what electrical requirements do I need from a battery?
09-21-2012, 12:33 AM
#17
Nordschleife Master
Bull**** ! many of those stock cars have 150,000 200,000 or more miles. It is OK if the car discharges slightlty at idle with the A/C radio and lights on. Bigger is NOT always better. If you had to rev the engine most likely the exciter circuit (light) is faulty and you need the RPM to kick start the charging.
I'm at almost 130k and take diligent care of all matters on the car. I tend to my battery cells, and have a heavy duty Bosch alternator. I get 13.4v output on a warm engine idling at 590 with headlights, fogs, sidemarkers, radio. Will drop a little when the fans come, but I don't drive my car when I'm idling for a purpose.
09-21-2012, 08:54 PM
#18
Drifting
light weight battery???
So You replace the 70lb battery with one at 50lb and find out it doesn't crank the engine very well, the lights are dim and the AMP meter is alwayd pegged at the bottom?!?!?? If you want to take some weight out of the a$$ just never put more than 10 gal of gas in it!! Gas weighs 7lb per gallon-10 gal of gas=70lb!!
09-21-2012, 08:55 PM
#19
Nordschleife Master
So You replace the 70lb battery with one at 50lb and find out it gon't crank the engine very well, the lights are dim and the AMP meter is alwayd pegged at the bottom?!?!?? If you want to take some weight out of the a$$ just never put more than 10 gal of gas in it!! Gas weighs 7lb per gallon-10 gal of gas=70lb!!
09-21-2012, 11:49 PM
#20
Instructor
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Thanks for the...uh...abuse
Guys: WTF??? I asked a simple question about what electrical requirements I need from a replacement battery. What do you guys care if I put a physically smaller battery in my car? It's buried in the trunk and you can't even see it. For my efforts to learn about my new (to me) car, I get chewed out about upsetting weight distribution?? Then I am told I need to figure out how to keep it from sliding around. I am told to lose some weight and keep less gas in it. Wow. But nobody knows the answer as to how many CCA I really need at a minimum and maybe a solid recommendation on amp hours. WallyP tried to help. (Thanks man!) I am sure some of you work on your cars yourselves and want to understand more than just how to slap a new (OEM!) part on it. Just trying to learn about a car I've always dreamed of owning. Gain some knowledge. And I'll pass it on when I can. I know that originality is king here on Rennlist. But you all really need to lighten up a little, don't you think? I'm just trying to keep another 928 out there on the road and have a little fun with it.
09-22-2012, 01:59 AM
#21
Nordschleife Master
Sounds like that other kid from Pebble Beach who was on not to long ago.
Given good advice, warnings, and links yet still cries foul.
Best Wishes and Good Luck.
Given good advice, warnings, and links yet still cries foul.
Best Wishes and Good Luck.
09-22-2012, 02:25 AM
#22
Chronic Tool Dropper
Lifetime Rennlist
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Lifetime Rennlist
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OK, the plain and simple--
Got a brand new car with great electrics, everything in it is perfect? The factory battery size is perfect. 750CCA and about 75AH. If they could have gotten away with a smaller battery, they would have.
If I didn't describe your car accurately (and I'm pretty sure I didn't...), install the largest CCA largest AH capacity battery you can find that will bolt in the battery box securely without termanals sticking up high where they will short on the battery box lid.
Does that make you feel better?
Got a brand new car with great electrics, everything in it is perfect? The factory battery size is perfect. 750CCA and about 75AH. If they could have gotten away with a smaller battery, they would have.
If I didn't describe your car accurately (and I'm pretty sure I didn't...), install the largest CCA largest AH capacity battery you can find that will bolt in the battery box securely without termanals sticking up high where they will short on the battery box lid.
Does that make you feel better?
09-22-2012, 10:03 AM
#23
Team Owner
^^^^ what DR Bob said.
I can appreciate your consternation, and you probably feel that no one has answered the question you have asked.
Just realize a few things, most of the info your getting is coming from owners that have many years of care and feeding of the 928.
And I will bet a few have tried putting in different somethings,
only to find that after a while the new better somethings didnt seem to work as well or were quitting.
The info your seeking and the answers your getting are the best possible advice you can get for free.
Sticking in another smaller something because your not really sure about anything,
you asked a question and many have been saying the same thing in different ways.
Put the stock battery in the car and it should always start when you turn the key.
Make sure to have the correct battery hold down installed as well.
Something over 700CCA is OK 850 CCA is better.
It doesnt get any clearer than that my friend
I can appreciate your consternation, and you probably feel that no one has answered the question you have asked.
Just realize a few things, most of the info your getting is coming from owners that have many years of care and feeding of the 928.
And I will bet a few have tried putting in different somethings,
only to find that after a while the new better somethings didnt seem to work as well or were quitting.
The info your seeking and the answers your getting are the best possible advice you can get for free.
Sticking in another smaller something because your not really sure about anything,
you asked a question and many have been saying the same thing in different ways.
Put the stock battery in the car and it should always start when you turn the key.
Make sure to have the correct battery hold down installed as well.
Something over 700CCA is OK 850 CCA is better.
