Carver 325 Aft Cabin Battery Configuration and Wiring

[ETCM]

Hello All,

I own a 1997 325 Aft Cabin. Had a problem with my port side losing power under load. Wasn't fuel or fuel venting. Voltmeter showed low on port side. Had to run across the Chesapeake on 1 engine to save power for docking.

I've got it narrowed down to electrical. Odd thing is that I'm not showing my alternators charging but I'd like to see a wiring diagram. My "Captains Kit" that came with the boat does not go into detail with electrical schematics and Carver's site does not contain the material either.

I've got twin 350 Crusaders, and no generator. I'm trying to see drawn out how they installed the batteries with relation to the charging system. Is there an isolator or automatic charging relay installed?

Thanks!

[mjk1040]

If you have just two batteries the wiring should be straight forward. Charger attachments may be on the selector switch and not to the batteries. Alternators could very well be bad. remove and have tested at auto store.

[km1125]

Hard to say what's been done to the boat since it was manufactured. Doubt it was originally supplied with an isolator or a charging relay, but the original purchaser could have requested that those were added. Or someone could have added something at a later time.

As mjk1040 said, I would have the alternators tested. DO NOT replace with an automotive unit though, as you need the ignition-protection that a marine unit requires. You could have your original ones rebuilt too (with the same caveat).

If you have the typical "1-2-all-off" switch, then either engine alternator is charging while underway. This also means you could lose one alternator and not know it at all until the other fails. Then you have no charging. Also, an inadvertant switch to "off" while an engine is running could cause you to lose an alternator (the voltage spikes and you fry the diodes inside).

Are your Crusaders 350 HP or 350 CI? They made that confusing by making one of their 454's a "350 HP"

[ETCM]

They are 350 C.I. Spoke with Carver today to confirm what the original wiring was. There was never an isolator or an ACR.

Basically, whatever switch position you are in determines what you are running off of and charging. I'm trying to wrap my head around how 2 alternators are trying to charge one battery depending on what position the switch is in. I'm with you guys on testing the alternators. I'm going to pick up a load tester and want to see what that does when I look at it this week as well.

Seems like if I'm going through replacing the one or both of the alternators I may want to install an ACR. I just need to get everything together and drawn out to see what makes the most sense. Here is my latest correspondence with Carver. They were really helpful BTW especially for assisting with a build that was done over 20 years ago.

"Paul,

This is the only print I can find, not much help.
The system is fairly simple: from the alt, there should be a cable going to the starter; from the starter, a cable should go to the feed or line side on the battery selector switch. You should a lead from 1 and 2 leading directly to the batteries. There is no isolators, sensor wires, ACR’s, or anything like that. If your switch is on 1, then it will only charge on the 1 lead; switch on 2 then it will only charger on the 2 lead. From what you mentioned, your batteries are 13.8v, they will not call for a charge from the alt when they are that good. I think the best way, is to do as we discussed, draining your batteries ( at shore ) and then check your charging system."

[km1125]

Yes, you have a typical factory setup with dual batteries.

You can just run one engine at a time and check voltage. If 13.2-14.2 volts, then the alternator is charging (don't have your shorepower charger running, or it will confuse you!). Anything less than 13 and the alternator is not working. That will tell you if one or the other alternator is not charging.

Engine alternators are not sophisticated chargers like your 3 or 4 step chargers. They are pretty much constant voltage chargers and will put out whatever current the batteries will accept. If the battery is severely discharged, then the alternator will put out a lot of current trying to get it to 13.6v but as the battery charges, the current will naturally drop off. So having two alternators running, then they both just try to get to 13.2-14.2v and will both contribute to the overall charge.

[tomschauer]

I can't find the alternator wiring diagram, but I believe each alternator connects to an individual battery. if I start my port engine, I see the port volt meter move to 14v. If I start the starboard, I see the starboard volt meter move to 14v. If I am at the dock and the charger is on, both meters move between 13 and 14.4 v.
I have not dug into this yet, but you should have about 14.4 v from each alternator to the connected battery. I personally would verify the battery condition before removing an alternator.

[ETCM]

Thanks. I'll be doing most of my testing in the morning. When this is all sorted out, I may install an ACR. If it is the batteries, I suppose I can complain. 3 years isn't a long lifespan but they've never left me truly stranded.

[ETCM]

Just wanted to follow up. Both batteries tested good as well as both alternators once the port belt was tightened up. My loss of power actually is coming from the first "screen" fuel filter that is in line before the racor.