I left the main switch on now my battery is dead.. had it hooked up to a battery tender for a week and still no charge... what else could be wrong..

 

If the battery voltage is below 10 vdc or so, the Battery Tender won't bring it up to charge....

The battery tender is for a maintenance charge, not a booster to revive a dead battery...

You need to get it on a trickle charger for a while, and after it is up to about 11 vdc steady, then the battery is strong enough to reinstall, and be hooked up to the Tender...

 

+1 on Shovelhead Bob