Thanks to all the excellent advice I received here, I did a pre-purchase survey, liked what I saw, and bought a new to me C&C 30. I love it. I moved from a Cat 27 w/ outboard to an inboard diesel(16 HP Yanmar). I know NOTHING of diesel engines(yet). Now to the problem: I have no shore power hook up at the pier yet, and can't charge the batteries. My question is can I run the engine at idle while at the dock for an hour or so to charge the batteries without overheating or damaging the engine? Should the trans. be in nuetral? Should the engine be under some load (i.e. in gear)? What rpm's do I need to charge?
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Motor around
You can run at idle but that's neither good for the engine nor will it generate much current since most alternators will typically produce only a few amps below 1000 rpm. Better to take her out and run the engine at full rpm for an hour and then check resting voltage. Don
You can run at idle but that's neither good for the engine nor will it generate much current since most alternators will typically produce only a few amps below 1000 rpm. Better to take her out and run the engine at full rpm for an hour and then check resting voltage. Don
Agree with Don
Running in neutral won't run the alternator, so you need to move it around. Not necessarily at the max rpm but 75-85% of max, which on a 16 I would estimate at 2500-2600 rpm. Deisels are meant to run that high to avoid coking up the mixing elbow. An easier alternative is to take the batteries to the car repair place you use for inspections and get them topped off for free.
Running in neutral won't run the alternator, so you need to move it around. Not necessarily at the max rpm but 75-85% of max, which on a 16 I would estimate at 2500-2600 rpm. Deisels are meant to run that high to avoid coking up the mixing elbow. An easier alternative is to take the batteries to the car repair place you use for inspections and get them topped off for free.
Right on Don.
Harry: Don is on the mark here. You really do not want to idle the engine for than long. Your engine probably has a 55amp alternator. Depending on the size of the battery bank it may take a couple of hours of running the engine. Worse comes to worse, you can always take the batteries home and charge them there. If you need something to read about the Yanmar engines, check out www.yanmarhelp.com. They recommend that you run the engine at 80-90% of the max. RPM (3400). This is about 2800+/- rpms. Keep the fuel/oil clean and the engine should give you many years of service.
Harry: Don is on the mark here. You really do not want to idle the engine for than long. Your engine probably has a 55amp alternator. Depending on the size of the battery bank it may take a couple of hours of running the engine. Worse comes to worse, you can always take the batteries home and charge them there. If you need something to read about the Yanmar engines, check out www.yanmarhelp.com. They recommend that you run the engine at 80-90% of the max. RPM (3400). This is about 2800+/- rpms. Keep the fuel/oil clean and the engine should give you many years of service.
I agreem move the boat BUT
make sure your alternator works. Measure to voltage before you start the engine at the battery. THe measure it after with the engine rev a little. It should be almost 2 volts higher. If your alternator is not working you better have a towing plan.
make sure your alternator works. Measure to voltage before you start the engine at the battery. THe measure it after with the engine rev a little. It should be almost 2 volts higher. If your alternator is not working you better have a towing plan.
motor at dock
I start my engine once a week at the dock if we don't use the boat that week. If your mooring lines are set ok you can put it in gear and rev up to whatever you want i usually go to 2000 RPM and let her run for about a half hour. Helps keep the prop and the bottom clean. Jim
I start my engine once a week at the dock if we don't use the boat that week. If your mooring lines are set ok you can put it in gear and rev up to whatever you want i usually go to 2000 RPM and let her run for about a half hour. Helps keep the prop and the bottom clean. Jim
Bad Advice
Why do you need a towing plan?? This is a sailboat!! If the motor won't run put up your sails and sail to where you are going. Internal combustion engines have only been around for a hundred or so years. People have been sailing for thousands of years. Dave
Why do you need a towing plan?? This is a sailboat!! If the motor won't run put up your sails and sail to where you are going. Internal combustion engines have only been around for a hundred or so years. People have been sailing for thousands of years. Dave
Don't be surprised how long it will take ...
