I had to service the battery on our garden tractor in preparation for winter recently. It had a typical molded cover over it that made cleaning of the terminals and wire ends difficult. Its flap cover latches had become a bit loose a long time ago, so often the flaps would become unhooked anyway. Worse, the molded cover cavities tended to accumulate debris and the typical crud that appears on the battery terminals even if you grease them. The battery in our tractor is safely hidden beneath the top hood so there really is no need for all of that.
For that reason I created this bar which easily holds down the battery and fits neatly between the terminals and the water caps. It is 8.5" (215mm) between centers for the tie down bolts and is designed for standard 1/4" tie down bolts. Its height matches the bolt area heights of the original cover pretty well, so the original bolts work perfectly.
It is very stiff in the vertical direction, which is all that really matters. I added a single strip of foam tape to the bottom of it to cushion against the battery top. This also makes tightening of the bolts less critical. Speaking of which, don't go crazy torquing them down. It is not necessary.
It is just a simple thing, but it does make maintenance of the battery much easier.
In case you prefer a taller bar I have also included one that is about 3/4" (19mm) taller. It may be useful if you need to ensure vertical clearance between a cover or some other item and the battery terminals. The shorter version is plenty strong enough, but this version is even stronger. On our tractor the shorter version remains in use.
I hope this may be of use for you. Thanks for looking at it.