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Call me anything, but don't call me late for dinner.
DC electric problem
Moderator: Jim Walsh
D. C. Electric Problem
All is not lost Lee. You got some good dc electric system hands-on knowledge albeit pretty expensive. Another possible thought is to install a switch that selects either battery or outboard generator, fused of course, to drive lights and/or accessaries when powered up. That would save the battery while you are running on the outboard. Cheers, Charlei
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Lee Kaufman
- Posts: 95
- Joined: Apr 22nd, '05, 12:31
- Location: CD25 #12 "Morning Star"
switch
That's a good idea. Thanks.
D. C. Electric Problem
If you do decide to go that route there are some cautions so bring it up for discussions. Charlie
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Lee Kaufman
- Posts: 95
- Joined: Apr 22nd, '05, 12:31
- Location: CD25 #12 "Morning Star"
Good idea, Charlie
As much info as I have been able to glean from this discussion I am sure I would get some really good ideas about switching the power source. It will be a while before I am able to get back to the boat so I will wait to pose the question 'til then. I think I have everyone wore out for now anyway.
To everyone else:
Thanks a lot for the education and assistance.
As much info as I have been able to glean from this discussion I am sure I would get some really good ideas about switching the power source. It will be a while before I am able to get back to the boat so I will wait to pose the question 'til then. I think I have everyone wore out for now anyway.
To everyone else:
Thanks a lot for the education and assistance.
Nissan alternator results
I have a 6HP extra long shaft with factory installed alternator.
I think it works quite well for my sailing.
I do have an analog expanded scale volt meter connected across the battery with a switch so it is turned off when away from the boat. Normal full battery charge shows 12.6-12.8 volts. With engine running at starting throttle (out of gear) the voltage goes up to 13.5 volts with no other electrical devices turned on.
I normally sail with a depth sounder and VHF radio energized. Getting in and out of the harbor under power takes a total running time of about an hour at about 2/3rd throttle. This amount of running keeps the battery "topped up". If I have used more power the battery voltage falls to less than 12.4 and then I connect a small trickle charger over night to get back to full charge. Note that a small solar charger might be able to do the same.
Even though the charging rate is very low, I like the ability to get a bit more charge in the battery in case of emergency. For example charging a cell phone or getting out on the VHF radio.
I do think that you will see very little voltage increase if the battery is much below 12.4. But any increase in volts shows that the alternator is helping.
I think it works quite well for my sailing.
I do have an analog expanded scale volt meter connected across the battery with a switch so it is turned off when away from the boat. Normal full battery charge shows 12.6-12.8 volts. With engine running at starting throttle (out of gear) the voltage goes up to 13.5 volts with no other electrical devices turned on.
I normally sail with a depth sounder and VHF radio energized. Getting in and out of the harbor under power takes a total running time of about an hour at about 2/3rd throttle. This amount of running keeps the battery "topped up". If I have used more power the battery voltage falls to less than 12.4 and then I connect a small trickle charger over night to get back to full charge. Note that a small solar charger might be able to do the same.
Even though the charging rate is very low, I like the ability to get a bit more charge in the battery in case of emergency. For example charging a cell phone or getting out on the VHF radio.
I do think that you will see very little voltage increase if the battery is much below 12.4. But any increase in volts shows that the alternator is helping.
Again, it is not an an Alternator, but...
It does produce electricity 
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M. R. Bober
- Posts: 1122
- Joined: Feb 6th, '05, 08:59
- Location: CARETAKER CD28 Flybridge Trawler
Re: Thanks
Lee, around these parts the plural of ya'all is "all of ya'all."Lee Kaufman wrote:...
By the way, for those up North, the plural of ya'all is all ya'all.
Happy New Year
Mitchell Bober
Sunny Lancaster (Where we wish all of ya'all a Happy New Year,) VA
CDSOA Founding Member
Lee sent me a link to this thread as I have worked with him in the past on his engine in regards to the rpm issue. I have a beneteau First 235 with the same engine on it labeled under the tohatsu brand.
I had issues with this so called alternator when I first hooked it up. however my issues were that it was wired up backwards from the factory and put out 16+ volts into my instruments when we first tested it. thankfully the gps that was on has an over voltage protection built in and shut itself off after detecting the excessively high voltage. After we figured out the problem we rewired it and it seemed to work correctly. At this point I have just been assuming it was charging my batterys for about 3 to 4 hours every time I took the boat out. From where Lee and I keep our boats it is about a forty five minute to an hour and a half motor to get to the ocean where we can sail. I haven't had a chance to get up with Lee and look at his charging setup yet but it sounds like mine in operation. I had kind of wondered at how little gain in my batteries I seemed to get from its charging. I have a 5 watt solar panel that does a good job of keeping the 184 amp hour battery bank charged if I use the boat one day a week and it charges back up the other 6 days. I have a lot of electrical systems on this boat for it's size so I have been very happy with as small a solar panel as it is keeping up with the one and two day a week usage.
