Voltage drop

[bigjudge]

Fellas need some input,having some issues with chart plotter/radar combo(furuno).
Freezes up for a few secs when boat restarted i understand this could happen due to momentary voltage drop, but it looses all routes from where you have just been also says cant find satillites, then comes good, will tell you cant find sats while travelling,i have two batteries running at all times,boat motor 200/suzi 4st,upon inspection found 1 leg of earth bus bar slightly loose, now fixed,just seeing if anyone else has had a similiar problem and how they fixed it,have sent plotter to be checked out.Any advice appreciated.
CHEERS AND BEERS

[mitch92]

Re: Voltage drop

Voltage drop comes from resistance. High resistance joints, too small cable etc. Larger cable would overcome it, but if it is a hot/high resistance joint then it needs fixing. What current does the plotter draw?

[bigjudge]

Re: Voltage drop

manual says 12/24v-5.9-2.8A

[peterbo3]

Re: Voltage drop

Voltage drop comes from resistance. High resistance joints, too small cable etc. Larger cable would overcome it, but if it is a hot/high resistance joint then it needs fixing. What current does the plotter draw?

Mitch,
In this case the voltage drop & subsequent spike occurs when the starter motor is cranking. The only real solution is a dedicated house battery which is isolated from the start battery
via a Blue Seas ACR or BEP VSR combined with a four way battery selector switch.
BJ,
Constant voltage spikes may damage your Furuno display. It needs to have it's own dedicated power supply which is not subject to voltage drops/spikes associated with engine starts.

[TheRealAndy]

Re: Voltage drop

Mitch,
In this case the voltage drop & subsequent spike occurs when the starter motor is cranking. The only real solution is a dedicated house battery which is isolated from the start battery
via a Blue Seas ACR or BEP VSR combined with a four way battery selector switch.
BJ,
Constant voltage spikes may damage your Furuno display. It needs to have it's own dedicated power supply which is not subject to voltage drops/spikes associated with engine starts.

I find it amusing how spikes can damage marine electronics. Its piss poor design. Imagine if the computer that ran you motor died every time there was a spike... Its not hard to design around it. BTW, i think if you do a search on AF you will find its not only Furuno that makes these pathetic claims.

[marty666]

Re: Voltage drop

I find it amusing how spikes can damage marine electronics. Its piss poor design. Imagine if the computer that ran you motor died every time there was a spike... Its not hard to design around it. BTW, i think if you do a search on AF you will find its not only Furuno that makes these pathetic claims.

It is not just marine electronics, we are always dealing with similar things in the car game and the biggest contributor is none resistance spark plugs and coil over plug coils failing that cause these spikes will take out a cars ecm in micro seconds.

[mitch92]

Re: Voltage drop

Mitch,
In this case the voltage drop & subsequent spike occurs when the starter motor is cranking. The only real solution is a dedicated house battery which is isolated from the start battery
via a Blue Seas ACR or BEP VSR combined with a four way battery selector switch.
BJ,
Constant voltage spikes may damage your Furuno display. It needs to have it's own dedicated power supply which is not subject to voltage drops/spikes associated with engine starts.

Very true, only half read it. On re-reading i agree with what you have above with the switch/isolator. VSR i would say optional

[johncar]

Re: Voltage drop

Totally agree with peterbo3, If you have any serious electronics on board and you don't want these dropouts and possible damage from engine starts etc you either need dedicated start battery and separate house battery which can be both charged from the engines alternator via a BEP VSR (Voltage Sensitive Relay) or Blue Sea ACR being a similar thing, many boats are set up this way now because of the nature of the gear we now use and distances we travel.
Whether just using a basic dual parallel battery system or the better separate dual battery system you still need to check all your terminal lugs, inline connectors , all terminations, fuses, switches, adequate capacity, condition and age of the batteries. It is typical for a boat to be fitted with batteries that are barely adequate in cranking capacity when new and not up to the task 12 months down the track.
I often find rotted cables hidden inside connectors that owners are oblivious to and it's amazing there was any power getting engine starter let alone the electronics. This is just due to poor quality materials, installation, maintenance and very common even on your better brands of boats.
I am not having any problems at the moment with my rig and I run a separate battery system for electronics but I am about to go through the whole system and replace any of the remaining automotive type wiring and connectors with marine grade cables and certified heatshrink fully sealed connections. I don't want to have any breakdowns at sea that could have been avoided for the sake of a few $ for better quality electrics.

[oldboot]

Re: Voltage drop

I have to agree with andy, any electronics that cant cope with a momentary drop in voltage or a small spike in voltage is just poorly designed...the designers need to go back to 1st year colledge and revise their voltage regulator theory....any spotty youth with an interest in electronics sould be able to manage better

The second battery seems to be the only solution though........Think however that you may not need to provide any means of charging the battery that runs ya electronics...any decent sized battery in good health should run a few bits of electronics for a week without a recharge.

So many of us could simply fit a battery and charge it a home between trips.

cheers

[tunaticer]

Re: Voltage drop

As Peter said, isolate your batteries and fit a voltage regulator for charging at the minimum.

One thing that always surprises me is that MOST boats have their main fuse board / switch board / bus bar connections whacked under the dash or console but still open to the atmosphere. How can you expect to maintain a good clean tight connection that will not break down unless it is in a controlled environment with reduced humidity? Mounting all of these major connections inside a large junction box or sealing a large junction box over the rear of your dash is not a really hard thing to do in most cases. Whack a few of the silica crystal sachets in there and replace them every year or so and your connections will remain good for decades.

[Relaxedcamper]

Re: Voltage drop

I just have a quick question. I had a similar issue as BIGJUDGE one day out on the water. We have a duel battery system and when I got home and put the cteck charger on the battery, it showed that it was quite discharged. Since then I have religiously been alternating the charger over to the other battery on a weekly basis. Since I have done this, the problem doesn't occur.

My question is about voltage spikes.

Is my electronic equipment safe from spikes when it is turned off. I thought that perhaps I could protect my equipment by having all the nav/plotter/sounder turned off, then start the motor, then turn it all on?.

Cheers.

[oldboot]

Re: Voltage drop

That depends on what you call " turned off".

By far the majority of electronics have logic operated switching to "turn the device on and off", the suposed power switch is nothing of the sort, the power supply section and at least some of the controll electronics remains connected while there is power in the power lead.

For this reason I have all my electronics connected thru switches on the switch panel.
When they are turned off the electronics IS turned off.

Isolating your electronics with a switch can also reduce corrosion in power plugs and such too.

cheers

[Fed]

Re: Voltage drop

Back in the real world most people connect their electronics to their battery & go fishing.
That works for me.

[oldboot]

Re: Voltage drop

Back in the real world quite a lot of people are having exactly the problem reported in the first post, particularly with certain brands of equipment.

This is far from the first post detailing exactly this problem and certainly will not be the last.

And just connecting their electronics to their battery and going fishing is not working for them.

cheers

[Gon Fishun]

Re: Voltage drop

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