New battery

Mercury · 23 November 2008, 17:19

I think I am going to need a new battery soon, it's for my Brown band 50hp. Mercury it has leccy start & power T&T. has any one got any recommendations? Will an ordinary car battery do the job, or is there such a thing as a boat battery? and if there is, are they any different. Cheers.

Nasher · 23 November 2008, 18:33

Some will say you need a proper marine leisure battery at 2 or 3 times the price of a 'normal' car battery.

I've used Halfords Car batteries for a few years now, and they have not let me down, even after long periods of non-use.

Do a search on here for batteries, and you will end up with loads of reading.

Nasher.

Nos4r2 · 23 November 2008, 19:08

I was only paying 35 quid a time for a leisure battery from our local motor factors.

Agusta109 · 23 November 2008, 21:58

Get an AGM type battery
It’s the best battery type going for ALL marine applications. It is a DUAL PURPOSE battery meaning it is both a starting and deep cycle type.
A bit more expensive but last twice as long.

codprawn · 24 November 2008, 02:12

AGM are better but I really don't think they DO last any longer. I have known a cheap car battery last 5 years and an optima last 2 years - so much depends on the way it's treated.

leisure battery are only really any good if you use them for running things like fridges etc - for engine starting they aren't so good.

A cheap sealed car battery is what you need - just remember they aren't as well sealed as an AGM so they still have to be kept upright and not underwater!!!

Tim M · 24 November 2008, 07:32

I went to buy a new battery a few weeks ago (130 a/hr). Cost was around £130 at the local motor factors

jyasaki · 24 November 2008, 16:48

Quote:

Originally Posted by Mercury

I think I am going to need a new battery soon, it's for my Brown band 50hp. Mercury it has leccy start & power T&T. has any one got any recommendations? Will an ordinary car battery do the job, or is there such a thing as a boat battery? and if there is, are they any different. Cheers.

Lots of differences; you need to have an idea of what the battery is supposed to do before deciding on which you need (or, alternatively, which you can do without.)

Marine Deep Cycle batteries (I assume that's what you guys are calling leisure batteries?) are built with thicker, less-foamed plates, and are designed to be drained down to a low percentage (30%?) of capacity without harm. They typically have cycle lives of about 1000 or so. This is what you need if you spend long hours with the motor off, but lights, TV, stereo, blender, and electric massage chair running.

Starting batteries are less tolerant of deep discharge, preferring less than 25% discharge or so. If all you use your battery for is, say, an anchor light and your VHF for a few hours, plus starting duties, then you can probably go with one of these.

Dual purpose batteries are built somewhere in between, but are (my opinion) closer to starting batteries than deep cycle batteries.

Biggest factor in longevity is, I think, care. Make sure you don't drain them down below their minimum charge level (causes sulfation), and make sure your charging system doesn't fry them (for external charging, a good three-stage smart charger is a wise investment.)

A search for "Battery Primer" should get you more info than you care to read.

jky

Nos4r2 · 24 November 2008, 18:58

Quote:

Originally Posted by Tim M

I went to buy a new battery a few weeks ago (130 a/hr). Cost was around £130 at the local motor factors

I wasn't using 130ah batteries though-the 80ah did the job of firing up a 50 very well.

Downhilldai · 25 November 2008, 23:15

4-cyl Merc 50 needs hardly any CCA to fire it up. Local motor factors will sell you a dead basic car battery for around £25, which will be fine, unless, as jyasaki says, you're running lots of electrical gear while the motor isn't running/charging. If you are, then consider a 2nd battery (leisure type), to run your toys, when the motor's switched off.

codprawn · 26 November 2008, 03:26

Quote:

Originally Posted by Downhilldai

4-cyl Merc 50 needs hardly any CCA to fire it up. Local motor factors will sell you a dead basic car battery for around £25, which will be fine, unless, as jyasaki says, you're running lots of electrical gear while the motor isn't running/charging. If you are, then consider a 2nd battery (leisure type), to run your toys, when the motor's switched off.

I've got some dead ones he can have for a fiver each!!!

Searider · 26 November 2008, 11:34

Quote:

Originally Posted by Downhilldai

4-cyl Merc 50 needs hardly any CCA to fire it up. Local motor factors will sell you a dead basic car battery for around £25, which will be fine, unless, as jyasaki says, you're running lots of electrical gear while the motor isn't running/charging. If you are, then consider a 2nd battery (leisure type), to run your toys, when the motor's switched off.

Exactly.

When the battery on the 5.4 went dead I replaced it with the cheapest one Halfords (because they're open on Sundays) could supply. Worked a treat with my 90hp 2 stroke.