to recharge a battery especially if you are using it for autohelm under sail ... If you don't have a 0-15 volt dc meter on your panel you can get one at a local electric supply ... radio shack used to have one that was about $15. charging is about 14.6 V and OK batteries are about 12.6+ V. Right after you stop charging ... the voltage will register higher than it will after a couple of hours ... something to do with the chemicals. But you at least have an idea of what the batteries look like. My Yanmar will start at about 12.3 even a little lower when both batteries are used together. Vic "Seven"
to recharge a battery especially if you are using it for autohelm under sail ... If you don't have a 0-15 volt dc meter on your panel you can get one at a local electric supply ... radio shack used to have one that was about $15. charging is about 14.6 V and OK batteries are about 12.6+ V. Right after you stop charging ... the voltage will register higher than it will after a couple of hours ... something to do with the chemicals. But you at least have an idea of what the batteries look like. My Yanmar will start at about 12.3 even a little lower when both batteries are used together. Vic "Seven"
Charging batteries
COngrats on the new diesel-powered boat! I love my diesel, and you will too. One of the issues you now face is how to determine what advice you get here is actually useful - including mine! Good luck sorting it out. My advice: Running the engine with the transmission in neutral is perfectly fine for charging battereies at the dock (assuming shore power is unavailable, or there is no battery charger). You should warm up the engine at slightly above idle (I use 1000 RPM on my M25) and then charge at higher speed (I use 2000 RPM). The only draawbacks to this approach are that is is less than ideal for the engine to run it at less than 75% or so of full output, and battery chargining is not a big load - but it is not fatal, or even "bad" to do this. The effect is to possibly glaze the cylinder walls. Long-term idling will cause it to start blowing oil past the rings, which you'll see as blue/black exhaust smoke. The good news is that if you motor under load for any length of time the rings will re-seat and the smoke will clear up. NOTE: glazing and black smoke is an extreme case. I've never seen this on my engine nor on any friends. I usually charge batts this way for 1.5 to 2.0 hours per day while cruising and running the fridge, unless I've been motoring (as we have had to this year due to lack of favorable winds). I recommend strongly against running in gear at high RPM for any length of time while tied to the dock - I think its dangerous. How much battery capacity do you have? What size is your alternator? What kind of regulator do you have? jv
COngrats on the new diesel-powered boat! I love my diesel, and you will too. One of the issues you now face is how to determine what advice you get here is actually useful - including mine! Good luck sorting it out. My advice: Running the engine with the transmission in neutral is perfectly fine for charging battereies at the dock (assuming shore power is unavailable, or there is no battery charger). You should warm up the engine at slightly above idle (I use 1000 RPM on my M25) and then charge at higher speed (I use 2000 RPM). The only draawbacks to this approach are that is is less than ideal for the engine to run it at less than 75% or so of full output, and battery chargining is not a big load - but it is not fatal, or even "bad" to do this. The effect is to possibly glaze the cylinder walls. Long-term idling will cause it to start blowing oil past the rings, which you'll see as blue/black exhaust smoke. The good news is that if you motor under load for any length of time the rings will re-seat and the smoke will clear up. NOTE: glazing and black smoke is an extreme case. I've never seen this on my engine nor on any friends. I usually charge batts this way for 1.5 to 2.0 hours per day while cruising and running the fridge, unless I've been motoring (as we have had to this year due to lack of favorable winds). I recommend strongly against running in gear at high RPM for any length of time while tied to the dock - I think its dangerous. How much battery capacity do you have? What size is your alternator? What kind of regulator do you have? jv
One more thing...
One more thing to think about running the engine at the dock is the CO from the engine exhaust. Watch the way the wind is blowing, and make sure there is a free and easy path to clear the air. Steve
One more thing to think about running the engine at the dock is the CO from the engine exhaust. Watch the way the wind is blowing, and make sure there is a free and easy path to clear the air. Steve
There's a lot of smoke being blown here!
I have an O'Day 30 that also doesn't have any shore power equipment. I've had this boat for 12 yrs and never, well almost never, had any problem with battery's going down. to recharg you only need to motor for about 30 min to bring them back up. if you have a 55amp alt and they need a lot then in 30 min you have put back aprox. 27 amp hrs back in them. if your on the magothy then more than likely you'll be motoring for a short while to get out anyway. if a boat is sitting and not being used you loose very little /month in the battery. mine is in ct. now on a mooring and after sitting for 45days with 2 auto bilge pumps i still had plenty of power to start. volt was only down about 1.5 volts. if you need to recharge at dock be careful of co. running at about 1500rpm in neutral for 30 min won't harm anything. think about it. truckers sit and let their rigs run at idle for hours at a time to keep warm or cool while they sleep. if it was harming their engines you can be sure they would'nt be doing it.
