I purchased a 1952 Ford 8N tractor this summer and it has an 8 volt battery installed in it. During the cold winter Ontario months I would like to connect a trickle charger/tender to the battery to keep it fully charged for the odd time I will use the tractor. What would be my best option for a trickle charger/tender for what I am looking to do? I do not want to connect something that will fry the battery or worse cause damage to the electrical system. Thanks Lots.