Skeeter man thank you for that, I was thinking that but didn't know for sure. I'll match the same size wire coming out of the unit - on one dedicated 12v battery,

Most graphs power cords are about 20-22 gauge wire and only about 1.5’ long. Running the same gauge from the battery to the bow will create too much resistance to carry the needed amps.

Try that tech school again to learn about voltage drop over wire run. Using the same wire gauge does not somehow give the maximum amp flow to a load. In fact, too light of a gauge wire causes more voltage drop, which in turn causes the power draw to increase! (Watts = voltage x amps). The unit wants a certain number of watts, so if the voltage is lower due to wire resistance or a failing battery (examples), the amps will be higher. The goal is not to draw maximum amps at the load, but MINIMUM!

Matching that skinny-wire power cord's gauge all the way from stern to bow is one of the best ways to insure you have electrical power issues. Be my guest - or be smart and use 12 or 10 gauge wire. The end goal is to deliver the highest voltage possible to the load so that the amps are minimized!

Thank you Flippin-Out your advice will be taken and applied!
I'll use 12 or 10 gauge wire from my dedicated battery to the short smaller wire coming out of the unit.
again, Thank you!

My boat was rigged with 16 gauge wire to the electronics and I was having problems with them blinking and going out. I ran dedicated 10 gauge wires to them and all my problems were solved. The actual electronics have about 22 gauge, no way they would work with wire that small run to the batteries or fuse block.

Use at least 10 gauge wire.

Voltage drop is the result of resistance loss in the wire. The thicker the wire the lower the resistance.

I power mine straight to a 30AmpH lithium battery that i keep in the rod locker next to the black box. Powers both the head unit and the black box for 2 days with no issues. Its wired directly into the power cords from the units so no need to add any more wire. Works great and barely drops to below 13 volts in the two days.
$200 simple fix

Show me your math you wont have enough voltage drop in 20 foot or less with 12 vdc to matter. I will say that use what ever the manufacturer suggest regardless of what anyone here says.

I am almost certain that it was in the Garmin instructions to use 10 gauge wire for my LS. It's been a few months since I installed it, so it could have been on a YouTube channel, but I am thinking it was the Garmin instructions. At any rate, I used 10 gauge stranded wire and put both the LS and a 93sv on the same circuit and it has worked without issue. The power wire for the LS was larger than the power wire for the 93sv. It may not have been 10, but it was likely at least a 12.

Here's what I found to be a big issue that I didn't expect - you have got to have a heavy duty switch for the LS or it will pull power out of your battery all the time. It takes an unusually large 12 volt switch to meet the power needs, and it also must have large terminal screws to do a good job of connecting a 10 gauge stranded wire. I found one at AutoZone that would work; I believe it is rated for 30 amps. I also put a 30 amp fuse near the battery to protect the wire. The LS and the fish finder have fuses to protect them, but you also need one to protect the wire in case of a short. Good luck! Mine wasn't hard to install but I had to buy heavier components than I expected.

Thanks Coosa for the info - first time I've heard the LS will pull power out of your battery all the time - I have to ask, does it pull power when the unit is in "sleep mode"?
I always put mine in sleep mode when the trolling motor is out of the water.
I do not have a switch on my LS unit but will consider adding.
The lake I fish is only 640 acres and has timber everywhere so I don't have very much run time in my boat to be able to fish. I am usually on the water 4 to 7 hours and fish 3.5 to 6.5 hours of that time. Using one 12 volt battery has not failed when it begins the trip fully charged.
I was told that by increasing the voltage to the LS it will result in better brighter imaging especially noticed at distances 50 to 70 feet.
Thank you

Here’s what is recommended from Garmin .

Length of wire is also import as well as gauge for current draw / voltage drop. . Do not run more wire than needed such as coiling up wire.

The reason the unit can have a small gauge wire is that it’s a sort distance and ok for the current draw for that short distance.

Both Garmin and most of Humminbird factory instructions request you to run 10 guage wire not sure about Lowrance. Never hurts to run larger wire, one of the biggest problems I have had is that I have to take every battery connection apart once a year and get a small wire brush and clean all the connections along with the battery post. hope this helps.

When you change batteries, clean the connections and coat them with marine grease. You’ll never have to clean a battery connection again until you change batteries. Been doing this for 30 years.