Question: I just had a survey done on my boat for insurance purposes and the survey report says that I need to add a properly sized fuse to my battery charger output lead “in accordance with ABYC recommendations." I think the surveyor may be wrong here. I think the fuse for the output from my boat's battery charger is inside the charger. Any help would be appreciated.
Answer: A good question and one that can be confusing. Your surveyor is quite right that the ABYC does recommend a fuse for the output leads on your battery charger. But as you suggest, many times the requisite fuses are indeed inside the case for the battery charger; and often not too obvious either! In the photo above, which shows one of Xantrex’s newest charger units, the small cover has been removed to show the two 20-amp output fuses for the unit. These meet the ABYC recommendations. So, depending upon the exact make and model of your charger, you will need to get the original documentation to show where exactly the fuse(s) for your charger are located.
I can recall some of the early Statpower chargers that had a fuse just like the two in the photo here, but there was absolutely no indication on the units as to where the fuse was located. Worse yet, you actually had to do quite a bit of disassembly to get to the fuse. One screw removes the cover on the unit above. Some of the Newmar units use the same fuse type, and they just plug into a holder in plain site on the outside of the case.