Walmart offers the Schumacher 1.5-amp Maintainer Vehicle Charger, model no. XM1-5, for $17.72. Opt for in-store pickup to avoid the $4.97 shipping charge. That's $7 under our March mention and the lowest price we could find by $7. This microprocessor-controlled battery charger features a quick-disconnect harness, automatic voltage detection, temperature compensation, reverse hookup protection, and LED charging indicators.