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Projects: Batteries

This page describes C34 owners' battery upgrade projects.
Please contribute yours!

New.gif (167 bytes)The Ultimate Electrical System Upgrade? Beat This!

The question of refrigeration "at sea" was solved in our case by a major upgrade to the battery system.   We also fit an inverter/microwave and other mod cons needing much power.   Our solution was to fit 6 (six) Trojan T105 golf cart batteries aft in the lazarette as the inverter bank; 4 (four) T105 batteries midships in two banks for the fridge and house; and a single 12 volt just aft of the engine as a dedicated start battery.   All banks except the engine bank are breakered.   

All are fed through two battery switches (original at the board and second one under the sink in the head) allowing individual parallel connection "to the bus".    Normal operation isolates each back for its own use.  We have limited shore power available so most charging is engine or wind turbine provided (Marine Air).   May go to a larger alternator but haven't missed it so far. 

When on shore power a two leg built-in charger and the inverter "in reverse" works wonders.  Batteries are interconnected !during charging via West Marine battery combiners.   One of the major requirements for the engine harness upgrade was solved when the alternator was fed direct to the engine battery first, hence to the other banks via the combiners.   This also eliminates the potential of "switch off" damage to the alternator. 

The six volt Trojan T105 golf cart bateries are brutes and our fridge runs 2-3 days on the forward bank without charging depending on the weather and the number of ice cubes needed for the gin.   If there is much wind at all the Air Marine wind generator makes all ergs required.   The other part of the upgrade which was essential in my view was the replacement of all 4 gauge cable with 00 gauge.   Its tough enough to make the amps without wasting them in the cable!   (The original system had 14 feet of #4 from the batteries to the starter! NOT!)   All in all the new system works a treat.   The effect on my crew of a toaster, curler and hair dryer at anchor was wonderful!   The computer and margarita blender were, of course, incidental!   Gary Wiseman (Up Spirits, #894 [1988]).

Freedom 20 Inverter

The following describes a Freedom 20, 2000 watt inverter installation,  mounted under the nav station. It is connected to 2 - 8D Gelcell batteries located under the starboard settee which I converted to a battery compartment after removing the existing water tank. To make the connection I used the recommended 2-0 cable which I had made up at a local battery shop and I purchased the 300 amp fuse for safety. The fuse is mounted on the inside wall of the combination Settee/Nav seat. Being located there it is easy to string the wires from the F-20 back through the power panel compartment and down behind the settee to the fuse. The 2-0 wires from the batteries are taken to a Battery switch mounted on the aisle side of the old battery box. (just in front of the sink/water heater area) two cables (+ & -) are then brought out the bottom of the battery box/settee to the same area via the bilge. 

For backup I also added a battery and fiberglassed shelf behind the engine next to the muffler to hold an additional Group 24 GelCell battery. This is my emergency starting battery and is hooked to the #2 side of the battery selector switch in the Nav station. The other Battery Switch wires are connected to the #1 position. 

When I use heavy loads like a microwave (mounted under the sink) or a toaster (what a luxury!) I tend to run the engine with it's 124 amp Ample alternator. I do not like to discharge the batteries below the 50% mark. I like the Gelcells as I do not have to equalize them like the Wet Cells (Gerald Misener).   

Important: The opinions expressed here are those of the individual contributors to this page, and not those of the Catalina 34 National Association or Catalina Yachts, Inc. Additionally, this material has not been reviewed by Catalina Yachts, Inc. for technical accuracy. This page's maintainer cannot guarantee the accuracy of this information or the desirability of suggested modifications or upgrades. Please obtain assistance from a competent marine mechanic or boatyard prior to making any significant modifications to your vessel.   


Last modified by Phil Imhof, Wednesday, August 11, 2004 . Copyright 2001 by Catalina 34 International Association.  All rights reserved.