Hi everyone!, Hey I'm having a small but irritating problem with an
electrical circuit on my 1993 OMC Sunbird.
The problem is that sometimes the engine doesn't start right away and
requires a few more cranks by the starter to get it going. I'm talking
about a 3 - 4 second crank time altogether before it starts. When the
cranking hits the 4 second mark it seems I lose power briefly to my fish
locator and stereo. If the engine manages to start in the 2 - 3 second
time frame this doesn't happen. I have load banked my battery and it
tests really well. I have the locator and stereo connected to my
accessories dash rocker switch.
Is there a quick fix for this besides installing a second batery?
Do I need to install a diode in the accessory circuit to prevent the
started from sucking power back from the locator and stereo?
Thanks. Chris

Chris Mares wrote in news:7sXGg.6579$Tl4.3557
@dukeread06:

Is there a quick fix for this besides installing a second batery?
Do I need to install a diode in the accessory circuit to prevent the
started from sucking power back from the locator and stereo?


No, what you need to do is to turn off ALL ELECTRONICS while cranking the
engine to protect the electronics from the inductive kick and low voltage
the starter drawing 300 amps from the poor little battery creates.

Go out to your car and turn on the switch. Turn on the radio. Now, notice
how your radio turns OFF while the car is cranking to protect it from the
awful surges cranking produces? Do you think car manufacturers do that to
spend more money building the car....or to keep owners with warranties from
getting free radios?

All electronics hooked to the same battery the starter is hooked to need to
be OFF WHILE CRANKING!

The reason for the shutdowns you're seeing is the battery voltage drops to
10V or less from the awful current drain, especially if you hold it and the
battery runs low on electronics as its chemistry is under such a shock....

--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.

300 amps? How big is the motor he's cranking?

Or, he has a dirty battery terminal. My Crown Vic 302 showed me how
that works. After the dirty terminal gets warm, it's resistance starts
to go up, then it gets hot. Depending on how the terminal reacts,
strange things can happen in the course of a few seconds.

The terminal got worse until, if the car didn't start right away, it
quit trying and even the dash lights went out. An hour or two later,
it was ok. Got caught downtown after a short stop, called a cab for a
boost. Voltmeter was bouncing all over the place. Low idle speed,
engine quits.

Brownish crumbly snow around terminal connection. Clean terminals, no
more probs. The battery was a little low, but OK.

Terry K

"Terry K" wrote in news:1156440924.118445.64140
@p79g2000cwp.googlegroups.com:

300 amps? How big is the motor he's cranking?

Or, he has a dirty battery terminal. My Crown Vic 302 showed me how
that works. After the dirty terminal gets warm, it's resistance starts
to go up, then it gets hot. Depending on how the terminal reacts,
strange things can happen in the course of a few seconds.

The terminal got worse until, if the car didn't start right away, it
quit trying and even the dash lights went out. An hour or two later,
it was ok. Got caught downtown after a short stop, called a cab for a
boost. Voltmeter was bouncing all over the place. Low idle speed,
engine quits.

Brownish crumbly snow around terminal connection. Clean terminals, no
more probs. The battery was a little low, but OK.

Terry K



I always assume they've at LEAST cleaned the terminals before posting
here...(c;

300A is easy on a diesel engine with 22:1 compression ratio and cold oil.
800A if it stalls the starter motor The conductors JUMP!....(c;



--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.

Is there a quick fix for this besides installing a second batery?
Do I need to install a diode in the accessory circuit to prevent the
started from sucking power back from the locator and stereo?

Clean the terminals to the battery. Clean the terminals on the starter.
Replace the wires to the starter (both positive AND negative). This is
about the extent of 'quick fixing'.

Possibly use heavier gauge wire to the "locator" (chartplotter or
something?). This to make sure it's getting enough juice anyway. If it's
using too small a gauge wire it may not be getting the right level of
voltage to begin with.

But if you've got these devices on the same battery you really should be
TURNING THEM OFF before cranking the starter.

