P.S., Blast, what's the watt rating of your solar panel? Are you using a charge controller?
It's a 30 watt panel which plugs directly into the charging port of my Xantrex Powerpack 400Plus without a charge controller. According to the Powerpack's manual, this is okay to do with any solar panel of 30 watts or less. It's been hooked up this way for just over a year now with no problems.
-Blast