Car battery question

[Vince in Milwaukee]

Even though I'm pretty sure of the answer, I'd like to get the input from the group here.  My car needs a new battery.  I plan to have a shop do it for the sake of convenience.  For the sake of argument, let's say it's at 80% capacity.  It I just install it, will the alternator charge it back to 100%, or will my "new" battery always have that 80% as a base line and have its life shortened?

[Triple Jim]

It will charge fine after installation.

[oldbike54]

 Hmm , lots of new smaller cars have just barely enough alternator output to run things under normal conditions . I say give it a full charge . YMMV .

 Dusty

[Wayne Orwig]

The alternator will charge it. You really do not need to worry.
BUT, if you are one of THOSE people  , it is not a bad idea to use a properly regulated charger to make sure it has a full saturation charge.The car charge should always do a good bulk charge, unless it is broken.  It is unlikely to affect it, but won't hurt if it is a good smart charger.

[old head]

just be sure to pick the newest one in the rack.  They usually feed new batteries to the back, so you may have to dig a little, but its best to get the freshest battery.

all batteries have a letter and a 2 digit number to indicate month and year made. you would look for K17, 11th month of the year.

Old Head

[Yeahoo Whoyah]

Hmm , lots of new smaller cars have just barely enough alternator output to run things under normal conditions . I say give it a full charge . YMMV .

 Dusty

 :1:  I "top off" any type vehicle new battery using a charger, either a Battery Tender or Pulse Tech Xtreme 
Wal Mart will install for free if you purchase from them. I've had good luck with their EverStart auto batteries, sorta the new Die Hard now that Sears has left the building. 

[Triple Jim]

Too much mental energy spent on such a silly thing.

[Chet Rugg]

charge it     

[Vince in Milwaukee]

Too much mental energy spent on such a silly thing.

   I have minor OCD.  You probably wouldn't like working with me either.  Not much fun having a battery go south during our nice Wisconsin winters.  I want to maximize the use I get out of one. 

[Triple Jim]

  I have minor OCD.  You probably wouldn't like working with me either.  Not much fun having a battery go south during our nice Wisconsin winters.  I want to maximize the use I get out of one.

I would probably get along working with you just fine.  I love attention to detail.  I just meant that the battery doesn't care one bit whether it's charged fully when it's installed.  After driving with it a few weeks, whatever state of charge it has will be completely dependent on the car's charging system, not what what done to it weeks before.

[Rough Edge racing]

Hmm , lots of new smaller cars have just barely enough alternator output to run things under normal conditions . I say give it a full charge . YMMV .

 Dusty

 Hmm, exactly what cars? And what is the capacity of the alternators ?

[Kev m]

I think this thread is the same as the current ABS thread, which is the same as every oil thread, every gas thread, every EFI thread etc...

What it boils down to is simple, there are two types of people in this world.


A. Those who will charge that battery, change that oil every 3k just because, take tremendous pains to avoid corn fuel, and insist that carbs (and often points) are "better".

and

B. Those who are right.


 

[Mike Tashjian]

And lets add one more thing people in the North should consider, CCA.  Cold Cranking Amps are your friend up here in the cold weather states and more is always better.  I have found many times one brand or another will rate somewhat higher than the rest for the particular case size.   Mike

[stonelover]

 

I think this thread is the same as the current ABS thread, which is the same as every oil thread, every gas thread, every EFI thread etc...

What it boils down to is simple, there are two types of people in this world.


A. Those who will charge that battery, change that oil every 3k just because, take tremendous pains to avoid corn fuel, and insist that carbs (and often points) are "better".

and

B. Those who are right.


 

[Two Checks]

Quote from: Yeahoo Whoyah on November 20, 2017, 09:43:38 PM

:1:  I "top off" any type vehicle new battery using a charger, either a Battery Tender or Pulse Tech Xtreme 
Wal Mart will install for free if you purchase from them. I've had good luck with their EverStart auto batteries, sorta the new Die Hard now that Sears has left the building.

The Sears by me is open.

[oldbike54]

Hmm, exactly what cars? And what is the capacity of the alternators ?

 W/O getting all weird with specifics , the fact is that stock charging systems aren't really designed with more than about 5% reserve to recharge a battery . In Vince's case at 80% he would probably be alright considering he has a fairly long commute , but there is a reason why the manufacturers recommend a 100% charge before use .

 Dusty

[bmc5733946]

An automotive charging system is not a battery charger.

An automotive charging system is a battery recharger.

Brian

[n3303j]

14.2 volts DC will charge your battery the same way  whether it's coming from a box plugged into your wall or the alternator under your hood.

[oldbike54]

14.2 volts DC will charge your battery the same way  whether it's coming from a box plugged into your wall or the alternator under your hood.

 It isn't an issue of voltage , rather available amperage .

 Dusty

[n3303j]

It isn't an issue of voltage , rather available amperage .
 Dusty

I realize that. But even my tiny Denso alternator on my Ural delivers over 40 amps at RPM. Can't imagine the average auto alternator couldn't put out enough to run the regular systems (and still have a surplus) unless you had every on board light and fan motor running and you were in stop and go traffic.

[Wayne Orwig]

It is mainly a voltage thing. (not going to call it an issue, since it really isn't much of one.)
The car alternator is not SMART enough, and generally does not operate for enough hours at once, to do a full saturation charge, then a long standby charge, to reach 100% of the material. Car alternators normally just run up to a fixed voltage. Good enough to bulk charge and some saturation charge, without boiling the battery dry.