Charging

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Caladh

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Is it worth me fitting a Smart Alternator charger to the existing 100 amp alternator fitted to my Yanmar 4JH. I am charging up a 6 x 90amp battery setup. I had a Balmar alternator setup on the previous boat with an ARS-5 smart unit. These now seemed to be a very high price. i.e £350+
 
It depends on what kind of sailing you do. My sailing consists of either sailing, or motoring on passage for anything from one to eighteen hours, so I have managed perfectly well without a smart charger. If you only use the motor for a few minutes every now and again just to get out of harbour and back, then you may want a smart charger, though a supplement such as solar panels may be as effective.
 
Caladh said:
Is it worth me fitting a Smart Alternator charger to the existing 100 amp alternator fitted to my Yanmar 4JH. I am charging up a 6 x 90amp battery setup.
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If it's a fairly modern alternator, it will probably already be set to output around 14.4v, so you wouldn't see a great improvement. However, if you have splitter diodes in the charging circuit, the voltage reaching the batteries may be reduced. Is the alternator battery sensed?
 
Money would be better spent on solar panels, which will keep the batteries charged whilst you are away and help with usage when you are onboard.

If you do have split charge diodes i'd change to a low/zero loss method of split charging.
 
Caladh said:
Is it worth me fitting a Smart Alternator charger to the existing 100 amp alternator fitted to my Yanmar 4JH. I am charging up a 6 x 90amp battery setup. I had a Balmar alternator setup on the previous boat with an ARS-5 smart unit. These now seemed to be a very high price. i.e £350+
Click to expand...

What is the problem that you think you have that is making you consider the addition? Or what do you think will be improved?

So... given the various answers to date.... what voltage is your existing alternator regulated at? If it reaches 14.4V or more, then you will gain little/nothing. If it is an old one that regulates at around13.6V, you could be as well having a 14.4V regulator fitted, or buy a more modern alternator.
 
It all hinges on what sort of split charge unit is fitted, assuming the engine battery is not in parallel with the bank of 6. (if all are in parallel and the alternator is reaching 14.4 to 14.6 then no need to change anything.)
 
My batteries are definitely more charged more of the time than before I fitted a Merlin booster. The engine is a modern Volvo with a 110-amp alternator.

The booster waits for about thirty seconds after starting the engine before kicking in, and you can clearly hear the engine note changing when it does so so it's obviously extracting more energy. I do have AGM batteries which can be charged harder than sealed lead-acid (not sure how they compare to serious add-distilled-water wet cells); you might not derive so much benefit from a booster if you can't pack in the power rapidly.

I'll motor all day on passage occasionally, but if I'm sailing locally I'd rather adjust my destination to suit the wind so a lot of my use is of the "fifteen minutes out of harbour then sail all day" variety. A system that maximises those fifteen minutes is important to me.

Pete
 
If you have the Hitatchi alternator then this will sense at the alternator. Another point with them is they are extremely sensitive to temperature for some reason. As the engine/bay/internals get hot, the voltage reduces and current is limited.

Some Hanse installations had the Hitatchi removed and a different one put on to give better power management but am unsure of the details.

Adverc or similar could be worth it or just change the alternator for a new type.
 
Thanks for the advice all. I don't see the charge voltage go much above 14.1/2 volts indicated on the Victron amp metre. Currently (ha ha) in the UK I'm like PRV so sail when possible to to maximize the "15 minutes out of the harbour". I don't think it's a big issue and yes when and if we go south again I'll add solar etc

I believe the alternator is the Hitachi. Have yet to locate any split charge diode (1996 Malo 39) but I guess there is one there somewhere!
 
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