Charging amps?

[unclejed]

Reading these posts, I have realized that I've had alot of misconceptions about batteries. I have done a search and didn't find the answer to my question. I have always heard to charge at 2 amps and the batteries would run longer, then recently I was told that it's not good to charge marine batteries at 2 amps. Could someone please clear this up for me? I've always used a regular charger at 2 amps. I just bought a 2, 10, 15 amp marine charger that has an std, amg, and gel settings. Am I correct in charging these Everstart Wal-mart batteries on the amg setting? Thanks in advance for your help.

[Team_Dougherty]

You want to charge at 10% of the battery's capacity.

so if the battery is 100AH you want to charge at 10amps.

you want to charge at the STD setting.

everything you wanted to know about batteries.

http://www.batteryfaq.org/

[Way2slow]

2 amp is no good because it does not make the acid bubble, not enough to do any good, and will let the battery stratify (the acid gets concentrated in the lower part of the battery and is a very weak solution in the upper part).

As mentioned, 10% of the rated capacity is the recommended slow charge rate.  That's not chiseled in stone, you can go 8% - 15%, but the most most all manufactors prefer the 10% for optimum battery care. 

[Fishing Rhino]

SULPHATION

In the normal operation of a battery the plates are converted to lead sulphate each time it is discharged. The sulphate takes the form of fine crystals which are easily and completely dissipated on recharging.

However, should the plates be allowed to remain in the sulphated condition for a long period, the "temporary sulphate" may be converted to "permanent sulphate" and become impossible to remove. The formation of permanent sulphate is accompanied by the growth of large crystals leading to uneven expansion of the plates and eventual buckling.

Short circuits may result if the buckling causes wear and penetration of the separators.

"Permanent" Sulphation is caused by: Operating a battery in a low state of charge for lengthy periods. Allowing a battery to stand in a discharged state for a long period. Leaving a charged battery for long periods without regular recharges.

Possible Remedy: A sulphated battery may recover by charging at 1 amp for seven days or until specific gravities of the electrolyte have reached maximum and constant values. This state, then indicates the limit of recovery.

Note:

No benefit will be derived from the use of additives of dopes which neither prevent nor cure sulphation.

Insufficient charging will cause permanent sulphation because the temporary sulphate is not completely removed from the plates during recharging allowing the remainder to convert to permanent sulphate. (See Sulphation). 

http://www.batterycentre.co.za/BatteryCare.htm