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Discussion Starter · #1 ·
Can someone explain the proper way to charge a battery using your auxiliary diesel engine? Seeing diesels like to run at high rpm with a big load on them, what is the proper way to run a diesel if you are at a dock or sailing in a race where it is against the rules to use the engine to turn the prop? My alternator would use about 1/2 hp to charge and the engine is 20 hp. So I am using a small fraction of full load on the engine. Does charging in this way damage the engine?
 

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Hey,

You will probably get a lot of replies on this.

This is my OPINION:
-If you are racing and need to charge the batts, start the engine and rev it high enough so that the alt is putting out over 14V. Leave it at that throttle setting until the batts are charged. Since you don't be doing this often (maybe just a few times a year) I doubt you will do any damage to the engine

-If you just need to charge batts and are going somewhere, I would put the trans in gear and run at 1/2 throttle if you are sailing, and higher power if you aren't.

-If your are on a mooring or a dock and don't have AC to charge the batts with I would put the engine in gear and run it high enough to get 14V from the alt and leave it there.

I am assuming that this is a relatively RARE occurrence. I also don't believe you will damage the engine at all.

I would avoid having the engine just idle for hour, that is not good for the it at all.

Barry
 

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islander bahama 24
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Agreed however solar is so cheap now days install a couple one hundred watt panels and save the fuel and all associated costs like maintance and if it really was so bad to idle then why do so many or rigs and off grid diesel gennys do it for hours a day
 

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-If your are on a mooring or a dock and don't have AC to charge the batts with I would put the engine in gear and run it high enough to get 14V from the alt and leave it there.
Barry
It might not be a very good idea to put the engine in gear, if you are on a mooring??
 
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Can someone explain the proper way to charge a battery using your auxiliary diesel engine? Seeing diesels like to run at high rpm with a big load on them, what is the proper way to run a diesel if you are at a dock or sailing in a race where it is against the rules to use the engine to turn the prop? My alternator would use about 1/2 hp to charge and the engine is 20 hp. So I am using a small fraction of full load on the engine. Does charging in this way damage the engine?
This topic always gives me a chuckle especially when I work on so many engines with 10,000+ hours of "light loading".

#1 If you need to charge and have no other means then by all means RUN THE MOTOR.

#2 There is no need to race it beyond where the alt makes about 80-90% of the alts rating. Figure out where this is, often just a fast idle, and run it there.

#3 The next time you run the motor, run it hard. Once she is warmed up run at wide open for two to four minutes then back her down to 80%..

#4 The idea that you will fully recharge a lead acid battery AGM, GEL or Flooded is fools gold unless you sit there and run it for ten + hours. "Charging" by alternator is what trawlers do, not sailboats...;) We restore energy in bits and pieces and hope to get back to full at a dock or via solar, wind etc. on the hook..

#5 Run the motor only until the batteries hit absorption voltage and perhaps just a bit longer while current is still pretty high in early absorption. Anything more is inefficient charging and wasteful..

#6 Motor charging is best used for bulk charging unless you are motoring for a long distance with no wind or are motor sailing.

#7 I work on piles of motors with thousands of hours of idle running. These motors purr perfectly, burn no oil and have not had any shorter life. These owners simply know how and when to run it and what to do after you run it with minimal load... Our own engine is one of them.. We have engine driven refrigeration so a lot of the engine running has been lightly loaded. I would not trade our 4000+ hour engine for a 200 hour engine owned by an in and out of the harbor guy.

*Change the oil regularly
*Run it hard when you run it
*Stop worrying about putting some energy back into the bank
* Stop charging when you attain absorption, if running only for charging purposes
 

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Discussion Starter · #9 ·
Agreed however solar is so cheap now days install a couple one hundred watt panels and save the fuel and all associated costs like maintance and if it really was so bad to idle then why do so many or rigs and off grid diesel gennys do it for hours a day
I do have solar panels and they take care of all my power needs. The ac dock power was taken out by the Japanese Tsunami a couple years back and has not been repaired. Just want to know the best way to charge if I need to.
 

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I do have solar panels and they take care of all my power needs. The ac dock power was taken out by the Japanese Tsunami a couple years back and has not been repaired. Just want to know the best way to charge if I need to.
You could string some 100' extension cords together for temporary charging. A power strip with circuit breaker at the power source could help keep the current down to 15 amps to protect the temporary cord.

Regards,
Brad
 

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It might not be a very good idea to put the engine in gear, if you are on a mooring??
Why not? I do that pretty regularly. Put the engine in reverse and it is really no different than when you are setting an anchor. Any mooring that can't hold your boat, in reverse gear, at a high idle is most definitely NOT a mooring that you want to spend a night on! Same thing when you're anchored.

Of course, someone should be on deck to keep an eye on things while you are doing this, and make sure that you don't, in fact, break the mooring loose, break the pendant, or whatever.
 

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Why not? I do that pretty regularly. Put the engine in reverse and it is really no different than when you are setting an anchor. Any mooring that can't hold your boat, in reverse gear, at a high idle is most definitely NOT a mooring that you want to spend a night on! Same thing when you're anchored.

