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I'm having trouble understanding the relationship between the so called "house battery" and the "engine batteries" and there seems to be alot of conflicting information regarding the use of each power source in this forum. I just bought my 1999 328 Vista a month ago by the way and I'm trying to work a couple bugs out. My boat is equipped with 3 group 27 batteries, guest switch, isolator and charger. After reading the owner manual and looking at the "Guest" battery switch panel, it stands to reason that the "house" battery is for emergency starting and powering purposes only, Not running all the DC components (without engines running) when the battery switch is in the "on" normal operating position. Rather, each engine start battery is used to run all DC (house) components, when the switch is in the "on" position. This theory makes sense because, in the event power is completely drained while at anchorage, the "emergency" or "house battery" can crank the engines once the engine batteries are depleted by switching to "Parallel or Ship Systems, Emergency start only".

In reading the other battery related threads, it seems everyone here has the relationship of house and engine batteries backward. I thought I must be wrong, but how can it be so, that the so called house battery powers all the boat electronics (without the engines running) then somehow the engines batteries mysteriously drain and the miracle house battery comes to the rescue after it's been powering everything else for 8 hours. Not possible. Right?

In my own situation, I think it's time to replace the engine batteries as I'm beginning to have trouble starting the engines, even after being plugged into shore power. My Port engine will not crank with battery in the ON position. It will only crank in parallel or ship system. The starboard engine is slow to crank but once it's running and I try to crank port, starboard will quit running and port just clicks once. I checked the battery cells and had to add fluid to both engine batteries. The port battery volt level has improved after adding water and recharging but is still not able to crank. The engine batteries are both deep cycle gp27 600cca and the house battery is dual purpose gp27 770cca. My assumption is that both engine batteries are beyond their useful life, the port being more depleted. I think they are just over 3 years old. Am I on target here with all of the above?

I'm thinking about replacing both engine batteries with gp31 deep cycle 800+ cca as I have no generator but I'm worried about cranking amps and the use of deep cycles for cranking. Would dual purpose be better or should I stick with the deep cycles for the engines? Why not just go with a regular cranking battery for the engines since the house battery supposedly powers all the electronics at anchor? Or is it accepted that the house battery is actually an emergency dual purpose battery? Additionally, I'm thinking about adding another deep cycle or two for more overnight power, hence the lack of generator... Any thoughts on this battery topic?

Our 328 has three batteries as well. Two starting and a house. The house battery does power the DC stuff, while the two starting batteries power their respective engines and one of the starting battery also starts the genny.

As you know you can parallel the house battery to help start either engine via the battery switch.

The ships systems toggle switch (right beside the battery switches) turns the house battery on/off.

I think you will find some boaters are quite content with using a dual purpose battery or a deep cycle battery as starting batteries. Personally, I wouldn't be concerned with using a good quality dual purpose battery as a starting battery.

Sounds like if you need to have your starting batteries in parallel beacuse one is weak and starting the other engine causes the first to die, your battery is toast. The engine's alternator that was running likely wasn't outputing enough to keep up with the starting demand of the other engine.

I'll bet if you raised the running engine to say 2000 RPM and then went to start the other engine that it wouldn't stall then. I had the same thing happen with my previous twin engine 30' Doral Prestancia.

Mike.

_________________

Current Boat
- 2001 Four Winns 328 Vista "Hour Decision"
- 2010 310 Mercury Inflatable

Previous Boats
- 30' Doral Prestancia
- 25' Doral Citation

I have a Vista 258, only one engine, oh well.

Hear is my take on this: My boat was wired so the house always used the #1 battery. BUT, you could switch from 1 to 2 in starting. I move the "house" wire to the common side of the switch. This did 2 things, when I turned the battery switch to off, everything turned off. Also, I can power the house from ether battery if one went completely dead. I do have a 3rd battery, I use that to power the head, windlass & 2000W inverter. I combine battery #2 & #3 for inverter use.

My real point is, say on a weekend, I use the #1 battery on Saturday & the #2 battery on Sunday for both house and starting. In this way I know ether battery could start the engine if needed. Also, the house battery is not drained from powering the house if the starting battery is dying. And yes, we always have the third battery to fall back onto.

