The direct current (DC) electrical system draws its power from the batteries which are kept charged by the engine-driven alternators.
The alternators charge the batteries through an ammeter shunt. The batteries supply power through a central fuse panel to the various navigation lights, cabin lights, instruments and accessories.
The negative terminal of all banks of batteries is attached to the grounding stud of the propulsion engine and in the twin screw boats, the ground stud of each engine is connected together with battery cable.
In all cases, the direct current wiring systems are two color-coded wires. The white wire is common to the battery negative terminal which is grounded to the engines. This wire is run to each light, instrument or accessory. The black wire is common to the battery positive terminal and the fuse and switch for each device is installed in this wire.
A wiring diagram is placed aboard each boat when delivered. Additional copies are available through your dealer.
The DC fuse panel is located in an accessible area and includes spare fuses for the customer's use when installing additional DC equipment.
All additional DC equipment must be adaptable to the negative ground DC system.
When contracting for the installation of additional equipment, it will be necessary to stipulate that its wiring be run to the central fuse panel. If additional fusing is necessary, it should be added in that area. Do not allow any power feeds for accessory equipment to be taken from the ammeter terminals.
Enlist the aid of your dealer for a careful analysis of DC power needs on your boat. It may be necessary to add batteries or alternate charging methods to supply adequate power for the additional accessories you require. Read carefully the section on batteries. Careful attention to them will add to your carefree hours afloat.
The alternator is rapidly replacing the generator as the engine-driven battery charging devise. Its advantage lies in the fact that a higher charge rate -- 40 or more amps -- is made available, economically, with a device no larger than the replaced 12 amp. generator. Other advantages are:
Many will recognize the word alternator as meaning an AC power generator. This is still true with the ones used on propulsion engines, but a new device called solid state diodes are installed in the alternator so that its output is changed to DC power. It could now be called a self-rectified alternator. The alternator does its job best when the feed wires to the battery and to the voltage regulator are kept as free of voltage drop as possible. For this reason, it is no longer in the best interests of our customer to run the charging feed wires to the ammeter on the bridge before it goes to the battery.
We now put a shunt in the feed wire from the battery positive terminal to the alternator and from each end of this shunt a wire is taken to run to anew -type ammeter on the bridge. The shunt and ammeter are so matched that any charge that goes through the shunt will show on the ammeter. Fuses are put in each feed wire to discourage the practice of taking power from the ammeter to run accessory equipment. The factory has left spare fuses at the central DC fuse panel for that purpose.
As installed, the ammeter will show you the exact charge being supplied by the alternator. If the needle goes sharply to the discharge side of the ammeter, a fault has occurred in the alternator and that engine should be turned off until the trouble is fixed.
This new 40 amp. charge system and 60 amp. ammeter make it impossible to show the discharge of power used by the engine electrical system when the key is turned on as was possible when we had only a 12 amp. charge generator and a 30 amp. ammeter.
Always disconnect the battery ground cable before doing any work on the engine electrical or alternator wiring. To prevent sparking, or damage to the alternator.
The batteries used by Chris-Craft have been selected for their ability to furnish quick power in large quantities for engine starting, their ability to accept re-charging by high capacity alternators and their ability to hold their charge and release it when required for lights, bilge pumps and other accessory equipment.
Under the cap of each cell there is a grid to prevent foreign matter falling into the cells. The water level of each cell should be about 1/411 above that grill. This leaves a large space above the cell to take care of the electrolyte expansion during charging, so that none will be forced through the vent in the cell cap.
Any spilled acid on batteries, battery boxes or other parts should be neutralized and cleaned up with Arm and Hammer baking soda in warm water. The terminals and clamp bolt nuts may be cleaned in the same manner. The battery manufacturer recommends that the terminal and the battery tops be coated with Dow Corning Compound #3 as a corrosion preventative.
The specific gravity of the electrolyte is 1. 260 full charge. A hydrometer with temperature reading and correction factor combination should be used to test each cell.
