re voltage

[yam50fet]

I have a yamaha f50fet that charges at 14.82-14.92volts.too high for all but calcium batteries
Have tried lead acid and agm batteries in good condition but the voltage doesn't shift
My question is what should the voltage be,what does the regulator rectifier look like,and is there a cheap way out of it i.e.like fit an external regulator to bring it down

[boscoe99]

Why do you think the voltage is too high?

Yamaha often states minimum output specifications. Rarely (if ever) do they provide a maximum voltage output. Some model output 15.5 volts.

An F50 is producing so little current, for such a low period of time, that I don't see any problem with your motor being connected to any type of lead acid battery. AGM being one type of lead acid battery for instance if you want to go that route.

Other than seeing what you believe to be higher than normal charge output voltage are you having any operational problems?

[RetiredGuy]

I too believe Yamaha outboard Rectifier/Regulators produce excessive voltage

Even a few amps at 15 volts for almost any period of time harms sealed aka AGM Lead Acid batteries. Take a look at the battery manufacturers charging specifications NONE recommend a constant 15 Volts. From what I have seen/experienced the charging system is the weakest link of the entire motor.
Replaced my 2010 F90 TLR rectifier/regulator under warranty which was producing a constant 15.2Volts (WAY To HIGH) - the replacement had a pigtail as compared to an integrated connector - Have to guess Yamaha finds it less expensive to replace the rectifier/regulator when not IF it burns up rather than the entire wiring harness. Sure would like to see a proper designed multistage charging systems using the ECM - but NOT holding my breath.

[boscoe99]

Why are we not hearing more about Yamaha's damaging AGM lead acid batteries?

I can't recall hearing anything at all about this?

[rodbolt17]

but Yamaha SPECIFIACLLY states NOT to use GEL or ABM batteries for that motor.
use only lead/acid.
at least for the US market stuff.

[boscoe99]

but Yamaha SPECIFIACLLY states NOT to use GEL or ABM batteries for that motor.
use only lead/acid.
at least for the US market stuff.

That is what they SPECIFICALLY stated about all of the motors for years and years.

For years and years Yamaha said not only no but hell no to the use of AGM batteries with their motors. Even though many were using them very successfully.

All of a sudden Yamaha said that the use of AGM batteries is perfectly fine. Only problem is they said it is only for certain models.

If they were so wrong in the past for so many years about certain models, might they still be wrong today about certain other models?

But having said all of this, you are wrong. Better get up to speed on Yamaha stuff. Get out of the shop and read some bulletins. Yamaha approves the use of Gell Cell and AGM batteries with all of their four stroke models.

[yam50fet]

re voltage

I have a yamaha f50fet that charges at 14.82-14.92volts.too high for all but calcium batteries
Have tried lead acid and agm batteries in good condition but the voltage doesn't shift
My question is what should the voltage be,what does the regulator rectifier look like,and is there a cheap way out of it i.e.like fit an external regulator to bring it down

Actually have two optima 66ah agms one starter one house (solar)separate systems so over time I can compare them.Local yamaha man said 8amps on my 50 fet but manual(owners) said 17.Agms ,according to all literature should charge max 14.7 but so far no operational problems.I suppose they get warm if overcharged.Anyway thanks to all,I feel a bit more reassured.

[boscoe99]

A carbureted F50 is shown as having an electrical output of 10 amps.

An EFI F50 is shown as having an electrical output of 17 amps.

Keep in mind that the motor needs electrical current to operate itself. What is left over is available to charge a battery. In the case of an EFI F50 the net output is 8.5 amps.

Once your battery is fully charged I suspect that you won't see more than two or three amps flowing to it.

Here is a Yamaha chart that depicts battery specifications for your motor. Note that the output voltage is shown as 15.0 .

Your RC is a bit on the low side but I would not worry one iota about this. A battery having an RC of 66 amps can operate your motor for about five hours time if the charging system fails. Plenty long enough to get back to port. Also, you have a second battery installed that can be used as a backup if needed. I hope.

[boscoe99]

More on charging an AGM lead acid battery. This is from Optima's website. They apparently have nil concern if one of their batteries is charged at 15.0 volts.

Support - Battery Care - Charging | OPTIMABATTERIES

[rodbolt17]

glad your the SPURT on this.
Optima is the ONLY batteries I have ever seen light on fire or melt the sides out with a Yamaha outboard.
however I don't read tech bullitens nor do I actually work in the field, I am the ex I guess.
I will bow to the spurt.

[RetiredGuy]

2nd that on Optima regarding - Fires / Short life / Expensive
The one battery I would Never use

[boscoe99]

glad your the SPURT on this.
Optima is the ONLY batteries I have ever seen light on fire or melt the sides out with a Yamaha outboard.
however I don't read tech bullitens nor do I actually work in the field, I am the ex I guess.
I will bow to the spurt.

No spurt here.

I only know what has worked for me personally.

I only know what many Yamaha owners have said works well for them.

I only know that Yamaha says it is OK to use AGM batteries.

If someone/anyone has a concern they are certainly free to use a flooded lead acid battery of their choice. They are also free to implement an additional voltage regulator to try and drive the output voltage down. This is not aviation where stuff is mandated by law.

[RetiredGuy]

Check out "Battery University" web site
Lots of good real world experience
Absorbent Glass Mat (AGM) Battery Information - Battery University

As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive. See Charging Lead Acid.

[bajakeith]

batts

As a Master marine Tech and marine electrican..The most electrical problems I see day in and day out are deep clycle batts on outboards..NO,,NO,,NOT good and don't ever,ever use a OpTIMO !!!! replaceing a stator on a oxxy 250 Thursday from being run on a deep clycle batt ..I have a lot of CDI test tools and talk to "Clark" the service tech guy on a regular basis about electrical systems and we both agree that this is the biggest outboard miss conception there is !!! read your owners manual and or the service book !! and please don't reply with a reply about billy bob said it was fine to run a D.C. batt.....FACT...Btw CDI electronics..makes all the replacement electrical (& upgrades) for outboards...so, ya think they might know what were talking about....DUH !!!

[boscoe99]

As a Master marine Tech and marine electrican..The most electrical problems I see day in and day out are deep clycle batts on outboards..NO,,NO,,NOT good and don't ever,ever use a OpTIMO !!!! replaceing a stator on a oxxy 250 Thursday from being run on a deep clycle batt ..I have a lot of CDI test tools and talk to "Clark" the service tech guy on a regular basis about electrical systems and we both agree that this is the biggest outboard miss conception there is !!! read your owners manual and or the service book !! and please don't reply with a reply about billy bob said it was fine to run a D.C. batt.....FACT...Btw CDI electronics..makes all the replacement electrical (& upgrades) for outboards...so, ya think they might know what were talking about....DUH !!!

Well, I know for a fact that my Mercury 175 EFI and my Yamaha F200 both ran just fine using maintenance free deep cycle batteries. Voltage output and current flow to the deep cycles was identical to the voltage output and current flow for flooded lead acid starting batteries.

Yamaha USA now approves the use of maintenance free and AGM batteries on all of their four stroke and HPDI models. They don't specifically address charging type versus deep cycle type versus dual purpose types. All they list for requirements are CCA/MCA/RC specifications with only two of the three needing to be met.

So, if a deep cycle Optima AGM meets the requirements for let's say an Offshore F300 (770CCA/160 minutes RC) then according to Yamaha you are good to go.

Who are folks to believe. A Yamaha Master Tech on the internet or Yamaha USA themselves?