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#1
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Battery heresy
Calder points out how battery life is increased by minimizing
discharge level. No matter how many batteries you have in the boat, you'll get maximum life by putting them in one bank. Keeping a starting battery isolated and in reserve is obviously a necessary compromise for most craft. However, with a 20 hp diesel, modest starting loads, and the ability to hand start, I'm thinking that the simplicity of a one bank system might make sense for a daysailing, short cruise boat, that is docked with shore power. If the batteries did get run down away from home, I'd be willing to hand start in penance. The key question is whether a two cylinder diesel like a 20 hp Yanmar 2QM can really be hand started or if it is an "only when your life absolutely depends on it" kind of operation. I don't have much experience with engines under 200 HP so I'd appreciate the benefit of actual experience. -- Roger Long |
#2
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Roger Long wrote:
Calder points out how battery life is increased by minimizing discharge level. No matter how many batteries you have in the boat, you'll get maximum life by putting them in one bank. Keeping a starting battery isolated and in reserve is obviously a necessary compromise for most craft. However, with a 20 hp diesel, modest starting loads, and the ability to hand start, I'm thinking that the simplicity of a one bank system might make sense for a daysailing, short cruise boat, that is docked with shore power. If the batteries did get run down away from home, I'd be willing to hand start in penance. The key question is whether a two cylinder diesel like a 20 hp Yanmar 2QM can really be hand started or if it is an "only when your life absolutely depends on it" kind of operation. I don't have much experience with engines under 200 HP so I'd appreciate the benefit of actual experience. Are you sure your engine is set up for hand starting? The heat exchanger version of the 2GM certainly isn't, because the water pump blocks the spot the crank would go into. Even if this were not the case, I don't think either of my engines are installed such that a crank could be swung. I'll be curious to hear the replies - although some will say it can be done, I've only heard a few people say they have actually done it. |
#3
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Are you sure your engine is set up for hand starting?
Yes, I saw the crank. It's the raw water cooled version. I have the service manual and it shows a hand crank setup for the fresh water version as well. I hear from another source that it's a rather athletic undertaking and a second person to close the compression release is a necessity. Also heard from another owner of the same boat who has run it exactly the way I describe for 17 years without a problem. I think I'll just leave the battery switch on boat all the time. -- Roger Long |
#4
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Are you sure your engine is set up for hand starting?
Roger Long wrote: Yes, I saw the crank. It's the raw water cooled version. I have the service manual and it shows a hand crank setup for the fresh water version as well. What the manual shows may not match what's on the boat. I've had a boat with a hand-startable diesel (a one-cylinder Volvo) that had various bits of the cabin in the way of the hand crank. I hear from another source that it's a rather athletic undertaking and a second person to close the compression release is a necessity. The only times I've ever successfully hand-started a diesel, it was necessary to manipulate the compression release. Also heard from another owner of the same boat who has run it exactly the way I describe for 17 years without a problem. I think I'll just leave the battery switch on boat all the time. You might want to visit him on his boat and get a demo. Another option http://www.springstarter.com/ Fresh Breezes- Doug King |
#5
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Another option
http://www.springstarter.com/ Hey, that is very, very cool. BTW it's a used boat. I inspected it personally and tried the crank in position. One of the first things I'm going to do is try and start it. I'll let you know how it goes. -- Roger Long |
#6
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Roger Long wrote:
Another option http://www.springstarter.com/ Hey, that is very, very cool. BTW it's a used boat. I inspected it personally and tried the crank in position. One of the first things I'm going to do is try and start it. I'll let you know how it goes. If you inboard is hand crank equipped like mine was on a previous boat, you REALLY don't need to hand crank it when the battery runs down. I killed my battery at anchor a few times (thank you Espar!). No problem. As long as you have two people aboard: 1 person lifts the decompression lever, which makes the engine turn over fairly easily. The second person pushes the start switch and once the engine is moving and the flywheel is doing it's job, just drop the decompression lever and she'll start like a charm. Hand cranking was never required and I killed the battery sufficiently that the lights were dim. I left the Espar running all night in cold fall weather. |
#7
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"Roger Long" wrote in message .. . Are you sure your engine is set up for hand starting? Yes, I saw the crank. It's the raw water cooled version. I have the service manual and it shows a hand crank setup for the fresh water version as well. I hear from another source that it's a rather athletic undertaking and a second person to close the compression release is a necessity. Once the compression levers are opened, an 8 year old can crank it. You don't need another person to handle the levers since they lock in the open position. Just get it spinning and reach up and close one lever. Then throw the other lever(s). I started my 3HM30 and 3GM30 this way several times. You can also start them using a string of a few D-cells. Also heard from another owner of the same boat who has run it exactly the way I describe for 17 years without a problem. I think I'll just leave the battery switch on boat all the time. -- Roger Long |
#8
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Is there some trick to starting? I just heard from someone on the
owner's forum for my boat, the only one responding who had tried hand starting, and he said he spent an entire summer bashing knuckles and getting thrown across the cabin without ever getting it going. He was using the compression releases, trying one cylinder at time, etc. What could he have been doing wrong? -- Roger Long |
#9
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On Tue, 15 Mar 2005 15:48:04 -0500, Jeff
wrote: I'll be curious to hear the replies - although some will say it can be done, I've only heard a few people say they have actually done it. I hand-start my 30 HP Atomic 4 once a year to make sure I can do it if I have to. Rubber-banding magazine shin guards to your legs is recommended G It works fine if the engine is in good tune. I am interested in finding out what popular marine diesels can still be started this way, if any, as I find it a great alternative. I recall more than one cruising/racing tale where a dead or damaged electrical system was circumvented by rigging a rope to a diesel flywheel through blocks and then using the force of a crash gybe to spin the wheel. (I am aware of the single-cylinder/flick the compression levers technique) Some time back, I saw a couple of firms that made wind-up starters, which I thought was a great idea. You could use them every time or keep one in storage as a spare starter (they had different mounting models and teeth for the common marine diesels. |
#10
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On Tue, 15 Mar 2005 19:08:41 GMT, "Roger Long"
wrote: Calder points out how battery life is increased by minimizing discharge level. No matter how many batteries you have in the boat, you'll get maximum life by putting them in one bank. Keeping a starting battery isolated and in reserve is obviously a necessary compromise for most craft. However, with a 20 hp diesel, modest starting loads, and the ability to hand start, I'm thinking that the simplicity of a one bank system might make sense for a daysailing, short cruise boat, that is docked with shore power. If the batteries did get run down away from home, I'd be willing to hand start in penance. The key question is whether a two cylinder diesel like a 20 hp Yanmar 2QM can really be hand started or if it is an "only when your life absolutely depends on it" kind of operation. I don't have much experience with engines under 200 HP so I'd appreciate the benefit of actual experience. I was completely unable to hand crank a 3-cyl Yanmar to start. I weigh 190 and am not weak. We repowered with a later (3GMH) about 12 years ago and that one didn't even have a place to put a crank. I suggest you try it on your own engine. I think it would work with a big enough flywheel, but as it is closing one compression release stops it instantly in my experience. OTOH, taking off the compression it will spin with a pretty dead battery and start when you close it. It is a matter of how fast you can get it to spin before you close the valve. I know a one-cylinder Volvo can be hand started, by a reliable witness. Rodney Myrvaagnes NYC J36 Gjo/a The sound of a Great Blue Heron's wingbeats going by your head |
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