Why does Garmin say you need 10g wire for Livescope?

[Highcentered]

Just something that has had me confused for a while since the wire for the plug is pretty long and it's not that big (16? maybe 14?). I think I remember it coming with an 8a fuse also? It's not pulling that much current either. Is it one of those things where they know many will be running 2-3 big screens up front and just want to make sure nothing starves for current when a shared power and ground is used? I just know the math doesn't even come close to adding up when it comes to what real world consumption is vs what they suggest. Is Livescope just really sensitive to voltage drop?

I use a shared 10g power and ground for my screens and black box up front because my boat came with it already run to the front. I wonder how many people question the 10g requirement? If there's a good reason why 10g is such a big requirement according to the manual I'm all ears. "Because they say so" isn't a good enough reason for me. I'm not sure how accurate the app is but my Monster Lithium app says my FFS, Echomap 9, Echomap 10, and Echomap 12 combined are only pulling a little over 1.5 amps.

[GPtimes2]

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[jjue1979]

It’s to make sure that the voltage drop over the distance from battery to fish finder/GLS10 is only around 3%. I could go into further details about how thicker wire prevents voltage loss over distances, but I don’t feel like pulling out some of my old EE textbooks or looking up online the formulas that explain this. Most charts given to electricians or available online tend to show that 10ga is acceptable for the length of a bass boat for the given current for a 3% voltage drop target.

[Highcentered]

It’s to make sure that the voltage drop over the distance from battery to fish finder/GLS10 is only around 3%. I could go into further details about how thicker wire prevents voltage loss over distances, but I don’t feel like pulling out some of my old EE textbooks or looking up online the formulas that explain this. Most charts given to electricians or available online tend to show that 10ga is acceptable for the length of a bass boat for the given current for a 3% voltage drop target.

I fully understand voltage drop and that was my suspicion all along. I was heavy into car audio for about 20 years and very well versed on theory and real world practice.

[JR19]

When people wonder why the wire is small at the unit and wonder why the manufacture suggest a much larger wire to supply the power I like to use this analogy to describe it. Think of it like the electricity in your house. The outlet in in your living room wall has wire that's a lot smaller than the transmission line that is supplying the electricity to your house. If your power coming into your house was on small wire in size like what's in your living room that feeds the plug in imagine the amount of voltage loss you would have over that distance. The same principle applies on a boat. You have a large wire from the battery to the unit and where it ties in the last couple of feet it is a small wire. Your carrying the voltage on the large wire ensuring the small wire has enough to supply the unit the last few feet. Hopefully that makes sense.

[MonteSS]

BTW per my Ionic app, a 106sv and black box draw 2.4a. My about 12 hour runtime on the 30ah lithium varifies this.

Mount your electronics battery in a front hatch and the wire run is very short. I use the thin (12-14ga?) stock wire from the black box directly to the battery.

IMG_20210528_121453742.jpg

[TOUCH OF CLASS]

https://youtube.com/shorts/1eIf2X45P...kEIia_ty4t5KP9

[jjue1979]

BTW per my Ionic app, a 106sv and black box draw 2.4a. My about 12 hour runtime on the 30ah lithium varifies this.

Mount your electronics battery in a front hatch and the wire run is very short. I use the thin (12-14ga?) stock wire from the black box directly to the battery.

IMG_20210528_121453742.jpg

Per calculations and reference charts, you can definitely get away with smaller with shorter distances. The stock 16/18 ga wire is definitely sufficient if connecting directly to a battery no further than the stock lead length.