Can I use a car battery? Or do I need a Marine Battery?

[andy_wilson]

Once you have worked out the capacity you need, double it if you want a leisure battery to last more than a few cycles, and tredle it if you are thinking of a car starter battery.

Aternativly consider one of those cheapy car emergency starter power packs. They have gel batteries so you can flatten them completely and repeatedly without causing a rapid loss of capacity. They are nicely cased with a handle and you can charge it by plugging it into the cigar lighter when travelling to and from the boat.

 

[Lakesailor]

Thought about a motocycle battery. Not a lot of capacity, but if you are really only using it for lights and stereo (and lights only at night or in poor vis) and will be taking it off the boat for recharching every trip it may well do the job. They only weigh about 3 kgs as well.

Motorcycle Battery (example)

 

[oldharry]

A car battery would be fine, but as people have explained is not the best thing for the job. My local caravan Shop does a 'Leisure battery' for £35 - a lot cheaper than most car batteries, and will stand up the abuse better. It has a handle for carrying which makes life easier - nly larger car batteries usually have that facility. It also has a 'Green Eye' charge indicator, which goes black as it discharges, so you know whether to take it ashore. Charging by car trickle charger. Dont try to start an engine with them - they cant give the current.

If you want low capacity portable batteries have a look at the Maplins website - they do a range of low capacity non spill (gel) batteries, but may need a special charger to avoid damage.

Someone asked about charging from their Montego as they drive around. Caravan Shops (and Halfords for a bit more) sell a 'Charging relay' intended to top up the caravan service battery. Fit one of those and you will not need to worry about running your car starter battery down into a discharged boat battery. Stow the whole thing in the boot, and forget it till you need it! Make sure the battery is secure because an acid spill in the boot can play havoc with metalwork and carpets! I have a bolted down battery box for mine.

Oh, and dont make any container airtight! Batteries give off explosive Hydrogen gas in use!

 

[Guest]

[ QUOTE ]
Hello,
I've got a 23ft racing yacht which I'd like to install with a battery to power nav lights, internal lights and a small stereo. It isn't needed to start an engine.

The battery would probably be taken off the boat after every trip.
Do I really need an expensive marine battery? Would a car battery encased in an airtight container not be sufficient?
If a car battery would do then I'd be able to get a standard charger wouldn't I?
Any help on this matter is much appreciated as the other owner and I have little experience in marine electrics.
Cheers,

[/ QUOTE ]

a) Standard car battery will do fine ..... (you could even save a lot of dosh by buying from a Scrap Yard .....)
b) Or a visit to local Caravan store and buy a battery box + leisure battery all in one go ...
c) Battery connectors from local Caravan Store also which are quick-release style clip on.

I would certainly NOT try to make box air-tight ... as all batterys will give of some gas at times which must vent.

Forget fancy over-priced "Marine" batterys ...

There is another way - get a Power Pack that is designed to emergency start a car and also able to supply 12V ... I paid about £35 in Halfords for a 7A/hr job that has built in light, meter, 12V and with car / mains charger etc.

Now I'm intrigued ... a 23ft race boat ... with no electronics ? No windy, log or other stuff that runs of 12v ? Considering some boaters - how do you get out of harbour ???? /forums/images/graemlins/wink.gif /forums/images/graemlins/wink.gif /forums/images/graemlins/wink.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[Talbot]

car battery wont like long discharge, then re-charge - its not designed for it. However, if you go to a caravan shop, you can purchase a leisure battery which will be as cheap as a decent sized car battery anyway, and is designed for the purpose.

 

[FARP]

SBC and others,

Going to go down to the boat this weekend and get it all squared away. Think I'll get a 70 Amp hr battery and a cheap charger. The charger will only ever be on over night whilst alongside in a marina. I'll get a solar panel for a slow recharge for when I'm not alongside.

At the moment I manage fine with a hand held VHF (a good one mind),a solar powered Tacktick and a 9v battery powered depth sounder (which doesn't really work). That's all I really need but in order for the other half to enjoy the sailing/racing she needs lights and of course somewhere to plug her iPod into!

Happy Sailing