Thanks for the reply. I haven't actually looked at the contacts on my timer, I bought the charger new (surplus) many years ago for the conversion that I started. Finally, last year, I started working in earnest to get this thing going and as part of that I purchased a pair of batteries from Sam's Club. I have used the charger but since the batteries have yet to see any significant usage the charger has only been used to keep them at a high charge level and while it did draw about 15 amperes the first time (straight from the store) I have never seen it go over about 10 amperes since that initial charge and then for only a couple of minutes at which time it tapered down to less than 2 amperes.
My charger came with only a partial chassis; back, top and sloping front. The back holds the Lester fuse assembly, the top is mostly ventilation slots and the front holds the timer, indicator light, power cord and rectifier heat sink. I will be transferring this into a NEMA 1 enclosure in the future and I will take your advice to add a sacrificial relay between the timer and the transformer.