Alternators need engine revs to work

[hjohnson]

What you’re 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 don’t want the big alternator dragging on the motor when I’m putt-putting into an anchorage and/or my slip.

The other reason, though, that it’s important is due to alternator cooling. At low speeds, the centrifugal fan on your alternator isn’t going to be all that effective. Higher RPMs move a lot more air, which keeps your alternator cooler.

[Scaramanga F25]

Ross Yacht could not install an 80-100 amp alternator on my Yanmar 10.

[svfinlandia]

Originally Posted by more

magnet rpm sensor on engine flywheel

Thanks, I will look for that.

Al, S/V Finlandia

[cottonsail]

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.

[Wotname]

Originally Posted by hjohnson

What you’re 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 don’t want the big alternator dragging on the motor when I’m 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.

[hjohnson]

Originally Posted by Scaramanga F25

Ross Yacht could not install an 80-100 amp alternator on my Yanmar 10.

What was the reason?

From what I’ve 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.

[carstendenmark]

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 ?

[Wotname]

Originally Posted by carstendenmark

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

[Sandy W]

It’s normal I just replaced my alternators with bellmar’s . They only kick in between 1600 - 2400 rpm

[svfinlandia]

Originally Posted by Sandy W

It’s normal I just replaced my alternators with bellmar’s . 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.

Al, S/V Finlandia

[Wotname]

Originally Posted by Sandy W

It’s normal I just replaced my alternators with bellmar’s . They only kick in between 1600 - 2400 rpm

Engine rpm or alternator rpm

Originally Posted by svfinlandia

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'.