Your best solution is to get a second battery installed. It may be simplest
to get a new one just for cranking the engine. That way you'd probably be
able to leave everything else wired to the existing battery and only have to
rewire for the starter/ignition.

Having a second battery helps make sure you don't end up stranded somewhere
after spending all afternoon/night on the hook listening to the radio...

In article ,
Larry wrote:

"Terry K" wrote in news:1156440924.118445.64140
@p79g2000cwp.googlegroups.com:

300 amps? How big is the motor he's cranking?

Or, he has a dirty battery terminal. My Crown Vic 302 showed me how
that works. After the dirty terminal gets warm, it's resistance starts
to go up, then it gets hot. Depending on how the terminal reacts,
strange things can happen in the course of a few seconds.

The terminal got worse until, if the car didn't start right away, it
quit trying and even the dash lights went out. An hour or two later,
it was ok. Got caught downtown after a short stop, called a cab for a
boost. Voltmeter was bouncing all over the place. Low idle speed,
engine quits.

Brownish crumbly snow around terminal connection. Clean terminals, no
more probs. The battery was a little low, but OK.

Terry K



I always assume they've at LEAST cleaned the terminals before posting
here...(c;

300A is easy on a diesel engine with 22:1 compression ratio and cold oil.
800A if it stalls the starter motor The conductors JUMP!....(c;

as well as the batteries......

Inductive kick from switching a starter motor off does not get
transmitted to the electronics. The inductive kick comes from the
induction of the windings in the starter motor when the current is
interrupted. But if the current has been interrupted it is no longer
connected to the battery so the spike is restricted to the starter
motor side of the switch.

Radios and accessories in a vehicle are turned off during cranking to
minimize additional loads on a struggling battery so its full output is
available for the starter motor. It has nothing to do with protecting
the electronics.

The problem with low voltage drop-out is when you have computer based
equipment that takes forever to re-boot or radar which has to go
through a warm-up delay before applying power to the magnetron.
Turning these off to crank an engine and then having to wait for them
to re-boot is not only frustrating but could be dangerous if you had an
engine failure in an emergency situation, right when you may need that
radar or depthfinder the most.

Most modern marine electronics can accept a very wide range of input
voltage so it sounds like the voltage is dropping too low during
cranking. As suggested above this could be a bad battery connection
(check the GROUND connections too) or it could be a battery failure in
progress.

If you have a combiner and a house battery, move the sensitive
electronics to the house battery where they will not be subjected to
the low voltage during cranking.

Terry K wrote:
300 amps? How big is the motor he's cranking?

Or, he has a dirty battery terminal. My Crown Vic 302 showed me how
that works. After the dirty terminal gets warm, it's resistance starts
to go up, then it gets hot. Depending on how the terminal reacts,
strange things can happen in the course of a few seconds.

The terminal got worse until, if the car didn't start right away, it
quit trying and even the dash lights went out. An hour or two later,
it was ok. Got caught downtown after a short stop, called a cab for a
boost. Voltmeter was bouncing all over the place. Low idle speed,
engine quits.

Brownish crumbly snow around terminal connection. Clean terminals, no
more probs. The battery was a little low, but OK.

Terry K

The terminals are clean, I clean them every 6 monthes and I have had the
problem for about 5 years now.

I think that sounds like the best solution is to add a house battery
that is on a seperate circuit that is isolated from the cranking battery
except for after the engine is running so it will recieve charge from
the alternator.


Andina Marie wrote:

Inductive kick from switching a starter motor off does not get
transmitted to the electronics. The inductive kick comes from the
induction of the windings in the starter motor when the current is
interrupted. But if the current has been interrupted it is no longer
connected to the battery so the spike is restricted to the starter
motor side of the switch.

Radios and accessories in a vehicle are turned off during cranking to
minimize additional loads on a struggling battery so its full output is
available for the starter motor. It has nothing to do with protecting
the electronics.

