Marine Electronics Forum - Hard Wiring Lowrance LCX-110 & NMEA 2k

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kitebuz
06-04-2007, 12:48 PM
Just making sure I am going to do this the right way...

I am hard wiring my Lowrance LCX-110 & network directly to my house battery. My plan is:

18g wire terminaled directly to the #2 battery, to:
inline fuse, to:
toggle switch, to
head unit & NMEA 2k power supply

I am including the toggle switch so I can shut the system down 100% w/ no battery draw. I know this is necessary for the NMEA 2k network with the GPS antenna that keeps drawing power even when off.

- Is it necessary to wire the head unit thru the switch as well?

I also just realized I will need to make two separate wire runs - 1 for the head unit & 1 for the network so they can both have their own in-line fuse.

I want to wire directly to keep the power supply as clean as possible.

Anything I am missing or doing wrong??

Also, any suggestions on a good self contained switch or switch box? I want to mount the switch under my console beside my main battery switch. This will avoid having to put another hole in my console, and will hopefully remind me to switch it off when I am shutting the battery switch off.

I will mount it either on a flat surface, or on the side of a box, but both will be surface mounted as no room behind.

Thanks.


kchace
06-04-2007, 01:05 PM
What you're doing is just fine, but you must make sure to seperately fuse each device leading off the switch - otherwise you could either allow one device to draw more power that it should without blowing the inline fuse - or have nuisance fuse 'blows'.

The main (head) unit has its own power switch, so you can also run it through the switch, but there's no need to. What is most important is making sure each piece of equipment is fused properly.

I am going to do something similar with even more pieces of equip using a fused switch fanned out through a small fuse block to eliminate all the inline fuses (The fuse block will provide the proper size fuse for each piece of equip). In my case, I will be switching off all my electronics with one switch. The only thing to watch out for in a case like that is that the switch itself be capable of carrying the total power required. In my case, a 15 amp switch (and fuse) leading to the fuse block fanning out to 4 or 5 3amp (max) loads.

I don't have a suggestion on the switch 'box', but I'm sure some must exist.

Ken

Got Salt?
06-04-2007, 02:30 PM
buz, i think you got the bases covered. i do agree, the head unit will power off and should not draw any juice, but if want to put the switch in there just to be certain, no problem with that.



i had a curious question from a dealer that was tinkering with our boat. he could not believe that we had the network powered by the batteries, instead of the key switches. i scratched my head and asked why would i do that? he said that the gages should turn off and on with the key switch, not the battery (im powered from a battery switch to a BUS for my electronics). i scratched my head again and said that if i did that, every time i switched off my keys--like anchored over a wreck or drifting over a reef or whatever, my network would die. he said 'so?'. well, i pointed at my dash and the lowrance bottom machine/radar/GPS plotter. duh. he was only figuring in my i-command / LMF gages as my 'network', not my whole network. lesson learned--make sure your installer/tech/service center knows what you are trying to accomplish with ALL your electronics.

cheers.
drew


kitebuz
06-04-2007, 04:22 PM
Thanks for the replies.

KC - So you need both an inline fuse before the switch, and a fuse after the switch if both the network and head unit are coming off the same switch (I will have seperate wire runs w/ individual in-line fuses before the swtich)? I think I will leave the head unit off the switch, since, as you say, it already has its own power switch - just for simplicity. Good to know, I would have never thought about the power/fuse issue coming off the switch.

Drew - that's a funny story. I came across the same suggestion of wiring via the ignition in my searches online. Funny how some folks don't think you would want to run your electronics w/out the engines running

I like the switch to bus bar, and will look into it when I get more electronics on board like radar, etc.

For now, sounds like this will work. I have a toggle switch, but would still like to figure out a more elegant mounting solution inside my console.

kchace
06-05-2007, 09:40 AM
kitebuz - 6/4/2007 4:22 PM

Thanks for the replies.

KC - So you need both an inline fuse before the switch, and a fuse after the switch if both the network and head unit are coming off the same switch (I will have seperate wire runs w/ individual in-line fuses before the swtich)? I think I will leave the head unit off the switch, since, as you say, it already has its own power switch - just for simplicity. Good to know, I would have never thought about the power/fuse issue coming off the switch.

Drew - that's a funny story. I came across the same suggestion of wiring via the ignition in my searches online. Funny how some folks don't think you would want to run your electronics w/out the engines running

I like the switch to bus bar, and will look into it when I get more electronics on board like radar, etc.

For now, sounds like this will work. I have a toggle switch, but would still like to figure out a more elegant mounting solution inside my console.

Please keep in mind I 'think' in the direction of power source TOWARDS the item to be powered. It sounds like you 'think' in the other direction, which is fine.

Yeah, the problem is you have 2 (or more?) wires coming off ONE switch and each goes to a seperate unit. Each unit needs to be fused right? Well, say each unit requires a 3 amp fuse, if you only used one fuse what would you make it? 3amps? That ONE fuse would then be supplying power to 2 units - each unit may draw more than 1.5amps, so the fuse might blow even though both units were fine. If you up the fuse to say 4 or 5 amps, it may now not blow, but if there was a problem in one unit, that unit may be able to draw more than 3amps without blowing that 5 amp fuse and you could then have a meltdown of some sort.

Depending on where you mount the switch and what kind of wire and/or sleeving you use, it could technically be required to have a fuse within 7 inches of the power source to the switch. You can up that distance if the wire is protected. Of course, its a technicality which may or may not be ok to ignore since you're not a boat builder. But if it were my boat, I'd want decent protection.

To do it best and most correctly you fuse the wire from the batt to the switch at something highish - like 10-15 amps (It just has to be no bigger than what THAT wire and switch can safely handle) and then you really have to fuse each line coming off the switch that runs to seperate instruments at whatever the instrument mfg says to use.

Ken

steelhead130
06-05-2007, 09:56 AM
I wired my unit to a panel in the console, and the GPS to a panel in the electronics box. Each has an inline fuse at the battery for the total amperage of the panel and a seperate fuse for each unit(radio, fishfinder, VHF, GPS) I have had it this way for a few years and have had no problems at all, I know the directions say to wire directly to the battery. As for the nema I wire that to an extra switch on my console dash panel, there were 2 extra switches which work out fine.

Butch Davis
06-05-2007, 11:56 AM
Your approach is very conservative which can be a good thing. My 111CHD is done exactly as you describe with each item fused. If I had it do do again I'd connect all my power leads through the accessory switch. That way I could turn both the head unit and the GPS antenna power off and on through a single switch on the dash.

BTW, I love the unit.

kitebuz
06-05-2007, 04:04 PM
kc - "Towards" or "Away" - my thinking is not very logical when it comes to electrical - I'm a neophite, but trying to learn the right way, so appreciate the advice. I work better w/ things I can see... You would laugh at some of my original "theories" which quickly get shot up when I start researching.

Steel - yours sounds like the "right"way, and similar to what kc & others have done. I'd use a spare console switch, but don't have any extras, and don't want to go putting more holes in my dash right now.

Butch - glad to hear you are happy w/ yours - I'm very stoked to get this up & running. I'm going to run the NMEA network thru a switch so the GPS ant. can be fully shut down, but will just wire the head unit directly to the battery (w/ an inline fuse) since it will fully power down w/ it's internal switch.



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