Topic: Power required by the 1197

[offroad]

Thats voltage power. Strange problem l seem to have.. When l use a volt meter on the power plug cable for the unit l get 12.5 volts. Now plug that cable in the unit fire it up and its says less than 10 volts on the screen . Could this cause the problem that l am having losing my SI screen because l am not getting enough voltage to the unit.. Hold the bus... just tried something else. Tried the power plug from my 898 on my 1197. l get 12..5 volts on the screen now.. So it looks like l have a faulty cable  Would you agree ?? or is 10 volts enough power ? and l have another problem !

[sonar2000]

Sounds like a plug problem.
 Initial power with out turning on the unit is only a measure of "potential" and not current flow. It rerquires a flow of current between positive and negative to accurately measure supply voltage.
 When a device is turned on, it causes a flow of current, the actual workhorse, to move. however there is never a "short, (hopefully) between positive and negative. this is why we fuse the positive line.   The measure of potential now is across the flow (resistance) and can show certainly less than the potential.
10.5 is the low end of the unit, but that is at the initial power on condition. after it powers on 10.5 may run.  The initial power on is called surge and usually requires more volts than operational condition.
Hope this helps. 
Chuck

[Humminbird_Greg]

For a volt meter to get an accurate voltage reading it has to have a very high resistance to current flow so that all of the potential (voltage) is dropped across the volt meter.  Resistance and current are inversely proportional – higher resistance means less current flow and low resistance means a high current flow.  So when you are measuring the voltage with a volt meter, it is only showing you what the possible voltage would be if an electronic device that draws very low amounts of current were connected to those same wires.  This is sometimes called a no-load or unloaded condition.  A better measure of the voltage would be while it is under load.  To do this you would have to connect the volt meter in parallel to the electronic device which unfortunately is not easy to do with the power connectors that we use on our products (measuring the voltage where the power cable connects to the boat’s electrical system is not the same but is a second best test).

Short answer: measuring the voltage at the plug without the unit connected and turned on does not show you the amount of voltage (and therefore current) available when the unit is plugged in and turned on.  When you see a difference in voltages like this it means that you have either a loose electrical connection, a dirty/corroded electrical connection or are using wires that are too small of a gauge and cannot carry the current needed.  Be sure and check the fuse and fuse holder as well as this is one area where we still see many problems.  Resolder and seal all of your electrical connections as well to keep from having future problems as a boat is a terrible place for an electrical connection due to the moist environment along with all the vibration and shock forces that occur.

[offroad]

Thankyou gentlemen for your quick replys.

[Bob B]

Offroad,
What are you using for a power source.? Are you connected to a battery or some external power source?

Like Greg says, the voltage you are reading before plugging the unit in is the "unloaded" voltage.....no current flow.   Once you plug in the unit and have current flow the voltage drop can be casued by cabling, connections, or the power source.  Take a voltage reading directly at the power source (e.g. battery terminals) with the unit powered up and you can determine if the voltage drop is because of the cable or the power source.

Some of the 120vac to 12vdc power supplies don't seem to have as much capacity as they are rated for.

[offroad]

Bob B  thanks for your reply. The power source is the main starter battery for the motor directly off the battery.  And so is the power supply for my other unit the 898  So both unit use the same power source.  Must be a problem with the power plug for the 1197 l think.. l might have "other " problems with the unit as well. But l will buy a new plug and go from there .

[Bob B]

The cable seems like the most likely cause, especially since the 898 cable works OK.  I have seen posts with people talking about having to slightly bend the pins to get a better connection, but haven't had any experience with that.

In my experience with electronics, a bad connection will usually result in a fluctuating voltage, not a steady voltage drop, since the resistance of the bad connection will vary.

[Wayne P.]

offroad, when you state that the units are powered directly off the starting battery, do you have each unit's power cable extended with another wire and that wire connected directly to the battery or do you just have the unit power cables connected to the boat wiring harness?

[offroad]

Wayne
           Both unit have there own dedicated power cables.But again reading HB Greg post l went through both units power supply . And yes Greg you where right.. The fuse holder was quite hot when the unit was powered up. When l removed the fuse. it fell apart in my hands. That Problem solved when l put the new fuse in. 12volts+ on the screen.Can somebody tell me the minimum power supply that the 1197 would work at ?

[sonar2000]

See page 154 of the user manual.
7.5 to 7.9 Volts DC, unless you have customized higher levels.
This is of course the operating voltage and not the startup (surge) voltage..
You may also check the high end alarm setting.
Chuck

[Wayne P.]

The spec voltage operating range is 10-20 volts. The problem with the supply power is that when the voltage is the lowest, the amperage is the highest. The wattage of the unit remains the same.

Do yourself and your equipment a favor and replace the fuse with the spade type fuse in a water proof holder. Radio Shack and most auto supply places carry them. Use the spade 3A fuse.
That way you won't be passing voltage thru the spring and two contact points in the glass type fuse holders.

http://www.radioshack.com/product/index.jsp?productId=3150583

[sonar2000]

For minimum supply potential voltage you first need to get the unit powered up. Startup voltage 12 + to 20 VDC with at least 3 amp is the optimal power on. Once the unit is on and operational, it will optimally work at 10 to 12, but will continue to work at 7.5 to 7.9 although "settings" can highly influence that.
As a general rule of the thumb, set your voltage alarm at 10.5 so that you will have an opportunity to save any recordings or other recently entered unit data.
If you run from the boats main battery, then the "available supply" may decrease quickly if running other devices and not charging by having the motor running.
Which is one reason trolling motors mostly use their own supply.
It is no fun to run out of battery supply (amps).
Chuck

[xSilmarilSx]

Just an information here, you should never discharge a lead-acid battery below 11.8v
So setting the voltage alarm around 12V is better.

At 12V alarm, if you have other electronics connected, it would be wise to use some power management to keep the battery high enough for the run home.
Below that voltage, your are starting to kill the battery real fast.