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kev13
United Kingdom
114 Posts |
 Posted - 21 Oct 2011 : 14:00:02
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| My Norman 23 has a 55amp alternator (whatever that means) and I'm fitting two 105 amp domestic batteries and a starter battery. I don't think the alternator will be up to recharging all three batteries. Can I just swop the alternator for something bigger? What would be the most suitable please? |
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Deano
United Kingdom
1843 Posts |
Posted - 21 Oct 2011 : 16:48:35
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As with many things...... it just depends...........
55 amps is more than enough to charge your batteries, it all depends on how long you are prepared to wait for them to reach maximum charge and also how discharged they are.
My 200 Ah bank takes about 3-4 hours to come up to max charge when seriously depleted with a 55 amp alternator.
I have now got an alternator regulator to fit this winter, which should speed things up a bit. Google X-alt or Sterling alternator regulator and have a read. The capacity of the alternator is not the problem. The other problem I have is that the pulleys are geared for high engine revs, so at river speed the alternator is not running efficiently. I have a smaller pulley to try too.
The other problem is that alternators much above 70 amps will slip if only fitted with a single vee belt.
Dean - Boating on the Great Ouse.
Freeman 30 "Silver Gem"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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kev13
United Kingdom
114 Posts |
Posted - 22 Oct 2011 : 15:42:07
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Thanks Deano
What alt reg are you going to fit and is it relatively simple. I assume I would remove the the split charge relay I've just installed?
Kevin |
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Deano
United Kingdom
1843 Posts |
Posted - 22 Oct 2011 : 17:24:30
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Yes and no..
The alternator regulator does not have anything to do with the split charge system. It just better regulates the alternator for charging leisure batteries rather that it's 'normal' job on a car.
They are a bit tricky to fit as you need to connect it up inside the alternator, but nothing that a competent DIY'er can't achieve carefully following the instructions.
I have the Driftgate 2000 X-alt. Rather than tailing off to a 5 amp charge as soon as the batteries have a bit of charge in them, it sustains the 30 or 40 amp charge for much longer, auto sensing when the batteries are full and then reducing to a float charge to achieve 100% full batteries.
A normal alternator with it's standard automotive regulator cannot do this. It will take 3 times as long to charge the boat domestic batteries and then it will only achieve 75% of a full charge.
When you consider you should not discharge leisure batteries lower than 50%, if you can charge to 100% rather than 75%, you are gaining double the capacity of your batteries!!!! In half the time!!!! WIIN WIN situation!!!
Blimey - I should be selling these things!!!
(No financial interest!!)
Dean - Boating on the Great Ouse.
Freeman 30 "Silver Gem"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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kev13
United Kingdom
114 Posts |
Posted - 22 Oct 2011 : 17:39:09
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any one told you your brill Deano
I will start looking for one and the intricies (think thats right - how difficult) of fitting one rather than the new alternator I was being sold
Thanks |
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stumpy
United Kingdom
33 Posts |
Posted - 23 Oct 2011 : 16:11:25
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Hi all, is there a similar thing available to fit outboards? I know the system is different just thought i'd ask.
Mick. |
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df
United Kingdom
5994 Posts |
Posted - 23 Oct 2011 : 17:18:03
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With outboards you're pretty much stuffed as they generally produce too much voltage and dissipate the spare as heat where an alternator has coils instead of fixed magnets so the strength of the magnets can be varied to alter the output amps, if you have a long cable run to your batteries you can help the cause by moving the reg/rec unit closer to the batteries eliminating voltage drop but thats about it, I did it on my old boat and it made quite a difference to the batteries.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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stumpy
United Kingdom
33 Posts |
Posted - 24 Oct 2011 : 15:18:22
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Thanks df, my battery is about as close as possible so should be ok.
Mick. |
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Boatmad
United Kingdom
1092 Posts |
Posted - 24 Oct 2011 : 18:19:57
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One little point to note about these high output regulators is that you really need batterys with removable cell caps. This is because the higher voltage achieved causes gasing which depletes the electrolite, that means you need to be able to top up the water.
The sealed type car batterys are only of any use with a normal car alternator and regulator set up which will only get to about 80% charged.
pagreenwell |
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Deano
United Kingdom
1843 Posts |
Posted - 24 Oct 2011 : 21:05:02
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Perhaps many years ago, but not any more --
X-Alt - Lead Acid or Gel & AGM battery user selectable as standard.
Sterling - Programmable for 4 different battery types
Taken from their respective technical specification pages.
Dean - Boating on the Great Ouse.
Freeman 30 "Silver Gem"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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Topic |
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Alternator swop
