recharging batteries

[R72K5]

ok battery gurus: how in the heck do you figure out how long to charge a battery for ?

do chargers know when to quit charging, or will they run non stop even if battery is full ?

if they run non stop then how are you supposed ot tell when battery is done charging then, and not overcharging ??

what is the goal when charging up a battery ? to get volts abck up to 13.8 or whatever, or to get the amps all back into it ?


settings on charger are
2 amp, 12 amp and boost
its one of those cart roll around ones you see in shops, a cheap version, probably ten years old, maybe a few more, dunno


has timer on it, can go up to like 60 or 90 minutes

what should i set it to for these batteries in question and be ok ?

how do you figure this stuff up ?

ive got a battery thats totally dead and is 575 cca

got another one thats been used ot start a 350 about ten times without running for much longer than a couple or few minutes, and is 1100cca

both batteries are about thee months old


or should i just take to auto zone or something and let them charge them ?
how do they do it ?

wheres Tim ? he would know what they use there and how they do it



thanks

 

[R72K5]

also lets try and learn some other info related to charging systems

is it true that alternators wont actually charge a battery up say for example after a jumpstart, etc ?

you hear it all the time that an alternator will maintain but not charge a battery

is this fact or myth ?

 

[ryoken]

get yourself a load tester.... heres answers to all your questions..

http://www.repairfaq.org/ELE/F_Car_Battery.html

 

[Fierospeeder]

that says 1996, so dyeager might say, it isn't true cuz its not up to date.



When you have a dead battery. You want to get it charged as much as you can. When you put it back in the vehicle. It will try and put all the current back into the battery. On some vehicles, the wiring harness cant handle the current and will burn up. But, yes a vehicle will be able to charge the battery if you drive it for more then a half hour with your accessories turned off.


Some battery chargers will overcharge a battery. This is something you have to look at in the service manual. You know it is overcharging when the battery starts getting hot and the acid/water inside is starting to boil.

You know it is charged when it will reach 12.6volts.


If you dont care about your batteries life, then you can get the shop type chargers. Batteries have shorter life when they are charged quicker with higher amperage.

Sears has a nice digital charger that costs over 100 dollars. It will automaticaly shut off when the battery is fully charged.


Im not much into the time settings. But either you can rely on the gauge on the charger, or pull out your multimeter every 30 min and just check what your battery voltage is at, with the charger off and one of the charger cables disconnected.

 

[diesel4me]

Battery blues....

If theres on thing I need,its more good batteries!--Having 3 trucks means at LEAST one dead one all the time,mostly from sitting...So I've had lots of charging experience!

First off,a completely dead battery that wont even light a bulb may NEVER recharge again,and may suffer permanent cell damage--a long slow charge at low amperage(5-10 amps) will work better than trying to "fast charge" a dead battery--it may take 3-4 DAYS! of charging at that rate to properly charge it--charging a battery drives the acid out of the plates and back into the electrolyte,when the battery is discharged by using the starter or lights(any load really)the acid goes back into the plates---thats why they used to use a hydrometer to measure the specific gravity of the electrolyte--it changes with the state of charge in the battery---not many people have seen or own a hydrometer anymore--now we have newfangled computerized testers to tell us the battery is dead!

I have heard the myth about altenators not being battery chargers--false--an altenator certainly can and will charge a battery--as long as there is enough voltage to activate the field in the altenator it will produce the current and voltage needed to charge,but many manufacturers say not to use an altenator as a charger because it is a severe strain on it,it was made to maintain a charge more than be a "charger" pumping out its maximum rating constantly--but then I see homemade welders,and lawnmower engines with GM altenators at the drag pits charging batteries,and running tools,and yet they live!--I dunno--

Most modern chargers made in the last 20 years have a "sensor" of sorts that can tell when the battery is building up a charge,and it will taper off the amps as the charge increases--so if you set it a 12 amps,it will"back off" to 2-3 amps all by itself if it has this feature--if it doesnt you have to keep an eye on the temparature and amount of water in the battery so you dont boil it dry...

Most of my batteries are due to be scrapped--I charge them and they are fine if I drive far enough and use the vehicle daily--but a few days of sitting and they are dead or too low on charge to crank,they must have bad cells,because leaving the cables off didnt help,so I dont think anything is draining them--they just have gone dead and been left dead too many times,too long..thats why I hate buying new ones,they just sit and go dead,and after a few times,they seem to never recover...

My brother has a brand new charger at his work they use for forklift batteries,it has a "pulse charge" feature that claims to reclaim batteries with "sulfated" plates--so far its worked well for him,he hasnt had to buy any batteries for quite awhile since they got this charger,and it did revive a few batteries he used around the shop to jump start cars,and they seemed to be junk before,but now they are holding a charge--might be something in all this new "technology" after all--its hard to tell what really works and what is BS...

I think batteries are a PITA!--its the one thing mankind hasnt figured out yet,how to make a good one--Electric cars are the best example,they couldnt make a battery go enough miles to make them practical,so now they made them a "Hybrid"--which means nothing more than a generator recharging them while you drive,using a smaller gas motor than the car would normally have powering it--not exactly "electric"---

My friend had a solar cell on his boat to keep his battery charged--it was 75 bucks and it put out 2.5 amps--seemed to work,he didnt have a dead battery all summer,despite not using the boat very much....thats what I need on the roof of all my heaps..