I have an O'Day 30 that also doesn't have any shore power equipment. I've had this boat for 12 yrs and never, well almost never, had any problem with battery's going down. to recharg you only need to motor for about 30 min to bring them back up. if you have a 55amp alt and they need a lot then in 30 min you have put back aprox. 27 amp hrs back in them. if your on the magothy then more than likely you'll be motoring for a short while to get out anyway. if a boat is sitting and not being used you loose very little /month in the battery. mine is in ct. now on a mooring and after sitting for 45days with 2 auto bilge pumps i still had plenty of power to start. volt was only down about 1.5 volts. if you need to recharge at dock be careful of co. running at about 1500rpm in neutral for 30 min won't harm anything. think about it. truckers sit and let their rigs run at idle for hours at a time to keep warm or cool while they sleep. if it was harming their engines you can be sure they would'nt be doing it.
Good Batteries
I had an O'Day 27 without shore power and I never had a problem. You need two batteries, so that you have redundancy, and good quality ones. Normal use will take care of charging needs. Don't just let it idle in the slip. Bad on the engine and not much charging output. The alternator needs at least 1500 RPM to put out much charge, assuming its a 3,400 RPM engine (rather than an 1,800). I haven't read the other posts, so sorry if this is redundant.
I had an O'Day 27 without shore power and I never had a problem. You need two batteries, so that you have redundancy, and good quality ones. Normal use will take care of charging needs. Don't just let it idle in the slip. Bad on the engine and not much charging output. The alternator needs at least 1500 RPM to put out much charge, assuming its a 3,400 RPM engine (rather than an 1,800). I haven't read the other posts, so sorry if this is redundant.
Thoughts......
First...in most cases if you are down 55amps on the batteries, a 55amp alternator isn't going to get close to putting back 55amps back in to your batteries because batteries have a low acceptance rate the closer to full charge they are. Second. If your batteries are down 1.5 volts that would put them at 11.1 -11.3 volts (experts say the 24 hour rested voltage of a 12 volt battery is 12.6-12.8 volts) Either way, this means your batteries are almost dead and will greatly reduce their life span....unless you are measuring the voltage right after a charge which might have it over 13 volts...but that insn't an accurate measure of the battery's voltage. I would reccomned getting Don Casy's "Electrical Systems for Sailboats" (he makes electrical stuff seem very easy) or one of the other good electrical books for boats. They really opened my eyes. 3rd...as far as it "being a sailboat and not needing an angine" I challenge anybody to "sail" up the New River down here in Fort Lauderdale without an engine... or for that matter most of the intercoastal in Florida... Cheers Brian Crew Rest
First...in most cases if you are down 55amps on the batteries, a 55amp alternator isn't going to get close to putting back 55amps back in to your batteries because batteries have a low acceptance rate the closer to full charge they are. Second. If your batteries are down 1.5 volts that would put them at 11.1 -11.3 volts (experts say the 24 hour rested voltage of a 12 volt battery is 12.6-12.8 volts) Either way, this means your batteries are almost dead and will greatly reduce their life span....unless you are measuring the voltage right after a charge which might have it over 13 volts...but that insn't an accurate measure of the battery's voltage. I would reccomned getting Don Casy's "Electrical Systems for Sailboats" (he makes electrical stuff seem very easy) or one of the other good electrical books for boats. They really opened my eyes. 3rd...as far as it "being a sailboat and not needing an angine" I challenge anybody to "sail" up the New River down here in Fort Lauderdale without an engine... or for that matter most of the intercoastal in Florida... Cheers Brian Crew Rest
Day Sailors
Evidently most of the good advice here is from day sailors. Cruising sailors who don't have good solar or wind power will run their engines from one to two hours a day, in neutral. We spend 2 to 3 months per year on the hook running a lot of DC power and run the engine every day to put back the amps. It's nice to have instrumentation to see how you are charging, i.e. amp meter. I found that 1200 to 1500 rpm would give me a good charge. The stock alternators on the engine won't do a real good job of charging. A good 3 stage smart regulator will keep the amps up to charge the batteries quicker. When you are motoring, run the rpm's up to get rid of some of the carbon buildup. Bill
Evidently most of the good advice here is from day sailors. Cruising sailors who don't have good solar or wind power will run their engines from one to two hours a day, in neutral. We spend 2 to 3 months per year on the hook running a lot of DC power and run the engine every day to put back the amps. It's nice to have instrumentation to see how you are charging, i.e. amp meter. I found that 1200 to 1500 rpm would give me a good charge. The stock alternators on the engine won't do a real good job of charging. A good 3 stage smart regulator will keep the amps up to charge the batteries quicker. When you are motoring, run the rpm's up to get rid of some of the carbon buildup. Bill
What a diesel needs
Things that are not good for diesels: running cold, ie the usual sailor's use of a diesel inboard is the 20 minutes to exit the marina and get the sails up. Fuel combustion is poor and the engine is inefficient. Another thing is low rpm. Diesels in big highway trucks have a variable timing which allows them to idle in the compression "sweet spot". Sailboat or other stationary diesel engines do not. They have a fixed timing advance, likely around 17 degrees, meant to be efficient at one particular RPM where they deliver most power. When you run a diesel at lower RPM it carbons up, the usual cause of bad starting and and overhaul. So, when you do use this diesel, be kind to it and take it out every now and then for an "Italian tuneup", ie under load and warmed up, rev it up and hold it there long enough to dislodge the carbon and blow it all out the exhaust. Batteries are cheaper to replace than that diesel. I took a course on diesel maintenance at a local tech school and recommend to all owners of a diesel inboard to do the same. My ignorance on these engines was quite profound before the course, less so now, and I have the books to refer to.