I would like to get a charge controller and a slightly larger solar panel as well as a link 10 monitoring system or something similar so i can track detailed input and output on the batteries. It would be interesting to see what the alternator would show on that.
here is a write up on the alternator and solar when i did it. http://www.scottcarle.com/wordpress/?p=279
If rpm is the constraint on this engine then there is probably no solution. My experience and testing shows that these engines are vastly underpowered compared to what the manufacture claims.
I replaced a running 4hp 2 stroke long shaft johnson with this 6hp 4 stroke engine and lost about 10 percent of my speed on the water at full throttle. Engine weights are about the same as the johnson was a much older model and the new 4 stroke fairly light at 54 lbs.
With a stock from the factory 8 pitch prop this engine will only get 3800 rpm in a static thrust test. On the water with it pushing the boat at about 5.2 knots WOT it is only getting 4200 rpm. The manufacture sent me the lowest pitch prop they sell for the engine which is the 6 pitch prop and it only brought the rpm under way up to around 4500 rpm. This is 1000 to 1500 rpm below what the manufacture say the engine needs to be turning to give 6hp at the shaft it is rated for. Under Ideal conditions I have run at over 6.2 knots over the water speed with the older 4 hp engine. Under Ideal conditions I have been unable to get the boat over 5.5 knots with the new engine.
Lee's engine is a one year older but identical model branded under Nissan. I ran the same static thrust tests on his engine that I ran on mine and got identical readings. Up until then I had been under the assumption that there was something wrong with my engine. I now believe that the manufacture has played with the numbers on these engines to make them seem more powerful than they are.
I have gone through an arduous and grievous 10 month battle with the manufacture and dealership over the under power issues. They just say that the boat is two big for the engine. end of story even though the factory specs for the boat are within the weight range they sell the engine for.
If you have any interest in reading about this.. its pretty borring but you can find details in the following links both for and against this engine
http://www.scottcarle.com/wordpress/?s=tohatsu
http://www.sailinganarchy.com/forums/in ... ohatsu+6hp
http://www.sailnet.com/forums/showthread.php?t=36963
Using a boat speed prop calculator and calculating prop speed with this engine It should have been a nice performance increase over the 4hp engine. however the engine is not powerful enough to run at nominal rpms with the lowest pitch prop tohatsu usa sells for it.
I have had one dealer tell me that they can get a high thrust prop not available to tohatsu usa directly from japan that might help get the rpm up higher.. this spring I will test it on my boat and Lee's boat to see what it does to performance and rpm.
I would never buy one of these one cylinder four stroke engines again. I could have stayed with a 4hp two stroke for half the cost and gotten the same performance. Other than that I would have moved to a two cylinder four stroke in the 8 to 9 hp range.
other impressions of this engine
1 the 25 inch ultra long shaft is the bomb.. I love that.
2 Also fuel consumption is excellent in the new engine..
3 It vibrates a lot !!
4 It is almost as noisy as my 2 stroke at wide open throttle.
I had issues with this so called alternator when I first hooked it up. however my issues were that it was wired up backwards from the factory and put out 16+ volts into my instruments when we first tested it. thankfully the gps that was on has an over voltage protection built in and shut itself off after detecting the excessively high voltage. After we figured out the problem we rewired it and it seemed to work correctly. At this point I have just been assuming it was charging my batterys for about 3 to 4 hours every time I took the boat out. From where Lee and I keep our boats it is about a forty five minute to an hour and a half motor to get to the ocean where we can sail. I haven't had a chance to get up with Lee and look at his charging setup yet but it sounds like mine in operation. I had kind of wondered at how little gain in my batteries I seemed to get from its charging. I have a 5 watt solar panel that does a good job of keeping the 184 amp hour battery bank charged if I use the boat one day a week and it charges back up the other 6 days. I have a lot of electrical systems on this boat for it's size so I have been very happy with as small a solar panel as it is keeping up with the one and two day a week usage.
I would like to get a charge controller and a slightly larger solar panel as well as a link 10 monitoring system or something similar so i can track detailed input and output on the batteries. It would be interesting to see what the alternator would show on that.
here is a write up on the alternator and solar when i did it. http://www.scottcarle.com/wordpress/?p=279
If rpm is the constraint on this engine then there is probably no solution. My experience and testing shows that these engines are vastly underpowered compared to what the manufacture claims.
I replaced a running 4hp 2 stroke long shaft johnson with this 6hp 4 stroke engine and lost about 10 percent of my speed on the water at full throttle. Engine weights are about the same as the johnson was a much older model and the new 4 stroke fairly light at 54 lbs.
