NHRA Battery Rules

[DIV3CR]

On a stock car if you have a battery in the trunk and one under the
hood what does the front battery power and what does the battery
in the trunk power, buy NHRA rules.

[Lew Silverman]

I don't think the rules drill that far down - the only requirements are that both batteries be physically the same (no dummy battery up front!), the rear battery is mounted properly and that your battery shutoff kills the power to the whole vehicle. Other than that you're on your own, although most folks power the fuel pump/module with the rear battery through a heavy-duty relay.

[B Aceves]

Originally Posted by DIV3CR

On a stock car if you have a battery in the trunk and one under the
hood what does the front battery power and what does the battery
in the trunk power, buy NHRA rules.

It does not matter . Most guys wire them in series so it doesn't matter what you have hooked to either battery they will draw the same other than the difference in length of wire and voltage drop because of that. My concern has always been the live wire going from front to back even with the master switch off .
Until NHRA realizes that it just isn't safe because of that among other reasons maybe they will finally let us move the other battery to the back .
Last time I brought that up though I received some death threats and powder laced letters in the mail lol..But hey we got roller rockers now so everyone is much safer now and all is good.

[magnumv8]

According to what I understand...if they check the batteries each one
by itself MUST be able to start the vehicle.....also with the rear cut-off switch being required with the rear battery install, the vehicle must shut down when the switch is turned off....alternator kill.....batteries are wired parallel, series doubles the voltage, parallel doubles the current...

D L Rambo...STK 1300

[7423]

Originally Posted by B Aceves

My concern has always been the live wire going from front to back even with the master switch off .
.

BINGO..............starter in the front, battery in the back, 12 foot of positive cable, not very safe. If it was such a good idea the OEM would have done it years ago. Run one battery in the factory "stock" location in your stocker. What a concept, something stock in a stocker.

[426Fred]

Forgive me if I am wrong but don't the big three (GM, Ford, and Chrysler) install batteries in the rear of a lot of their new vehicles now? Super Stockers have been running batteries in the rear only since the early 60's. If you pay attention to what you are doing and follow safe wiring practices too include the correct size positive and negative battery cables, you will be just as safe as only having one battery in the front.

[FireSale]

Originally Posted by B Aceves

It does not matter . Most guys wire them in series so it doesn't matter what you have hooked to either battery they will draw the same other than the difference in length of wire and voltage drop because of that. My concern has always been the live wire going from front to back even with the master switch off .
Until NHRA realizes that it just isn't safe because of that among other reasons maybe they will finally let us move the other battery to the back .
Last time I brought that up though I received some death threats and powder laced letters in the mail lol..But hey we got roller rockers now so everyone is much safer now and all is good.

Whenever the topic of dual batteries comes up, series and parallel get mixed up. Series is wired + to - and doubles the voltage. Parallel is wired + to + and doubles the amperage. Parallel makes two 12 volt batteries into one big strong 12 volt battery. Never wire 12 volts in series in a race car.

Dale

[Coleydog]

If you have an alternator why do you need two battery's? Sounds redundant.

[B Aceves]

Originally Posted by FireSale

Whenever the topic of dual batteries comes up, series and parallel get mixed up. Series is wired + to - and doubles the voltage. Parallel is wired + to + and doubles the amperage. Parallel makes two 12 volt batteries into one big strong 12 volt battery. Never wire 12 volts in series in a race car.

Dale

Yep I mixed them up my bad .
I worked on tractors also so I always confuse the two

[Terry Cain]

Well, since it was brought up I'll add something to the mix. 68 and up Corvettes have the original battery located behind the drivers seat inside the interior less than 12 inches from the tunnel where the driveshaft is rotating. Think about that.