MARINE BATTERIES

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SCHARVEY

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Looks as though I may need to replace my 2 x 75 amp hour domestic batteries on my Nimbus 37,as they do not seem to be holding their charge very long.

Any experience of different types on offer - seems prices vary from £60 to £200 !

Any advice welcome...........
 
Batteries can be a bit scientific really, all depends on how scientific you want to be and naturally the the cost increases with the science.

I settled on Squadron batteries in the end, got good press here and other places, good value for money etc etc.

Link here not connected in any way etc.

Note: always check the measurememts before ordering replacements though.
 
Good info.

If you go too technical your battery charger may not be able to deliver the correct charge in the most appropriate way.

Agm (absorbed glass mat) require a lower voltage charge then lead acid.

Also ensure you order the batteries with the correct orientation of the connecting lugs, you do not want to have to rewire because the pole's are reversed.
 
First let me say that if you are charging your batteries with a smart charger when on shore power then you should stick with wet cell batteries. A smart charger will, at power on, take your batteries up to 14.8volts, during this cycle it will produce lots of amps and will "shake" the battery plates which stops the plates sulphating.

This process also makes the batteries gas a little therefore this can only be done with wet cell batteries. If you use Gel or wet sealed batteries then the charger must be set to 14.4volts as this stops any gassing. If a gel battery gases it's finished and if a sealed battery gases you can't refill them, so IMHO wet cell batteries are better, except to say that when using this type of charger you should keep an eye on the water level in your batteries more often.

Barry
 
More a PBO area really, but I bought 16 1.2V 2.4 Ah NiMh AA cells from Maplin for £19.98 the other day.

Occurs to me that 50 of them, for about £60, would be 12V 120Ah. Being NiMh they'd stand many more full discharges than Lead Acids.

I'm just worried about charging them, and, more particularly, what happens when I overcharge a dying one? Could sink the boat, so they'd need to be in an outward facing on-deck locker. Or perhaps in strong tubes so that I could shoot them at other boats or start yacht races...

Any elec genii care to comment? Maplin 1.2V 2,400 mAh cells.
 
There is no doubt that 'cheap' batteries are false economy.
And make no mistake the market is flooded with smart opperators selling cheap batteries at quality battery prices. There is also a lot of 'badge engineering' goes on.
I fitted two Vetus bateries two years ago and confidently expect them to last five years. They did on my last boat.
I will finish as I started - cheap batteries are a false economy - you KNOW they will always let you down at the most inconvenient or embarasing moment.
Good luck...
 
Accept that. Buy cheap, buy twice.

Just wondering if we are at the 'Holy Grail' point of other battery types becoming cheaper than Lead Acids?

The Maplin batteries I bought are doing what they are advertised to do - although I have not tested them in a lab. My point was that the world seems to accept that NiMh is better than Lead Acid for deep discharge, and price-wise they are the same as the cheapest quoted above.

Gotta be worth a thought.
 
Victron produce a booklet (more a book) explaining on-board energy. In there is a section on different types of batteries, lead acid, gel etc. etc.
Heavy going and I gave up but you may have more staying power.
 
You are talking 2.4 Milli AH, not AH, so 50 would be 120 mAH, not 120 AH, sorry, unlikely to run a boat for very long! The give away is AA size!
 
well no, and err yes really



2400 mAH AA's are common ( yes, that's 2.4AH ) so Boguing's right on that part; however, you'd need let's say 10 in series to make a nominally 12V cell, with a capacity of 2.4AH. the 50 of em mentioned would only make 5 cells of 12V, with a total capacity of 12AH.


I have seen nicads in bigger sizes sold as suitable for boats etc, some claiming no special charging requirements; but prices were umm, scary.
 
Your biggest problem is finding batteries that will fit. This will limit your choice as they have to be exactly the siame size as the old ones to fit in the space provided on a Nimbus 37 trawler.
 
For my money, the alternators are more of an issue than the batteries. Standard alternators will cook even the best batteries as they chuck out a high voltage regardless of the state of charge.

Also beware of fitting too much capacity for the alternators: I overloaded and burned out two alternators and one battery bank before fitting smart regulators to the alternators and an electronic charge splitter that pools the output of both alternators before splitting to each bank.

I now run a total of 730Ah fed by a dual 40A smart charger (shorepower) and two 60A alternators in parallel. So far, my cheapo camping batteries are doing fine and I expect to get a good few years out of them, as I'm treating them nicely.
 
[ QUOTE ]
There is no doubt that 'cheap' batteries are false economy.

[/ QUOTE ] Two of my neighbouring boats are now into the fourth year using Halfords 120ah leisure batteries for both starting and domestics.
 
Quick question along the same lines, my Falcon 275 has twin commercial (truck) grade 90amp/H batteries to serve the domestics. They dont seem to hold up very well between charges. I am thinking about replacing them for leisure batteries, but not sure about the amperage. Would twin 120amp/H be better for domestic use.
 
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