I actually run a car battery in my S150..... It has yet to give me any problems, but i don't use my machine as much as others may. I spent the extra on a bonded element battery for my 743 years back, it didn't fail, but neither has the car battery. If you depend on your machine for a business, get the correct type of battery, if it's just for home use, a car battery may serve you just as well. Just don't expect it to last as long.You can try the parts manual, or the Interstate Battery website or the dealer. Once you know the group, get an Interstate. Some people try and jam in a car battery from Walmart and they have trouble latter on.