Catalina 30 sailboat internal cabin lights only work when connected to shore power

Aug 6, 2024
1
catalina 30 tyee marina
We have a Catalina 30 sailboat and the indoor cabin lights work fine, but only when connected to shore power. The outlets in the cabin also only work when connected to shore power. It’s weird because everything else connected to the main power bank (autopilot, bilge, etc) works when NOT connected to shore power. Any ideas on what’s causing/how to fix this issue?
 
Sep 24, 2018
3,405
Catalina 30 MKIII Chicago
You would need to install an inverter and a transfer switch to make the outlets work when not plugged into shore power. This has the potential to drain your batteries very quickly
 
Apr 8, 2010
2,116
Ericson Yachts Olson 34 28400 Portland OR
If your interior cabin lighting consists of AC fixtures, they will only operate when AC power is applied (usually from shorepower).
Doesn't your boat have interior/cabin lighting that is powered by a DC breaker on your DC distribution panel? It not unusual for boats to have both systems in place, but I was not aware of this for a (stock) Catalina 30. What year is your boat?
Check your DC panel for a breaker marked 'cabin lights' or similar. Can you publish a photo of your boat's breaker panel. That will help others to help you.
 

Joe

.
Jun 1, 2004
8,196
Catalina 27 Mission Bay, San Diego
Your 110 AC powered lights are not compatible with 12 volt appliances. Unless your boat has an inverter, or "smart" charger, that converts AC to DC then my guess is that your 12 volt instruments are simply running off the battery.
So from that point it is just the simple task of educating yourself on how 12 volt systems work. Pretty simple
if you acquire a copy of "the 12 volt Bible" by Miner Brotherton.

Every boat owner should have this basic, easy to understand book in their boat library. All answers will be there.

(just a note, in the early days of Catalina yachts, ordersheets were the norm, which means almost all functional equipment. From anchoring ground tackle, bilge pumps, stoves, Shore power systems, which are the 110 v AC circuits, etc. In most cases there was only one battery, which was usually charged by the motor's alternator, and provided a source for running lights and a few instruments, maybe a couple of interior lights..but litte else. These systems could all be upgraded on the order sheet so they were installed an operable when the boat was delivered. People were pretty thrifty back in those days. But eventually Catalina and the other production builders included these systems as standard. It's importatant for you to research your boat's systems so you can modernize it got comfort and performance)
 

LloydB

.
Jan 15, 2006
927
Macgregor 22 Silverton
You need to turn the off grid AC switch on and turn the on grid switch off. Probably, but three other best guesses come to mind because your boat may not have those switches labeled as such. Google is faster This site is friendlier but may have long delays as if it was snail mail because it is more like a bulletin board.
 
Jan 7, 2011
5,592
Oday 322 East Chicago, IN
Photos of the lights (and the bulbs if possible) as well as the electrical panel (DC and AC) might give us a better idea what you have on your boat. I assume every boat has DC cabin lights….but maybe some have both. Hard to imagine a boat with only AC lighting.

Greg
 
Apr 22, 2011
939
Hunter 27 Pecan Grove, Oriental, NC
We have a Catalina 30 sailboat and the indoor cabin lights work fine, but only when connected to shore power. The outlets in the cabin also only work when connected to shore power. It’s weird because everything else connected to the main power bank (autopilot, bilge, etc) works when NOT connected to shore power. Any ideas on what’s causing/how to fix this issue?
Your cabin lights must be wired for ac and have an ac capable bulb. Are there two bulbs in the light fixtures, one for ac and one for dc?
 
Jun 17, 2022
236
Hunter 380 Comox BC
There are AC electrical systems, which only work on shore power and DC electrical systems which draw on the battery. The AC systems typically draw a lot more power and although an inverter could allow them to work off a battery, it would deplete it very quickly.