gauge will bounce in pattern with the clicking of them.
If you're running the early style ford\autolite alternator then it is likely only rated around 30-40 amps even if it's 'new' (reman). Back then that was plenty since there were fewer electrical accessories. These early ford alternators also would drop output significantly at idle. A good alternator will maintain minimum 13.0 volts with ALL accessories on at idle.

Running 2 batteries will help maintain voltage under short periods when the load exceeds the alternator's output but as stated previous, not the best way to go. You will overwork your alt trying to maintain 2 batteries.

Upgrade your alternator and you'll be fine.
 

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Discussion Starter · #13 ·
If you're running the early style ford\autolite alternator then it is likely only rated around 30-40 amps even if it's 'new' (reman). Back then that was plenty since there were fewer electrical accessories. These early ford alternators also would drop output significantly at idle. A good alternator will maintain minimum 13.0 volts with ALL accessories on at idle.

Running 2 batteries will help maintain voltage under short periods when the load exceeds the alternator's output but as stated previous, not the best way to go. You will overwork your alt trying to maintain 2 batteries.

Upgrade your alternator and you'll be fine.
Yes exactly....at a 800 rpm idle its only a little past 12v on my gauge and just jumping the idle to 1,000 goes up to right under 14v.... So I'm not sure how to keep a higher volt at idle
 

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Well...

You could just live with it. As long as you're not just idling around all the time you'll probably be fine.

Or...

You could put a smaller pulley on your present alt to speed it up and help maintain voltage at idle

Or...

You could do as suggested and upgrade your alt.
 
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