Finally found the charger that will work: http://www.xantrex.com/productcart/pc/viewPrd.asp?idcategory=26&idproduct=141 Specifications 13.8vdc, 750 mA, positive inner plug tip. Please note this product can be used in place of 074-1003 for the smaller Xantrex Powerpacks; it is safe to use and the only difference you will notice is slightly faster charge time. Price: US$19.95