Electronics Wiz Required. Autopilot

[nick8489]

My low battery alarm on a ST4000 + Raymarine auto pilot continually comes on when the motor is running. I have concluded that it is actually over voltage that is the problem.
Is there an electronic wiz out there who can draw me a circuit to fit a Low Dropout Positive Regulator into the circuit to keep the voltage down to 12 volts. I have a National Semi co doctor LM 1085 3 amp device which re salesman told me will do the job but have no connection diagram.

 

[woodster]

see if this helps

http://www.farnell.com/datasheets/1771457.pdf

 

[dparilla]

What alternator are you running?

 

[Maine Sail]

My low battery alarm on a ST4000 + Raymarine auto pilot continually comes on when the motor is running. I have concluded that it is actually over voltage that is the problem.
Is there an electronic wiz out there who can draw me a circuit to fit a Low Dropout Positive Regulator into the circuit to keep the voltage down to 12 volts. I have a National Semi co doctor LM 1085 3 amp device which re salesman told me will do the job but have no connection diagram.

This was a pretty well known failure mode of the ST4000+ series. It is an internal problem and Raymarine no longer services not can repair these heads..

As long as the head is seeing a measured 10V to 15V it is well within its operational range. If you are getting the low bat alarm within this voltage range it is a head failure...

 

[nick8489]

What alternator are you running?

just the standard yanmar 60 amp

 

[nick8489]

Thanks

 

[Ken Cross]

make sure you check the voltage at the head while it's operating. Corroded connections could be the culprit.
Ken

 

[Lee Hadjiosif]

Did you put a voltmeter behind the A/P display and the A/P motor to see what voltage they are seeing? Also measure the alternator output when the engine is running. If you really have an over voltage situation, you should be looking at the alternator and it's regulator. It should be putting out about 13.8V. Good luck.