Will you be riding frequently thus winter or putting the scooter away? If you'll be riding, don't waste your money as there will be no need to use one. If you are putting the scooter away for a few weeks or longer, consider the Deltan Battery Tender Plus. It cost more, but unlike the cheaper Jr model the plus uses better components. The Jr has been known to cook batteries as has been reported on other PTW forums. Last year I used a BT Jr and two OEM batteries test dead within 6 months of purchasing the scooter. I can't say for certain it was the BT. It could be a case of a bad battery lot.