Evinrude 9.9 alternator open circuit DC voltage ?

cyclops2 · Mar 9, 2012

What are the typical DC voltages with NO battery connected & the motor at WOT ?

F_R · Mar 9, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

Never measured it, but I would think pretty high. Are you wondering because of danger of blowing cheap rectifiers? I don't know of any other reason to be concerned.

Will Bark · Mar 9, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

My owners manual for my 77 15hp evinrude says "do not operate the engine without being connected to a battery, since this will damage the rectifier". Given that I would assume that there would be no voltage to measure.

cyclops2 · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

Thank you Will.
That is what I needed to know. Lost a rectifier to a open battery 1 time. Lost the battery because the motor has no voltage regulator to stop cooking the battery on long WOT trips.
I have a I C chip voltage regulator to hold the battery at a constant 13.60 vdc all the time. Problem is when the battery is fully charged, the Evinrude Regulator will have almost 0 % load on it. That WILL ALLOW the alternator to climb to ...open circuit voltage.... too high. So I will also build a VERY HIGH voltage rectifier to laugh at the alternator WOT voltage & currents.

Thanks Will.
Rich

F_R · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

Ah, you are smarter than the average bear. You know what you are doing.

tx1961whaler · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

What kind of voltage regulator are you planning on using?
Make sure you account for the current rating and power dissipation of the regulator when you're designing this.
This will work:
http://www.mfgsupply.com/snowmobile/snowel/snowregs/01-090.html

steelespike · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

I don't know the charge rate but wouldn't it be easier to just run the lights?
and put the lights through the key switch so you don't leave them on by mistake.

cyclops2 · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

I made 5 of these regulators for mower, emergency generator, 2 Bilge pumps that are used as floor pumps & car batteries in a power failure & the 9.9 hp Evinrude.
The are rated for reversed input polarity & will shutdown it overloaded. I did short circuits & reversed inputs. No problems

F-R. I THINK ??

it is a 4 lead. 2 yellow, grey & yellow ?? I do not remember. Boat is in storage till 1st week of may.

I am RAMY :facepalm:

Hate getting a old brain

F_R · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

I posted the schematic in your other thread. I believe you are right, four wire. The three yellow wires are all alike, electrically. A tachometer is supposed to be connected to the grey striped one, but it really doesn't make any difference. A lot of rectifiers don't even identify one for tach.

cyclops2 · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

Thanks F_R.
I thought it was 2 seperate " lighting coils " under the flywheel, that was on the page. Looked like a old center tapped full wave rectifier setup ??
I think the Maximum amps. was 4 amps at WOT ??

Wet weather in N J has 25 big Cedars fallen over for the Geezer to cut up & give away. I can only do 1 hour a day. Then I eat till sundown in front of the TV watching hockey till 11 PM. Somebody has to do it.

the machinist · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

The info I have been able to run down is that these alternators put out 300 volts AC, then to the rectifier which steps it down to between 13 & 14 volts DC

F_R · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

cyclops2 said:
Thanks F_R.
I thought it was 2 seperate " lighting coils " under the flywheel, that was on the page. Looked like a old center tapped full wave rectifier setup ??
I think the Maximum amps. was 4 amps at WOT ??

Wet weather in N J has 25 big Cedars fallen over for the Geezer to cut up & give away. I can only do 1 hour a day. Then I eat till sundown in front of the TV watching hockey till 11 PM. Somebody has to do it.

Yeah, I guess you are correct on the coils. I had it in my head that they were three coils, Delta fashion. Must have been thinking of something else. Anyhow, the six diode rectifier that I posted is the correct one.

cyclops2 · Mar 10, 2012

Re: Evinrude 9.9 alternator open circuit DC voltage ?

Hi Machinist.
Can you give me the website of the information ?
Rich

Evinrude 9.9 alternator open circuit DC voltage ?

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