NHRA Battery Rules

[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.

[Coleydog]

Talk about taking an acid trip if the shaft brakes! Look out I see an explosion proof box in the future from the guys up top.

[SSDiv6]

Originally Posted by Coleydog

Talk about taking an acid trip if the shaft brakes! Look out I see an explosion proof box in the future from the guys up top.

Would not be surprised if it happens, especially with Lithium batteries.
Last year there were several fires caused by runaway Lithium batteries.
The FAA even put a stop to shipments of Lithium batteries from a well know manufacturer due to lack and failures of compliance testing.

[Coleydog]

Originally Posted by SSDiv6

Would not be surprised if it happens, especially with Lithium batteries.
Last year there were several fires caused by runaway Lithium batteries.
The FAA even put a stop to shipments of Lithium batteries from a well know manufacturer due to lack and failures of compliance testing.

Hmm. I was looking at one of these, being like 2 pounds 3x6x6 600 cca. Might not now.

[Larry Hill]

I have a disconnect switch on the drive shaft hump next to me that kills all power and engine when when switched off. Its on the negative side of the battery. Just in case something bad happens.

[Rich Biebel]

Originally Posted by 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.

Very bad deal there and I know first hand how bad.
I pulled an engine on a '69 Vette at home for a customer and we rebuilt the engine at the shop I worked at. An LT-1 350.

Reinstalled fresh engine and recall tugging on positive battery cable as it was very tight going on the starter solenoid.

Got engine running and all was ok after struggling with a few typical Corvette issues....

Started to drive it to work....a 10 mile ride....Heard some odd crackling noises and saw some smoke at the shifter console....realized something was burning up electrically under the console......pulled over and was able to push the console out of the way and stop the dead shorted battery cable that had been whacked repeatedly by the u-joint and had shorted out....console luckily was loose...

Car was dead in water.....parking brake did not work.....nosed it into a curb on a down hill street.....more to the story but that was plenty already...

I never had anything but bad things happen anytime I worked on a Corvette.....and I have a much worse story....!!!

[George Mirza]

The original reason for the second battery came about when Nhra stopped the practice of cooling the cars in the staging lanes with cold water. They allowed a second battery to run extra fans and water pump drives to make up for the cooling. But over time the use of the second battery became blurred and now is used as part of the electrical system. Problem is in a stocker you need a working alternator which makes the ability of the master cutoff switch to kill the car a complicated issue. This is one of those gray areas where every tech guy and division has their on take on it. The master switch on my car has never shut the car off, only the accesories hooked to it. I always started and ran my car with the front battery and alternator. The rear battery was used for cooling only and not tied into the charging system.