With a stock from the factory 8 pitch prop this engine will only get 3800 rpm in a static thrust test. On the water with it pushing the boat at about 5.2 knots WOT it is only getting 4200 rpm. The manufacture sent me the lowest pitch prop they sell for the engine which is the 6 pitch prop and it only brought the rpm under way up to around 4500 rpm. This is 1000 to 1500 rpm below what the manufacture say the engine needs to be turning to give 6hp at the shaft it is rated for. Under Ideal conditions I have run at over 6.2 knots over the water speed with the older 4 hp engine. Under Ideal conditions I have been unable to get the boat over 5.5 knots with the new engine.
Lee's engine is a one year older but identical model branded under Nissan. I ran the same static thrust tests on his engine that I ran on mine and got identical readings. Up until then I had been under the assumption that there was something wrong with my engine. I now believe that the manufacture has played with the numbers on these engines to make them seem more powerful than they are.
I have gone through an arduous and grievous 10 month battle with the manufacture and dealership over the under power issues. They just say that the boat is two big for the engine. end of story even though the factory specs for the boat are within the weight range they sell the engine for.
If you have any interest in reading about this.. its pretty borring but you can find details in the following links both for and against this engine
http://www.scottcarle.com/wordpress/?s=tohatsu
http://www.sailinganarchy.com/forums/in ... ohatsu+6hp
http://www.sailnet.com/forums/showthread.php?t=36963
Using a boat speed prop calculator and calculating prop speed with this engine It should have been a nice performance increase over the 4hp engine. however the engine is not powerful enough to run at nominal rpms with the lowest pitch prop tohatsu usa sells for it.
I have had one dealer tell me that they can get a high thrust prop not available to tohatsu usa directly from japan that might help get the rpm up higher.. this spring I will test it on my boat and Lee's boat to see what it does to performance and rpm.
I would never buy one of these one cylinder four stroke engines again. I could have stayed with a 4hp two stroke for half the cost and gotten the same performance. Other than that I would have moved to a two cylinder four stroke in the 8 to 9 hp range.
other impressions of this engine
1 the 25 inch ultra long shaft is the bomb.. I love that.
2 Also fuel consumption is excellent in the new engine..
3 It vibrates a lot !!
4 It is almost as noisy as my 2 stroke at wide open throttle.
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Oswego John
- Posts: 3535
- Joined: Feb 5th, '05, 20:42
- Location: '66 Typhoon "Grace", Hull # 42, Schooner "Ontario", CD 85D Hull #1
audeojude wrote: If rpm is the constraint on this engine then there is probably no solution. My experience and testing shows that these engines are vastly underpowered compared to what the manufacture claims.
Audeojude,
My way of thinking is that this type of small engine develops it's horse power in direct proportion to its RPMs. It reaches full HP somewhere near full throttle. It will probably never attain 6 HP until it gets up to maybe 5 to 6,000 rpms.
Since they don't carry anything less than a 6 pitch prop, I wonder if the high end rpms could be raised if the reduction gears at the lower end of the shaft could be changed.
If the prop shaft speed could be lowered through gearing, it might be enough to give the engine enough mechanical advantage to increase it's rpms.
Talk about truth in advertising. I wonder how many other people were taken in by the company's specious claims in their advertisements.
O J
tohatsu usa told me on the phone that the engine has to turn 5500 rpm to get a nominal 6hp at the shaft.
I would have just sucked it up and agreed with them if any of their props had let the engine run at its rated rpm. however even the lowest pitch prop they sell will under way only allow the engine to turn at between 1000 and 1500 engine rpm less than nominal and max rpm.
If my boat didn't get the performance I expected and the engine was running at its rated rpms I would have just said.. hmmm.. engine/prop to small.
Going from an engine rated at 4hp to one rated 6hp and getting less performance was a shock. $1400 for less performance hurts.
I went for this engine based on wanting to upgrade my performance to give myself a little more power in bad conditions. It isn't unknown for me to be out in 6ft and better seas and high winds 40+ knots at the worst, and my 4hp though usable starts to hurt in those conditions.
im editing this to add after going back and reading it that my 4hp is scary to depend on when i have gotten stuck out in these conditions. It trys but is marginal in dealing with that much wind or big short period seas.
I would have just sucked it up and agreed with them if any of their props had let the engine run at its rated rpm. however even the lowest pitch prop they sell will under way only allow the engine to turn at between 1000 and 1500 engine rpm less than nominal and max rpm.
If my boat didn't get the performance I expected and the engine was running at its rated rpms I would have just said.. hmmm.. engine/prop to small.
Going from an engine rated at 4hp to one rated 6hp and getting less performance was a shock. $1400 for less performance hurts.
I went for this engine based on wanting to upgrade my performance to give myself a little more power in bad conditions. It isn't unknown for me to be out in 6ft and better seas and high winds 40+ knots at the worst, and my 4hp though usable starts to hurt in those conditions.
im editing this to add after going back and reading it that my 4hp is scary to depend on when i have gotten stuck out in these conditions. It trys but is marginal in dealing with that much wind or big short period seas.
