I am now convinced. It appears that the Battery Tender brand has the electronics to maintain the battery without damage. This I learned from some other reviews of the product. I'm thinking I need several of the devices - ATV, lawn mower, boat, and the Farmall (although it is a six volt it will be worth finding a float charger for it too). Batteries have gotten expensive and responsible disposal is important to me. By extending the life of the batteries I have it just seems like the right way to reduce consumption and items in the recycling stream. Plus the devices will pay for themselves in reducing my blood pressure alone
It will make sense to examine the various brands some of you TBNers have mentioned. Harbor Freight Schumacher, Deltran and others. Seems better to have several than try to manage the rotation- I do have a real job for the time being.
I appreciate all the responses!
Battery Tender (trade mark) is the only tender I would purchase. Not saying the others are not up to the task, it's just that in the 16 years I've used them I've had excellent service from them. I had a 6v tender on my 8n, so I know BT makes them too. I currently have 4 Battery Tender Plus's and couldn't be happier with the product. Keeping all the chargers/tenders the same brand means they can be swapped around as needed since all the connections and such will be the same. JMHO! YMMV!