Help for the guy in the slip next to me

S

SteveOgden

New Member
Jul 16, 2008
1
The guy in the slip next to me in Annapolis MD has recently bought a 1984 Sea Ray 340D Express and he cannot operate any of his 12 volt DC systems unless he has the engines running.

It's his first boat so I'm trying to help him out as he is 'living aboard'.

I am a very experienced boater with my own 46 foot sailboat and have lots of experience with the electricals but I cannot work this one out.

The boat appears to have a starter battery of about 100 AH and what looks like at first glance a house battery of 2 x 100 amp cells but these do not appear to be connected in parralel like a normal house battery.

It has 2 battery on/off lock switches and does not appear to be wired as per the manual's wiring diagram.

Does anybody have any clue about what's wrong here or at least have a wiring diagram for a 340D (1984) which shows the DC distibution circuitry?

Any help/suggestions would be appreciated as he wants to go down the ICW but at present can't do anything which requires DC power (e.g. water pump, anchor light, cabin lights etc) unless his engines are running.

Thanks in advance.

SteveOgden
 
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I'll bite. The main house 12 volt power might be tied to the ignition circuit when it should be tied to the house disconnect switch.
 
I have an '89 340 DA. I have the battery wiring diagram on the boat and I will bring it home this weekend and if I remember, post it.
 
Each 12V bank should be isolated but still wired thru the master switches. Each bank serves as the starting battery for its engine and one or the other is usually the house battery...if one bank has 2 batteries, then that is the house bank. Even with the engines not running, the 12V circuits on the main panel in the salon should be energized. I would open the main panel face......it's hinged on one side and has screws on the other.....swing it out and check the voltage on the main 12V buss or the inlet side of wach switch. If you have no voltage there, work your way back upstream by following the 12V cables thru the bulkhead to their source.

Sea Ray did not regularly publish the wiring diagrams in the 80's so you will probably have to go to the nearest Sea Ray dealer to see if you can copy or look at theirs........if they have been a dealer since 1984.

But, this one sounds like some one has changed the factory wiring for some reason. Perhaps the house battery switch is wired backwards so that the selector positions control the loads rather then the sources......????

Hope you get it worked out.
 
If loads only work when the engine is running then:
  1. The batteries are dead and he can only run the loads from the alternator
  2. The boat is mis-wired. The batteries are disconnected from the loads but not the alternator.
Hard to say what the problem is without examining the wiring. Look for non-factory connections or wiring. Also check the battery switch. Also, does he have to do anything unusual to start the engines, or is it simply a matter of turn the key and they start?

Best regards,
Frank C
 
I thought about dead batteries, but how would he get the engines started if the batteries were so dead that nothing happened on the 12V panel? The boat should have 7.4's and it takes a decent charge in a battery to crank one.

So, I'm voting for a wiring problem................
 
He jump starts it with the starboard battery using the emergency start switch or a portable pack. Who knows? It's darned hard guessing with partial information provided by a third party. Steve is giving it a good try, but it's not his problem, so you don't know what he knows and doesn't know about the problem. So assume nothing. So if I assume nothing, then the batteries are dead.

I'm a mathematician by education. If I remember anything, it's to always start your solution with givens and assumptions, then apply logic.

Best regards,
Frank
 
It would be strange to see anyone redo the wiring to have such an effect. Only an imbisile would rewire something so screwed up on that boat. My thought was that the house battery is dead, but that the starting battery works well enough to get the engine cranked over. Steve, get a multimeter on each of the batteries and come back with some numbers. Check the wiring as per Frank's instructions. Check to see if there are any breakers on the DC side that are shut off downstream of the engines that control the other 12v appliances. My marina shuts them all off as part of winterization but I think I would still be able to crank the engine as I don't think the engines tie into the panel. You're getting 12v while running because of the alternators, which should be feeding juice back into system and charging the starting and/or house battery.
 
It's a 24 year old boat, with electrical gremlins and the guy wants to take it down the ICW? Not anytime soon.

Start with a volt meter and document what is actually present and how it's wired. Until you know what's actually THERE it's pretty much pointless to speculate.

Better yet, if he's not handy enough to do this himself them advise him to pay someone that is. There are plenty of yards in the Annapolis area that'd be more than capable of doing a good job.
 
Sea Rays use the same wiring and circuit designs on almost all boats in a given category. What has been posted previously isn't pointless speculation, but an explanation of what he should have and a basic idea of where to look for variances to that. Personally, I'd rather start with an understanding of the design than to have to deduce it with a volt meter.

But I will agree that if the owner doesn't have a basic understanding of DC current/circuits, he would be money and time ahead to get professional help.
 
The speculation comment wasn't aimed at this thread's comments, more toward the original post and the second-hand nature of the situation (3rd hand?). Sorry if that wasn't clear. And my suggestion about the volt meter was to use it to at least establish some baseline info about what voltages are present. A dead battery is easily detected with one, certainly more so than by looking at a schematic alone. You can do it without a schematic, as most boat systems are very similar, but I'd certainly want one if possible. Given the age of the vessel there's as good a chance as not that the system no longer resembles factory designs.

When using a volt meter, voltages present at one location, but not at the next expected part of the circuit can help narrow down bad switches and terminal contacts. On a boat of that age, and with unknown history (like a partial sinking that corroded the wires), all bets are off as to even the status of the wires, let alone the breakers or switches.

It's the intention to get out and travel the ICW that's worrisome. For lots of reasons it's best to be sure things like the electrical system are KNOWN to be free of problems well before embarking on a long trip. If you're paying someone to deal with this problem it'd certainly be a good idea to let them know of your travel intentions. Beyond just fixing the immediate problem they may be able to give a better idea as to whether the rest of the ship's systems will meet the travel needs.
 
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