The charger has alligator clips built in.

Having a poor connection will not increase the current draw. The current in a closed circuit is the same throughout the whole thing unless it branches which it doesn't. A poor connection (higher resistance) would mean that a higher voltage is required to get the same amount of current.

The power supplies I had were both cheap and used so it could be just that.

I looked on ebay and all the power supplies I saw had screw terminals to the 110AC power which is not safe.

That Pro-Peak power supply looks really nice and I might end up getting that if I can't find a cheaper alternative.

EDIT: How does the Pro-Peak power supply plug into 110AC? It says the input is 4mm banana plugs, does that mean you have to make your own cable?

EDIT again: I just ordered a power supply from New Egg that is rated for 30A for $50.
[link=http://www.newegg.com/Product/Product.aspx?Item=N82E16817139008]http://www.newegg.com/Product/Product.aspx?Item=N82E16817139008[/link]

Thanks,
JR