Looking for small OB that will power my tiller pilot Capt Jim M15 Get Outlook for iOS<https://aka.ms/o0ukef>
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner. Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water. A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
Thanks again Dave Maybe solar or towable hydro will keep up with my autohelm. I need to hook up the amp meter today any make some test tacks Capt Jim Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: Dave Scobie <scoobscobie@gmail.com> Sent: Friday, November 5, 2021 9:34:34 AM To: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Subject: M_Boats: Re: Outboard generator I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner. Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water. A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
Dave, Have you ever sailed on the Columbia River? I have. There are times when my M-15 needs to go against the current, like every time I return. When there is no wind, more than 2hp motor is needed, something more like 4hp. The alternative is to let the river current carry the M-15 out to sea. Steve M-15 #335 -----Original Message----- From: Dave Scobie Sent: Friday, November 5, 2021 9:34 AM To: For and about Montgomery Sailboats Subject: M_Boats: Re: Outboard generator I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner. Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water. A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
Steve: Respectful stated: you can't make a displacement non-planning hull go much faster than hull speed no matter how much horsepower you throw on the transom. I've motored Sages and Montgomerys against current often and successfully and most times with a Honda 2/2.3 (excluding my M17 that.wad powered with a Suzuki 4). Yes slow going but going against adverse currents up to 4 knots. Watch first two minutes of this video - https://youtu.be/yc0ELdF7Zxs Horsepower can help _somewhat_ against wind as here what is slowing you is windage (hull, cabin top, and standing rig) and waves. I'll add it is generally unsafe to go against or with current flowing close to hull speed. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Fri, Nov 5, 2021, 4:30 PM Steve Trapp via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:
Dave, Have you ever sailed on the Columbia River? I have. There are times when my M-15 needs to go against the current, like every time I return. When there is no wind, more than 2hp motor is needed, something more like 4hp. The alternative is to let the river current carry the M-15 out to sea. Steve M-15 #335
-----Original Message----- From: Dave Scobie Sent: Friday, November 5, 2021 9:34 AM To: For and about Montgomery Sailboats Subject: M_Boats: Re: Outboard generator
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner.
Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water.
A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom.
:: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs. Sincerely, Tyler -----Original Message----- From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner. Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water. A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
Any skippers know the hull speed of M15? My 2 hp will get the Pelican to 3.5 knts. To exceed hull speed would require that the vessel plane any exponentially more HP. That is my understanding Capt Jim Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: casioqv <casioqv@usermail.com> Sent: Friday, November 5, 2021 7:24:51 PM To: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Subject: M_Boats: Re: Outboard generator Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs. Sincerely, Tyler -----Original Message----- From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner. Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water. A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
4.87 knts in theory, but it helps if you are going with the current! http://www.msog.org/specs/race_ratings.cfm On Sat, Nov 6, 2021, 3:49 AM Jim Sadler <jimsadler@jascopacific.com> wrote:
Any skippers know the hull speed of M15? My 2 hp will get the Pelican to 3.5 knts. To exceed hull speed would require that the vessel plane any exponentially more HP. That is my understanding Capt Jim
Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: casioqv <casioqv@usermail.com> Sent: Friday, November 5, 2021 7:24:51 PM To: For and about Montgomery Sailboats < montgomery_boats@mailman.xmission.com> Subject: M_Boats: Re: Outboard generator
Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs.
Sincerely, Tyler
-----Original Message-----
From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner.
Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water.
A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom.
:: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
And, the closer you get to theoretical hull speed, the power to go a bit faster increases greatly. It's not a linear graph. Swoops upwards steeply as you get up towards hull speed. Similar to other reports...my M17 will go 4 to 4.2 knots at about half throttle of my Honda 2.3 in calm conditions. Loses about half a knot in gusty headwinds and some chop. But back to calm conditions - after about 4.2 knots and half throttle, I will not get much beyond 4.5-4.6 knots even at near full throttle, because of that steep upward power vs. speed curve for the displacement hull. And as mentioned these small outboard props are shaped for planing boat speed at high throttle, or trolling kickers at low speed. Not ideal for pushing heavy displacement hulls. cheers, John On 11/6/21 8:46 AM, Sam wrote:
4.87 knts in theory, but it helps if you are going with the current!
http://www.msog.org/specs/race_ratings.cfm
On Sat, Nov 6, 2021, 3:49 AM Jim Sadler <jimsadler@jascopacific.com> wrote:
Any skippers know the hull speed of M15? My 2 hp will get the Pelican to 3.5 knts. To exceed hull speed would require that the vessel plane any exponentially more HP. That is my understanding Capt Jim
Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: casioqv <casioqv@usermail.com> Sent: Friday, November 5, 2021 7:24:51 PM To: For and about Montgomery Sailboats < montgomery_boats@mailman.xmission.com> Subject: M_Boats: Re: Outboard generator
Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs.
