Ideal Battery capacity for long-distance cruising-?

Jock89

Jock89

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Hello everyone,..As a land-lubber I've been reading this Forum, along with cruising blogs/my heroes-the Pardeys/ books & videos etc...for many years, & now finally, I've upped & gone & done it.! I've waited 30 years for this & now I'm refurbishing my Nic-38 slowly, & scrapping most of the old kit that came with the boat & now-while my old engine's out & waiting for the new one-I'm onto Batteries. I have no idea of how much capacity I'm going to need in the future so can I just install 2-3x 225A Lifeline Batteries & a Smart-charger to cover all eventualities, even though I don't need that much just now.? What have some of you chaps done, or, what would be your ideal installation for long-distance cruising.? BTW, I know of Nigel Calders book but I'm in Aussie just now & can't get it until I get back. Many thanks indeed for your comments & advice, & may I say that it feels good to finally be a part of this Forum.! Jeff
 
Hi Jeff,

I'm going through a similar process at present. My thinking on battery capacity is only a part of the larger thinking on consumption and replenishment of Ah. I currently have 2 x 180 ah for domestics and 1 x 180 ah for starting/thruster. I currently think that 180ah to start a 4 cyl diesel is OTT and therefore am considering reducing engine battery to maybe 120 ah and adding another domestic 180ah. That would give me 540ah total domestics. However that never to be consumed beyond 50% of capacity therefore 270ah is practically available. Assuming average consumption @5ah continuous (fridge!) that gives me a max uncharged consumption period of a little over 50 hours. So, in theory at least I'd need to recharge every second day at anchor. In reality of course I think it would be every day charge so as not to have a massive recharge task every second day. (Recharge every day also produces some calorifier hot water!)

Having decided on battery capacity one then has to think of recharging; both from shorepower and alternator. I've seen guidance suggesting that the battery charger should have a capacity equal to 25% of battery capacity. So, 540ah x 25% is about a 130A charger. In reality I'm going to try and get away with a smaller one than that - maybe 100A charger. As to the alternator - my plan is to have a smart regulated setup with two alternators. The existing 50a alternator wll feed the engine start and I'll add either a 90A or 120A alternator (treble pulley on crankshaft) for the domestic bank. This has the advantage of building in redundancy (2 alternators) and the load on the big alternator is significant - about 3hp so it will provide a bit of a load for the diesel (so as not too polish the bores maybe?) when engine running is just for charging. And of course the purpose of the big alternator is rapid (ish!) recharging.

I'm also factoring an inverter (probably 500W) in to this setup.

There are some very helpful sites about that give guidance on the whole issue of power storage and charging- here are four:


http://www.adverc.co.uk/

http://www.victronenergy.com/

http://www.sterling-power.com/

http://www.mastervolt.com/

A long answer to a short question - I hope this helps.

rob
 
Rob, thanks a lot for that.! Just checked out the 1.st one, Adverc, & they're very handy for where the boat is so I'll deal with them. Thanks mate, but I think I'll go for a larger starter-battery as well, in case I find myself in the N of Scotland or possibly one of the Scandinavian countries some sub-zero winter.! I've just replaced the huge battery in my Land-Rover S/Wagon after 10 years use in Scotland, & in well below zero early morning start-ups I wasn't caught out once in 10 yrs. Unknown wet-cell make, heavy-duty, but by golly that was some battery.! Sometimes OTT is OK.
Talking about not having the batteries fall below 50% & charging routines, Yep, I think I'll stick to the original plan of having 3x 225A Lifelines. I had thought maybe 2 would do. I suppose batteries of that sort of weight are going to need some sort of support frame in the hull. You couldn't just put those onto a battery shelf could you.! I plan on getting out to my old stamping-grounds in Mozambique someday, where I'll have to be independent of shore-facilities for many weeks at a time, hence the large capacity. Wind-charger & large solar-panel will be added before I leave UK. Regards...Jeff
 
We are managing very well on 525AH of Liflelines. That gives us 2 days between charges, having consumed half of it.

IMHO you can't have too many Ah's worth.

Pops
 
[ QUOTE ]
I know of Nigel Calders book but I'm in Aussie just now & can't get it until I get back.

[/ QUOTE ]

Why not? I've seen it for sale in chandlers here!

And they brought in that newfangled 'electric light' just recently too! /forums/images/graemlins/grin.gif
 
Quote:

IMHO you can't have too many Ah's worth.
***********************************

I agree with Pops. We went for 5 X 210Ah Lifelines because we had 5 holes that would taken them fairly easily. We can go 4 days without charging and can power our 12,000 BTU heating /Air Con from the batteries for a couple of hours! We use a lots of AC through a 2.5KVA Victron MultiPlus inverter, which also acts as a 120 Amp charger and a shore power suplement. If you're in the med with only a 6 amp breaker and you need more power, the MultiPlus acts in series with the shore power and delivers the extra AC amps needed from the batteries via the inverter. Also found it very useful living aboard last winter. We were taking 16 amps from shorepower for heating etc., and the little extras for microwave etc. came from the batteries - which are then charged up again when the inverter can draw amps from the shore power. We also have a 12 volt Fischer Panda diesel genny which we have mounted under the bed and runs with just a small purr! This charges at up to 280 Ah! The start battery is an absolutely tiny Red Flash that's on a trickle charge from a 5W solar panel, and via alternator through a VSR (voltage sensitive relay).
 
