which batteries to get

tomainsley

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after a slightly bothersome time at sea when all our batteries died and the engine wouldn't start (we were able to sail back onto our pontoon) its been decided to get some new batteries ( the old ones came with the boat) and possibly a new and fancy charger. Having read the article on Sterling Power's website I have a couple of questions;
1) Is it worth actually getting a marine battery for starting, or will a regular car one do? Do any of you have experience/advice with this choice? Sterling seems to reckon that the difference is all in the price and marketing, although i suspect marine batteries may be built tougher.

2)Are lead acid really a better choice than gel or AGM?
 

Stemar

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Car batteries are designed to give a bit belt to start the engine then be recharged. That sounds to me just like the use I give my engine battery. I have an ordinary car battery on Jissel. Her engine is a rather tired VP2003 that takes a lot of churning to start from cold, but so far (5 years), no problems. That's with a split charging relay, but no fancy gizmos.

When that battery dies, I reckon I'll just get another one the same.

The domestic battery is an ordinary leisure battery from a caravan shop. It was on the boat when I bought it 6 years ago so, again, when it dies I won't be looking for anything cleverer, though I acknowledge that the case for something posh is better on the domestic side.
 

brianhumber

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Have never used anything but bog standard vehicle batteries. I put new ones into the starting bank and transfer old starting batteries into the domestic bank. I tend to start on the domestic bank as well so engine battery is kept unused for unforseen problems. This way the batteries have tended to last 6/7 years including when I was on swinging mooring with only alternator recharge. Key is maintenance and not to run them down.
So I would say I do not see the need to buy the expensive types as I note others with these tend to replace them at more frequent intervals than I do. Perhaps having 'deep cycle' batteries makes people more gung ho in running them right down and reducing life.

Brian
 

Playtime

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For engine starting there is no question that a standard car battery is the correct one to use. Size should be similar to the original.

For the domestics, the choice is slightly more difficult. Ideally, deep cycle (leisure?) batteries should last longer than standard car batteries. However, they are more expensive and maybe more difficult to fit. I recently replaced (after 7 years) the standard domestic Bosch vehicle batteries on my Bavaria (2 by 140AH) with the same again. I was looking to buy deep cycle batteries but after discussion with Barden (Fareham) I decided that the problems of fitting different form/fit batteries outweighed the possible benefits.

The biggest killer of domestic batteries is deep discharging. If you can avoid discharging them to less than 50% capacity and re-charging them as soon as they are discharged, they should last 7 or 8 years. Fitting a good quality mains battery charger and a 'smart' alternator controller are also well worth considering.
 

mocruising

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I had to make the choice two weeks back. I have 4 x 140 AH lead acid for my domestic (24 V) and 1 x 140 AH engine start and 1 x 140 AH 12 V for some nav. equipment and radios and one smaller 60 AH for the dedicated gen set start. The 12 V lost a cell and the engine start was on the way out. I knew this as I do a hydrometer test every 4 months and record the results. I thought about all the options and looked at the expense and also the available space. In the end I put a Bosch 140 AH back for the enging start and a 180 AH back for the 12 V nav equipment and radios. Why. The old batteries lasted 6 years the space is not suitable for deep cycle, I did not wish to mix battery types and people have advised that buy cheap and they wont last, so I went for a good brand.
 
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