[C320-list] Problem purchasing Battery Charger inline Fuses

[Jeff Hare]

Hi All,

We originally had FNM-30 amp slow blow midget inline fuses from the factory
for our ProMariner 20-3 charger.  We upgraded our ProMariner to a Charles 40
years ago and never gave a thought to the inline fuses at the time.  We
never had a problem until Thor struck this summer and blasted those little
guys to pieces.  So, we replaced our blown Charles 40 with a new Charles 50
charger and all I had was more 30a slow blow fuses.  That seemed to work
fine.  The charger is a 3 bank charger that will produce up to 50a on one
leg, 25a on two legs, or 17a on 3 legs.  Catalina wires the 320 for 2
batteries so the third charger leg isn't normally used anyway.

But the largest fuses I can find like these are KTK-40 amp fast acting
fuses.  I looked (I think) everywhere for higher rated ones in the same
physical size.  No luck.  But I was finally able to find AGU type glass
fuses rated at 50and 60 amps (fast acting) that LOOK like they might fit the
factory inline fuse holders.  Has anyone used AGU fuses in the charger
inline fuse holders?

So all that got me thinking that to be safe (ie: protecting myself against
Warm Beer Syndrome), I need 50a inline fuses because, so if one of those two
were to blow or one leg were connected to a fully charged battery and the
other connected to a discharged battery, I'd likely blow the remaining fuse
the next time the charger kicked in. . and suffer the aforementioned WBS.

Anyone know what kind of fuses fit these holders that are >= 50a?

-Jeff

PS:  This all came to be, because someone on the dock shut off my breaker by
accident and the fridge drained my batteries. AND I had forgotten to replace
one of the two blown charger fuses when installing the new charger.  53amps
through a single 30amp fuse isn't an ideal match.  I fired up the engine
with the new AmpTech 125 alternator / Balmar MaxCharge regulator and watched
the current hover around 100amps charging current for over an hour (or
basically until I was about deaf from the engine noise).