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If you have a battery that's in good shape but your car sits in storage, give it a 2 amp trickle charge once a month. This will keep your battery from failing when you really need it..
If your battery is weak, charge it over night at 10 amps. Then have it checked.
Most small charger will shut off automatically when the battery is fully charged. Get a charger with auto mode.
The difference is in the time that it takes to charge up a totally dead battery. NEVER let a lead acid battery totally discharge because each time you do that, the battery loses some of its amp-hour capacity. Also, car batteries self discharge up to 1% each day even disconnected and during discharge, lead sulphate collects on the plates. Left for long (4+wks) periods, the lead sulphate becomes hard and will not convert back to lead and sulphuric acid upon charging. Lead sulphate is an insulator and a fully sulphated battery will not draw current from a charger and is a door stop. Charge your stored battery periodically or get a battery tender which is a , "smart" charger which measures the battery voltage and only charges the battery when its state of charge drops about 10% and then turns off.
Use 10 amps if the battery is completely dead and has sufficient water/acid in it. Make certain you remove the battery caps to reduce the chance of explosion when you remove the charging leads.
Use 2 amps to keep the battery conditioned.
When using the 10 amp, once the charger (if it is late model) detects a full charge condition, it will drop down to 2 amps to maintain the battery.
Once you charge the battery, go to Sears and get a two dollar specific gravity tester. It looks like a eye dropper with colored ***** in it. Use it to check for shorted cells. You suck up acid from each of the six holes in the battery. None of the ***** shoud drop down, if they do, buy a new battery because no amount of charging gonna fix it. A shorted battery will cause you to buy an alternator down the road.
What is the difference between using a 2 amp charge vs a 10 amp charge
for the battery?
The rate of charge. Amp is an abbreviation of ampere-hour, a unit of electric charge.
The charge rate should be based on the size or capacity of the battery
to be charged. A 2 amp rate is appropriate for smaller batteries as
used for motorcycles, lawn tractors and so on. 8, 10 & 12 amp rates
are suited for automotive sized batteries.
Faster charge rates than recommended reduce charging time but
lead to increased heat which can warp components or possibly rupture
the battery case. I do not well understand the issue with lower charge
rates but I believe it can be detrimental over the long term.
I'd like to mention the Schumacher SC1200A charger here.
After using a series of fixed output chargers over the years, I switched
to the 1200A. It has performed well and has kept my current ACDelco
battery alive long beyond the time that previous batteries needed
replacement.
The 1200A is one of the chargers that uses a variable voltage charging
approach. Initial charge voltage is relatively high, then it tapers back
as charge level increase, finally charging shuts off. This charger also
offers settings for lead-acid, glass-matt (AGM), gel cell and deep-cycle
batteries. This lets me use it on the ACDelco, on a Yellow-Top Optima
and on some instrument gel-cells I have.
Undercharging a battery, even to a small degree, if continued, leads to
excessive “sulfation”. The same is true of batteries which have been
left standing in an undercharged state for an extended period. High
temperatures rapidly accelerate sulfation when batteries are left
standing in a partially charged condition. The cells of a sulfated battery
will give low specific gravity and open circuit voltage readings. On
charge, voltage readings will be unusually high. The battery will not
become fully charged after a single normal charging when sulfation has
taken place over a prolonged period.
I'll throw my recent experience in for you to ponder. I just bought 2 battery chargers, A Vector and a CTEK. Both of these have the "Recondition" mode that can reverse the sulfation condition. It is like a 24+ hr process but it does work, saved one of my Optima D31 Yellow tops. I used the 2amp charge to prevent heat buildup on the optimas, heat boils the liquid/gell inside and kills them since you cannot add water. The complete process took 4 days, and the battery never got hot. Like Slalom4me mentioned the Schumacher charger, the newer Microprocessor controlled chargers are worth it, less risk of battery overheating and possible explosion. Al
if you drive them everyday, you won't need to charge the battery -
still have my original, my one and only, my old ray-o-vac, 6 amp charger. bought it around 1968 for about $10 - back then, just about everything was made in America!
04-21-2007, 11:21 AM
Car battery charging - 10 amp or 2 amp?
