Solar and No Tach Readings

[MaineCapeSailor]

I am finding that with solar panels keeping my batteries fully charged, the alternator's external regulator shuts down the alternator so that it no longer generates the signal that my tach needs to receive in order to provide an RPM reading.

I believe that there are some workarounds to generate a signal, one from Tiny Tach and another from Auto Meter.

Does anyone have experience with a fix for this problem?

 

[gabriel]

The tiny tack will only work on gasoline engines as it works by receiving signal from a conductive wire wrapped around a spark plug wire. If you do have gas then yes, the tiny tech works pretty well, I own two of them. Buy a generic one on Amazon they are the same exact thing for 1/3:

Tach on Amazon

 

[Elgyn]

You can try setting your solar charge controller(s) to a slightly lower voltage than your alternators output (Eg, solar 13.8-14v and alt 14.4v). Might take a little longer to get up to absorbtion charge but your alternator should output

 

[MaineCapeSailor]

Today I tried the Tiny Tach for diesel which has a transducer that clamps on the injector high pressure fuel line and a Pizo amplifier. Still no reading on my tach.

The vendor warned me that it puts out a square wave signal, not a sine wave, so it might not work. His concern was on the mark.

ihad previously tried lowering the float voltage on my solar controller below that on my alternator’s regulator - did not help.

 

[southofvictor]

What alternator regulator do you have? I‘ve heard that you can set a minimum field voltage that will keep the tach operating even when there’s no charging called for. Does yours have any allowance for that?