Do not test batteries right after adding water.
To accurately test the batteries, the charging devices must be turned off for at least 20 minutes.
The average charge at different specific gravity readings will be:
Full Charge 3/4 Charge 1/2 Charge
Specific Gravity 1. 260 Specific Gravity 1. 220 Specific Gravity 1. 190
As batteries will freeze and damage their containers when discharged, we recommend that all batteries should be kept at a 1. 230 specific gravity reading in freezing weather.
The freezing points are:
Specific Gravity Freezing Point
1. 260 Full Charge -70 0 F 1.230 -40 0 F 1.200 -18 0 F 1.170 0 0 F
1.125 +140 F above zero 1.100 +20 0 F above zero
When adding water to battery cells in freezing weather, be sure to re-charge sufficiently to thoroughly mix with electrolyte to prevent freezing.
Batteries in storage or idle for months at a time should be kept under trickle charge or to be fully charged once a month.
A battery that has its electrolyte under 1. 230 for long periods will have internal chemical damage due to standing in a discharged condition.
A battery will explode if a flame or spark ignites the free hydrogen given off by the battery during charging. For this reason, never use an open flame in the battery storage area. Also, avoid striking sparks at terminals. Be sure battery covers are always installed to prevent shorting by any other means. Always recheck battery terminals for tightness and never disconnect under load.
On sailing boats the batteries and the use of them will need constant attention so that adequate power is always retained to start the auxiliary propulsion engine.
Many owners add additional batteries for DC electrical accessories and cabin lighting and keep them charged from an extra engine-driven alternator and/or a permanently installed 115V AC battery charger which requires that an electric cable be connected to a shore 115 VAC outlet when docked.
The wiring for 115V AC systems installed on Chris-Craft boats consists of two color-coded ungrounded wires. The white wire is the neutral wire and the black wire is the hot feed. All distribution fuses and switches for AC equipment are installed in the black wire. The metal enclosures of AC devices, fuse boxes, and switch boxes are bonded with green covered #10 wire to the central grounding point which is the ground stud on the propulsion engines.
No AC feedwires are grounded in the boat and it is necessary that when AC equipment is installed, any jumper wires from enclosures to the white neutral wire must be removed. A separate green-covered bonding wire must be added to connect the enclosures to the central bonding point mentioned above.
As factory installed, a fuse or circuit breaker is placed in both the white neutral feed and the black hot feed wires from the shore power inlets. This will fuse both feeds when plugs are reversed at the shore connection.
The polarity lights are a matter of choice for the owner. We offer an economical unit which is available from our dealers.
The normal cable to shore power for this 115V AC system contains two color-coded wires (white and black). We suggest a yellow jacket for all shore cables so that your decks or hull sides will not get marked.
If it is preferred and ordered, a three-wire 115V AC shore power connection will be installed at the factory. The hull receptacle and plug will be changed to one with three prongs and the shore cable will have three conductor color -coded white, black and green. The white and black wires will be wired as shown for the two wire systems above and the green conductor is connected to the bonding stud on the engine. Neither white nor black wire will be grounded on the boat.
The wiring of 115/230V AC - single phase - 60 cycle - shore power to our boats, requires inlet receptacles and plugs for a four-conductor cable, color-coded white, black, red and green. The white wire is the neutral conductor and the black and red wires are the two hot feed wires that are wired through main line circuit breakers and the green covered wire is the bonding conductor which is connected to the bonding stud on the engine. The white, red and black conductors are not grounded on the boat.
When the 115/230V AC shore power inlet system is installed on the boat, it will service all the 115V AC equipment through a labelled rotary switch when its shore cable is attached to a source of 115/230V AC - 60 cycle - single phase power on shore.
It might be pointed out that the 115V AC three-wire shore power system and the four wire f 15/230V AC shore power system connect the underwater gear of your boat to any of the grounded metals on shore and, unless your marina maintains a protective system, your zincs will try to protect the shore metals connected to it and waste away at a faster rate.