I am 74 years old and have been a bike rider a long time and I just recently converted my Trek Hybrid to a Ebike. I have a 36 volt 13 Ah 500 watt Battery which give me about 25 mile range but have been trying to find a 15 AH for more range. I want to keep the same style Dolphin Battery as the brackets would be the same. I can find the 13 AH and smaller. Any help would be appreciated as I have checked about all the distributors.