[C320-list] In-line fuse on battery cables

[dean at vermeire.us]

   I recently installed a new ProNautic 1230P (30A) and have the original
   configuration of 2 4D batteries with one on each bank. The inline fuses
   on mine are 30A.
   Everything is working great.
   Since your charger will automatically adjust the amperage up to 40A on
   a bank, I would think a 20A fuse would be easy to blow.

   On Sep 14, 2020 11:33 AM, SARA SCHROEDER <saras951 at comcast.net> wrote:

     I had reached out to the group regarding recommendations on battery
     charges, echo-chargers and solar panels.  As a reminder I have two
     4D deep cycle batteries, did not have a starter battery or
     echo-charger and my batteries were either not being fully charged or
     were losing capacity. After doing research, my helper and I ganged
     the two 4D batteries together into one house bank which became bank
     #1 and installed a new starter battery which became bank #2.  We
     also installed a new ProMariner ProNautic 12V 40 AMP battery
     charger.
     After a full weekend away from the dock, this set up turned out to
     be an epic failure.  The batteries were not being charged at all -
     either by the new charger or the alternator.  Upon further
     inspection we discovered that both the alternator and the new
     charger were blowing the 20amp in-line fuse located in the positive
     battery cable. We considered just putting in a larger fuse but Platt
     Electric recommended we not do this.
     We undid everything and reverted back to the factory settings.  One
     4D is back to house bank #1 and the second 4D is house bank #2.  The
     starter battery and echo-charger are on hold for the moment.  We
     installed new fuses in both positive cables, fired up the new
     battery charger and my batteries finally started getting a charge.
     At first the ProNautic was pumping in about 40amps but this quickly
     came down to about 20amps.  After about 30 minutes of charging my
     helper reached down and touched the in-line fuse casings. They were
     shockingly hot. We could not really even touch them.  I stayed at
     the boat to monitor them and after about 3 hours I could touch them
     and the cables themselves were "slightly" warm but not hot.
     I suspect the fuse housings are original which makes them 20 years
     old.  Does anyone have these round in-line fuse housings or is it
     just me? Have you had problems with them failing or replaced them?
     If you replaced them what did you use?  Thanks as always!
     Sara
     Wandering Star
     2000 / #707