To me, the term house battery is just that. It powers the house and nothing else. Same hold true for the starting battery. As the terms go.

As to the engine's alternator, it's job is to keep the batteries charged up. Yes, it will power the house, but thats not it's job. Keeping them charged up at the slip or out on the water is another story for later.

+1 on Decision's comments with the exception that I know of no way to parallel the starting batteries.

Each battery selector switch only controls 2 of the batteries, the respective engine and the ship systems battery (you called it 'house')

NORMAL OPERATION 'Battery switch ON'
Ship Systems Battery - All 12V systems not part of an engine, including bilge pumps, windlass
Engine Battery - All engine related tasks, including starting

This is where your switch should typically be.


ENGINE BATTERY DEAD, SHIP SYSTEMS GOOD 'Battery switch SHIP SYSTEMS'
Ship Systems Battery - All 12V systems not part of an engine, including bilge pumps, windlass + All engine related tasks, including starting
Engine Battery - Nothing

You can use this position if your engine battery is not starting the engine, and your ship systems battery is not run down. You might also use this if there is an issue with your engine battery, say an internal short.


EMERGENCY OPERATION 'Battery switch PARALLEL
Ship Systems Battery - All 12V systems not part of an engine, including bilge pumps, windlass + All engine related tasks, including starting
Engine Battery - All 12V systems not part of an engine, including bilge pumps, windlass + All engine related tasks, including starting

You can use this position if both your ship systems and engine battery function, but both are low on available current - this leaves the voltage at 12VDC but sums the current of both batteries. Careful with this one - if you leave it here and say go to the beach or anchor, you can drain both your engine and ship system batteries and have no way to start your engine.

In all cases the breaker labelled 'ship systems' on the battery switch panel allows 12VDC power to flow to all 12V systems that are not engine related, from where ever the selector switch says that power should come from. (OFF,ON and SHIP SYSTEMS - from ship systems battery / PARALLEL - from both engine and ship systems battery). Only the bilge pumps do not run through this breaker.

_________________
1969 Chris Craft Commander 47
1999 Four Winns 328 Vista - SOLD

Thanks for all the comments. It makes better sense to me now. I also carry a portable battery jumper just in case all batteries are drained. This has saved me on one occasion in another boat. Needless to say, I was grinning when I pulled myself out of that mess.

328DayTripper,

Where do you do your boating?

Mike.

_________________

Current Boat
- 2001 Four Winns 328 Vista "Hour Decision"
- 2010 310 Mercury Inflatable

Previous Boats
- 30' Doral Prestancia
- 25' Doral Citation

Well put!!

Beaware, in the "EMERGENCY OPERATION 'Battery switch PARALLEL" will allow less current to pass then moving the battery switch to the BOTH setting.

Hey Mike,

I am on Lake Lanier in Georgia.

Thanks again Weather and Decision for the excellent explanations.

In re-reading your post, 2 things came to mind. I have a group 24 battery which is one or 2 sizes down from your battery. It is rated 880CCA, which sames odd to me that your CCA are low. You might want to conceder bigger batterers or AGM type. You don't want anything under 400CCA, for a 350ci block, thats under good conditions. I would go with a bigger CCA battery, it will put less strain on the battery and last longer.

In "The starboard engine is slow to crank but once it's running and I try to crank port, starboard will quit running and port just clicks once." Check your battery cables, I will bet you have corrosion on the cables going to the port engine, you have a starter problem or the batteries are starting to short them selves out. It is pulling so much current that the other engine shuts down.You still need new batterers, but once the starboard engine is running it should be charging both batteries and adding 70 to 90 amp to aid in starting the port engine.

Please let us know what you find.

"but once the starboard engine is running it should be charging both batteries and adding 70 to 90 amp to aid in starting the port engine." ----- I don't think his engine at idle speed (if it was at idle speed) will have the alternator adding much to help out with the weak batteries, hence the reason why the engine stalls out when attempting to start the other engine.

I experienced the same scenerio when I had a weak battery, when one engine was running at idle and trying to start the other would cause the first engine to stall. Raising the running engine's RPM (causing that engine's alternator to output more) would start the other engine without causing a stall condition.

