I know most chargers run of car batteries,but I was looking at an ad for one and i think it was using a laptop power supply for power. Does that seem normal ?

Depends on what charger you have and what you are charging with it -- if your laptop supply is able to supply 5 amps at 12 v., you can use any of the small "50 Watt" chargers and charge a 3-cell at almost 5 amps, a 4-cell at about 3.5 amps, etc.  (Most of the laptop supplies that I have seen lately are at least 5 amps and many have a selectable voltage output that usually goes from 11 volts up to 18 volts).

If you have a charger with more than 50 Watt capabilities, you will need a proportionally larger, more powerful supply.  If you are not into modifying electronic devices, your can find 12 volt, 10 amp (and larger) supplies from various suppliers for reasonable prices.