Disclosed herein is a modular 
battery system having at least one set of battery modules, preferably monoblock modules connected in series. Each of the battery modules may be designed with a first endplate and a second endplate, wherein each battery module is set between the first and second endplates and at least one band member couples the endplates to each other, binding the battery module between the endplates. The endplates are secured between a pair of rails and the 
system is disposed in a 
system housing. A cooling manifold provides a 
system wherein 
coolant flows into and out of each battery module. The system housing preferably has a 
coolant inlet and a 
coolant outlet. The cooling manifold is in flow communication with the coolant inlet and the coolant outlet. A battery 
monitoring system, which may include a battery control module and at least one 
remote sensing module, preferably monitors and collects performance and status information, such as 
voltage and temperature, of the battery modules. An integrated 
control unit (ICU) may be disposed in the system housing. The ICU supports 
electronics, some of which are used to collect electrical energy produced by the battery modules and / or monitor the system.