Adding extra batteries to existing system

[sprocker]

As we are planning to do more extended cruising this year, which will include multiple overnight stops where we will have no shore power. I am aware that we would need to keep our power drain to a minimum, and would probably be able to limit ourselves to the anchor light, LED house lighting, water pump and WC pump, but am always worried about draining the starter battery.

The boat is a 2006 Sessa C30 with twin D3-190’s, and our power setup is currently:-

SBC Advanced Plus charger (40Amp I think) with 3 outlets.
1 - Port engine starter battery
2 - Starboard engine starter & domestic battery
3 - Bowthruster battery

Ideally I would like to have two dedicated starter batteries, a separate domestic battery, and the bowthruster battery, so in effect adding an extra battery to the system, but am unsure if I could charge all of these with the current 3 outlet charger or would need to replace with a larger charger, or add an extra charger.

Can anyone offer advice on the best solution to this? Or am I worrying unnecessarily about battery drain?

 

[simonfraser]

a Victron Cyrix would allow you to piggy back a further battery onto the system afaik
if you have the space to keep another battery, why not ?

but monitor the battery charge first, and if you go for daily pootle you might well be ok.
leave the heater / fridge / etc. on all night and that might be a problem.

 

[Croftie]

I would have thought the simple solution would be to add a small (Ctek?) charger for the bow thruster battery leaving the main 40 amp charger for the 3 big ones. Or could you bring the BT battery into play for domestics?

 

[snowbird30ds]

I'd go for one starter for both engines, bank of two for domestic, and other for bowthruster, you don't start both engines at the same time do you and you can always add a starter solenoid across starter and domestic bank so you can jump from domestics at the press of a button.
This is how my boat is wired (except no bow thruster) and works well, I've had to use the jump button when my engine battery died of old age and it was very handy.

 

[rafiki_]

If you add additional capacity to each of the charging circuits, this is not a problem to the charger, it will just charge more slowly. I added 3 times domestic capacity with my previous Sunline for exactly ther reason you are contemplating, so we have 3 x 115 ah service batteries. No change to the charging. This allowed us to run fridge etc overnight, use the kettle and microwave off the inverter, and no challenge to the starter batteries, as they were a separate ring.

 

[BruceK]

I'm not sure if this helps but I have no shore power and the system works well for me and I do a lot of cruising with 2 kids in tow and they are power hungry.
I have 3 x 140Ah leisure batteries charged off stb engine. I have 1 large CCA battery for starting engines and windlass (I only use windlass with engines running) powered by the port engine. I have a relay shunt from the helm that will join the house batteries to the starter battery should that ever go so the starter battery always has backup. The starter battery has a small ~20W solar panel to keep it topped up during the week. Yes 20 W seems to do it. Go figure the battery is always in good order. With no shore power or genny this setup stands me in good stead and where as I have run the house batteries down twice in two years one was due to leaving the fridge and tv on by accident for a week while away and the other was the kids draining the system during a 5 day anchorage leaving cupboards etc open (I have 67 incandescent 12v bulbs in the boat. A source of great irritation. Every drawer has it's own light for crying out loud. Go Formula! I know it's 67 because I wet myself at the cost for changing them all to LED). I'm out most weekends and will average about 50 miles or 3 - 4 hour runtime.
Once a season and during winter I will take the boat into a marina for whatever reason and give the batteries a good charge, otherwise she's fine as is.

 

[sprocker]

Thankyou for all your replies gents, all read and understood. Ill give it all some more thought before jumping in and spending my hard earned.

 

[Richard10002]

You could just the add extra battery or batteries to bank 2. The only extra wiring would be to connect the new battery.

 

[Bigplumbs]

If you are just worried about not starting one day why not do it simple and just carry a loose battery as a starting back up and some jump leads. This could be taken home to charge from time to time.

While wise I actually think people worry a little too much about the amount of battery power they carry. I know I do and I have only got 1 battery

Dennis

 

[sprocker]

If you are just worried about not starting one day why not do it simple and just carry a loose battery as a starting back up and some jump leads. This could be taken home to charge from time to time.

While wise I actually think people worry a little too much about the amount of battery power they carry. I know I do and I have only got 1 battery

Dennis

I had thought about carrying a spare battery and jump leads Dennis, but it was the 'taking home and charging from time to time' that put me off. My thoughts now are that if I think it necessary to have an extra battery, why not make it permanent and keep it simple.
Also locating extra battery/batteries on the port side will go a little way to helping correct the slight imbalance that I have due to storing the outboard on the starboard side.

I never used to worry when we had smaller boats, but now that we have more 'luxury' and my wife has found the delights of fridges, heating & tv's on board, I do tend to consider power a lot more.

 

[sarabande]

Whatever configuration you go for, don't just cable the extra battery to an existing one, add a b i g fuse on the pos cable.


Sorry if grandmother ,eggs ,suck.