Generator Specific Battery?

N

NickB

New Member
Feb 14, 2017
19
Huntington NY
Boat Info
2004 Sea Ray 320 Sundancer, Garmin GPSMAP 840xs, Raymarine SL-70 Radar
Engines
Twin inboard Merc 6.2 MPI 320HP gasoline engines
Hi -

Is their a reason to not have an extra battery installed just for a genny? I like to hang out for hours with the radio on and the fridge keeping my beverages/lunch/dinner cold. I am always worried about killing the battery and not being able to start the engines. I cant for the life of me understand why they don't come set up this way.

Any thoughts?

Thanks,

Nick
 
No reason not to. Mine came from the factory set up with the gennie battery separated from the rest.
 
Ok, it seemed obvious to me. Sea Ray seems to have such a well engineered boat ('04 32) that I assumed there was a reason not to do it...

Does anyone have any advice/pic's if I decide to attempt this myself?
 
Well engineered? maybe.If your using the bank that supplies the house12v, the main engine starting FOR ONLY 1 ENGINE and generator starting , you should modify it so the engine batteries are dedicated. Each engine has its own battery, port, stbd and genny
dedicate 2 house batteries in parallel for the house 12v power.With a dedicated house you eliminate the worry of draining engine batteries or gen battery
 
I am always worried about killing the battery and not being able to start the engines. I cant for the life of me understand why they don't come set up this way.

Being cheap comes to mind.
 
With a seperate gen battery at least you can start the gen and charge the engine starting batts if they fail? Or use the emer start to start one engine etc.? I never killed my engine batts on our 320 with stereo and fridges running for cpl hours at a time.
 
THis is a project I am doing on my 390 MY this year. Last year killed my port batteries while at a transient dock in town with just the fridges running. Just so happens the generator is wired to start off the port side as well and couldn't start the generator or port engine. Luckily the starboard side started and used the emergency crossover to start the port engine. After studying the wiring schematic and opening up the main breaker box in the engine room, it doesn't look that difficult. The generator has its own relay and there is a bus bar connecting it to the port side relay. If this bus connection is removed and a separate charger circuit put in to the generator relay with its own battery, should be good to go. I am fortunate the boat already has a three bank charger with only two banks used. Ordered a new breaker to put in for this circuit from Sea-Ray Parts. I plan on completing this project myself and will keep everyone posted on the outcome.
Rob
 
I prefer manually operated battery switches, but to each his own
Each motor has it`s own battery, any or all can be charge with the shore power charger
by switching to #2 or "Both" position. Normal position is #1 for all switches.Using the "Both" position on all 3 switches gives you the motor , generator, and house batteries to try and start a motor or generator.
Gen on 1 will charge house batteries thru the AC charger , on "Both" the generator charging system can charge the house .
DSCN4049_zpsvk34cebr.jpg
 
Couple of years ago I had to jump start a guy cause all 4 batteries were dead from overcharging and dry cells.and Yes, the charger cables are 20 feet long and I had 4 batteries that could be conbined to start some poor soul.
 
The PO of my boat apparently had a dedicated genny battery installed. I now have a port starting battery, two starboard starting batteries that are also the house batteries and the genny battery. All running through a battery isolator and on separate charging circuits. Nice knowing that the genny battery will not be drained if I run the starboard batteries too low, and that I can jump the port battery to the starboard, too.
 
Thanks everyone for their input. I think I may be more concerned then most regarding the genny because of my experience on a mooring where you cannot keep the batteries as topped off as you can on shore power. I think this season I am going to start with new batteries and monitor them, see what happens then make a decision.
 
you could just invest in a good quality portable 'battery jumper pack' and take it with you while out on the boat in case you drain the batteries....just leave it charging on shore power while at the dock....be sure to get one you can leave plugged into 110VAC all the time and not overcharge the built in battery......

cliff
 
Last edited:
I would personally like the 4 battery setup to be three banks, house, port and starboard with emergency cross-over for unifying the banks for startup. The generator could be tied to port or starboard, it really shouldn't matter -- it's a small engine and if it doesn't start when crossing over 4 batteries you have other problems to worry about. House would be two batteries, and one each for starboard and port engine starting.

If you can move as many accessory loads as possible off the starting batteries, one each (with crossover backup) ought to be enough for starting.

From what I can tell, though, getting to this setup would be a ton of work for probably a marginal return on investment. It's easier just to run the generator and charger if you've been anchored for a few hours and are concerned about the batteries.
 
I agree, if I could isolate the starting batteries from the house easily, I would, but because of Sea Ray's set up and the electronic battery switches, they make this very difficult without rewiring the entire system. I will start with isolating my gen so I always have a backup if I kill everything else. I will further review separating the house once I complete this project. The portable jump starter is a quick fix, but I like my boat systems to be self sufficient and you always run the risk that the one time you need that jump starter the battery is not charged or it has gone bad.
Rob
 
Do these jump packs back feed thru the 12V cig lighter (via pig tails)? Otherwise I'm not going to be able to get the deck up with a dead battery.
 
Sorry for another question on this, I'm a little bit of a novice when it comes to electrical. Plugging this into the cig lighter (just to get ER open) won't blow the fuse while trying to start engine would, and this because of the different amps they draw correct?

With boats mistakes tend to kill people, so I like ask as many questions as possible!
 
NickB said:
Sorry for another question on this, I'm a little bit of a novice when it comes to electrical. Plugging this into the cig lighter (just to get ER open) won't blow the fuse while trying to start engine would, and this because of the different amps they draw correct?

With boats mistakes tend to kill people, so I like ask as many questions as possible!
Click to expand...

Yes, starting an engine requires 100's of amps, while raising your hatch may only be 15 amps or so.
 
Awesome, thanks.
 
You must log in or register to reply here.

Forum statistics

Threads
113,196
Messages
1,428,298
Members
61,103
Latest member
Navymustng
Back
Top