3 Battery Bank - Inconsistent information - '04 280 Sundancer

[Nathan007]

Hello everyone (newbie here - prior owner was original - I just purchased end of 2020), I have searched and searched without luck as I keep running into inconsistent information on my battery bank. I'll try to keep as short as I can. I have 3 batteries and two switches. Left switch is 1-both-2 and Right is On-Off. Battery setup can be seen in picture. Manual says left battery is port battery, cannot find one forum/post that agrees with this. These questions may seem redundant, but I'm not afraid of constructive criticism - lay it on thick - it's how we learn. (Twin Mercruiser 5.0 MPI with Genny)
1. All three batteries are cranking (interstate 27m-xhd), should one be deep cycle (or maybe dual purpose)? Which one? I want to keep as lead acid as my converter/charger specifies.
2. Please confirm which battery is my house battery. Best Map I have found is also attached, but again brought up inconsistent information. Or are both Right batteries considered House (ran parallel?)
3. Bottom right battery has lowest handheld voltimeter reading, but dash/instrument cluster says Starboard battery is lowest (consistent with manual - not with forums/map - doesn't answer #2 for me).

NOT SO IMPORTANT BUT CURIOUS:
4. I'm 99% confident the left battery switch (1-both-2) controls the 2 right batteries, but again I have been plenty wrong before.
5. I keep both keys switched Off along with both battery switches Off when gone for the week, shore power On, AC Converter in galley panel On. All 3 batteries are charging as needed correct?

I may have talked myself into a tornado here, but hey I'm from the Midwest.

 

[Little Ducky]

I think you have it figured out.

One question. What's the red light on your charger mean?

 

[hughespat57]

Sea Ray often marks the cables with a wrap of green or red electrical tape.
The red indicates the port batteries, the green the starboard batteries. (think running light colors)

 

[Lazy Daze]

Just an FYI... there's good info in your manual about (can download it from SR's site, too) this - the wiring diagrams are very informative on this, as well. So, rather than go into detail and repeat things that are easily found, the jist of it is...

The single battery is for the port engine. The double bank also serves the house. Ideally, house batteries would be dedicated to house only and be DC, but in this case, since running DC for starting an engine isn't ideal... I'd seriously consider the bigger DP (dual purpose) that Deka makes, now. It's actually a really good DP battery.

Not sure what you mean by #3. But if the batteries are 5 years old, just get new ones.

Yes, the 1-2-Both switch would control the two battery bank setup.

Batteries will be charged regardless of the switch position - by the charger, that is. The switches will control/direct charging from the engine.

 

[Creekwood]

Agree 100% with Lazy Daze. If your generator is working, I would not worry too much about running down the house bank with the switch set to "both" because worst case, you can fire up the generator to top up the house bank to start that engine. But get the best dual purpose batteries you can get for that bank.

If you don't have a battery bridging or emergency start switch on your dash you can also carry a set of booster cables to link your banks to get the other engine started in an dead bank issue.

 

[Nathan007]

I think you have it figured out.

One question. What's the red light on your charger mean?

"power"

 

[ttmott]

I think you will find that both banks not only start their engines but also power a variety of other things both with the switches on and switches off. Consequently, both for the charger's operation and the fact that both banks are really dual use I would recommend new dual purpose Group 27M batteries for all. As far as modifications go, the only thing I would do is add a second battery to the Port bank.

 

[Henry Boyd]

The wiring diagrams in manual are excellent and will answer everything. One key point, there is really no such thing as a “house battery” on the 280. The pair controlled by the 1-both-2 switch are both house loads,i.e. electronics, fridge, lights etc. and the engine. A good practice to follow is when moving keep that switch on “both” so the alternator will charge both, and when anchored switch to “1” or “2”. If you do run down the battery, the other will still start the engine. On our 280 we used the 1 setting on odd numbered days and the 2 on even to balance out the wear.

 

[Nathan007]

The wiring diagrams in manual are excellent and will answer everything. One key point, there is really no such thing as a “house battery” on the 280. The pair controlled by the 1-both-2 switch are both house loads,i.e. electronics, fridge, lights etc. and the engine. A good practice to follow is when moving keep that switch on “both” so the alternator will charge both, and when anchored switch to “1” or “2”. If you do run down the battery, the other will still start the engine. On our 280 we used the 1 setting on odd numbered days and the 2 on even to balance out the wear.

Thank you so much! This helps greatly! The wiring diagram/manual I have must have been printed on a bad ink day The lines all cross each other in small areas and are all black, can't follow them.

 

[Lazy Daze]

Thank you so much! This helps greatly! The wiring diagram/manual I have must have been printed on a bad ink day The lines all cross each other in small areas and are all black, can't follow them.

Zooming in helps. Or print them out and use a straight edge... or ask someone with younger eyes to help