And when you go too large you create issues. If only someone had said that....

Truce? I’m tired. I’m old. I’m going to bed.

It is not trolling if it is correct. I get it, you just can not admit you're incorrect. As we ALL know here, you're the biggest and baddest person to walk the earth, we have heard it... from you... you are the embodiment of " FIGJAM" to a tee! If you feel posting pics of an NFL players car is not a brag, or seeking attention, then you're in a whole different solar system of TO syndrome.

This is a lot in the weeds.. but Ohms law for AC circuits is different unless only resistance is one of he variables. In most AC circuits.. Resistance is not the variable, its impedance.. which is a much more complex issue than resistance. Here is the pure explanation.

The rules and equations for DC circuits apply to AC circuits only when the circuits contain resistance alone, as in the case of lamps and heating elements. In order to use effective values of voltage and current in AC circuits, the effect of inductance and capacitance with resistance must be considered.

The combined effects of resistance, inductive reactance, and capacitive reactance make up the total opposition to current flow in an AC circuit. This total opposition is called impedance and is represented by the letter Z. The unit for the measurement of impedance is the ohm.

Think of the ratings of speakers.. They are rated in ohms but its not resistance, is Impedance. Audio is AC, so calculation for impedance is used involving the inductive reactance and capacitive reactance components.. is complicated.

…. Just run 10 gauge wire.


Goodnight fellas.

Bill to be simple and blunt:

You need to run power wires 21' for something electric like say a "livescope pan optics" and " Sonar Display Device" and the load is say 2.3a @12 VDC.

If you take the above made up system and run it in 14ga, 12,ga,10,ga,8ga,2ga, etc.. each set of wires will have a differing set of characteristics. They will not handle the load the same. The 14 ga might work, and so might the 2ga, but the voltage at the end needed will not be the same. You can undersize and oversize the wires. Why else would the "Ugly's book" have sections on properly sizing wires? Much less the engineers that have spent years learning and putting this into practice.

The information I provided is based on a real application of installing LS on a 21'; boat where Garmin specified 10 gauge wire direct from the battery for the 1022 and LVS32 box. Having worked many years with electricity, troubleshooting circuits, installing, designing, etc I provided the opinion above. When called out and attacked I retorted providing information and facts. The attached picture below shows what I refer to. Look at the calculated info and see that 10ga is far above and beyond ( While they don’t warrant excessively larger wire with the amp draw) what is rated.

That is what Garmin says, and is far oversized for the rated load. Which happens to be the subject of my post you latched on to.

Here's a video by Russell Marine where they do a on the water test of LiveScope using 12 volt and 24 volt power sources and how it affects image quality.



The brain boxes for the "Live" technology tend to be power hungry and the image quality starts to degrade with voltage drop. There are two common factors for voltage drop. One is wiring, that's why the manufacturers recommend going with 10 gauge wire all the way back directly connected to the battery. The length of the power cable plays into it as well and was explained in a previous post. Second, when you're using your electronics, the battery discharges and voltage drops - a fully charged battery normally starts above 13 volts. Below is a discharge chart to illustrate this. What you'll notice with lithiums is that they maintain voltage over 13V for a longer state of discharge or duration which is where modern electronics like to operate. Again this chart is strictly for illustration and not of any actual battery.



AH(amp hour) is an indicator of how much capacity a battery can maintain a nominal voltage. The way I like to think about this is the size of the gas tank in your truck. You know you have 25 gallons of capacity but your range can be affected by how full it is, towing, city versus highway driving, keeping your foot on the pedal, etc. You can correlate this with a 100AH battery, 90% charge (how full it is), start adding in the draw from the electronics (tow weight), how often you have "Live" in the water vs just mapping (city vs highway), running sonar (keeping your foot on the pedal). It's not apples to apples, just to give you an idea.

Aside from increased voltage, drill batteries make a cool hack because they are small enough to tuck away in the rod locker making the power cable much shorter, relatively cheap, and you can carry multiple spares. I didn't even think about using them until I read through this thread.

If we just had the Mr Fusion doc had in the DeLorean.

I ran separate 10 ga wires to all 4 of my units. My 16in Garmin and livescope are running off of a 16v lithium battery. There is a clear difference between the 12v and 16v and it’s nice fishing all day without losing your image.

Couple of things I was thinking about. When talking about length of wire, I believe in a DC system you count the direction from the battery to the device and back to the battery. So 20’ to bow and 20’ back, one would assume 20’ total; but it’s really 40’. That might be wrong, but sure seems like I’ve read it some place. I’m sure I’ll be corrected if it’s wrong.

And for those want to run 16v lithium’s with their Lowrance graphs, read the print at the bottom of this link.

https://www.impulselithium.com/product/16v-60ah-platinum-series-marine-electronics-battery/

it would only be 20', positive side is what you measure.

is AC the same way, sure seems like there was something where you were supposed to count both directions. It’s possible my brain dreamt it up, wouldn’t be the first time.

I solved all of this and wired an independent battery directly to the power supplies for both my Garmin and the black box. I got a 30AH battery that will run both of them for 2 days without needing to be recharged. Keep it in the rod locker all connected by the factory wires. No added connections or extra wires. Cleanest power you can have.

That's a great idea. I am running my LS off the cranking battery, but it is a deep cycle group 29 battery and I've never gotten it below 12.4 volts after a day of fishing. You should never run a lead acid battery below 50% of it's capacity. There is a chart posted in this thread that shows that being about 11.9 volts, but charts put out by other companies show it being 12.1. I've always thought that a good general guide is to never let one get below the rated voltage - 12 volts for a 12 volt system, 24 for a 24 volt system, and so on. One reason that marine batteries wear out prematurely is that nobody is ever gonna stop fishing because a battery dropped below 12 volts. You are just going to keep fishing and deal with the consequences later, so it's best to design your system so that doesn't happen.

One thing that I was not aware of until after I bought my LS is that it continues to draw power even when turned off. So I had to look for a switch that was rated to carry enough current. A small 12 volt switch is not what you need; you've got to either have a heavy duty switch that will carry the required current, or you have got to disconnect it when not in use. If you are using a tool battery, you can probably just skip the switch and take the battery out when not in use. Is that what you are doing? A switch can be a real bottleneck on a system using this much current.

I am just an old Ag teacher and wouldn't wanna argue electrical theory with anyone, but I don't think your wire being too big is going to be an issue in any practical situation. I ran size 10 wire for mine, and you are just throwing money away to use bigger. But if you already have some larger wire and want to put it to use, it will work. The electric golf carts made by EZGO used to be made with 6 gauge cable. Guys trying to improve performance started using 4, and that was what everyone recommended for a while. Go to any of the cart forums now and they will tell you to use 2.