Thursday, July 4, 2019

[Electric Boats] Re: Success! 37ft electric conversion

 

Hi, yes we would love to see your boat.  We are moored in Blaine, WA and are doing some things to our boat this summer to get it a little more sea worthy (just replaced the chainplates, adding a 2nd anchor, AIS, and right now I am installing four more Lifeline 125A AGM batteries to give us 48V at 375AH, or 18kWh (less than that of course is usable).  One thing we urgently need to do is haulout our boat since our prop zinc just spun off the last time I was testing the motor and it is now zinc-less.  I am going to try and do that after this July 4 holiday.


We might be able to make the trip to Anacortes in our boat actually, perhaps with a stop at the Bellingham marina to overnight and recharge....or we could just drive down sometime this summer when you are going to be around.

__._,_.___
Posted by: lightdoesnotage@yahoo.com
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (14)

SPONSORED LINKS
.

__,_._,___
Posted by at No comments:

Wednesday, July 3, 2019

[Electric Boats] Pearson 35 yawl electric 10 kw

 

I just bought a Pearson  35 yawl..and has an electric motor from thunderstruck  motors..it is  a 12 .5 kw running at 72 volts battery bank. I haven't said it yet. But I can wait for this coming weekend..I'm bringing on board a 2000 watts generator since don't know what is the autonomy  I'm going to have...thinking if it is possible some sore of solar system I can Install so some have I put back some amps while sailing..
Any experiences???

__._,_.___
Posted by: Sergio Monfort <sermft@gmail.com>
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (1)

SPONSORED LINKS
.

__,_._,___
Posted by at No comments:

Re: [Electric Boats] Amp draw vs speed for 37ft sailboat with 10 ft beam, displacement 13,000 lbs

 

Jeff,  

I have a 2:1 reduction, and my 15" prop has a pitch of 15".  Having a "square" prop makes the transfer of energy from motor to water efficient, but at the cost of motor heat, and a higher propensity for cavitation.  The motor provides adequate power for my boat but it tends to heat up if I stay above 5.5 kts for more than a few minutes.  It was a deliberate design decision to pursue efficiency over power and heat, but I have no complaints.  If I ever decide I want to be able to run faster than 5 kts I would start by adding some cells to make my battery 72V instead of 48.  That would provide more power with less heat generating current.  But then I'd be over the 48V nominal where additional electrical safety issues present themselves along with additional USCG requirements.  If you have the Motenergy 1115 from TSM like I do, it is actually rated 12kW.  Not sure why TSM doesn't advertise it as such.  A 20kw motor would suck down more power but could do more work without overheating.  But, it would be heavier, more expensive, require higher voltage, and would probably move you into an AC motor rather than the BLDC you probably have.  It's a different animal with it's own strengths and weaknesses, and probably way more of everything than you really want.

Darin

Darin

On Wed, Jul 3, 2019, 2:18 PM Jeff LaCoursiere jeff@jeff.net [electricboats] <electricboats@yahoogroups.com> wrote:
 


I'm curious what motor/reduction you are using, and if that should even make a difference.  I suspect your boat, like mine, is on the edge of 10KW versus 20KW.  If these numbers are with a 10KW motor, would we expect them to be significantly different with a 20KW motor?  Perhaps only at the top end?

Cheers,

j

On 7/2/19 8:14 AM, armyofpenguins@gmail.com [electricboats] wrote:
 
I completed my conversion a couple of months back and am loving it.  It's time to start sharing what I've learned.  ;)  

I've collected data during a couple of outings under relatively calm conditions (65F, 5-10 kt winds), and I used excel to generate a trend line and a formula (using a power series if you're into math) that provides a pretty reliable estimate of how much speed I can expect for a given amp draw.  This is really easy to do in excel and if anybody needs help I am happy to show how to do it.   Here's the formula (keep in mind the formula would be different for a boat with different characteristics than those in the subject line of this post):

Speed (in kts) = 1.3728 X Draw (amps) ^ 0.2704

Some examples: 

At 20A, my s peed would be about 3.1kts.  
At 40A, my speed would be about 3.7kts.  
At 50A, my speed would be about 4.0 kts..  
And at 100A, my speed would be about 4..8 kts.



__._,_.___
Posted by: D C <armyofpenguins@gmail.com>
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (3)

SPONSORED LINKS
.

__,_._,___
Posted by at No comments:

Re: [Electric Boats] Amp draw vs speed for 37ft sailboat with 10 ft beam, displacement 13,000 lbs

 


I'm curious what motor/reduction you are using, and if that should even make a difference.  I suspect your boat, like mine, is on the edge of 10KW versus 20KW.  If these numbers are with a 10KW motor, would we expect them to be significantly different with a 20KW motor?  Perhaps only at the top end?

Cheers,

j

On 7/2/19 8:14 AM, armyofpenguins@gmail.com [electricboats] wrote:
 
I completed my conversion a couple of months back and am loving it.  It's time to start sharing what I've learned.  ;)  

I've collected data during a couple of outings under relatively calm conditions (65F, 5-10 kt winds), and I used excel to generate a trend line and a formula (using a power series if you're into math) that provides a pretty reliable estimate of how much speed I can expect for a given amp draw.  This is really easy to do in excel and if anybody needs help I am happy to show how to do it.   Here's the formula (keep in mind the formula would be different for a boat with different characteristics than those in the subject line of this post):

Speed (in kts) = 1.3728 X Draw (amps) ^ 0.2704

Some examples: 

At 20A, my s peed would be about 3.1kts.  
At 40A, my speed would be about 3.7kts.  
At 50A, my speed would be about 4.0 kts.  
And at 100A, my speed would be about 4.8 kts.



__._,_.___
Posted by: Jeff LaCoursiere <jeff@jeff.net>
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (2)

SPONSORED LINKS
.

__,_._,___
Posted by at No comments:

Tuesday, July 2, 2019

[Electric Boats] Re: Success! 37ft electric conversion

 

hi lightdoesnotage, 


We would be happy to show you our setup if you want to make a short trip down to Anacortes.  I don't have any vibration that concerns me at 60 amps now, but I did when I first took it out.  Turned out the belt was slipping.  After tightening the belt the vibration went away.  Motor mounts, cutlass, and prop damage all come to mind as possibilities to check.  

__._,_.___
Posted by: armyofpenguins@gmail.com
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (13)

SPONSORED LINKS
.

__,_._,___
Posted by at No comments:

[Electric Boats] Amp draw vs speed for 37ft sailboat with 10 ft beam, displacement 13,000 lbs

 

I completed my conversion a couple of months back and am loving it.  It's time to start sharing what I've learned.  ;)  

I've collected data during a couple of outings under relatively calm conditions (65F, 5-10 kt winds), and I used excel to generate a trend line and a formula (using a power series if you're into math) that provides a pretty reliable estimate of how much speed I can expect for a given amp draw.  This is really easy to do in excel and if anybody needs help I am happy to show how to do it.   Here's the formula (keep in mind the formula would be different for a boat with different characteristics than those in the subject line of this post):

Speed (in kts) = 1.3728 X Draw (amps) ^ 0.2704

Some examples: 

At 20A, my speed would be about 3.1kts.  
At 40A, my speed would be about 3.7kts.  
At 50A, my speed would be about 4.0 kts.  
And at 100A, my speed would be about 4.8 kts.


__._,_.___
Posted by: armyofpenguins@gmail.com
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (1)

SPONSORED LINKS
.

__,_._,___
Posted by at No comments:
Subscribe to: Posts (Atom)