Same with using jumper cables to start a car with a dead battery, you sometimes need to increase the RPM's of the running car to get enough alternator output to start the vehicle with the dead battery.

I'm not saying it might not be a corrosion issue with cables/connections etc., but he may have good connections and the weak battery may be his only issue.

Mike.

_________________

Current Boat
- 2001 Four Winns 328 Vista "Hour Decision"
- 2010 310 Mercury Inflatable

Previous Boats
- 30' Doral Prestancia
- 25' Doral Citation

I only have one engine. From what you are saying, you understand were I am coming from and were you had the problem before. You should know!!!

If I ever get a boat with 2 engines, now I know. Thanks

The battery connections are clean and tight. No corrosion at all. The batteries appear new as boat hasn't been used much. When I switch to parellel, it cranks perfect and immediately. There is no date clearly punched out on the engine battery but I believe they might be about 3.5 years old. Fluids were low and I topped them off and recharged to no avail. I did try raising rpms but still stalled the other engine. Maybe I didn't rev it high enough. I find that strange. I have not checked the alternator output, however both volt gauges read over 13 when running, not sure the exact reading.

Question 1: In a pinch, could I use a jumper cable between both starting batteries?

Question 2: I was shopping for group 31 batteries at Batteries Plus and they recommended a commercial vehicle dual purpose battery (for 18 wheelers) as it is built with the same plate retention construction and it has the power I'm looking for. 1000 CCA I believe and 180 reserve cap. It's cheaper than the marine battery. Under 100 bucks. Is this battery safe for a marine application?

Question 3: Is there a way to add another house battery without major surgery? I'd like to just chain them together in a series. Is this a viable and safe option. ie: battery 1: positive terminal to ship, negative terminal to battery 2 positive. Battery 2: positive terminal to battery 1 negative terminal, negative battery 2 to ship. I have a 3 battery charger and think that it may continue to charge the 2 house batteries as 1. Is this a bad idea? I'm going to be running lights, sometimes the fridge, maybe an inverter, a stereo amplifier, etc. So I want to make sure I don't run out of juice.

Thanks.

To question #1: Yes

To #2. Generally speaking, marine wet-cells have a heaver casing & plating, because of the pounding they take. Yes, you could use them. I would at lest look into the AGM type, Sears sells them at a great price. There car & marine AGM are built the same other then the wing nut connects. The car AGM has a 48 month replacement & is 100 month prorated. Pound for pound & size, more output!

#3. Yes. It is never a good idea to connect batteries in parallel as a norm. If left connected, one battery could drain into the other, giving you 2 dead batteries. You will need to upgrade your on board charger or add a 1 bank charger for it.

You could up grade your isolator to take the extra battery or add a combiner that can be manual switched off & on. The isolator would be better, but more work & more $$$.

You will need a battery switch combine the 2 batteries to give you the amp hours you need to run the house.

To get more life out of my house battery, I did add LED lighting to anything that stays on for any length of time. More so, my anchor light and engine compartment.

I added a third battery that powers my windlass, head & 2000W inverter (I can use it for starting or the house). I do have a combiner that I can use to recharge it off the engine. In 2 years of use, I have not used the combiner. I did add a 2nd 120v on board charger for it. It is only a 6 amp charger, but after a weekend out (over nighting too) in less than 24 hours, it is fully recharged at the slip.

I think this is happening because if you are in 'PARALLEL or SHIP SYSTEMS' (and have a bad battery of course), you have effectively removed the intended isolation of the engine electrical systems. In this case they both are connected through the common ship systems battery. When both switches are in the ON position, the engine systems are separate and therefore one should not cause the other to stall.

I would connect known good batteried to the engines and leave both selectors in 'ON' position and try the starting of both engines. Swap in the house battery for this if you think the starboard battery is dead. I think by using PARALLEL, you are making a much more confusing situation to troubleshoot as it may be causing your engines to affect each other.
If you still get engines causing each other to stall in the ON position, I would verify that the isolator is working correctly (easy to test with a volt meter). I suppose depending on the charger, and if it is having issues, it might defeat the isolator and cause one engine to affect the other.

_________________
1969 Chris Craft Commander 47
1999 Four Winns 328 Vista - SOLD