NHRA Battery Rules

[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.

[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....!!!

[John Dinkel]

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

[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

[FireSale]

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

[Jeff Stout]

Originally Posted by FireSale

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

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.

[DIV3CR]

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?????

[SSJ343]

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.