The problem with low voltage drop-out is when you have computer based
equipment that takes forever to re-boot or radar which has to go
through a warm-up delay before applying power to the magnetron.
Turning these off to crank an engine and then having to wait for them
to re-boot is not only frustrating but could be dangerous if you had an
engine failure in an emergency situation, right when you may need that
radar or depthfinder the most.

Most modern marine electronics can accept a very wide range of input
voltage so it sounds like the voltage is dropping too low during
cranking. As suggested above this could be a bad battery connection
(check the GROUND connections too) or it could be a battery failure in
progress.

If you have a combiner and a house battery, move the sensitive
electronics to the house battery where they will not be subjected to
the low voltage during cranking.

"Andina Marie" wrote in news:1156600889.991305.164080
@b28g2000cwb.googlegroups.com:

Inductive kick from switching a starter motor off does not get
transmitted to the electronics. The inductive kick comes from the
induction of the windings in the starter motor when the current is
interrupted. But if the current has been interrupted it is no longer
connected to the battery so the spike is restricted to the starter
motor side of the switch.


Ah, but what about the inductive kick that happens when the starter is
running and the commutator brushes in it kick like hell switching
windings on their way around? This kick, working against the normal
corroded up terminals, wiring, connections in a boat can, indeed, be
substantial.

Just leave it until the damned radio won't transmit any more.....It's too
much trouble to flip the breakers off....

Oh, by the way folks, turning electronics OFF with the switch on them
doesn't turn electronics OFF, for the last 30 years or so. When you turn
off any VHF transceiver, for instance, you are switching off the low-
level electronics...receiver, transmitter exciter, PARTS of the synthesis
electronics. Other parts, notably MEMORY for channel scanning and that
big RF power brick that makes 25 watts bolted to the heat sink are
CONNECTED TO THE DC ALL THE TIME! So, my suggestion to turn off the
electronics at the source....

Aboard Lionheart is a continuous-duty master contactor. The contactor is
controlled by a panel push-pull marine switch that simply turns the
contactors coil on and off and lights a big red pilot light so my captain
doesn't go off for 3 weeks and leave it all running. This contactor
controls the "Electronics DC Bus" throughout the boat. The only radio
that's not on it is the emergency VHF, an Icom M59, that has its own
breaker. All the other electronics operates from the bus. Disabling the
bus, disables all those continuously-connected devices NMEA doesn't want
to waste money on switches to shut down.

A few years ago, a little seawater made it way around the chinzy speaker
seal of a Standard Eclipse Plus VHF radio, ran across the main PC board
behind it and puddled up against the back heat sink on top of the board
right under the power amp brick pins, driving the power amp control
circuit into a continuous conduction state. This did NOT blow the
radio's manufacturer fuse as the brick was only pulling 3 amps, all
converted to 36 watts of heat that discolored the metal surface of the
radio's heat sink in back, we later found. The boat was on a trailer and
not hooked to a charger, so the radio simply killed the boat battery
REALLY dead, so dead it would never recover. Since figuring out that
one, all electronics needs to be hooked to some kind of disconnect device
that totally disconnects all electronics on the boat from DC power before
the boat is put away from use.

I found another phenomenon that took me a while to comprehend. The boat
had been put up for a month and a half while I was on Lionheart in
Florida, dealing with engine flooding in Daytona Beach. The next time I
went to use the portable GPS, I noticed the plastic plug on the dash had
gotten really hard and brittle, so brittle it crumbled in my hand! The
plug was the power/data plug for a Garmin handheld GPS. It simply
disintegrated! This was caused by 12 volts DC and a little humidity
caused by rain making it under the cover. Evidently, the 12VDC conducted
around, and maybe through, the plastic the plug was made of, completely
changing the chemistry of the plastic by electrolysis. The most damage
was nearest the +12V pin near the surface of the hole the +12V was in.
That pin simply fell out in my hand. This is another reason to secure
all 12V power from all electronics, even electronics plugs just left
open!

How DO they engineer plugs so cheap 12 volts DESTROYS them?!

--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.