Recharging car battery

[Stormin Mormon]

Are the warning lights clearly labelled?

[clare]

On my '53 Coronet I had lucite rods mounted on the edge of the headlight with a little red "gumdrop" on the top that lit up when the lights were on. For as common as they were "back in the day" it's strange I can't find a picture of them on the internet!!

[Ed Pawlowski]

I remember them about halfway down the page

[clare]

Width marker 3, 5 and 6 are close. Had the "sidewall protectors" too - AKA Kerbfeelers.

[nestork]

I have a 6 amp trickle charger and a digital timer that I want to use for charging a spare battery for my car. Batteries can go dead just about any time 5 years after purchase, and so I'd like to keep a spare battery on hand.

I connect the leads of the trickle charger to the battery posts, plug the trickle charger into the digital timer and plug the digital timer into the wall.

My digital timer will allow me to charge the battery for any where from

1 minute to 23 hours and 59 minutes every day.

What's a reasonable amount of daily charging time to use?

My own thought is that if people commute to work every day in their cars, and the trip is anywhere from a 10 to 20 minute drive, then their alternator spends approximately 1/2 hour every day charging the battery. However, this seems excessive to me. I'm more thinking of 5 to 10 minutes of charging every day just to keep it fully charged.

Does anyone have any rules of thumb to go by or experience in this matter?

[clare]

Well, if the car is driving to and from work it is being started at least twice and you need to put that power back in. With a battery just sitting, that is not required 5 minutes a day should be more than adequate. I'd be more likey to do 10 or 15 minutes every saturday, or something similar

[J Burns]

Self-discharge is much faster in summer heat than in winter cold. I use a digital volt meter when the battery has been sitting several hours. For a fully charged conventional or low-maintenance battery, the fully charged voltage is about 12.6, depending on temperature (12.6 at 90F to

12.8 at 40F). A maintenance-free battery varies less (12.8 at 90F to 12.75 at 40F).

Both types lose about 0.2 V at 75% charged, 0.4V at 50%, and 0.6V at 25%.

So if you take a voltage reading 12 hours after charging a battery fully and subsequent readings are taken at roughly the same temperature, they'll tell you the state of charge. I like to charge before it's down

0.2V (25%).

I have a manual 6 A charger but don't use it anymore. A good microprocessor charger not only regulates the voltage but takes temperature into account in setting the correct voltage. Mine doesn't say so, but I've discovered that it charges with pulses. That's kinder to the plates than a steady voltage.

A lot of modern chargers charge a battery fully, switch off, monitor the voltage, and turn back on when it drops a certain amount. That way, you can connect it and forget it.

[Tekkie®]

Higgs Boson posted for all of us...

And I know how to SNIP

Higgy, this post does not directly respond to your post. If this battery has been dead before the you probably have very little reserve capacity in it. Goggle it.

[Tekkie®]

[e-mail] posted for all of us...

And I know how to SNIP

+1

[Tekkie®]

[e-mail] posted for all of us...

And I know how to SNIP

yeah, what a circus! Also don't forget to "pulverize" the generator when replaced. (Attributed to my buddies girlfriend)

[nestork]

I've been surprised by batteries before.

I had a battery that didn't have enough juice in it to turn over the starter motor. The starter would just make a ticking sound when I turned the key.

So, I checked the battery voltage with a multimeter. 11.2 volts.

I figured "Well, that's pretty close to 12 volts, it should start."

Then I phoned up a battery place, and they said the battery was garbage. It should have about 12.6 volts, and 11.2 volts is a dead battery!

11.2 volts is almost 90 percent of 12.6 volts. Does anyone know if the cold cranking amps of a battery with 11.2 volts would be almost 90 percent of it's rated cold cranking amps?

I'm thinking that maybe when the voltage gets down to 11.2 volts, the ability of the battery to deliver amperage is much more severely reduced, and that's why the starter motor wouldn't turn the engine over. I can see how it's possible to have 11.2 volts in the battery and almost no amperage. If you simply connect two 9 volt TV remote control batteries in series you'll have 18 volts, but almost no amperage. I guess it's really the amperage that determines if the starter MOTOR cranks because motors work on magnetic fields, and it's the amperage through the wire that determines the strength of the magnetic field around that wire, not the voltage across the wire.

[dpb]

...

As you found out, "nope".

The ~11 V indication is you've got one bad cell. In Pb-acid battery, the voltage/cell is just a little over 2V/cell when in good condition/charge.

It'll either be that or it's not charged or it's bad; those are the alternatives.

[clare]

Considerably less than NINE percent, actually. 11.2 volts is STONE DEAD.

[bob haller]

perhaps the vehicle isnt charging good?

put your volt meter firmly on the battery terminals with the vehicle running, it must be at least 13.8 volts

the only way to really test a battery is to charge it overnight, then load test it to see if it puts out enough current like 200 amps and stays around 11.8 volts for x time.

OP needs his alternator tested, a new battery, and since he repeatedly leaves his lights on, a alarm....

its easily added by any shop that does auto electronics for under 20 bucks

perhaps the battery is still under warranty? of some type?

sfor awhile sears and others sold a battery with a switch on it that could be moved to access reserve power, for people who leave their lights on.

[Tekkie®]

philo  posted for all of us...

And I know how to SNIP

Philo, thanks for that. I really enjoy you doing this!

[bob haller]

WOW AWESOME UNREAL Tekkie knows how to SNIP!!!!!

[Stormin Mormon]

I bet he's potty trained, too? No, that would be too much.