Of course, someone should be on deck to keep an eye on things while you are doing this, and make sure that you don't, in fact, break the mooring loose, break the pendant, or whatever.
It is not a worry about damaging the mooring it is because prop walk will spin you around, and around, and around.....;)
 

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Why not? I do that pretty regularly. Put the engine in reverse and it is really no different than when you are setting an anchor. Any mooring that can't hold your boat, in reverse gear, at a high idle is most definitely NOT a mooring that you want to spend a night on! Same thing when you're anchored.

Of course, someone should be on deck to keep an eye on things while you are doing this, and make sure that you don't, in fact, break the mooring loose, break the pendant, or whatever.
Yeah, like Maine Sail said; I'm guessing you've got zero prop walk on your boat, then. Most of us aren't so unfortunate.
 

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my diesel mechanic, not a yottie, not even a marine specific mechanic, thank intelligence and good choosing, advocates use of diesel even in neutral for charging batteries,. he says in perfect spanish that that will not harm the engine. man does not even speak english. is a master mechanic on diesel engines
he stated that placing in gear is optional and up to the operator
i have heard so much from yotties who are not diesel experts claiming the running of diesels in neutral scores or glazes cylinders, when opposite is truth.
watch the long distance truckers--never shutting down, running hours in neutral with no adverse effect.
so what is this--as soon as we place same engine into a boat, the scoring is gonna happen??
get real.
learn about your tools and thrive.
yes your engine is a tool.
 

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just a slight disagreement truckers arent at idle per se

they are at high idle running all the auxiliaries so there is a load so its not a complete no load idle like some say.

scoring doesn happen from idling by the way GLAZING does especially on an engine that has never properly seated their piston rings

also engines that sit for prolonged times will develop and aggravate this glazin sometimes causing broken psiton rings, how this happens is best left for another thread but on diesels in a marine envirnment with an open INTAKE you get caking of oil, rust and the piston and ring dries up...when this happens and you dont pre oil your rings via the injector or sparkplug hole its very likely and frequent to damage rings, once rings are damaged you get all the other problems associated with bad rings like carbon sooting, blow by...low comp etc...

however I agree with maine too Ill take a lightly ladden diesel with thousands of hours over an engine that never gets up to temp and is always shutdown like a car...this will lead to all the problems we all should know regarding engines diesel or not.

peace
 

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I know some have heard this story before but it applies to this thread too..

My buddy Darren owns a good sized excavating, irrigation and landscaping company in Colorado and we talk diesels quite a bit. He has a good sized fleet of small and large diesel engines and a couple of them have over 20k hours with no rebuilds.

The last time I spoke with him about engine longevity he had one Yanmar block and one Mitsubishi block with over 20k hours that have never been rebuilt. He bought both of these machines used with about 5k hours on them back in the late 90's.

Most of his smaller engines are either Yanmar or Kubota but he does have a few Mitsubishi's too and one or two Shibaura (also Japanese; read Perkins / Volvo engines are Shibaura). His engines on this equipment run all day and barely ever shut off. They idle for long, long, long hours especially in the winter months.

Now granted these are not in a marine application but in well over 500,000 hours of combined run time on his fleet he has yet to rebuild an single small diesel engine. All his machines run Shell Rotella and it gets changed regularly. Of course he buys his oil in 55 gal drums and I buy it by the gallon...

If mid to heavy equipment running Yanmar, Mitsubishi, Shibaura and Kubota blocks can rack up 10k to 20k hours, while doing hundreds and hundreds of hours of idling per year, with no rebuilds, then a well maintained marine diesel should be able to do the same, if run properly AFTER you idle it...

When we had the discussion about not letting diesels idle a few years ago he just laughed about polishing or glazing the cylinder walls. His sarcastic comment was something like "Sh&t I better let my guys know not to let them idle". Course he'd already been doing it for 25 plus years, with no failed engines or rebuilds needed, so he was surprised to find out his engines were going to die and imminent death soon...;)

About three years ago myself and a Beta dealer here in Maine had a long discussion with Stanley of Beta Marine, at the Maine boat builders show. The conversation was specifically about bore glazing and idling to charge.

Stanley's take was this is a "non-issue" for the Beta engines. He very boldly insisted they have not seen a single case of bore glazing in a Beta / Kubota block. Not a single one (this was as of three years ago).

This is the US distributor/importer of Beta engines and a guy who has been working with diesel engines his entire life. He is one of the more honest guys in the business and if we had to replace our Westerbeke tomorrow the guy who would get the engine sale.... He also admitted that the majority of their customers idle to charge. Still not a single case of bore glazing or polishing leading to an engine failure.

Why do I get a chuckle out of this topic..??? If more sailors worried about how long they run the engine and how hard they run the engine, before shutting it off, and actually took care of their engines, we'd likely never hear of an engine failure....;);)

Both of these engines have very high light loading hours and neither has ever been rebuilt. They purr like kittens.... This is why a get a chuckle when a sailor with 400 hours on their Kubota is worrying about running it at idle for 40 minutes here and there.....;);)



 

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I know this is anecdotal only... I tried a high idle (900 rpm) to get great charging from our 2 alternators (start and house are separate), so we could get 50 amps of charging into the house battery. When I did this for 3 hours, at the next start a little oil came out of the exhaust, for the first time. After motoring for an hour, the symptom disappeared completely.

