The original OVP was so troublesome that a change to the new style is the way to go. [ short $$$ at Fast Lane]
However, as most of them have been changed by now, I would pull it and check the part # on the side. The orig will be
part # 000 540 52 45. Manufactured by Siemens. If so, replace it.
As posted, behind the black panel at rear of battery. Tall aluminum can, fuse on top. There is a hidden securing nut on the side that has to be removed .