Open 12vdc Switch on Yanmar 4JH4-TE

[sypsyche]

Yanmar 4jh4-TE reduces the 12 VDC voltage from the starting switch to the engine to 5 VDC. My battery Smart Regulator asks for: "It must be turned on with a normally open oil pressure switch, ignition relay, or other switch that has no other loads on it to cause a voltage drop or "sag" that produces 12 VDC when engine is running.
I have been advised by a Yanmar dealer not to cut into the harness. How do I connect connect the alternator Smart charger to the Yanmar?
Any one?

[CharlieJ]

Use a relay. 12 VDC from any constant source on the line side of the relay and the regulator fed from the load side of the relay. The trick is going to be finding a 6 VDC operating relay but a little looking thru Digikey, Grainger, JC Whitney, etc. should yield one that will work.

Charlie

[sypsyche]

Thanks for your reply. Could I connect the smart charger sensing wire directly to the ignition switch START/ON (12 VDC) without the use of a relay?

[CharlieJ]

Sure. Just run large enough conductor to minimize voltage drop between the key and the alternator regulator.

Charlie