2 batteries

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Ken Blackman

Blacks1971Duster
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I,m installing an electric fan and water pump in my 1971 Duster, 360 cid drag car ( mid 12 seconds). I want to install a second battery, do I install the second battery by connecting the positive to positive and negative to negative ( parallel ) and what size wire should I use to connect the batteries.

Thanks

Ken Blackman
 
I don't see any reason to run two batteries in these cars. Nowadays you can buy INCREDIBLY powerful auto batteries, most of which are overkill with most street engines

What engine combo, HP are you running?

AND it's "not the battery" that is needed to run big stereos, fans, etc, it's a larger alternator, and you do NOT want to try that with factory wiring, the factory bulkhead connector, and the factory ammeter

Please READ this article, which details a few of the problems:

Generally,

not a large enough alternator, nor do the factory originals put out enough at lower rpm

not large enough wiring

the bulkhead connector was NEVER designed to carry much amperage

the factory ammeter has it's own problems

http://www.madelectrical.com/electricaltech/amp-gauges.shtml


which came from here:

http://www.madelectrical.com/electrical-tech.shtml
 
Ken Blackman said:
I,m installing an electric fan and water pump in my 1971 Duster, 360 cid drag car ( mid 12 seconds). I want to install a second battery, do I install the second battery by connecting the positive to positive and negative to negative ( parallel ) and what size wire should I use to connect the batteries.

Thanks

Ken Blackman
Click to expand...
Hello Ken, you run + to + and -to -, this give you still 12 volts, but 2x the cranking amps, use typical battery wire, same size/gauge from your starter, ground, etc. 6 or 8
 
Hello: Tribute SS/A 68
I'm not looking for more cranking amps. just more battery storage capacity inorder to run electric fan and water pump when I get back to the pits. If I get 2X the cranking amps is the chance this will burn out the original wire in the car? ( such as the factory bulkhead connectors)

Ken Blackman
 
The cranking amps do not put any extra load on your wiring, they give you more reserve for cranking. This reserve is storage.

Grant
 
OneOfMany said:
The cranking amps do not put any extra load on your wiring, they give you more reserve for cranking. This reserve is storage.

Grant
Click to expand...

Actually, if you have the typical factory stock Mopar ammeter/ bulkhead connector wiring, it CAN strain the wiring, because two big "high cranking amp" batteries can behave with a lower charge impedance that a single, smaller battery.

If you try and compensate with a larger alternator and the factory wiring, you are inviting trouble. Time to read the MAD article on the subject:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

But you MIGHT want to read the race rules now that we know what you are after. I believe NHRA only allows ONE battery in some classes, but I could be wrong.

From the 2011 rulebook:

"A
maximum of two automobile batteries, or 150 pounds combined
maximum weight (unless otherwise specified in Class
Requirements), is permitted"
 
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