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Old 08-01-2022, 12:31   #31
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Re: Alternators need engine revs to work

What youíre describing is exactly how I plan to setup my charging system. The plan is to configure my external regulator to only minimally excite the alternator below around 1000rpm, just enough to get the tach signal, and then start ramping up the power after that.

This is mostly a consequence of having a relatively big alternator (80A) on a small engine (Yanmar 1GM10). I donít want the big alternator dragging on the motor when Iím putt-putting into an anchorage and/or my slip.

The other reason, though, that itís important is due to alternator cooling. At low speeds, the centrifugal fan on your alternator isnít going to be all that effective. Higher RPMs move a lot more air, which keeps your alternator cooler.
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Old 08-01-2022, 15:51   #32
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Re: Alternators need engine revs to work

Ross Yacht could not install an 80-100 amp alternator on my Yanmar 10.
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Old 08-01-2022, 16:12   #33
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Re: Alternators need engine revs to work

Quote:
Originally Posted by more View Post
magnet rpm sensor on engine flywheel
Thanks, I will look for that.

Al, S/V Finlandia
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Old 08-01-2022, 16:18   #34
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Re: Alternators need engine revs to work

f you want an independent tach I use "Tiny Tach'. A transducer clamps around an injector line for imput and add 12 volts. About $100.
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Old 08-01-2022, 17:09   #35
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Re: Alternators need engine revs to work

Quote:
Originally Posted by hjohnson View Post
What youíre describing is exactly how I plan to setup my charging system. The plan is to configure my external regulator to only minimally excite the alternator below around 1000rpm, just enough to get the tach signal, and then start ramping up the power after that.

This is mostly a consequence of having a relatively big alternator (80A) on a small engine (Yanmar 1GM10). I donít want the big alternator dragging on the motor when Iím putt-putting into an anchorage and/or my slip.
.......
Unless it has been modified, the 1GM10 takes it's tach signal from a magnetic flywheel sensor not the alternator.
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Old 08-01-2022, 19:50   #36
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Re: Alternators need engine revs to work

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Originally Posted by Scaramanga F25 View Post
Ross Yacht could not install an 80-100 amp alternator on my Yanmar 10.
What was the reason?

From what Iíve seen, deliberate/dynamic derating of the alternator based on engine RPM and/or user control (both achievable on the Wakespeed regulator and maybe the balmar) should deal with most of the lugging issues, especially at idle and low speed.
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Old 08-01-2022, 19:55   #37
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Re: Alternators need engine revs to work

GordMay, the links to the pdf's gives me a "danger to download" code.
Anyone else have had this problem ?

OP, have this problem always existed, since you've got the boat ?
What is the idle speed in the manual ?
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Old 08-01-2022, 22:19   #38
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Re: Alternators need engine revs to work

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Originally Posted by carstendenmark View Post
GordMay, the links to the pdf's gives me a "danger to download" code.
Anyone else have had this problem ?

......
No, but I do get an advisory that the site is "not secure" so I guessing it is 'http' and not a 'https'.

More info here https://www.venafi.com/blog/what-are...n-http-https-0
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Old 14-01-2022, 02:39   #39
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Re: Alternators need engine revs to work

Itís normal I just replaced my alternators with bellmarís . They only kick in between 1600 - 2400 rpm
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Old 14-01-2022, 08:16   #40
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Re: Alternators need engine revs to work

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Itís normal I just replaced my alternators with bellmarís . They only kick in between 1600 - 2400 rpm
That is interesting, seeing how my old Perkins 4.236 diesel tops out at 2200 RPM and I only normally run it at around 1500 RPM.

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Old 14-01-2022, 13:28   #41
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Re: Alternators need engine revs to work

Quote:
Originally Posted by Sandy W View Post
Itís normal I just replaced my alternators with bellmarís . They only kick in between 1600 - 2400 rpm
Engine rpm or alternator rpm
Quote:
Originally Posted by svfinlandia View Post
That is interesting, seeing how my old Perkins 4.236 diesel tops out at 2200 RPM and I only normally run it at around 1500 RPM.

Al, S/V Finlandia
The alternator / engine pulley ratio has a huge effect on when the alternator will 'kick in'.
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