The dealer replaced my battery with an AGM( absorbant glass mat). They seem to charge very slowly. I have a battery tender jr. they are lead acid batteries but they are sealed and the design is different. I had work done on a defective front sprocket and the dealer said it was time for a new battery. The work was done two weeks ago and the first battery proved defective. I am on my second battery and the battery tender jr. seems to-be having an issue charging it. I never had a problem with the old fashioned acid battery but will see.