2010 F90 Charging Voltage

[RetiredGuy]

Hi

Today I noticed my 2010 F90TLR engine charging the battery at 15 Volts!!!
I have two volt meters the Yamaha stock one in the dash and one I installed which connects directly to the battery both read very close the same - as in high 14's and as much as 15 Volts after 10 minutes of 4K rpm from the engine

What is the normal range for the alternator voltage?
Is there a way I can reduce the voltage to say a fixed 14.4?

Thanks for the info

[rodbolt17]

14.8 should be about the max.
its also why sealed batteries are strictly a no no and checking battery electrolyte level and cable condition is nessasary.

[RetiredGuy]

Rodbolt - thanks for the comment

Where is the voltage regulated - The ECM?
Is it software con*****ed or hardware?
What about adding a high current (100amp) diode in series with the alternator to drop 0.6V?
There has to be a way to reduce the max voltage to no more than 14.4 Volts
14.8 for long tiime durations is NOT a good thing

Why did Yamaha design there charging circuit with such excessive Voltage?
Do they understand multistage battery charging?
14.8 volts for hours on end will destroy many batteries, as you stated an AGM or other sealed battery will die an early death due to this poor design.

A simple multi stage timed circuit that does something close to the following, would be GREATLY preferred
14.8 volts for a short time duration then drop to 14.2 volts or so then drop again to 13.6 volts for the long term

[RetiredGuy]

Bump - Please I would really like some techincal help

[99yam40]

the rectifier/regulator is what regulates the voltage.
It is attached to the lighting coil wires that come out from under the flywheel

[RetiredGuy]

Thanks
Just wondering what the connections on the schematics showing the ECM connected to the Stator wiring does?

[CatCam]

My F90 runs anywhere from 14.4 - 14.6.....but it usually sits at the 14.4 when I'm running 4,800 - 5,000 rpm.

Question -- are you using wing nuts on your battery? Why I ask is that I FRIED my voltage regulator and CDI (burnt when regulator fried!) because of loose wing nuts on the battery......When this happened My multifunction Speedo was flashing 16.0V!! Smoke and fire shortly after that!! Expensive lesson - over $600 in parts alone!

[rodbolt17]

would you like to pay $17K for a 90 hp?

as it is its a very simple 3 phase stator,the flywheel is called the rotor cause it contains the rotating magnetic field.
this feed a 3 phase sine wave A/C voltage to a rectifier/regulator assy.
there it is rectified by a full wave bridge rectifier and fed to the regulator side.
there,what is not used is simply shunted to ground.

automobiles have used this for at least 45 years.
Some autos even had altenators with mechanical regulators.
now I am showing my age.

its also why Yamaha SPECIFICALLY says.
NO AGM,NO maintenance free batteries.
they also want NO wingnuts on the battery posts.

if the cables are loose or defective or the battery is weak or defective the voltage sensing circuits in the regulator get whiggy.

[RetiredGuy]

Catcam

No wing nuts - been using nylock nuts on the posts and they are tight.
Good to see others, not only me have such high voltage. The Troubleshooting section of the official F90 Yamaha Manual clearly states 13.0 Volts as the output of the regulator however it gives no +/- tolerance for this voltage

rodbolt

Showing age... I still have one of those mechanical relay's on an old Chevy of mine. It works great at 14 Volts never any more

Me personally I would not mind spending more money for something a bit better when it comes to the design of the voltage regulation system on these machines. You should easily have enough processing power in the ECM to do a simple PWM control of the voltage regulation with a proper multistage charging function.

How long has Yamaha been saying no wing nuts? My 2008 G3 aka Yamaha boat came from the factory with wing nuts on the bettery posts. The good news was that 2011 G3 with the high voltage issue had nylock nuts from the factory.

I see on the schematic the stator connected directly to the ECM am I missing something?

[CatCam]

Hey - just finished a run this morning using my brother's boat that has a 2010 F115 and his voltage read 14.4V - 14.8V, battery is about 3 months old but his boat hadn't been run for the last 3 months....
SO I guess this is about normal for the animals.

BTW - The jokers who rig up boats are not the sharpest tools in the box. They'll do the quickest, easiest way to get the boat out the door.....too many shortcuts, I could spend 3 days rigging a boat correctly so you won't have problems doen the road, but that is not their philosophy.

[RetiredGuy]

Thanks
That voltage is closer to what I had expected to see on mine
Did a bit more research and found that Yamaha says up to 16 Volts is "Normal". Not sure they understand sensitive electronics as in my Hummingbird and other electronics that get really upset and sometimes die and early death if the voltage is greater than 15.4 volts.

Currently in process of modifing mine for the desired voltage (35 years as an electronics engineer - translates to I have to do something about it myself). The first thing to be modified are the damn seats supplied with my latest G3 boat the back is exactly 90 degrees and I MUCH prefer to lean back at least 5 to 8 degrees. Always something to do around this place

PS - I agree 100% about the riggers - it took me all winter (heated large shop with a great stereo so no issue) to rewire the new boat - Hard to understand what they were thinking when they rigged this one

[rodbolt17]

14.4-14.8 is about right.
its also where 90% of automobiles and sterndrive run the charging system voltage.

anything over 15V is a problem that needs to be addressed.
typically its going to be incorrect/defective battery or cables.
next a regulator issue.

years ago,when working on some older systems that typically saw extended high speed runs with non regulated systems we would have to shift all electronics to a regulated buss feed from the battery.

so could yamaha make an ECU con*****ed charging system?
Could yamaha plasma or ceramic coat all internal water passages?
Could yamaha use more 1700 series stainless?Monel?
yes they could.
however,by then the 9200 dollar 90 HP would cost about 17,000 and the competitors 90 hp would still be old school and less than 9500.

and thats why you see more 4dr fords on the road than 4dr porsches.
both vehicles will get you safly from point A to point B and back.
Both vehicles do a decent job.
not all consumers can afford the initial and subsequent costs of the Porsche.

[RetiredGuy]

rodbolt

Thanks for the update - I agree that a fixed 14.4 Volts is about right - too bad it is not a simple mulltistage circuit - Yes 15 Volts is too high

I set my expectations on a BMW and got a Ford instead - live and learn

[rodbolt17]

so far no one makes an ECM con*****ed type regulator. its a cost thing.
if yours is making 15+ volts I would call the yamaha consumer hotline and ask them.
dont take a dealerships word, yes they are franchised by Yamaha for warrenty and repairs to Yamaha products,however the dealership does not have the final word.

if you call the hotline have your engine PID ready and any dealership info you have as far as trying to resolve the issue.
15V on that engine is excessive.
you may have a defective regulator assy.
you may have a poor connection someplace.
its a very simple regulator/rectifier assy.
doesnt need ECM con*****ing.
you send 3 phase A/C to it.
its rectified by a full wave bridge rectifier and sent to the regulator side.
there a series of SCR's feed through a Zener diode regulates voltage.
the rest is simply by the speed of the rotor assy.

[jazzman44]

What a brilliant thread. this is why forums like this one where set up.
some excellent reply's this is why you should always be vigilant and take notice of what your clocks are telling you if not it could be costly