yeah after i got rid of my street charger i just got a multi battery charger and i was good for 2-4 weeks runnin a 2 pump settup 48 volts with 4 batteries.
link to a great charger for a good price
http://www.batteryservice.com/products_final.aspx?ModelNumber=SE-1072
best price i have found, just thought of it but i need to get one soon