Things that are not good for diesels: running cold, ie the usual sailor's use of a diesel inboard is the 20 minutes to exit the marina and get the sails up. Fuel combustion is poor and the engine is inefficient. Another thing is low rpm. Diesels in big highway trucks have a variable timing which allows them to idle in the compression "sweet spot". Sailboat or other stationary diesel engines do not. They have a fixed timing advance, likely around 17 degrees, meant to be efficient at one particular RPM where they deliver most power. When you run a diesel at lower RPM it carbons up, the usual cause of bad starting and and overhaul. So, when you do use this diesel, be kind to it and take it out every now and then for an "Italian tuneup", ie under load and warmed up, rev it up and hold it there long enough to dislodge the carbon and blow it all out the exhaust. Batteries are cheaper to replace than that diesel. I took a course on diesel maintenance at a local tech school and recommend to all owners of a diesel inboard to do the same. My ignorance on these engines was quite profound before the course, less so now, and I have the books to refer to.
Battery Charging
Harry John Visser and Bill came closest to answering your question. Yes, you can run in idle, but just don't do it for long. If you're going to be at the boat dock for an hour or so, why not take the boat out for a motor as some have suggested, rather than sit at idle in the dock? But your question was about charging the batteries. If you don't have an external regulator, Bill's right, you'll get little out of your alternator in terms of amps, especially at idle, even if motoring. If all you have is the factory installed alternator, which is internally regulated and therefore not very efficient, you have a couple of choices. Invest in some solar panel(s) to avoid dependency on engine charging. Get a smart regulator and a new alternator or have your alternator modified to match with the new external regulator. The solar option is least expensive, and if you're only using your boat on weekends, a perfect answer. You'll need to do some research on sizing and connecting. Check the West Marine Advisors and other sources. Given your new boat status, if you haven't, most of us suggest you buy Nigel Calder's Boatowner's Manual. It'll answer all your questions. Stu
Harry John Visser and Bill came closest to answering your question. Yes, you can run in idle, but just don't do it for long. If you're going to be at the boat dock for an hour or so, why not take the boat out for a motor as some have suggested, rather than sit at idle in the dock? But your question was about charging the batteries. If you don't have an external regulator, Bill's right, you'll get little out of your alternator in terms of amps, especially at idle, even if motoring. If all you have is the factory installed alternator, which is internally regulated and therefore not very efficient, you have a couple of choices. Invest in some solar panel(s) to avoid dependency on engine charging. Get a smart regulator and a new alternator or have your alternator modified to match with the new external regulator. The solar option is least expensive, and if you're only using your boat on weekends, a perfect answer. You'll need to do some research on sizing and connecting. Check the West Marine Advisors and other sources. Given your new boat status, if you haven't, most of us suggest you buy Nigel Calder's Boatowner's Manual. It'll answer all your questions. Stu
I will buy the book
Thanks much for the advice & opinions. Especially the link to Yanmarhelp(below). What a great site! I've learned how much I need to learn, and at this point I'm just more than a little intimidated by all this stuff. Good advice on Casey's book. I'll buy that. Sounds like just what I need. I should have the shore power to the dock by next weekend. EXPENSIVE!! The "little" box was $92.00 alone! Thanks again; glad ya'll (I'm south of Mason-Dixon)are there.
Thanks much for the advice & opinions. Especially the link to Yanmarhelp(below). What a great site! I've learned how much I need to learn, and at this point I'm just more than a little intimidated by all this stuff. Good advice on Casey's book. I'll buy that. Sounds like just what I need. I should have the shore power to the dock by next weekend. EXPENSIVE!! The "little" box was $92.00 alone! Thanks again; glad ya'll (I'm south of Mason-Dixon)are there.
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