Battery Charger Raritan R3012-3

120-V AC Battery Charger

    NOTE: This wiki page contains our original writeup in the Systems Description of operation 
    of the shore-power battery charger that was aboard in 2007.  It was removed approx 29Jul08,
    and we struck out the text 10Aug08.

This unit is located directly forward of the nav station and under the port-side settee. It is powered by 120-V AC shore power, and outputs three isolated lines of +13.x V DC for charging 3 batteries. There is a common "-" also.

The converter also accepts a 12-V DC signal from the engine which inhibits charging output from the Converter when the engine is running; i.e., when the signal line has 12-V on it. This input comes (by the small blue wire) from the engine such that the 12V is ON when the fuel-pump switch is closed. If the batteries are weak when starting, such that voltage in the "blue wire" drops sufficiently, the charger will boost starting current to the engine if the charger is ON.

There is a switch for turning ON the 120-V AC input to the Converter. The main AC switch (left one on bulkhead above the Nav station) activates the 110-V AC power source for the charger.

On Nevermore, there are two 2-conductor "romex" wires with the 12-V DC charging current, each with 1 black and 1 white wire); these four wires are used as follows:

• 2 whites to "+" of Batteries #1 and #2, connected to these terminals on top primary battery switch;
• 1 black to "+" of Battery #3's terminal on lower primary battery switch; and
• 1 black common "-" connected to the common ground 12-V "-" point of the engine.

On Nevermore, the blue charge-inhibition wire is connected to the fuel-pressure switch on the engine, such that it delivers +12v when the engine is running, i.e. when the fuel-pressure switch is ON.

 NOTE: This blue wire was disconnected while trouble-shooting a problem with the 
 alternator in Fall 2007.  As of May 8, 2008, it was still disconnected.  It must
 be reconnected before attempting to use the charging system.

Circuit protection includes:

• 2 30-amp fuses in 110V-AC input line, one in each line (white & black); schematic shows them wired before the unit's on/off switch, which is only in one line (black);
• 2 1-amp fuses in the 12V-DC "blue wire" charging shutdown circuit which is activated when the engine is running; we only use one of these lines; note that -- if the fuse blows -- the charger will NOT be shutdown when the engine is running;
• a 50-amp circuit breaker, mounted on front panel, is in series with the common "+" point of the 3 isolation diodes for the charging currents to the 3 batteries;
• a thermal breaker on the transformer, modulates a point within the semiconductor charge-control-feedback circuitry.

The output voltage is adjustable (with a wire-wound resistor tap, Thom believes) but it isn't something that is done in normal operation. E.g., the instructions say to have the batteries all charged up when you adjust it, so that it's not the kind of thing we'd do to quick-charge a battery, for example.

• More 12-V DC charging functions of this Converter are detailed in subsection 4 of 12V schematic walk-thru
• The 110-V AC function (shore power) for this battery charger are given in 120-volt AC section below.

Specifications - 120-V AC Battery Charger

Input power:	100 to 130-V AC, 8 amp
Output power:	12-V DC, 30 amp (Thom assumes 30 amp shared across all 3 ckts)
Duty cycle:	80 [something?] GR
Manufacturer:	Raritan Engineering Co, Milville, NJ
Model:	R3012-3 Crown Automatic Marine Converter
Serial No:	1090621 (probably; Th's notes soiled)

Operation:

The ship's main 110-V AC switch to left of nav station must be ON, and of course the shore power cord should be powered, before the charger's front-panel switch will turn on power; the front-panel pilot light should then illuminate. The pilot light will remain ON even when the engine is running such that the charger output is inhibited.

The following admonitions are given to prevent serious damage to the converter:

• Always use a battery with the converter; don't run it open-load;
• observe correct polarity of the battery line on hook-up;
• do not test for converter output by momentarily flashing the positive and negative DC out leads (as is sometimes done with batteries.)

Observation:

Looking to the future, we observe that the charger (converter) is designed to charge up to 3 12-volt lead-acid (flooded) batteries. There's NO indication that it is useful for more modern battery types (e.g. Gel or AGM). Its charging profile for lead-acid batteries appears pretty trivial: it was observed (Nov07-Jan08) to charge moderately charged-up batteries for just maybe 10 minutes and then fade fairly quickly to a trickle-charge, as would be appropriate if Nevermore were kept at a pier with shore-power for long periods of time.

• TODO: find exactly where the blue wire connects to engine-running signal.