Any good ?
http://www.ebay.com/itm/BMS-for-48V-13-cells-Li-Ion-Battery-Pack-50A-10A-limit-With-Balance-Function-/161242799250?pt=US_Rechargeable_Batteries&hash=item258ad1dc92
or this?
http://www.ebay.com/itm/44V-48V-50-4V-12S-45A-Lithium-ion-Li-ion-LiPo-Li-Polymer-Battery-BMS-PCB-System-/221274095686?pt=US_Rechargeable_Batteries&hash=item3384f6c046
http://www.ebay.com/itm/BMS-for-48V-13-cells-Li-Ion-Battery-Pack-50A-10A-limit-With-Balance-Function-/161242799250?pt=US_Rechargeable_Batteries&hash=item258ad1dc92
or this?
http://www.ebay.com/itm/44V-48V-50-4V-12S-45A-Lithium-ion-Li-ion-LiPo-Li-Polymer-Battery-BMS-PCB-System-/221274095686?pt=US_Rechargeable_Batteries&hash=item3384f6c046