Automotive How long to charge Dead Car Battery

[nitsuj]

Why get away from something so cheap to make? Just make it so that it doesn't fail. (this would be kinda like thinking inside the box:) )
It can be done, just saying...:D

Super Capacitors! if I understand right is just "static" electricity. but how to stop "leakage"? None the less The power requirement of starting a Gasoline engine pairs well with a cap. Environmentally, lead acid batteries are bad for a number of reasons, in comparison to a Capacitor. Though are "highly" recyclable.

 

[nsaspook]

Super Capacitors! if I understand right is just "static" electricity. but how to stop "leakage"? None the less The power requirement of starting a Gasoline engine pairs well with a cap. Environmentally, lead acid batteries are bad for a number of reasons, in comparison to a Capacitor. Though are "highly" recyclable.

The equivalent capacitance of a small car battery is huge. (15,000 F)

A SC with normal car starter motor cranking capability would be at least several times the size of a same capacity lead-acid battery. I'm sure you could make 1 or 2 second cranking system with Super Capacitors in about the same space as a car battery but unless it's combined with a battery of some kind to maintain voltage it's not very practical for daily use (operating car electronics with the motor off) and would be more expensive than a just a good battery.

 

[leroyjenkens]

Read this thread yesterday and by god my battery went dead while sitting at the bank. The bank teller asked me what was wrong and sent the security to charge my battery. They were all nice. I also have a bunch of money in their bank, so they better be. I knew my battery was weak, because when I had an oil change about a year ago they told me my battery was weak and should get it replaced soon. I apparently wanted to wait until I got stranded somewhere.

 

[OCR]

... by god my battery went dead...

Most every thing you need to know about a lead-acid battery ... charging and discharging, sulfation, and freezing, just about every battery failure mode is metioned...

ROFLMAO... I'll have to edit Wikipedia now, just to add that...

 

[russ_watters]

So, the battery has been working "ok" for the past few weeks, but starting is a touch slow and the voltage is down from where it should be. After running it for a while and then letting it sit for a couple of hours, it reads 11.9 volts and leaving it overnight, it decays to 11.3. According to a chart on wiki, that represents a half charge and near completely dead.

So do you guys think re-conditioning will help?

I'm going to buy a charger, but I don't really want to spend $120 if I don't have to. Looking at Amazon, that apears to be about par for the course though. Opinions?

Also:

Starting batteries are lighter weight than deep cycle batteries of the same battery dimensions, because the cell plates do not extend all the way to the bottom of the battery case. This allows loose disintegrated lead to fall off the plates and collect under the cells, to prolong the service life of the battery. If this loose debris rises high enough it can touch the plates and lead to failure of a cell, resulting in loss of battery voltage and capacity.

I'm guessing this is what causes sudden failure of a seemingly ok battery? Like what leroy experienced? I had the same thing a few years ago: First time I noticed an issue, I was at work and the car took a few extra tenths of a second to fire up when I left for lunch. By the end of the day, it was completely dead.

 

[Borg]

How long do you expect to keep the car? If no more than a few years, I would just opt for a cheap battery with a 24 month warrenty.

BTW, congrats on the round number Russ. 23,000! :w

 

[russ_watters]

How long do you expect to keep the car? If no more than a few years, I would just opt for a cheap battery with a 24 month warrenty.

No less than 3 more years, probably more like 5 (it is less than 3 years old now: 50,000 miles). So if I replace it, it will be with a good battery.

BTW, congrats on the round number Russ. 23,000! :w

Thanks!

 

[Bystander]

it overnight, it decays to 11.3.

That has the ugly sound of one cell having an "adolescent identity crisis." I've never been able to straighten them out when they "rebel" and reverse polarity.

 

[psycho rich]

My automotive electrican sez that you'll over work the alternator, you really should charge the battery.

 

[jim hardy]

It got me to Harrisburg, so I'm good for now...

As they age they lose capacity. It's a gradual tapering .
I learned to tell by the sound of the starter when a battery was nearing end of life. It's more pronounced in a diesel with its twenty-something to one compression... if it drops below 9 volts while cranking it's weak.
Five years isn't too bad for a OEM battery.
Dont buy a cheap one is my advice. I've had two from "bargain" auto parts stores fail when inter-cell connectors inside cracked. One of them i tried to check cranking voltage and it exploded in my face, blew the top off and spattered acid everywhere. Good thing i was wearing glasses.. acid wrecked a pair of Dockers and a good shirt.
The neighbors came running over thinking somebody had got shot.
Moral: only check cranking voltage from cigarette lighter socket with hood closed.

About fifteen years ago Consumer Reports did one of their studies and concluded that over 3/4 of the batteries in US are made by Johnson Controls. They're sold under myriad brand names.
At the time that's where Wal-Mart got their batteries. CR recommended Walmart because they sell so many they're always fresh.

my two cents

old jim

 

[jim hardy]

ps i use the generic 6 amp charger. I prefer the heavy ones with a ferroresonant transformer, but they're getting hard to find.
My neighbors have not had good luck with the all electronic computerized-inverter ones.
http://www.tractorsupply.com/en/store/travellerreg;-2-6a-manual-battery-charger-101588799--1

http://media.tractorsupply.com/s7viewers/dhtml/images/spacer.gif

http://media.tractorsupply.com/s7viewers/dhtml/images/spacer.gif
Get one at a yard sale and replace the wires. Sniff it for burnt transformer smell, though.

old jim

 

[OmCheeto]

...
Five years isn't too bad for a OEM battery...

my two cents

old jim

That reminds me. My brand new truck is now 6 years old, and hasn't been starting as fast as she used to. hmmmm...

12.46 VDC

Time for a new battery.

Although a value of 12.46 indicates my battery is at around 80% charge, it should be reading 100%, which is around 12.6 volts.
I destroyed my last deep cycle battery this winter, by ignoring it. I just checked it, and it's reading about 12.3 volts, which indicates that it's 50% charged.
But, my last test discharge, even after being fully charged, indicated it had pretty much zero capacity left.

@russ_watters , you never did tell us what kind of new battery you got. As I mentioned, I'm now in the market for a new one.

ps. This thread reminds me of my very first "helpy" post.
Danger seemed to approve.
Probably a bad sign.