There is no special charger for charging a hybrid battery which is completely discharged or low on charge. The simplest way to push some charge into it is to start the motor and keep it running until you see the battery is recharged enough. If you want to accelerate the charging process, remove the #15 fuse and run the engine at 3000 RPM. This way, the it will be charged faster. A hybrid battery shouldn't interfere with the engine starting since it also has a usual battery and a starter. Such a system is designed to serve as a spare battery and can be used to run the motor during low temperatures.