It doesnt get any clearer than that my friend
09-22-2012, 10:14 AM
#24
Guys: WTF??? I asked a simple question about what electrical requirements I need from a replacement battery. What do you guys care if I put a physically smaller battery in my car? It's buried in the trunk and you can't even see it. For my efforts to learn about my new (to me) car, I get chewed out about upsetting weight distribution?? Then I am told I need to figure out how to keep it from sliding around. I am told to lose some weight and keep less gas in it. Wow. But nobody knows the answer as to how many CCA I really need at a minimum and maybe a solid recommendation on amp hours. WallyP tried to help. (Thanks man!) I am sure some of you work on your cars yourselves and want to understand more than just how to slap a new (OEM!) part on it. Just trying to learn about a car I've always dreamed of owning. Gain some knowledge. And I'll pass it on when I can. I know that originality is king here on Rennlist. But you all really need to lighten up a little, don't you think? I'm just trying to keep another 928 out there on the road and have a little fun with it.
Calm down, if what has been said in this thread gets you this worked up I'm not sure it's going to be an easy road for you.
09-22-2012, 10:37 AM
#25
Race Car
In the late 90's I took some minor weight saving battery advice and tried a battery designed to fit a Volkswagen - don't recall which one. It started the car just fine, but my radio was fried shortly after the changeover. Could just be coincidence. I have since replaced batteries 3 or 4 times - all correct size and spec.
The best free weight savings as mentioned earlier is to run on 1/4 tank. When I used to frequent the track, I stopped filling the windshield reservoir.
If you are looking for the smallest, lightest battery that CAN start a 928, go ahead and search for threads from years ago where people have put tiny little things in their race 928 cars - but keep in mind that most race cars are stripped of everything that is not needed so they are at less risk of accidental draining of the battery. For a street 928, there does not seem to be much good compromise available for modest weight savings. You can get a smaller battery with similar cranking amps, but you have to add materials to secure it properly, or redesign your battery box.
What makes this an awkward topic is that thousands of 928 drivers know that we should always replace with what fits, which is only one size and the only choice when shopping is how long of a battery warranty/life we want to prepay for. We never once think about battery or electrical specifications and I doubt that there is any viable technical materials that get into automotive electrical theory. If you can get the wires to the terminals, just about any new battery will probably be able to start an operable 928.
You can get your answer at Walmart. Look up Porche 928 Model Year xxxx, look at the specs on the recommended battery on the shelf.
The best free weight savings as mentioned earlier is to run on 1/4 tank. When I used to frequent the track, I stopped filling the windshield reservoir.
If you are looking for the smallest, lightest battery that CAN start a 928, go ahead and search for threads from years ago where people have put tiny little things in their race 928 cars - but keep in mind that most race cars are stripped of everything that is not needed so they are at less risk of accidental draining of the battery. For a street 928, there does not seem to be much good compromise available for modest weight savings. You can get a smaller battery with similar cranking amps, but you have to add materials to secure it properly, or redesign your battery box.
What makes this an awkward topic is that thousands of 928 drivers know that we should always replace with what fits, which is only one size and the only choice when shopping is how long of a battery warranty/life we want to prepay for. We never once think about battery or electrical specifications and I doubt that there is any viable technical materials that get into automotive electrical theory. If you can get the wires to the terminals, just about any new battery will probably be able to start an operable 928.
You can get your answer at Walmart. Look up Porche 928 Model Year xxxx, look at the specs on the recommended battery on the shelf.
09-22-2012, 02:15 PM
#26
Three Wheelin'
So You replace the 70lb battery with one at 50lb and find out it doesn't crank the engine very well, the lights are dim and the AMP meter is alwayd pegged at the bottom?!?!?? If you want to take some weight out of the a$$ just never put more than 10 gal of gas in it!! Gas weighs 7lb per gallon-10 gal of gas=70lb!!
You want a solid answer? For a big V8 motor running a thick oil, 730CCA... i work at a Chrysler dealership and all the new Ram's and Caravan's have 730CCA batteries. There. You got a real answer. Maybe a little less so like 600 or more. But really a car's OEM battery is the best... it was sized based on resistances like the cranking motor itself, engine size, complexity of electronics and wiring, wire gauges, the alternator charging circuit etc.
09-22-2012, 02:44 PM
#27
Banned
Let me get this straight.
Are you guys telling him to get the largest amp battery that will fit, which is probably OEM spec.?
Why didn’t someone just say that?
Geez!
Are you guys telling him to get the largest amp battery that will fit, which is probably OEM spec.?
Why didn’t someone just say that?
Geez!
09-22-2012, 03:27 PM
#28
Nordschleife Master
Get a battery that will securely fit in the 'box'. Be sure the contacts of the battery will not touch the compartment lid. Essentially get a unit with the most amp hours and cold cranking amperage that will fit.
Below is a link with a nice discussion about batteries.
https://rennlist.com/forums/928-foru...hlight=battery
Below is a link with a nice discussion about batteries.
https://rennlist.com/forums/928-foru...hlight=battery
09-22-2012, 07:31 PM
#29
Burning Brakes
Join Date: May 2010
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Guys: WTF??? I asked a simple question about what electrical requirements I need from a replacement battery. What do you guys care if I put a physically smaller battery in my car? It's buried in the trunk and you can't even see it. For my efforts to learn about my new (to me) car, I get chewed out about upsetting weight distribution?? Then I am told I need to figure out how to keep it from sliding around. I am told to lose some weight and keep less gas in it. Wow. But nobody knows the answer as to how many CCA I really need at a minimum and maybe a solid recommendation on amp hours. WallyP tried to help. (Thanks man!) I am sure some of you work on your cars yourselves and want to understand more than just how to slap a new (OEM!) part on it. Just trying to learn about a car I've always dreamed of owning. Gain some knowledge. And I'll pass it on when I can. I know that originality is king here on Rennlist. But you all really need to lighten up a little, don't you think? I'm just trying to keep another 928 out there on the road and have a little fun with it.