On Tue, 22 Dec 2015 20:01:09 -0800 (PST), bob_villain
wrote:

On Tuesday, December 22, 2015 at 9:10:25 PM UTC-6, M. Stradbury wrote:
On Tue, 22 Dec 2015 19:42:20 -0700, Tony Hwang wrote:

Maybe your battery has internal short?

That would do it.

The sparks he is describing could not be produced by his 15 Amp charger! The arcing is from the battery somehow...Mike may be correct.
Or the battery has been charged backwards by a reverse polarized
generator. Sure sounds like the charger is connected backwards to the
battery