A power system suitable for use in a mobile cart, comprising: a battery assembly comprising one or more rechargeable batteries, a battery support for each respective one of said batteries wherein said battery support is mountable on the mobile cart and said respective battery is removably engagable with said battery support, and a battery connector for each respective one of said batteries which is engagable with said respective battery when said respective battery is installed on said respective battery support; and a battery control system adapted to recharge said batteries, which has a control unit comprising a power supply removably connectable to external power, a charge controller adapted to receive power from said power supply when connected to external power and to control battery charging and discharge, a first power outlet adapted to receive power under the control of said charge controller to provide power to electrical equipment on the mobile cart, a power connector (42/43) for each said battery support, which is selectively connectable to said respective battery through said battery connector, said charge controller being adapted to control power flow through each said power connector (42/43) to control charging of each one of said batteries, said power connector (42/43) being adapted to provide battery power to said first power outlet for use by cart equipment; characterized in that said charge controller is adapted to charge said respective battery to an upper charging threshold, wherein said upper charging threshold reflects a battery charge below which said battery is chargeable at a first charging rate and above which said battery charges at a slower second charging rate, said charge controller being further adapted to charge each one of said batteries to said upper charging threshold before beginning to charge each one of said batteries above said upper charging threshold to a full charge. a battery assembly comprising one or more rechargeable batteries, a battery support for each respective one of said batteries wherein said battery support is mountable on the mobile cart and said respective battery is removably engagable with said battery support, and a battery connector for each respective one of said batteries which is engagable with said respective battery when said respective battery is installed on said respective battery support; and a battery control system adapted to recharge said batteries, which has a control unit comprising a power supply removably connectable to external power, a charge controller adapted to receive power from said power supply when connected to external power and to control battery charging and discharge, a first power outlet adapted to receive power under the control of said charge controller to provide power to electrical equipment on the mobile cart, a power connector (42/43) for each said battery support, which is selectively connectable to said respective battery through said battery connector, said charge controller being adapted to control power flow through each said power connector (42/43) to control charging of each one of said batteries, said power connector (42/43) being adapted to provide battery power to said first power outlet for use by cart equipment;