Maybe I'm mistaken, but I think the whole issue is around a high idle, not idling in general.

Now I only do low idle, after momentarily going to 1K to get the alternator fields going. By taking one of the (huge) diode outputs on the starting battery circuit and connecting it to +12v, I get a good 20 amps of charging at idle, so that's good enough for me. I only had to do this once over the summer, when we had several days of clouds. We had 540 watts of solar but only 200 amp hours of battery bank, so it was a storage issue.

(By the way, we always let our engine run for a few minutes at idle before shutting it down.)

Regards,
Brad
(4 cylinder Perkins)
 

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I know some have heard this story before but it applies to this thread too..

My buddy Darren owns a good sized excavating, irrigation and landscaping company in Colorado and we talk diesels quite a bit. He has a good sized fleet of small and large diesel engines and a couple of them have over 20k hours with no rebuilds.

The last time I spoke with him about engine longevity he had one Yanmar block and one Mitsubishi block with over 20k hours that have never been rebuilt. He bought both of these machines used with about 5k hours on them back in the late 90's.

Most of his smaller engines are either Yanmar or Kubota but he does have a few Mitsubishi's too and one or two Shibaura (also Japanese; read Perkins / Volvo engines are Shibaura). His engines on this equipment run all day and barely ever shut off. They idle for long, long, long hours especially in the winter months.

Now granted these are not in a marine application but in well over 500,000 hours of combined run time on his fleet he has yet to rebuild an single small diesel engine. All his machines run Shell Rotella and it gets changed regularly. Of course he buys his oil in 55 gal drums and I buy it by the gallon...

If mid to heavy equipment running Yanmar, Mitsubishi, Shibaura and Kubota blocks can rack up 10k to 20k hours, while doing hundreds and hundreds of hours of idling per year, with no rebuilds, then a well maintained marine diesel should be able to do the same, if run properly AFTER you idle it...

When we had the discussion about not letting diesels idle a few years ago he just laughed about polishing or glazing the cylinder walls. His sarcastic comment was something like "Sh&t I better let my guys know not to let them idle". Course he'd already been doing it for 25 plus years, with no failed engines or rebuilds needed, so he was surprised to find out his engines were going to die and imminent death soon...;)

About three years ago myself and a Beta dealer here in Maine had a long discussion with Stanley of Beta Marine, at the Maine boat builders show. The conversation was specifically about bore glazing and idling to charge.

Stanley's take was this is a "non-issue" for the Beta engines. He very boldly insisted they have not seen a single case of bore glazing in a Beta / Kubota block. Not a single one (this was as of three years ago).

This is the US distributor/importer of Beta engines and a guy who has been working with diesel engines his entire life. He is one of the more honest guys in the business and if we had to replace our Westerbeke tomorrow the guy who would get the engine sale.... He also admitted that the majority of their customers idle to charge. Still not a single case of bore glazing or polishing leading to an engine failure.

Why do I get a chuckle out of this topic..??? If more sailors worried about how long they run the engine and how hard they run the engine, before shutting it off, and actually took care of their engines, we'd likely never hear of an engine failure....;);)

Both of these engines have very high light loading hours and neither has ever been rebuilt. They purr like kittens.... This is why a get a chuckle when a sailor with 400 hours on their Kubota is worrying about running it at idle for 40 minutes here and there.....;);)



thats where things get murky

I for example used my yanmar 2gm exclusively as the sole charging source for my batter bank, often at high idle I did this for hundreds and huundreds if hours on my cruise and that on a very old and tired engine and I never even had to check compression on that engine ever so I agree with many on here with knowledge on the subject...however I correctly cooled down the engine, I correctly loaded that engine and treated that engine right!

in any case Im out of this one...these discussions as most that get opinionated never end well

bottom line maintain your engine and you can run it at idle, wot and anywhere in between if you just do whats correct before and after and in between as well

and you maintain and dont abuse or abandon or leave your engine sitting forever

ps. some engines are better than others...some owners are better than others AND THAT GOES WITHOUT SAYING

peace
 

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Discussion Starter · #19 ·
You could string some 100' extension cords together for temporary charging. A power strip with circuit breaker at the power source could help keep the current down to 15 amps to protect the temporary cord.

Regards,
Brad
I would need 423 of 100 foot extension cords to go from the boat to my house. The boat harbor has turned off all outside outlets (homeless were using them for rice cookers), and power to docks does not exist. The price of paradise.
 

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I would need 423 of 100 foot extension cords to go from the boat to my house. The boat harbor has turned off all outside outlets (homeless were using them for rice cookers), and power to docks does not exist. The price of paradise.
Is that 423 feet? If so, that's doable but not pretty.

Regards,
Brad
 
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