Can a car have too much battery?

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A group 24f fits just fine in my car... Specd for a group 35.... Used to be my car originally in the generation of 3.5 L motors we're specs for a group 24f... They changed it to a smaller and lighter group 35... To cut battery weight... 5-7 pounds is significant in their minds of dropping weight.
 
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I'd say no as well. The general consensus is the bigger the better too. My wife's Volvo has 3 threaded holes for the battery bracket depending on what size battery you use. Nice feature IMO.
 
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Yes and No. NO in that reserve power is always a good thing. YES If ones regular regimen cannot keep the battery charged at 80% or more then the battery will have a short life from chronic undercharging. A smaller battery kept well charged will live longer than a larger battery chronically undercharged. UD
 

wings&wheels

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Originally Posted by dlundblad
I'd say no as well. The general consensus is the bigger the better too. My wife's Volvo has 3 threaded holes for the battery bracket depending on what size battery you use. Nice feature IMO.
Interesting that some of the Euro makers do that. Our 996 and 986 have it as did my e36 and Wife's 5 series. Different battery sizes for different regions I assume. I almost always replace them with the biggest size I can fit. Thanks for all the replies.
 
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I ran H8s in our s60s and loved it. Could leave the lights on all day and it'd start no problem. The f150 in my driveway, same thing. BUT, the s60 and f150 have more than a 28 amp generator to feed that hungry beast. An overly large battery might never get the finishing charge it needs to recover from sulfation.
 
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Originally Posted by UncleDave
Yes and No. NO in that reserve power is always a good thing. YES If ones regular regimen cannot keep the battery charged at 80% or more then the battery will have a short life from chronic undercharging. A smaller battery kept well charged will live longer than a larger battery chronically undercharged. UD
+1 This. He nailed it.
 
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Why does the owner want to put in a second battery? My guess is that the reason is that the battery runs down as he is driving and doubling the battery will make that take longer. Cars went from generators to alternators for a reason. Alternators will reach full output at lower rpms and the rated output is considerably higher. Generators need to spin faster to reach the rated output. An alternator can put out close to full output at idle. A generator might only put out half its rated output at idle. If he's driving the car in the 4th of July parade, the generator won't be putting out anywhere near what the electrical system is demanding and the battery will make up the shortfall. If running the ignition, brake lights, headlights, radio etc draws 20 amps and the genny is only putting out 15 amps the battery will go flat in a hurry. Even with normal driving a generator will barely keep up with the demands of the car's electrical system. Doubling the batteries doesn't solve the problem, it just lets you run at a deficit longer. The car will need to be plugged into a charger when it gets home or driven at highway speeds for a couple hours to recharge the battery(s). I understand the desire to keep the car original, but an alternator would solve the problem. Adding another battery just papers it over. There's is a lot of good information on old time auto electrical systems here. http://www.madelectrical.com/electrical-tech.shtml
 
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Nice. Iirc, the gennie in our ‘57 might have turned out 7-8 amps at warm idle, which I think was 650 rpm, but might actually have been lower. I don't think it hit full output until 2000+rpm. We finally put a self-regulated junk yard alternator in it and it was amazing to have lights at night. That was such a cool car.
 

wings&wheels

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Originally Posted by dwgwater
Why does the owner want to put in a second battery? My guess is that the reason is that the battery runs down as he is driving and doubling the battery will make that take longer. Cars went from generators to alternators for a reason. Alternators will reach full output at lower rpms and the rated output is considerably higher. Generators need to spin faster to reach the rated output. An alternator can put out close to full output at idle. A generator might only put out half its rated output at idle. If he's driving the car in the 4th of July parade, the generator won't be putting out anywhere near what the electrical system is demanding and the battery will make up the shortfall. If running the ignition, brake lights, headlights, radio etc draws 20 amps and the genny is only putting out 15 amps the battery will go flat in a hurry. Even with normal driving a generator will barely keep up with the demands of the car's electrical system. Doubling the batteries doesn't solve the problem, it just lets you run at a deficit longer. The car will need to be plugged into a charger when it gets home or driven at highway speeds for a couple hours to recharge the battery(s). I understand the desire to keep the car original, but an alternator would solve the problem. Adding another battery just papers it over. There's is a lot of good information on old time auto electrical systems here. http://www.madelectrical.com/electrical-tech.shtml
thanks for the link, lots of good info there.
 
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