Our 2005 Hunter 44 was ordered with a Xantrex-Link 2000R battery monitor, a Link smart voltage regulator, and 120 amp Balmar alternator. The Yanmar engine tach gets its reading from the alternator. I also have solar cells on the boat, so the batteries are often nearly fully charged. When the alternator current drops below about 15 amps the tach reading becomes erratic. When the current drops below about 10 amps the tach reads zero. We can force a reading by creating a current load, such as by turning on all the cabin lights, the TV, etc, but this is a poor solution. Our dealer has been working the problem with Hunter, Xantrex, and Yanmar, but none of the manufacturers has taken responsibility for a solution. Working side-by-by with one of the dealer’s techs, and using an oscilloscope I think we have zeroed in on the cause of the problem. The un-rectified signal from the alternator drops to about 3V p-p ac when the battery reaches full charge (This is as it should be since the smart regulator is reducing the current to the field coils in the alternator). However, 3V p-p ac appears to be too small a signal to drive the tach. We know enough electronics to build an op amp circuit to goose up this signal to 12v p-p if this is what is required, but we don’t have the specs on the tach, and we would rather not build custom circuits. Has anyone else seen a similar problem with their tach and does anyone know what voltage levels and what currents are required to drive the tach circuit? Maybe our tach supplied by Yanmar is defective. Any insights would be appreciated.
tachometer troubles with smart alternator regulator
- Thread starter Larry Jackel
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Most high output alternators use...
Most hight output alternators use smaller pulleys than the stock alternator.
Most hight output alternators use smaller pulleys than the stock alternator.
On our H41, 2005
Larry, since you are getting little in the way of an answer in the forum, this is purely FWIW as something somewhat similar that IS working: For our H41, 2005 (yanmar 4jh4e), we ordered the optional Balmar alternator at the time of build at the Hunter factory. They installed it with a Balmar ARS-4 regulator. We had the dealer install a Link 2000 Inverter/Charge control (not the R model). The tachometer has always worked fine in this install (there is the predicted 90 second delay at every startup, and, it needed to be calibrated when we got it).
Larry, since you are getting little in the way of an answer in the forum, this is purely FWIW as something somewhat similar that IS working: For our H41, 2005 (yanmar 4jh4e), we ordered the optional Balmar alternator at the time of build at the Hunter factory. They installed it with a Balmar ARS-4 regulator. We had the dealer install a Link 2000 Inverter/Charge control (not the R model). The tachometer has always worked fine in this install (there is the predicted 90 second delay at every startup, and, it needed to be calibrated when we got it).
Problem solved
Our dealer, Kevin McGettigan at Sandy Hook Yacht Sales, made numerous phone calls and finally tracked down a technician at Mack Boring who confirmed that my engine could be retro-fitted with a magnetic flywheel-based pickup for the tack. Kevin drove up to Mack Boring yesterday, got the part, and had it installed today. Now the tach reads correctly and is independent of all the fancy alternator circuitry. The interactions between the smart regular and tach were complex. I am not surprised that it took a while to understand why the system wasn't working and to realize that giving up on the alternator-based pickup was the right decision. This whole episode shows the value of having a dealer who is committed to the customer and who persists in exploring all leads until a solution is found.
Our dealer, Kevin McGettigan at Sandy Hook Yacht Sales, made numerous phone calls and finally tracked down a technician at Mack Boring who confirmed that my engine could be retro-fitted with a magnetic flywheel-based pickup for the tack. Kevin drove up to Mack Boring yesterday, got the part, and had it installed today. Now the tach reads correctly and is independent of all the fancy alternator circuitry. The interactions between the smart regular and tach were complex. I am not surprised that it took a while to understand why the system wasn't working and to realize that giving up on the alternator-based pickup was the right decision. This whole episode shows the value of having a dealer who is committed to the customer and who persists in exploring all leads until a solution is found.
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