Which battery to use?

[Dean Lampe]

I am doing a little wiring and having the battery mounted would help a little with this. I want to use a dry cell battery but nothing to big. I don't intend to run headlights, A/C, radio, or anything that I don't need on the race car. With just the engine and the occasional brake light, how big do I need? Once the car is running, the alternator should keep it all running right?

I was thinking about a motorcycle battery strong enough to start the LS3 and leave it at that. Any thoughts?

Maybe something like this.
http://www.hrpworld.com/index.cfm?tp...action=product

[Doc Kaler]

Dean,

I chose the Braille battery listed by hrpworld:

Braille B3121 Carbon Fiber / Non-Carbon Fiber Premium & Extreme Use Lightweight Battery

Not quite as light as the motorcycle battery but with more CCAs.

[wayne]

Dean do not buy odyssey motorcycle battery junk.had two on my bike so when one quit I could switch to the other to get home.also to small run any thing like fans fuel system and so on.

[Howard Jones]

I have had one of these in my GT40 for 10 years. 9.5 to 1 302. Still going strong. I am going to use another one in my SLC.

Odyssey Battery PC925 - Odyssey Drycell Batteries - Overview - SummitRacing.com

[wayne]

Two different batteries one car battery and one motorcycle battery.

[Bill Musarra]

Not meaning to steal the thread, but since it is about batteries, I have a question or two.
What is the best way to judge a battery. In terms of Cold cranking amps, amp hours, reserve? I have seen some as high as 800CCA. My Red top Optima which is 6 years old and is about to give it up is that strenght. I have a lot of electrical items on my car. I also have the electronic ignition and fuel injection that need to be bolted to the battery. Should I get one like the Optima that has the bolt on feature or should I find a post clamp that will allow the wires to be bolted on? Have seen some good prices at places like Walmart etc. Are these to be avoided? Thanks,

Bill

[Grant S]

If your planning on your alternator to keep you car running you better have alot of alternator's you'll be killing them. You need a battery semi matched to your alternator output to stabilize the power in the system. If your running any kind of electronic's you could be burning them out as well with power
spikes if your battery is not big enough to handle it.

[Dean Lampe]

Thanks for the help Grant. What makes a battery "big enough". I guess I don't know what to look for. What perameters would you look for?

[Jack]

Dean, found this, hope it helps:

CCA is critical for good cranking ability. It's the number of amps a battery can support for 30 seconds at a temperature of 0 degrees F until the battery voltage drops to unusable levels. A 12V battery with a rating of 600 CCA means the battery will provide 600 amps for 30 seconds at 0 degrees before the voltage falls to 7.20 V (six cells).
Reserve Capacity helps to power your vehicle's electrical system if the alternator fails. It indicates the battery's "staying power" -- how many minutes the battery can supply ample power without falling below the minimum voltage needed to run your vehicle.
In general for both CCA and RC, the higher the number the better. HOWEVER, if you live in a cold climate, the CCA rating should be an important consideration in choosing a battery. Conversely, if you live in a high heat climate, you don't need as much CCA.

[David]

I always thought CCA was at 0°C not F, ie 32°F. Seems I was wrong and that's CA, CCA being -18°C/0°F

[Neal]

Odyssey 680 for 6 years now. Keep it on a battery tender. Cranks 10.5 compression w/o any issues. About as compact as you can get.

[Bill Musarra]

Question:
Does it really matter where the battery is located? I have about 9-10 feet of #1 wire from the front of the car to the starter(think it is #1, diameter is .5"). I believe it is causing a voltage drop that is causing my ring gear, starter gear, and alternator problems. If I move it to the rear with 2-4 feet of cable, or even 4-6feet from mid engine location, will that give a better response and less work on the electrical system?? I came across a 1000 CCA battery at Advance Auto for $104 today. It has the screw terminals on the front like an Optima and is 10"x6"x7". It comes with a 3 year warranty.

Bill

[David]

Bill, to a large extent no but shorter *is* better from a weight and voltage drop pov.
Weight because the cable itself can be a few Kg. Of course you have to trade that off against the biggest weight being the battery itself and it being desirable to balance the car.

A large number of FE production cars have the battery in the boot these days with no issues.

[Alan Watkins]

Originally Posted by wbmusarra

Question:
Does it really matter where the battery is located? I have about 9-10 feet of #1 wire from the front of the car to the starter(think it is #1, diameter is .5"). I believe it is causing a voltage drop that is causing my ring gear, starter gear, and alternator problems. If I move it to the rear with 2-4 feet of cable, or even 4-6feet from mid engine location, will that give a better response and less work on the electrical system?? I came across a 1000 CCA battery at Advance Auto for $104 today. It has the screw terminals on the front like an Optima and is 10"x6"x7". It comes with a 3 year warranty.

Bill

Bill --

#1 cable (which indeed is about 1/2" dia.) has a resistance of about .125 ohms/1000 feet. So with your 10 feet you've got a resistance of 0.00125 ohm. If your starter were drawing (say) 200A, the cable would drop the voltage by 200 x .00125 = .25 volts. Not enough to cause a problem if everything else is healthy.

But, theory aside, if you want to get to the bottom of any possible cable problems, get your voltmeter out, connect one terminal to one end of the cable, and the other terminal to the 10-feet-away opposite end (this requires a long piece of wire but it makes no difference what size wire it is). Measure the DC voltage while the starter is cranking. What you read (if anything) is the voltage drop caused by the cable itself.

You can use the same technique to march right along from battery to starter, particularly measuring across connections, to localize any problem spots that might be dropping voltage.

[Grant S]

Hello Dean I was on the net poking around and happen upon these batteries,
I have never heard of them but they claim to be for racers looking to keep the weight down. ( Braille Battery No-Weight standard Batteries ) might be what your looking for.
Cheers,

[Dean Lampe]

I am just going to through this out there.....

Why do I need a dry cell if the battery is in the back by the engine? Could I just use the standard battery? I know it weighs a little more but not that much and they have a warranty.

I think sometimes we spend money that doesn't need to be spent on these things and never really see the benefit. I have heard of racers losing track time because their Odyssey, optima or Braille battery wouldn't take a charge. I was thinking about buying a battery that would fit in my Denali. If the battery in the car went bad on the track, I would have a spare!

[Grant S]

Fran will know, he's been there, done that.

[Fran Hall RCR]

I can tell you that we used Braille batteries in 2011 in the 01 car and they were not the best....in fact one died and cost us a race win...
Having chatted with multiple DP team/crew members , they share my opinion...at one time Braille batteries were mandated in DP and one crew chief told me that they had to change batteries every fuel stop during one race...Grand Am then changed the requirement.

We ran old school reliable full size lead acid batteries during the 13 hr race...in fact we had a complete second charging system and battery installed that could be brought online/offline with the flick of a switch....worked like a charm..

[Grant S]

There you go, SL-C's are so fast you can sand bag them and still kick ass

[Jack]

Optima for my SL-C Dean. Red or yellow top, not sure yet.
Never had one fail in some other cars after 6 years of use.