Impressive. It is not easy to charge the 150ah battery with solar panel directly. For proper charging using solar panel you just need to use a solar charge controller. You must also place the batteries in parallel connection for fast charge. Using solar charge controller avoid reverse current flow from Battery to a solar panel and unharmed pannels from burning. For proper charging your solar panel must create power more than 150w 150w is the threshold point for your charging. More the power added ……charging rate improve.