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First time boat owner here, a MK III with a Yanmar single diesel. Can someone tell me if I should leave the key in the on position whilst the engine is going in order to charge, or could I just turn it to the off position after engine start.
Also, I believe that I should not switch batteries whilst the engine is running, is this true?
Alan Richards
Runaway, Mk III hull 804
Holyrood, NL
Alan Richards
Runaway, Mk III hull 804
Somewhere, NL
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Leave it on. A diesel, unlike a gas engine, will continue to run without electrical power, but your battery will not charge and the engine-stop control will not function.
The problem with switching batteries is that the current from the alternator must have somewhere to go, or the regulator will suffer. If you have the standard rotary switch, however, the second battery is added to the circuit in the intervening 'Both' setting without disconnecting the first until you go to the Battery 2 setting. Therefore the alternator always has a target battery and there is no risk to the regulator unless you accidentally turn the battery switch off.
The West Marine site has a lot of information on batteries and battery switch setups, but much of it is aimed at long-distance cruisers, not relatively short-term cruisers like most 27 owners; you may find it interesting, though.
If you are changing your battery setting to ensure a charge to both batteries, I suggest a battery combiner. You will never even have to think about your switch while the engine is on again. Search "battery combiner" or "combiner" to see a discussion with links. I've now have a Yandina combiner (once sold by West) for over ten years and I think it's an unsung essential.
David Weatherston
Towser, Toronto
C&C 27 Mk IV
Last edited by (2012-08-27 05:44:42)
David Weatherston
Towser, Toronto
C&C 27 Mk IV
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Thanks for the great reply David. I will definitely look up battery combiners through my local sailing outfitter (He is a West Marine dealer).
I was confused about the key position mainly because the person I bought the boat from showed his process for starting the engine, and he would turn the key off after start... that didn't seem right to me. However, I think he did that because the alarm would stay on until the key was turned off even though the engine was going.
The alarm no longer behaves like this so I think it has sorted itself out.
Thanks again.
Alan Richards
Runaway, Mk III hull 804
Holyrood, NL
Alan Richards
Runaway, Mk III hull 804
Somewhere, NL
Offline
Alan:
I'm no expert on electrical/charging systems on boat but I was cautioned by a reputable surveyor that you could seriously damage the alternator if you turn the key off while the engine is running.
Steve Reid
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Thanks Steve, I will definitely be keeping the key in the on position from now on. I have a lot to learn about owning a boat, so it is good to know that there is a great community here that has my back <img src="emoticons/icon_smile.gif">
My boat is still a mystery to me in many ways, part of me can't wait until haul-out so I can go through her inch by inch and make her truly mine.
Alan Richards
Runaway, Mk III hull 804
Holyrood, NL
Alan Richards
Runaway, Mk III hull 804
Somewhere, NL
Offline
If you turn the key to 'off' when the engine is running the 'engine stop' knob will still work correctly as it is mechanical, not electrical. It is item 28 on my Yanmar operation manual, and I actually checked it out last evening. Another problem is that the RPM reader and fuel gauge only work with the key in the 'on' position. If you turn the key to 'off' you will also lose the two warning lights, one to indicate when you have the circuit 'on', the other the engine overheat warning light. Apart from this you have David's warning about the alternator being confused about where to send the electricity. So, yes, it seems best to leave the key 'on' when the engine is running.
A combiner is a great idea, but Marcus of Cariden had a simple solution to keeping both batteries equally charged. He uses number one battery on odd dates and number two battery on even dates and it works well we are told. I follow his advise, so my on board clever charger is only plugged in to the mains a few times in the winter to avoid a frozen battery disaster.
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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Well, Alan, my shut-off is electrical, so there. Actually, this is probably a step backward, as I'm forever telling helpful guests, "No, turning the key is not the way to shut off the engine." But you're right about the gauges and so on.
Marcus' battery management trick is nice, but the requirement to know whether the date is even or odd is way too complicated for me. Other than knowing that it's race-night, I'm pretty much lost as to esoteric details like dates (and I can't read the date on my watch without my glasses, the finding of which is another fire-drill). The great virtue of the combiner is that you can install it and forget about batteries. Period. This has great value to someone like me who would forget about them anyway.
Note that the combiner I have is no longer sold by West. They now have a more expensive one with more operating options. The one I have is sold direct at http://www.yandina.com or by Defender.
David Weatherston
Towser, Toronto
C&C 27 Mk IV
David Weatherston
Towser, Toronto
C&C 27 Mk IV
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David, I seem to recall that some years ago you wrote an intriguing account of the thrills you experienced when changing Towser's A4 for a diesel. Hunt as I may I cannot find that thread, but perhaps you now have a non-Yanmar unit, hence such ultra modern technology as electrical shut-off? Is it not strange that the makers of many of the very latest cars boast of having 'push button' start...........finally catching up with the Yanmar of the 80's? I understand that they even have 'push button' stop.........if I live another year we'll have to crank the things to life.
Combiners, batteries and dates........Leap Year comes half an hour later, or was it earlier, in Newfoundland, as you once warned me? That means we start on "Both" I presume?
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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My diesel is a 2YM15. It's a nice unit, but they moved all the service locations to the "wrong" side for a 27. And it has electrical shutoff, which aside from guests, I don't think is a good idea. (Not as idiotic and showy as dashboard 'start' buttons, but getting there.)
You can start on 1 or 2 or both with a combiner, but if you're in NL, you will start half an hour earlier (an hour, if there's fog).
David Weatherston
Towser, Toronto
C&C 27 Mk IV
David Weatherston
Towser, Toronto
C&C 27 Mk IV
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