On Wed, 23 Dec 2015 03:48:31 -0500, Micky
wrote:

On Wed, 23 Dec 2015 03:10:17 -0000 (UTC), "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.

I don't think so. It could lower a 12v battery to 10 volts or less,
but a 12 volt charger woldn't spark that much tryhing to charge a
battery that was putting back 8 or 10 volts.

Anyhow, he should get a meter and measure the voltages.
and particularly the POLARITY.