Engine performance
Very Interesting.
Top speed under "ideal conditions" is an interesting value. However, the performance under really bad conditions may be of more use.
I have made many trips along the Oregon Coast with strong headwinds and adverse current with the boat pounding on every sea. (This was with a 12000 pound 35 foot boat). Attempting to make progress under power alone was generally not possible. The boat would virtually stop with a bad pounding sea and would only accelerate slowly before being hit by the next wave. Sailing was the answer. Motor sailing helped only a little bit.
Note that a static thrust test may show a better ability to accelerate from a nearly stopped condition.
I have the Nissan 6HP 4 stroke with the 6 inch pitch Mercury prop on my Cape Dory 25. The book on the Mercury prop shows a 8 3/8 diameter, but careful measurement indicates a 7.9 inch diameter.
I bought the Mercury prop because of a VERY LONG delivery on the Nissan 6 inch pitch.
I calculate the theoretical hull speed of the Cape Dory at 5.69 knots. (The square root of the waterline length in feet times 1.34) The 6HP Nissan motoring in calm conditions gets to about 5.5 knots. Adding a lot more power on the Cape Dory with its full keel and 4000 pound displacement seems like a low probability of giving a significantly higher top speed. I would put on a 5 inch pitch, if available.
Top speed under "ideal conditions" is an interesting value. However, the performance under really bad conditions may be of more use.
I have made many trips along the Oregon Coast with strong headwinds and adverse current with the boat pounding on every sea. (This was with a 12000 pound 35 foot boat). Attempting to make progress under power alone was generally not possible. The boat would virtually stop with a bad pounding sea and would only accelerate slowly before being hit by the next wave. Sailing was the answer. Motor sailing helped only a little bit.
Note that a static thrust test may show a better ability to accelerate from a nearly stopped condition.
I have the Nissan 6HP 4 stroke with the 6 inch pitch Mercury prop on my Cape Dory 25. The book on the Mercury prop shows a 8 3/8 diameter, but careful measurement indicates a 7.9 inch diameter.
I bought the Mercury prop because of a VERY LONG delivery on the Nissan 6 inch pitch.
I calculate the theoretical hull speed of the Cape Dory at 5.69 knots. (The square root of the waterline length in feet times 1.34) The 6HP Nissan motoring in calm conditions gets to about 5.5 knots. Adding a lot more power on the Cape Dory with its full keel and 4000 pound displacement seems like a low probability of giving a significantly higher top speed. I would put on a 5 inch pitch, if available.
It's a lot easier to compare ideal conditions than bad conditions as much more of my boating is done in nice weather. 
but it does make it easier to give a apple to apple comparison as far as conditions external to the boat compare.
Your right about sailing being the answer to most bad weather conditions. My boat might do 2 knots under power in some conditions yet do 6.5 knots under sail in the same conditions given how much power my sails can generate. However a lot of my time on the water is in restricted waters on the Intracoastal waterway with the wind on the nose. A motor is the only option there. head on into 35 knots of wind and 3 ft real short period chop will almost stop my small boat cold. It doesn't happen often but I was hoping that the new engine would give me a bit more edge when it did.
oh well... back to the drawing board when I can afford to.
I have the 6 pitch prop and it did improve things a bit over the stock 8 pitch but not enough to let the engine get to nominal rpm. I will be getting at high thrust 5.9 pitch prop one dealer has told me they can get from japan. I will let everyone know what happens with it when I test it out. It will probably be mid spring to late spring before I can do that though.
You bring up an interesting point. I have been taking for granted that these props are the advertised size and pitch. I should take them down and measure them to see exactly what the diameter and pitch actually are.
but it does make it easier to give a apple to apple comparison as far as conditions external to the boat compare.Your right about sailing being the answer to most bad weather conditions. My boat might do 2 knots under power in some conditions yet do 6.5 knots under sail in the same conditions given how much power my sails can generate. However a lot of my time on the water is in restricted waters on the Intracoastal waterway with the wind on the nose. A motor is the only option there. head on into 35 knots of wind and 3 ft real short period chop will almost stop my small boat cold. It doesn't happen often but I was hoping that the new engine would give me a bit more edge when it did.
oh well... back to the drawing board when I can afford to. I have the 6 pitch prop and it did improve things a bit over the stock 8 pitch but not enough to let the engine get to nominal rpm. I will be getting at high thrust 5.9 pitch prop one dealer has told me they can get from japan. I will let everyone know what happens with it when I test it out. It will probably be mid spring to late spring before I can do that though.
You bring up an interesting point. I have been taking for granted that these props are the advertised size and pitch. I should take them down and measure them to see exactly what the diameter and pitch actually are.