Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.

Have you tried Radio Shack to see if they have a fixed voltage regulator?

"Derek" wrote in message
...
Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.

I can'r say for certain in your case but I do know in other situations
removing the connection to the battery does cause an overvoltage that
sometimes will damage the diodes. It sounds like you know it all depends on
the reverse voltage rating of that bridge. I would look into a regulator
solution. A low budget solution might be to find something that will use
some of that power and wire it into your switch. Or wire something into
series with the charging line to the battery that could be controled by a
switch.

I added a "low" charge function to an unregulated battery charger by adding
a switched car headlight bulb in series. One of those newer small bulbs.
For normal charging the switch bypasses the bulb. For charging smaller
batteries like motorcycles and lawn mowers the switch adds the bulb in
series with the output line. It glows a bit when engaged. I'd guess the
total output current is not very high in your case too and it might not take
much to bring the voltage down.

"Derek" wrote in message
...
Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.

Derek wrote:
Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.


It takes voltage AND amps combined to cook the battery. Yes 17 volts is
a little high but on those old unregulated systems they could get away
with it because they didn't put out much power (as in volts plus amps)

This has only become a huge worry for people with the advent of elcheapo
digital multimeters, till now outta sight outta mind:-)

As for damaging electronics it's always "possible" but most unlikely,
modern stuff is well able to handle over voltage of that amount, a
normal alternator system will oft charge at 15-16 volts.

In the event you remain concerned, leave some load on it, the running
lights?? or similar, even a small load will reduce the voltage, because
again the sytem is low power output anyway.

K

The Krause lie of the day is:

Have you ever sailed from San Francisco to Hawaii? I have.
Have you ever rounded Cape Horn? I have, twice.
Have you ever transited the Panama Canal? I have.
Have you owned more than 20 boats in your lifetime? I have.
Have you ever sailed large boats competitively? I have.
Have you ever been hundreds of miles from land in a powerboat
under your
command? I have.

Imho, I would not be happy if I was reading 17v at the terminals of a fully
charged battery. But you could put an ampmeter on it and see.

"K. Smith" wrote in message
...
Derek wrote:
Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.


It takes voltage AND amps combined to cook the battery. Yes 17 volts is a
little high but on those old unregulated systems they could get away with
it because they didn't put out much power (as in volts plus amps)

This has only become a huge worry for people with the advent of elcheapo
digital multimeters, till now outta sight outta mind:-)

As for damaging electronics it's always "possible" but most unlikely,
modern stuff is well able to handle over voltage of that amount, a normal
alternator system will oft charge at 15-16 volts.

In the event you remain concerned, leave some load on it, the running
lights?? or similar, even a small load will reduce the voltage, because
again the sytem is low power output anyway.

K

The Krause lie of the day is:

Have you ever sailed from San Francisco to Hawaii? I have.
Have you ever rounded Cape Horn? I have, twice.
Have you ever transited the Panama Canal? I have.
Have you owned more than 20 boats in your lifetime? I have.
Have you ever sailed large boats competitively? I have.
Have you ever been hundreds of miles from land in a powerboat
under your
command? I have.

K. Smith wrote:
Derek wrote:
Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.


It takes voltage AND amps combined to cook the battery. Yes 17 volts is
a little high but on those old unregulated systems they could get away
with it because they didn't put out much power (as in volts plus amps)

Volts + Amps???? What electrical unit do you get when you to THAT
math???

In article ,
says...

Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.


An open circuit is bad, as the spike voltage is what will kill the
rectifier bridge.

No matter what anyone says about volts in combination with amps, all
battery literature for wet batteries allows a maximum of 14.8 volts
under any circumstance. It would be obvious at some point your charging
system put out enogh current to reach 17vdc, even if the actual current
at 17volts is somewhat lower, the damage was done in the process of
getting there. Someone suggested to me to run with the lights on, and
this is what I do. I like the one posters suggestion of inserting a lamp
across your 'charge' switch. with the switch closed you get full charging
output, and with the switch open and the lamp bridging the switch
terminals the lamp will glow, and the current through the lamp will
trickle charge the battery. Try an 1156, that should work, and you can
find a socket easily enough.

Best luck. Mine now peaks at 15vdc, it was once like yours.

On a somewhat related issue, I have an ammeter and voltmeter connected to my
Yamaha 9.9 4 stroke. It is relatively new, but I think it was showing charge on the
ammeter last season. Now, the needle hardly moves although the voltage of the
batteries seems to be increasing. The meter has a 'reverse' switch, so I can view
the charge used by lights, etc. That seems to be working. The only thing left that
I can think of is the reversing switch, but that is in series with the charging circuit, so
any open circuits would not allow the battery voltage to go up. Any ideas on what
is going on here?

Sherwin D.

Derek wrote:

Briefly, I have an old (1967) 45 HP Chrysler engine. It has the old
"points & condensor" type ignition and it runs just fine.

I installed a Volt meter in the dash, and I run the boat off a deep
cycle battery, only because I carry a trolling motor in the event of
engine failure, not for fishing.

Problem : After running for a while, the Voltage across the battery
rises to about 17 Volts, damaging the battery and possibly damaging
any other equipment I might run off the system (lights, fish finder,
GPS etc.) I intend to install a toggle switch to isolate the (Purple)
Positive charging wire, and flip it on as required.

Is there a possibility that this will cook the diodes? The charging
system has no regulator, just a bridge rectifier. Is there a safer
place to "break" the circuit? The ignition system takes it's power
from the battery, no magneto.

I'd rather this "wasted" energy of boiling the battery be removed 'cos
this old motor needs all the help she can get.

Note : The 17 Volts is across the battery, not the open charging
system. Also, do deep cycle batteries have a lower internal resistance
that's causing this high voltage? All connections and battery are in
excellent condition.

Thanks,
Derek.

In article , says...

On a somewhat related issue, I have an ammeter and voltmeter connected to my
Yamaha 9.9 4 stroke. It is relatively new, but I think it was showing charge
on the
ammeter last season. Now, the needle hardly moves although the voltage of the
batteries seems to be increasing. The meter has a 'reverse' switch, so I can
view
the charge used by lights, etc. That seems to be working. The only thing
left that
I can think of is the reversing switch, but that is in series with the
charging circuit, so
any open circuits would not allow the battery voltage to go up. Any ideas on
what
is going on here?

Sherwin D.


Usually when I find a battery that seems to charge to a higher than
normal voltage, and yet requires very little current to do it, the battery
is becoming sulphated and developing high internal series resistance.
This is sometimes evidenced by a battery which will run lights normally
and even for long periods of time, and yet will not crank over the engine.
And then the strange part is, even though it can't develope enough peak
energy to start your engine, it will appear fully charged about 5 minutes
after connecting it to your charger. Your battery seems to be acting this
way. Could you borrow a battery from someone, or perhaps from some other
piece of equipment around your home (tractor, mower, etc.) and see if
your system behaves more like you expect it to?

One other weird thing, a very dead battery that can barely light a lamp
will at first connection to a charger show a very high charge voltage
and draw almost no current, after about 1/2 hour the voltage will drop
somewhat and the current draw will go up (like when it goes to 6 or 8 amps
on a home charger with a green/yellow/red scale ammeter) then as you
approach full charge the voltage goes back up and the current comes down.