'84 johnson 90hp - regulated rectifier needed?

[Thirsty Endgrain]

It's sure is always something. I still haven't gotten the boat wet yet, as I sally forth into the realms of all things fiberglass, wood, electrical, mechanical, etc.

Anyway I just fired it up to check that the tach wiring was all Gravy, and noticed that as I increased rpm's the voltage would steadily increase to over 16V. From some research it seems like i need to get myself a CDI regulated rectifier. 16V is obviously way overvolted for electronics and battery longevity, even if the amperage is low (how many amps do these stators put out?).

So is one of those in my future?

https://www.iboats.com/shop/regulated-rectifier-johnson-evinrude-2-3-4-6-cyl.html

 

[F_R]

Sure, if the voltage bothers you. Truth is, though, that there are thousands of rigs out there running at 16V. Including mine. But I don't have any fancy electronics, either.

 

[Thirsty Endgrain]

I only have a fishfinder, and the vhf. Don't know which if either qualify as fancy. Just used to working with 12V systems that don't go above about 14.5ish volts. The only thing I wanna fry is fish.

Also wondering I'd there is any acceptable method of adding in say, an automotive regulator in line?

 

[Vic.S]

It's sure is always something. I still haven't gotten the boat wet yet, as I sally forth into the realms of all things fiberglass, wood, electrical, mechanical, etc.

Anyway I just fired it up to check that the tach wiring was all Gravy, and noticed that as I increased rpm's the voltage would steadily increase to over 16V. From some research it seems like i need to get myself a CDI regulated rectifier. 16V is obviously way overvolted for electronics and battery longevity, even if the amperage is low (how many amps do these stators put out?).

So is one of those in my future?

https://www.iboats.com/shop/regulate...3-4-6-cyl.html

Models without power tilt and trim have a 6 amp stator and a round non regulated rectifier
Models with power T&T have a 10amp stator and a water cooled rectifier/regulator

I only have a fishfinder, and the vhf. Don't know which if either qualify as fancy. Just used to working with 12V systems that don't go above about 14.5ish volts. The only thing I wanna fry is fish.

Also wondering I'd there is any acceptable method of adding in say, an automotive regulator in line?

Regulators for automotive alternators work differently, regulating the field current in order to control the output voltage

 

[Thirsty Endgrain]

Thanks for that info Vic.S.

So sounds like it's up to me, but with having a fishfinder and wanting the most out of a $350 AGM battery I think I'm gonna get one. I'm sure there are many running around without them, but I won't be taking my chances of electronics crapping out on me in the middle of the water somewhere. Thanks everyone.

 

[Crosbyman]

4 amps should be ok for the fish finder and vhf.... if not just put 2 in parallel for 8 amps

but... install diodes to insulate one unit's 12v output from the other this will prevent any cross feed between units

fuse each 12volt outputs ....since manuf says not to overdraw the current

https://www.amazon.ca/EKYLIN-Stabili...5596504&sr=8-3

 

[Thirsty Endgrain]

4 amps should be ok for the fish finder and vhf.... if not just put 2 in parallel for 8 amps

but... install diodes to insulate one unit's 12v output from the other this will prevent any cross feed between units

fuse each 12volt outputs ....since manuf says not to overdraw the current

https://www.amazon.ca/EKYLIN-Stabili...5596504&sr=8-3

I'm a bit confused by your comments, any chance you could clarify? I'm not concerned with amperage, but overvoltage to sensitive electronics can be fatal.

I guess you're referencing the regulator you linked?

Since that's a Canadian page and I'm not sure the same thing is available here, are you suggesting using something like a buck-boost converter on each sensitive device? And what do you mean by installing diodes to isolate each unit's output? How would I do that? I'm not too familiar with electrical design in that way.

The other thing I'm trying to avoid is supplying too much voltage to the AGM battery. I wouldn't be able to use anything like those units in series with the battery connection...

 

[Vic.S]

I'm a bit confused by your comments, any chance you could clarify? I'm not concerned with amperage, but overvoltage to sensitive electronics can be fatal.

.

MY experience with an unregulated rectifier and " sensitive electronics" is that its OK provided you have the battery connected because the voltage then wont rise above what the electronics can handle.

I once made the mistake of forgetting to connect the battery , left the mooring in a bit of a hurry to catch the tide and as a result fried the electronics in my autopilot

An AGM battery may not be the wisest choice ... at least with an open FLA battery you can top the electrolyte up if/when necessary

 

[F_R]

Just an opinion; shame on anybody making marine electronics that can't stand the unregulated voltages supplied by so many outboards.

 

[Thirsty Endgrain]

MY experience with an unregulated rectifier and " sensitive electronics" is that its OK provided you have the battery connected because the voltage then wont rise above what the electronics can handle.

I once made the mistake of forgetting to connect the battery , left the mooring in a bit of a hurry to catch the tide and as a result fried the electronics in my autopilot

An AGM battery may not be the wisest choice ... at least with an open FLA battery you can top the electrolyte up if/when necessary

I suppose l may just run things for a while and see how it goes. Or I may just install a little buck-boost converter - since they're fairly cheap - in series with the fishfinder. It's 8 or so years old and came with the boat. If it takes a crap it's not the biggest obituary to have to pen. I already have the 105ah AGM from taking it out of my van to replace it with a LiFePO4 battery, so using it in the boat seemed logical. I also have 2 6v FLA batteries in series for a total of 220ah at 12V that I could use, so I have battery options.

I chose to mount the batteries in the cabin under the seats, which I know is not ideal for voltage drop over the 12' or so run from the engine, and some day I'll test for voltage drop at the starter contacts under load (or check resistance), and up the cable size if necessary. But again here I'm using what came with the engine. So, since the batteries are up near the bow I thought using the sealed AGM would be better than bouncing an FLA battery around up front and having more spillage potential. Of course they'd be in battery boxes, yet still.

Just an opinion; shame on anybody making marine electronics that can't stand the unregulated voltages supplied by so many outboards.

Agreed.

 

[Thirsty Endgrain]

Models without power tilt and trim have a 6 amp stator and a round non regulated rectifier
Models with power T&T have a 10amp stator and a water cooled rectifier/regulator

Strangely, I have T&T but I don't think I have a regulated rectifier. I think someone added the T&T at some point in the engine's life because it also didn't have the relay box in the normal spot mounted on the engine. Putting the pieces together here, like usual. I don't know what the water cooled one looks like, but I don't see anything that looks like a water connection in the one that I do have. And then there's the fact that my voltage meter was reading over 16V...

 

[Vic.S]

Strangely, I have T&T but I don't think I have a regulated rectifier. I think someone added the T&T at some point in the engine's life because it also didn't have the relay box in the normal spot mounted on the engine. Putting the pieces together here, like usual. I don't know what the water cooled one looks like, but I don't see anything that looks like a water connection in the one that I do have. And then there's the fact that my voltage meter was reading over 16V...

The water cooled rectifier/ regulator fits on the top of the cylinder block where I think I can see a lifting eye a lifting eye and cover plate

You can see what it looks like if you look at the parts diagrams on this site

The round non-regulated rectifier is clearly visible bang in the middle of your photo

 

[Crosbyman]

sorry... back from cottage...

amazon pages ?? you should be able to use .com and find similar at US prices

diode are just one way valves ... putting them in series allows one way current flow and no returns from other sources

that way the individual devices ( regulated feeds) are protected