Battery advice

[Rapier]

Until recently all my motors were all pull start and as the Pearly Miss is going to a new home, I now need to buy a new battery for use in DIXIE. My primary concern is with the amount of pounding the boat takes, also I've generally taken the (automotive) battery out and topped it up post rallies - being worried about the discharge while running the bilge pump. Should I be buying a marine leisure battery, or a motorbike gel battery, or anything else? It's use is primarily starting a 4 cylinder 2-stroke, but will wire up the running lights, horn and possibly fit a bilge pump too.

[Alacrity]

I would use (I do) use a standard automotive one. A leisure battery is not designed for cranking loads so that is a no no, gel batteries will work but can be expensive, se7en uses one on Jade. I was advised by Duncan Walker to get a larger battery (if the outboard charges) as there is no regulation (on old Mercs anyway) so the battery has be of sufficient size to absorb the charge without boiling up. I can't remember what size he said though, I will look on Thunderball's battery & see what gives, that has been on her since I got the boat & has always held up perfectly even over a winter without a top up.

[se7en]

I use an Odyssey 680 battery in Jade, I also use the same type/ size in my Caterham seven, they are not cheap, however, they will stand for long periods without loseing charge, they can be used in any position, can take massive discharge loads, and have a long service life,are compact and will not gas, the one on jade was on the Caterham for five years before I put it on Jade, and its been on Jade for four, and still cranks the engine over like it did when new, I now fit them to anything I have to replace the battery on, My car, my motor bike, my caterham and Jade all have them fitted,they are cheaper in the long term, go to there web site and look at the video, the safety side alone is a good enough reason to use them.

[Alacrity]

Based on recent prices for std lead/acid car stuff we have bought here at work recently, £85.00 + carriage doesn't sound dear to me for the Odyssey, & they take up less space so can be hidden easier. I will probably start using them myself as batteries fail along the way.

[haventaclue]

I suggest that you install a marine deep cycle battery. They are built differently to car and truck batteries and are better able to take the hammering that they get on the water.
The minimum I think should be 70amp,better a 110.That's what I use on my 1969 merc800/80HP,I also have a 75amp deep cycle which is a little light to crank my engine. My tuppence worth

[Tremlett 15]

my 40hp 4stroke on the rib has a 85a/hr marine leisure battery, came with one & was told its the one ???? but when it comes to el on o/bs I am beat. so I look forward to all these posts too.......

[Rapier]

Is it the PC680 version?

N

[se7en]

Yes

[haventaclue]

Here's an explanation of the difference in cranking and deep cycle. I thought it would be easier than racking my ever decreasing brain cells http://www.thefishingline.com/marine.htm

[petrolhead]

our cruiser has 3 number 110HP leisure batteries, by Numax from memory. They are designed to deep cycle whithout problems but also suitable for engine starting with a high cranking amperage. The last three lasted near 8 years on board and I replaced them last year although only one was totally naf.

For MIN, which runs a non charging Big twin I use any old car battery laying around. A single charge has happilly held up for 2 nights in cardiff with lots of starting and the bilge pump on auto (she leaks well so pumps often enough!). Last years was a slightly ageing 65 Amp Hour.

Personally I buy the cheapest lead acid batteries from Europarts with a decent guarantee for car or boat. I have not had to yet, but if it failed you could lower yourself to taking it back on warranty as long as you know what car it fits