NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery 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.

Re: NHRA Battery Rules
 

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

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

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

Re: NHRA Battery Rules
 

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

Re: NHRA Battery Rules
 

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

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

^^

I totally agree with Charlie.

I have never liked the idea of a big fat " hot all the time" cable running from rear to front.
Once you have one short on you, you'll understand....ask me how I know. lol

Obviously this will not work on a Stocker, but this is how I have wired all my bracket cars for years ( not any of my Stockers tho)

The rear main power switch kills the engine and all power to the car immediately, but never handles the starter current:

http://i148.photobucket.com/albums/s...ocation3-1.jpg

Re: NHRA Battery Rules
 

Besides the NHRA rule that states batteries must be the same size can I use 2 different size batteries? This is a stock style bracket car and I want to switch from 2 red tops to 1 red top and a braille. I like the 2 battery for the amperage but trying to reduce weight. With the 2 size batteries I can save 14 lbs but not sure if charging will treat both batteries equally or will the smaller one get over charged.

Re: NHRA Battery Rules
 

For Stock, the 2016 rule book states you are limited to a max of two batteries weighing in at a total not to exceed 150 lbs. They must be the same size, type and weight. Brand isn't relevant. I have two 12 volt AGM batteries of the same class size in my Mustang that I built for GT/MA. One is Optima and the other is SuperStart. Both are heavy. One light and one standard is a no-go in Stock.

EDIT: Jeff, I read your first post, which said Stock and your last one which said Stock style Bracket (SSB/). You should be OK mixing battery sizes in ET/Pro or Sportsman, but email your tech before spending the money.

EDIT 2: In regards to charging, if they are wired in PARALLEL I don't think it will make a difference to the charger. It will see one big battery. I found putting two parallel connected batteries on a charger tripled the full charge time. AGM 12 volts on a charger with a AGM setting.

EDIT 3: I was wondering about the safety of using two different size batteries so I found this similar question on a boating forum:

Question: Due to space considerations I want to use two 105 amp hour and two 150 amp hour batteries as a house battery bank. Would this arrangement be detrimental to the smaller batteries?

Answer: My gut reaction is that mixing two sizes of batteries would be a bad idea. Having said that, I really can’t think of a technical reason that it would not work. Let’s see what our battery guru, Justin at LifeLine Battery says:

“It has previously been said that this is not a good idea; however, we have done some pretty extensive lab testing and we can find no differences in the batteries. Age is important but size is not. You can safely mix and match battery sizes in one bank.
Also, Sabre Yachts does this from the factory. This was one of the reasons we started testing this scenario. Sabre use a GPL-4DL and when they want to upgrade a battery bank they add a GPL-31T.”

Dale

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

I run my starter & ignition of the rear battery because the rear cut off
switch will stop the engine like I was told. The front battery runs the
water pump & fan. At RTE 66 points a NHRA tech guy said I have to
start my car with the front battery?????

Re: NHRA Battery Rules
 

Thank you for the info. I'm going to install 2 different sizes parallel and go for it. I thought 1 braille would work but it won't. It will start when engine is cold but not after its warmed up.

Re: NHRA Battery Rules
 

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....!!!

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

Here is what I did in ’67 Camaro Stocker: Installed main switch on roll bar horizontal pipe behind front seats. It was mounted behind passenger seat and operated via long ¼ inch diameter rod from rear of the car. I could turn it on and off from driver seat also. Equal length cables from both batteries to switch and relatively short cable from switch to starter etc.

Re: NHRA Battery Rules
 

Oldsmobile ran a 16 foot cable to the battery in the trunk 50 years ago, but it ran inside the frame.

Re: NHRA Battery Rules
 

You can shut off the engine with the cut off switch by wiring the MSD trigger through it. I also run a 4 gauge alternator hot wire, back to the switch.

Re: NHRA Battery Rules
 

My Pet Peeve,

The N.H.R.A. doesn't allow relocating batteries to the trunk in Stock Eliminator but allows aftermarket blocks and heads, roller rockers, solid lifters, any duration camshafts, aluminum radiators, electric water pumps and fans, aftermarket oil pans, exotic transmissions, aftermarket disc brakes, wheelie bars, fuel cells, Kirkey seats, hood scoops on cars that didn't come with one, bogus combinations and Factory Super Cars that don't belong in Stock Eliminator.

My Two Cents on a rainy Sunday morning in the Low Country.

Re: NHRA Battery Rules
 

Lots of new cars have the batteries in the trunk. They last longer because the heat under the hood is hard on batteries.

Re: NHRA Battery Rules
 

Allowing a front mounted battery to be relocated in the trunk would be a common sense move.

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

[QUOTE=Frank Castros;524802]My Pet Peeve,

The N.H.R.A. doesn't allow relocating batteries to the trunk in Stock Eliminator but allows aftermarket blocks and heads, roller rockers, solid lifters, any duration camshafts, aluminum radiators, electric water pumps and fans, aftermarket oil pans, exotic transmissions, aftermarket disc brakes, wheelie bars, fuel cells, Kirkey seats, hood scoops on cars that didn't come with one, bogus combinations and Factory Super Cars that don't belong in Stock Eliminator.


Well said on all the above!

Re: NHRA Battery Rules
 

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

Re: NHRA Battery Rules
 

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.

Re: NHRA Battery Rules
 

It doesn't matter if you disconnect the Positive or Negative cable with the disconnect switch or where the switch is located...........

If you have 2 batteries (1 in the front of the car and 1 in the rear of the car), the cables still have to connect to the disconnect switch......

Even with the switch off, in the event of an accident, there would still be cables that run from the batteries to switch, that if damaged would create a short circuit.............

If using a disconnect on the ground or negative side and the cable was damaged and/or crushed between the battery and the switch, the entire car would remain hot and not controllable by the disconnect, as in the fuel pump, fan, ignition would continue to be energized.

If the hot or positive cable gets damaged and shorts between the battery and the switch you have a dead short and a potential fire

The only safe way to wire 2 batteries, 1 in front and 1 in rear, is to use a continuous duty, high amp rated relay located at the front battery and controlled by the disconnect switch, which also controls the rear battery...

Just my 2 cents,
Bob Mulry


PS:
Not as safe as you thought it was...