Posted: August 18 2008 at 12:06 | IP Logged

A quick way to find out is with shore power on, rectifier on, main battery switch off,  disconnect a battery positive connector at a battery and with a voltmeter, read around 13.5 VDC at the disconnected Pos. connector to ground. if about 13.5 VDC is present and follows the on/off-on/off recifier's switch function, the rectifier is being used as a charger.

I'm thinking the rectifier is not hooked up as a charger. It sounds like the batteries are being drained by some sort of load, (assuming the rectifier was on) but are not being renewed with any sort of power source.  Chances are this is the original recifier. As such, C.C. used the rectifier as a power supply first for the vessel's 12VDC buss and as a battery charger as a secondary use. 1985 technilogy being what it was, it is not the best charger. My Catalina 280 Bats. were hooked up to the rectifier for charger function at the isolator lug. I bypassed the rectifier's charge function by disconnecting it there, but made sure the recitfier output continnued to feed the 12VDC Buss while on shore power. The feed wire to the buss was also connected to the same lug at the isolator-hence two functions- charger and shore power. I then installed a smart charger. It was my own choice, and there are many ways to this: I tapped the AC power after the rectifier breaker and used  the Recfifier AC voltage as the supply for the smart charger. I installed a second switch to shut off the charger. I did this in case I need to continue to use the recifier but need to service the charger.

Hope this helps   

Posted: August 20 2008 at 10:30 | IP Logged

Hi Pancho,

 In answer to you questions:

1) The rectifier should charge both batteries. C.C. did not print spacific schematics for their boats after 1982- they printed 'typical' schematics for a Model line. On my 280's schematic, the rectifier is not even shown- oh well. There was an additional, seperate drawing showing a generic schematic of a rectifier circuit, but it took some digging to find it and it wasnt much help anyway for hook ups on my boat.  So. You run twin engines, but the rectifier function should be the same as a single.

2) With the boat on shore power, the rectifier is on until the rectifier breaker is turned off.

3) Ok, 1st things 1st. A rectifier is used to supply 12VDC power from shore.  With all main Battery switches off and the rectifier on, can you run the boats 12VDC circuits (running lights, horn, fresh water pump, head, cabin lights) ? 

To continue working on your 3rd question: is there a voltage at both of the disconnected positive battery connectors with all Battery switches off?

Diver