Dave Platt wrote:

snip


If not, then it might be worth trying to recondition the battery.
There are electrical desulphators available, which hit the battery
with a high-voltage high-frequency pulse in order to break up and
redissolve the sulphate crystals - some people say these work very
well, others are less impressed.

http://www.homepower.com/files/desulfator.pdf

It works, but much depends on the condition of the battery.
According to the author, it eliminates the need for periodic
equalization, too. But it won't rescue batteries with
warped plates or shorted cells or those with too much of
the plate material gone, or polluted electrolyte.

Aside from attempting to rescue his battery, the OP has got
to fix or replace that charger, and adopt a maintenance
schedule that includes electrolyte level monitoring.

Ed