I had the same experience with my 1989 vintage merc/mariner 75. It started with
a new battery. All I could think was that they changed the way they make
batteries. I did notice lights didn't last as long after that and batteries
seemed to "boil off" a little faster but everything else was OK.

I had the same experience with my 1989 vintage merc/mariner 75. It started
with a new battery.
All I could think was that they changed the way they make
batteries.

That is exactly how mine did it. New battery and all the trouble started.
Every time I put the old battery back in it was fine but finally it just died
from old age. It lasted 4 years.

I had that same thought as you but from what I can see, refillable flooded cell
batteries are no different. Outside of adding some LED lighting, nothing on my
boat changed but the battery. I thought the LED's could have been suspect but
I took everything out of the system but the motor and it didnt change.
It almost has to be something with the battery. Right now I'm trying to find
out from an expert if a bigger CCA battery or a smaller CCA battery could make
a difference since it is the regulator in the system.

Thanks for the info.

Clamp it with a Zener Diode somewhere on the 12v output line. All excess
current will bleed off.

-W

Clamp it with a Zener Diode somewhere on the 12v output line. All excess
current will bleed off.

Thanks Clams,

I know I could regulate it easily. You are an old Merc fan and you know how to
fix it so you must have run into this before. What I am looking for is the
reason its doing this now after it ran fine all those years. Everything is
still in spec electrically. I really find this interesting. All the posts on
the web about it and no one can or has answered it yet.

"CCred68046" wrote in message
...
Clamp it with a Zener Diode somewhere on the 12v output line. All excess
current will bleed off.

Thanks Clams,

I know I could regulate it easily. You are an old Merc fan and you know
how to
fix it so you must have run into this before. What I am looking for is
the
reason its doing this now after it ran fine all those years. Everything
is
still in spec electrically. I really find this interesting. All the posts
on
the web about it and no one can or has answered it yet.


The biggest reason that voltage climbs so high on an unregulated system is
that the battery is too small a capacity, and/or is a sealed or "maintenance
free" version. You want a "flooded cell" battery, the largest you can fit
and afford, to run your boat's electrics. Get a group 27 heavy duty battery
and you won't have any problems. A cheaper way of regulating the charging
system is just to use an additional battery in parallel to absorb the extra
charging.

Years back we told customers to run the boat lights all the time and have
the dash lights wired into the key switch so they were always on. That also
cut down on the condensation inside the gauge faces.

Bill Grannis
service manager

The biggest reason that voltage climbs so high on an unregulated system is
that the battery is too small a capacity, and/or is a sealed or "maintenance
free" version. You want a "flooded cell" battery, the largest you can fit
and afford, to run your boat's electrics. Get a group 27 heavy duty battery
and you won't have any problems. A cheaper way of regulating the charging
system is just to use an additional battery in parallel to absorb the extra
charging.

Hey, good to see your still in the group Bill!
I have tried several batteries... I'm currently running a group 27 1000cca. I
have tried 3 BIG non maintenance free batteries. Everyone of them did the
same thing. The factory service manual calls for a minimun of 360 CCA. It
seems like Im not running them down enough to give the charging system
something to do. I just bought a 420 CCA to try that because a few of the guys
in the electricial engineering group said the bigger battery has MORE
resistance to charging once its full and is adding to the problem.
I gave up on electrical "experts", they cant agree on this at all. I'll trust
your experience on this. Money is not the problem. If you know of a specific
brand and model of battery that will work I will try one.
Now for a good laugh... I just happened to see another motor like mine Saturday
at the dock and talked with the owner... Now get this.. this guy didnt have a
clue about his old boat but he let me look at it. The thing is running a
perfect 14.5 volts and he's running a 520 CCA MAINTENANCE FREE battery.
ARRRRRRG.

"CCred68046" wrote in message
...
The biggest reason that voltage climbs so high on an unregulated system
is
that the battery is too small a capacity, and/or is a sealed or
"maintenance
free" version. You want a "flooded cell" battery, the largest you can fit
and afford, to run your boat's electrics.

Hey, good to see your still in the group Bill!
I have tried several batteries... I'm currently running a group 27
1000cca. I
have tried 3 BIG non maintenance free batteries. Everyone of them did
the
same thing.


What make, model, year outboard do you have?

Most modern batteries cram a lot of CCA (cold cranking amps) into the
design, but with a loss of reserve power. You want a battery with high
reserve minutes, above 200, and that will absorb the excess voltage. Imagine
charging a small garden tractor or motorcycle battery at a constant 6 amps,
the voltage would climb and it would boil away after a short time. Now
charge a huge bus or truck battery, like an 8D, and your voltage may not
even rise above 14.

A group 27, 30, or 31 deep cycle battery, as long as it meets your engine's
CCA requirement, works a lot better than a "new high tech, quick start"
battery, on unregulated systems.

Bill Grannis
service manager

Run into this? My boat is named *after* that very problem! And there ar
emany on this very board that watched me tear my hair out.

My 1962 Merc 1000 (advertised in '62 as the Black Phantom) had this problem,
which would cause the voltage to rise and then the condensors (at the
breaker points) to fail at about 17 volts. This of course, after about 10
minutes at WOT after the start-up. It took me a while to figure out *why*
the motor would always turn to crap after about 10 minutes runtime.
Overvoltage was the *last* thing that came to mind, I was looking for a
thermal intermittant in the ignition.

The problem itself, that motor, and (by default) that boat, *earned* the
name of "The Phantom Menace", as it would always quit once you were far
from shore.

I don't totally get the mechanics of the problem, just that the newer
batteries don't seem to be able to bleed off the excess output like the old
ones did. On my new boat (the PMII) I installed a later model rectifier /
regulator combo on my big Inline.

-W

(now you know why Mercury paint is called "Phantom Black" by the way)





"CCred68046" wrote in message
...
Clamp it with a Zener Diode somewhere on the 12v output line. All excess
current will bleed off.

Thanks Clams,

I know I could regulate it easily. You are an old Merc fan and you know
how to
fix it so you must have run into this before. What I am looking for is
the
reason its doing this now after it ran fine all those years. Everything
is
still in spec electrically. I really find this interesting. All the posts
on
the web about it and no one can or has answered it yet.