What causes interference

[jerson]

I'm installing a new colour sounder, the existing sounder will remain as a dedicated GPS. All existing wiring to the sounder, forward controls & accessories runs down the starboard gunnel. The cable to the GPS antenna runs down the port side.

When i run the tranducer to the new sounder, can i run it beside the GPS cable without getting interferance.

I will be running a dedicated power feed to the new sounder.

Thanks in advance.
Jerson.

[Moonlighter]

I have not heard of GPS interfering with sounders, I dont think you'll have any issues. In fact most sounders cables these days are shielded better and if your wiring setup is generally good, unlikely to have issues with electrical interference.

If possible run the sounder and GPS power off the house battery as this helps avoid voltage spikes that you get when running from the srarting battery.

[jerson]

Thanks for the reply mate.
I've only got the one battery.
The existing sounder has a dedicated power, could there be a problem if i ran the new unit of this power & fuse?

Jerson

[Moonlighter]

Jerson - are we talking about a boat capable of open Bay and offshore?

If so, then can I suggest fitting a second battery and dual sensing VSR setup (as per BEP setup available from BIAS etc) is a very wise investment and is quite easy to install. Voltage spikes when starting motors can do nasty things to electronics - I reckon over the longer term this probably contributes to a shorter life of the units. Such a setup also gives you great confidence of not draining the one battery with electronics etc and then not having enough power to start the engine. In an emergency both batteries can be joined to provide the power required to start the engine.

Re running both sounders/GPS from the one power wire and fuse, no. They should have separate fuses at the very least. If the wiring to the existing sounder has sufficient capacity, then you could split it and use it to power both, but add fuses after the split so that each unit is protected.

Cheers

ML

[FishHunter]

Jerson - are we talking about a boat capable of open Bay and offshore?

If so, then can I suggest fitting a second battery and dual sensing VSR setup (as per BEP setup available from BIAS etc) is a very wise investment and is quite easy to install. Voltage spikes when starting motors can do nasty things to electronics - I reckon over the longer term this probably contributes to a shorter life of the units. Such a setup also gives you great confidence of not draining the one battery with electronics etc and then not having enough power to start the engine. In an emergency both batteries can be joined to provide the power required to start the engine.

Re running both sounders/GPS from the one power wire and fuse, no. They should have separate fuses at the very least. If the wiring to the existing sounder has sufficient capacity, then you could split it and use it to power both, but add fuses after the split so that each unit is protected.

Cheers

ML

How do you explain car electronics lasting many years?

[jerson]

Jerson - are we talking about a boat capable of open Bay and offshore?

If so, then can I suggest fitting a second battery and dual sensing VSR setup (as per BEP setup available from BIAS etc) is a very wise investment and is quite easy to install. Voltage spikes when starting motors can do nasty things to electronics - I reckon over the longer term this probably contributes to a shorter life of the units. Such a setup also gives you great confidence of not draining the one battery with electronics etc and then not having enough power to start the engine. In an emergency both batteries can be joined to provide the power required to start the engine.

Re running both sounders/GPS from the one power wire and fuse, no. They should have separate fuses at the very least. If the wiring to the existing sounder has sufficient capacity, then you could split it and use it to power both, but add fuses after the split so that each unit is protected.

Cheers

ML

Moonlighter,

The boat is a 4.35 runabout, 30 hp electric with pull start.(no bowmount) Used mainly around bay islands. What you are talking about concerning voltage spiking is a bit beyond me.
Is this similar to power surges with 240V, if so is it possible to install a 12V surge protector to the sounders power supply.

Jerson

[Moonlighter]

Hi Jerson

Agree that dual batteries in such circumstamces probably a bit over the top!

Yes, you can get spike protectors to fit in the power line that will provde protection. BIAS, Whitworths etc have them. Would be worth considering I reckon.

If you (and fishhunter) do a search on this forum you'll find numerous threads about voltage spikes on boats, what causes them and the potential damage they can cause. By people who know considerably more than me about the topic.

Hi Fishhunter

Thanks for that insightful input mate. One suspects, just a thought of course, that modern car wiring/electronics electrical system design may be just a tad more sophisticated than standard boat wiring. IMHO of course.

Cheers

ML

[oldboot]

In all seriousnes, I think, there are some issues here that have been overblown.

as far as interfeerance......the sounder is more likley to be generating the interfeerance.....they produce high energy high frequency pulses and run them down a long cable to the transducer.....

best to keep the sounder cabling away from other sensitive cabling...like radio coaxes and yes the GPS cabling...........it may not cause a problem but there are plenty of cases where there are reports of this source of interferance.

As far as surges, pulses and spikes and such.......there have been reports of some marine electronics not being as robust as it should be against this sort of thing..... but I'm in two minds about the causes and the realities

The single most important thing to combat surges is to make sure you have good battery and good solid battery connections and good solid supply lines.

your battery is one of the best surge absorbers you can get......if the battery terminals fail to make good contact the terminal voltage of the outboard charging system can in some cases rise very high.....some up to hundreds of volts......this certainly can blow stuff up including the regulator in your motor.......

If you want to fit a purpose built surge supressor, you can buy one in a plastic box and pay $30 - $40 for it or buy an appropriately rated " transorb" for under $2, that does the same job.

But serioulsy I think the power supply surge thing is over stated.....keep those battery terminals tight and some basic common sence and you should be fine.

one thing that is a good idea is to run the sounder powersupply thru an external switch..this way the sounder can be disconnected from supply in storage and while starting.........remember most modern sounders there is power to the board if there is power on the wire.....there is no "power switch" as conventionaly understood.

cheers