Troubleshooting DC electronics ‘97 400DA

Z-Worthy

Z-Worthy

Active Member
Jun 20, 2014
457
Sandusky, OH
Boat Info
2002 Sunseeker 44 Camargue
Engines
450hp Cat 3208s
I spent the better part of my day commissioning all systems on our ‘97 400 Sundancer and found some electrical issues. I believe I have a bad port battery bank, but I’m looking to the forum for some clarification and assistance.

The boat was plugged into power and the A/C converter has been on for at least a few weeks. The port motor won’t start, spotlight won’t work, and the hatch lift won’t work. If I hold the crossover, I can start the motor and lift the hatch (didn’t think to try the spotlight with the crossover). The fact that the starboard bank is charged makes me think bad batteries rather than a charger issue.

But does anyone have a schematic showing which accessory electronics are tied into which banks? I had no clue the hatch lift and spotlight were on one bank; I assumed they would be on the house batteries. So now I’m curious what items pull power from which batteries. And at what level in the system does the crossover work? Does that work for just the starter and hatch? Or will that completely cross the entire electrical system over?

And lazy question; is the port bank the two batteries further fore or further aft? The labels have all faded and I like to know where to start poking around with a meter.
 
This may not be the most helpful....but I believe "most" or all of the accessory items will be on the same battery bank. Sounds like port. From the factory the boats should be wired so one side runs almost nothing except a starter for one engine. If you kill the other side with the accessories you can still start an engine and then cross-over to start the other.

My two cents on the batteries - replace them all (both banks and your gen) if you have any doubts on their ages. Do it once and be done with it for a few years. It's not too pricey if you shop around. Batteries plus has been very hard to beat in my area...
 
SeaRay didn't standardize battery configurations. There were lots of variables from the factory in boats with I/O's, v-drives, generator or not, gas, diesel, bow thruster... Add the 22 year age of our boats and all assumptions go out the window!

Generally speaking in 400DA's (gassers at least), the port bank runs the "critical" and safety systems while the starboard bank serves the house. My port bank does the hatch lift, the cockpit and nav lights, nav equipment, CO detectors and of course starts the port engine. (my spotlight died years ago, but your discovery of it on the port bank make sense)

Starboard has all interior lights, refrigerator, vacuflushes, stereo... They're the convenience items. You can skip a flush at anchor if you have to, or maybe your icecream melts if the house batts die, but your anchor light will stay on, and that keeps you safe. IMO, SeaRay put some decent thought into it.
 
These might not be what you need, but I thought you would like to see them...

I thought I had a better copy of the torn one, but I don't know what I called it...

400 DA DC wiring diagram.gif
400da batteries sm.jpg
 
Lets jump to the other end of this.....which is what you will need to do even if you trace the schematic on the boat:

Disconnect the + battery terminals on both port batteries to separate them from each other and the charging circuit, then load test the batteries. From your description, I suspect you have a bad (open or shorted) cell in one battery. Your battery charger will read that as a low battery and keep charging but the bad battery cannot take a charge.
 
Frank beat me to it! I’ll just add that if your batteries pass a load test then make sure all of your connections are good.
 
I just went through all of this over the weekend. Friday night I came up to the harbor and the boat smelled like rotten eggs (sulfur). I could smell it on the dock. As best as I can tell, I had a bad battery in my starboard bank, the battery charger kept charging trying to get it to full, and overcharged the system. When I opened the engine compartment I could hear air hissing out of one of the sealed batteries. Spent yesterday driving around to 3 different Sams clubs to replace all 5 batteries. Decision about replacing the charger is coming next.


[QUOTE="Z-Worthy, post: 1061291, member: 35364"
And lazy question; is the port bank the two batteries further fore or further aft? The labels have all faded and I like to know where to start poking around with a meter.[/QUOTE]

On my '98, the set to the left when facing the batteries (aft) is my starboard bank, the batteries on the right (forward) is my port bank. All are 4 in a row with the generator battery by itself to the interior. If I recall correctly, the negative cables have the label for which bank is which.

[QUOTE="Z-Worthy, post: 1061291, member: 35364"
But does anyone have a schematic showing which accessory electronics are tied into which banks? I had no clue the hatch lift and spotlight were on one bank; I assumed they would be on the house batteries. So now I’m curious what items pull power from which batteries. [/QUOTE]

The wiring diagram posted above by @Boat Guy comes from the owners manual and is reflective of my set up as well. An easy way to confirm is to use the battery switch to turn off one of your banks, and you can see what works and what doesn't.

I have two batteries wired to starboard and two batteries wired to port, each of which start the corresponding engine and handle different "house" functions. My starboard bank handles the bilge pumps, engine hatch, and cabin lighting. Port bank sends power to the helm and other items, and on my boat has aftermarket wiring to power the amps.
 
Thanks for all the great info! As mentioned, it’s the two forward batteries that are dead. Since the two aft are still charged, as is the generator battery, I’m guessing it’s a bad cell like Frank said.

Now to the bigger issue; these Vita Plate maintenance free batteries are around 3yrs old, which is within reason but a bit on the younger end to be toast already. Is there a way to test my charger to verify that it’s working at optimal performance? And what batteries does everyone else prefer for better performance and longevity?
 
You'll get a whole bunch of suggestions on batteries. The most pocketbook unfriendly will be a nice set of shiny new AGM's :).

I've had really good look with Duracell lead acid batteries from Batteries Plus. They are made by Dekka. They are also about as affordable as you can get. My experience has been that 4/5 years is about time to change 'em. This based on the way I use the boat, of course.
 
Ok, time to circle back around. I bought two new batteries, installed them, turned on the A/C Converter switch, and they lasted less than 2 weeks before they’re dead as a door nail. I didn’t even use the boat during this time. So now I’m circling back around to a bad battery charger. The current one was manufactured in 1996, installed in 1997. So I guess 20+ yrs is a pretty good run.

But what brands/types of chargers does everyone prefer? We tend to use the generator away from the dock, and we never spend much time on the hook. So the batteries don’t get much of a workout with the way we utilize them. But I also want to install quality hardware for whomever the next owner of this boat will be.
 
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