Sincerely, Tyler
-----Original Message-----
From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner.
Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water.
A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom.
:: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
Jim, the basic hull speed equation is 1.34 x the square root of waterline length. Take an m15’s 13.25’ waterline and you get 4.88 knots. Waterline length is typically lengthens as you heel, but in an m15 that is minimal given the short overhangs (now an old 6m is a different story); most boats will exceed slightly with enough power, especially with a flat run n wide stern like the motives have (supporting the boat even as the crest of the wave moves slightly aft of the stern)- so call that a max speed (except when surfing down a wave) of 5 knots. My mid 80s 2 hp gets my m15 to 4.6 knots or so at well under 1/2 throttle in calm conditions- any more and the efficiency drops as more throttle gets you less gain); the only time the little engine hasn’t done the trick was when I towed a broken down ski boat with a family of 5 in it off a lee shore and we tried to get them up lake to their trailer in 20+ knots wind and short 2’ seas (I ended up taking them to a more sheltered location downwind). My main issue in rough conditions has not been engine power; it has been keeping the prop fully submerged in short steep waves- something that got much easier when I cut the motor mount down 2”. I do still long for a replacement prop pitched to give more torque as you throttle up- I think that is one thing the electrics are doing well with their wide skinny bladed props to get full use of the engines power in slow speed applications- but the no doubt huge market for aftermarket props on a 2 hp built in 86 seems oddly underserved. Perhaps someone smart than me can set up a service to design and 3 d print affordable plastic props…. All in all I’ve been impressed by the m15 under power as long as I remember that she is a light, shallow draft boat that will never power into the waves like a full keeled heavy displacement boat (that would typically be far less lively to sail). Re autopilot power, perhaps one of the now common portable battery power supplies sold for campers- could even charge off outboard if you had the right set up, but still be able to run autopilot when outboard is off or at low power. Alex On Sat, Nov 6, 2021 at 3:49 AM Jim Sadler <jimsadler@jascopacific.com> wrote:
Any skippers know the hull speed of M15? My 2 hp will get the Pelican to 3.5 knts. To exceed hull speed would require that the vessel plane any exponentially more HP. That is my understanding Capt Jim
Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: casioqv <casioqv@usermail.com> Sent: Friday, November 5, 2021 7:24:51 PM To: For and about Montgomery Sailboats < montgomery_boats@mailman.xmission.com> Subject: M_Boats: Re: Outboard generator
Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs.
Sincerely, Tyler
-----Original Message-----
From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner.
Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water.
A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom.
:: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
Am I missing something here? I installed a Semrad 2000 in my M17 to operate from a marine 12 volt battery. If I was ever concerned about running the battery down and not making contact where I could recharge it I would buy the smallest Honda generator to recharge. Noise you say, I say running an outboard is also noises. Maybe a motorcycle battery would even work because of weight. For me I am researching installing a lithium battery with converter. In over my head just mentioning it but if anyone has any info it I would appreciated it. Charlie Sent from my iPhone
On Nov 6, 2021, at 6:49 AM, Jim Sadler <jimsadler@jascopacific.com> wrote:
Any skippers know the hull speed of M15? My 2 hp will get the Pelican to 3.5 knts. To exceed hull speed would require that the vessel plane any exponentially more HP. That is my understanding Capt Jim
Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: casioqv <casioqv@usermail.com> Sent: Friday, November 5, 2021 7:24:51 PM To: For and about Montgomery Sailboats <montgomery_boats@mailman.xmission.com> Subject: M_Boats: Re: Outboard generator
Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs.
Sincerely, Tyler
-----Original Message-----
From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner.
Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water.
A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom.
:: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
I did some more research on this... the small RayMarine ST1000/2000 autopilots can draw up to 5aH but steering a small boat probably only draw 1-2 aH, especially with the sails down and low tiller effort. A lighting coil on a 2-3hp outboard probably produces around 3aH, which is AC around 10-20v depending on RPM. With a rectifier to convert to DC this can be used to charge a 12v battery that will also stabilize the voltage level, however a voltage regulator would protect from overcharging. It would probably work- you would likely have just enough current for running modern LED nav lights plus the autopilot. For my old Yamaha 2hp it costs about $40 to get a lighting coil. One can probably be added to almost any small outboard, it uses the flywheel as an alternator in the same way the magneto does to make spark. Sincerely, Tyler ----- Original Message ----- From: "casioqv" <casioqv@usermail.com> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Friday, November 5, 2021 7:24:51 PM Subject: M_Boats: Re: Outboard generator Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs. Sincerely, Tyler -----Original Message----- From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner. Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water. A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom. :: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site! On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
Get Outlook for iOS<https://aka.ms/o0ukef>
How to do the math on this kind of thing: You neet to know what the average draw for the device is. If everything is nominally 12 volts, then it can all be done in amps (A). NOT amp-hours (Ah), that is a rating of battery capacity, or for a device, a draw over time, How many amps draw each instant, for how many hours? That's amp-hours. The autopilot uses some average amount of current to steer your boat. It may vary from moment to moment but if you have an average over a longer time like several hours, that is what to use. Say it uses 2A on average. If you use it for 2 hours, that uses up 4 Ah. If your battery is 40Ah capacity and is fully charged, you use up 10% of the (theoretical) battery capacity. Actually you use more than that, by 10-20% or more, but I won't go into the details on resistance losses and device efficiency and charging efficiency here. The lighting coil or alternator generates some average amount of current when you're motoring at a given throttle setting. Say at mid throttle it puts out 3A. If you motor for two hours at mid throttle that generates 6Ah of energy. So in theory you come out a bit ahead; in practice with losses in the system you'll probably at least break even, in this simple fictional scenario. In terms of putting energy from some device into a battery, you want a charge controller to charge a 12V DC battery from a nominal 12V source (PV panel, lighting coil/alternator that provides DC output, DC generator, etc.). The voltage from the source needs to be ~13.5V or more, or no significant charging will happen. So at low RPMs on the motor, you might not get enough voltage. Also at low RPMs you will get less current. The combo of voltage and current determines how much if any energy can be transferred into the battery. For comparison, a 30 watt mono-crystalline PV panel with proper exposure to full mid-day sun and no shading will put out about 1.7-1.8A. So if you manage to get 4 hours of exposure then that's ~7Ah. Best charge controllers (details on request): https://www.flexcharge.com/products.htm PV7D for PV only. NC25A for PV and also any kind of generator/alternator DC source (outboard alternator, lighting coil, wind gen, towed gen, etc.). This is all for lead-acid batteries of whatever kind (wet, sealed, AGM, etc.). For lithium batteries, different charge controller situation. But the power calculations are universal. cheers, John On 11/6/21 5:51 PM, casioqv@usermail.com wrote:
I did some more research on this... the small RayMarine ST1000/2000 autopilots can draw up to 5aH but steering a small boat probably only draw 1-2 aH, especially with the sails down and low tiller effort. A lighting coil on a 2-3hp outboard probably produces around 3aH, which is AC around 10-20v depending on RPM. With a rectifier to convert to DC this can be used to charge a 12v battery that will also stabilize the voltage level, however a voltage regulator would protect from overcharging. It would probably work- you would likely have just enough current for running modern LED nav lights plus the autopilot.
For my old Yamaha 2hp it costs about $40 to get a lighting coil. One can probably be added to almost any small outboard, it uses the flywheel as an alternator in the same way the magneto does to make spark.
Sincerely, Tyler
----- Original Message ----- From: "casioqv" <casioqv@usermail.com> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Friday, November 5, 2021 7:24:51 PM Subject: M_Boats: Re: Outboard generator
Some small outboards can take an optional lighting coil or charge coil, it's an installable option on my 80s Yamaha 2hp. It produces a really small amount of current, designed to run nav lights, but might work with an autopilot depending on it's current needs.
Sincerely, Tyler
-----Original Message-----
From: Dave <scoobscobie@gmail.com> To: For <montgomery_boats@mailman.xmission.com> Date: Friday, 5 November 2021 9:35 AM PDT Subject: M_Boats: Re: Outboard generator
I'm not aware of any outboard that is of appropriate size for an M15 that has an alternator. Alternators usually found as option for motors 5HP or greater. Some 4HP motors have identical powerhead (aka block) as a 5 and 6 HP so an alternator can be added by the owner.
Also, the alternator doesn't start putting out any significant power until the motor is turning higher RPMs ... meaning the M15 is being overpowered (trying to climb the bow wave and dragging the transom deep in the water.
A M15 has absolutely no need for a motor greater than a Honda 2/2.3hp. larger motors are bad for boat trim, aka sailing ability, because of excessive weight hanging aft of the transom.
:: Dave Scobie :: M6'8" #650 :: Baba 30 #233 DEJA VU :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - m15namedscred.wordpress.com <<-- new site!
On Thu, Nov 4, 2021, 11:32 PM Jim Sadler <jimsadler@jascopacific.com> wrote:
Looking for small OB that will power my tiller pilot Capt Jim M15
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-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
participants (9)
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Alex Conley -
casioqv -
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Charles Adams -
Dave Scobie -
Jim Sadler -
John Schinnerer -
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Steve Trapp