When the inverter is connected and no load, the voltage drops immediately down to 8volts - no sagging.  Disconnect the inverter and the voltage at the battery reads 12.x volts again.  I don't think it's a bad battery.  Since I cut off the posts to make it fit, it's mine now anyway.

On Jul 29, 2011, at 3:11 PM, Rocket J Squirrel wrote:

> So here's my guess: If you see normal charging voltage of 13.6 volts on
> the aux battery with the engine running and the inverter connected, but
> it sags quickly and heads towards 8 volts once you turn off the engine
> with the inverter still attached, then the yellowtop is a goner. Can't
> hold a charge.
> 
> -- RJS

Dan
Los Angeles, CA
'85 Westy Weekender