Michael Remski wrote:
Should I use the 2A or 6A setting on the battery charger when charing
a marine battery? Whats the difference (besides 4 amps....L)?


Joe Here wrote:
From my understanding, a "trickle" charge is preferred over a higher
Amperage charge, if time permits. The slower the electrons (?) bond to
the plates (?) the better they pack. Plus, gasses and plate buckling
are kept to a minimum.

Correct in essence, a lower amperage over a longer time frame will result
in a higher final charge and less temperature rise. However a cheap
trickle charger can still boil off a battery by running up to higher
voltage than the battery can take, even at very low amperage.



Hey, I know this isn't technical, but it's like trying to roast a
Turkey in half the time at twice the heat. But.... 6 Amps is hardly
considered a big charge current.

The problem is the volts vs amps curve. At lower charge voltage, batteries
can take a whopping amp load... consider it sort of like the jolt they
endure when kicking over a starter for a big engine, only in reverse.
However, as the battery approaches full charge, the voltage rises and the
amperage drops. To continue trying to charge at a fixed amperage will
damage the battery as the voltage climbs towards 15 or even 16V.

A 3-stage "smart" charger will actually taper off the amperage at a fixed
voltage, and then trickle a lower voltage to maintain the full charge. It
takes a fairly sophisticated controller to do this. But it's very well
worth the extra money IMHO because the batteries will have about 25% more
electricity available (when new, if you get a smart charger and hook it up
to an old battery it could be much much more) and they will last longer.

If you are going to plug in a charger and leave the battery for a few
days, absolutely use the lowest setting. At 2A it is getting almost
50amp-hours a day, which means that in two days a big Group 31 will be
fully charged, in three or four days it will be trying to soak up a
damaging overcharge. A smaller battery will fare worse.

Fresh Breezes- Doug King