F100 charging

[almetelo]

Hi!

A few months ago I posted a thread about remove a flywheel on my F100 because of a charging issue.

Last year when removed this boat/motor for winterize a couple of weeks before motor started a charging issue and what happen was that the charging as “really slow” if I can say so…

When started the motor the voltage didn´t raised and just raised max up to 13.6v or 13.8v and a few minuts later at least at 3500 rpm’s, when before quickly raised to 14.6v on idle or with a little throttle.

I had some rust on the stator and cleaned but the problem persisted.

I had a spare (used) R/R so I ground it, swapped leads and immediately voltage raised to 14.4v (or so) and all seemed to be OK but on the 1st or 2nd hours of this season had the same problem…

I’m using a auto 80Ah lead battery with 1 or 2 years old (can´t remember exactely) so I did a test using other auto lead battery 75Ah (used) and the motor was charging just fine.

The voltage quickly raised and at 3500rpm´s (+/- my cruising rev’s) was charging up to 15.2V (I’ve never seen such a high voltage on my 2 previous batteries when max voltage was 14.6v or 14.8v

Such a high voltage can be a problem?

When tested the voltage using other battery used a multimeter to check gauge was reading fine and is OK.

When swapped R/R’s I didn´t tested them but now after testing using other battery I tested the previous R/R by this vídeo and seems to be faulty

https://www.youtube.com/watch?v=F8EjV0IjW9Q

(used a MM Blue-Point DMSC683MP)

but if this last R/R that developed the same issue like the previous one should also be faulty (maybe isn´t) because is charging OK with this last battery.
I guess I need to change the battery but B4 test R/R by SM.

Someone experienced something like this?

Suggestions, comments are welcome!

Thanks!

[boscoe99]

Hello Almetelo,

15.2 volts is not abnormal at all for an F100. Maybe Yamaha uses different suppliers for their R/R's so the output voltages are not the same from maker to maker. So little current is being produced that it won't be a problem.

[almetelo]

Hi Boscoe!

Nice to “hear” you…

So such high current is not a problem and since the battery keep charged even with that low charging voltage is OK?

I’ve been concerned because I never seen this before since I have this motor.

I may also have the battery tested to find out why on one battery is charged with low voltage and the other with “normal” high voltage.

[boscoe99]

Within the limits of the lighting coil a higher voltage should provide a higher current which will recharge a battery faster.

13.6 volts seems low but if a battery is depleted you may see this voltage value until the battery gets close to being charged. What is happening is the current demand of the battery exceeds what the generator can provide. Once the battery is close to being fully charged the voltage will rise.

Most Yam regulators will output 14.5 volts to a fully charged battery. Some run at 15/16 volts however.

If the battery is not charged or if the battery is defective all bets are off.

[almetelo]

Thanks Boscoe!