How do you add in a voltage regulator?

[pman7]

I'd like to try adding one into my 71 Merc500 because I've got the common high voltage problem at WOT.

From under the flywheel comes the two yellow wires carrying AC current that connect to the rectifier. From the otherside of the rectifier flows one red wire with DC current.

First question, what's with the two yellow wires coming from the stator? Are they positive and negative? Are there two wires because it's an AC current which maybe can't use the frame for the negative because the frame is DC negative?

Where do I put the voltage regulator, between the rectifier and stator or on the DC side of the rectifier? Does it regulate the AC current between the stator and rectifier or does it regulate only the DC current on the DC side of the rectifier?

If on the AC side of the rectifier do I need a voltage regulator to hook onto both yellow wires before the hook into the rectifier or does the regulator only hook inline with one of the wires?


And does the regulator I buy need to match the amps my stator is suppose to create. My Merc manual says my stator should produce 6 to 9 amps. Should the regulator I buy be rated somewhere between those amp numbers or should it be rated at least a bit higher?

If the regulator itself will solve my problem I'd like to go that route rather than the $100+ for the combo reg/rectifier. It would more than cut the cost in half.

 

[Chris1956]

Re: How do you add in a voltage regulator?

Pman, From what I understand the stator on your motor only puts out about 6 Amps (72 watts) at 3/4 of max RPMs. Usually the battery has no problem absorbing this.

To answer your question, the cheapest device to install would be a voltage cut out, which would ground if the voltage went above a certain level, say 15 V. The easeist and cheapest way to do this is to get a zener diode rated at 15V, and connect it from the +12V to ground.

Unless you have a real problem with the unregulated system, why not leave it alone, or put a constant load (boombox or lights) on it.

 

[j_martin]

Re: How do you add in a voltage regulator?

Chris1956,
Where you gonna get a 100W 15V zener diode?

It isn't quite that simple, but there are some regulators available.

You could substitute one of the rectifier/regulators made for 16 amp or dual coil 20 amp system. They are just a little bigger, and you'd have to cut and crimp to make them fit, but it would work.

Mercury used to use a shunt type regulator, but they don't sell them any more. For a 6 amp system, a good battery and keep up on the water is probably the best solution.

hope it helps
John

 

[pman7]

Re: How do you add in a voltage regulator?

So neither of you think that the 17 volts will do any harm to my tachomter? My tach is a basic Mercury tach, 6K range, adjustable poles, 3-1/8" diameter. I don't have the item number right now but I don't think there's a lot of difference in most of them.

I've kept an eye on my battery fluid and my fishfinder is safe according to Garmin (supposedly safe up to 30v) but I'd like to stay safe with my tach also.

I've had multiple answers, anywhere from my battery exploding to everything's fine. But I haven't had anyone comment specifically on any possible danger to my tach.

 

[j_martin]

Re: How do you add in a voltage regulator?

The tach is using some of the ac off the coil side. Anything between about 6 v peak to peak and 100 volts probably will work fine. It doesn't get power there, just looks for a periodic voltage change to trigger a pulse counter circuit.

Having no regulator is tough on the battery. If you can push your battery to 17 V at 16 amps, it's near end of life anyway.

If you want it to behave in a more kosher fashion, buy one of these for 'bout a hundred bucks and splice it in. (replacing the bridge diode.)

hope it helps

 

[ricksrster]

Re: How do you add in a voltage regulator?

Here is a link to what J_martin is talking about:
http://www.iboats.com/CDI_Voltage_R...86221638--list_time.1179420159--view_id.47455