We are in our third year of live-aboard cruising on a Nic 38. We find that the combination of a 70Ah spiral cell starter battery and a 240Ah heavy duty lead acid together with 200 watts of solar cells and a Rutland 513 wind generator do the trick; keeping the fridge running, the computer up and able and sufficient lighting. This combination has the benefit of fitting neatly into the standard Nicholson battery bay.
 
At one level this is a very simple question:
1. Calculate your expected daily consumption.
2. Determine how long you want to go between charges

From that you can work out how much capacity you need and your charging regime/equipment.

In practice it's not so easy. First of course you can only rely on having about 30% of the nominal battery capacity usefully available. And consumption can vary wildly and be hard to predict - especially things like refrigeration. Then there is the question of whether you want to run your engines to recharge the battery routinely, or only when you really have to. This will determine how much you invest in solar, wind or a genset.

I know of few cruisers in hot climates like the Med and Caribbean who have less than 500amh. I know of no one who thinks they have too much solar power (most want as much as they can get installed). While wind is rated highly by some and regarded as a mildly useful adjunct by others.

I would put in as much battery power as you can. The problem with adding more later is that of course it's not generally considered a good idea to mix old and new batteries, so they are best changed as a batch. If you do only put your planned 3 in for now, try to plan the installation so you can relatively easily increase it later if you want to.

Best wishes
 
I'm sure 500 AH would be nice. We have nothing like the space for that much on a Sadler 34. We have 3 x 105 AH batteries, two domestic and one starting. Total solar power is 70 Watts, plus a Sterling regulator. We live on board in the Med throughout the summer. We have no problems running an 80 litre fridge constantly, plus plenty of music playing and all the usual consumers on a sailing boat. We have no battery problems, often going three days before engine charging becomes necessary.
 
The other consideration is how much you wish to limit the amount of discharge.

I my experence the less you discharge the longer the batteries will last

I had 4 200Ah on my previous yacht with no shore power. On my new yacht I will be fitting 12 105 Ah in 2 banks and a seperate 180 Ah for starting main engine and diesel generator.

I am also increasing the insulation on fridge and freezer to reduce daily consumption
 
[ QUOTE ]


On my new yacht I will be fitting 12 105 Ah in 2 banks......

/quote]

Perceived wisdom (of Nigel Caulder) is that you are better off fitting one LARGE bank than two smaller ones, because the life expectancy of the large bank will DRAMATICALLY extend the batteries life.
 
That "Perceived wisdom" is the based on reducing the depth of discharge which is what I recomended but I like the backup of having two banks so if one is totally discharged I can still use the other.

My switching arrangement is to allow either domestic bank to start engine and engine start battery to power domestic supply

Belt, Braces and string so to speak.

This is also based on my crusing ground of the Indian Ocean where backup and help is non existant.
 
''This is also based on my crusing ground of the Indian Ocean where backup and help is non existant. ''
Just doing the maths,12 batteries @ (say) 75 quid each=£900.Assuming a useful life of 5 years if cycled correctly,thats quite a lot of dosh to power the cold beer and chilled veggies box!
Plus the cost of the fridge,plus the biggest(highly thievable) solar panels and ,say,a reasonable wind generator.
The KISS principle of old would be investing in big starting handles for the diesel or a spring starter device,oil lamps(burning mosquito repellant oil natch),oars to keep you fit whilst you row ashore to spend some of the battery dosh on happy hour cold beers and a ciber cafe coffee..
I know this is a techy forum and therefore everyone here is very comfortable with a highly technical level of boating,but,you know,all that STUFF,all those things to maintain in far flung places,,
I think I am becoming a true Luddite.2 Batteries,one 18w s/panel and one Ampair windgenerator gave me all the power I ever needed and I have NEVER started an engine to make electriicity.Oh and those solar showers(£10 each)are superb in the tropics..if shy you just feed the hose through the porthole above the shower tray..
I am not implying any critisism in any way,please,but thinking outside the box does have its own benefits.
 
Hello Fudge, nice to come across someone else in the same boat as me.(Pun intended) I'd like to keep in touch with some Nic-38 owners, as there does'nt seem to be an Owners Association for the 38's. As I've still got a lot to do to my 38 would you be interested in sharing some ideas on fitting-out for long-distance/extended cruising.? (Privately or thru the Forum is fine) I'd like some advice on what particular For'ard escape Hatch to install, & who makes/where can I get new saloon opening port-lights. Mine are 30-odd years old, original to Nicholson & non-opening, & corroding. Any idea of cost.? Jeff
 
Arthur, Thanks for the comment. If I'd gone into more detail in my previous post I'd have said that Calders book is probably available here, but I'm guessing that it's more expensive in Oz than in UK. On top of that is the fact that I'm mostly working 7 days a week while I'm here, so don't have much opportunity for browsing through Chandlers. BTW, where are you in Vic.? I'm in Melbourne. Jeff
 
Hi Jock

Congratulations on taking the plunge.

I have 4 110ah (one for starting) 80w Solar, Rutland 913 wind generator, smart charger, 115amp alternator and occasional back up from from a 1kw portable Honda generator. I will probably add another 110 and convert the fridge to a keel cooler system but so far the set up has been fine and gives me about two days with fridge, computer etc.

Nigel's book is an absolute must and will pay for it's self. You can but it online and other cruising books from here .


Good luck and fair winds
 
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