HDS Gen3 versus Live voltage

[fisheye216]

I have an HDS12-Gen3 and HDS12-Live at my console and the same setup at my bow. The Gen 3's are 5 years old, and both Lives have been purchased over the last 2 years. All 4 units are wired exactly the same using the Sea Clear power harness ( which has worked great for my setup). When all 4 graphs are on, both Live units consistently have .2-.3 amp higher supply voltage than the 2 Gen 3's. No big deal since I'm getting about 12.6 Volts to the Gen 3's, but curious why the disparity. Any thoughts as to whether this is due to the difference in the units or old versus new power cords? Thanks.

[danieljanse]

My best guess is differences in the screens. I have a power supply in the kitchen where I like to do updates and look at my maps. I was able to hook a HDS Live 9 up no problem but when I switched to a HDS Gen3 12 there was not enough supply amperage (maxes out at 1.5). I thought the unit was bad until I brought in an actual battery. They have upgraded the screens for the Lives. Team Colibri keeps a nice comparison going between generations that should give all the details. Perhaps something else is obvious in the new features.

One other thing to check: is the brightness level the same between the units?

[fisheye216]

My best guess is differences in the screens. I have a power supply in the kitchen where I like to do updates and look at my maps. I was able to hook a HDS Live 9 up no problem but when I switched to a HDS Gen3 12 there was not enough supply amperage (maxes out at 1.5). I thought the unit was bad until I brought in an actual battery. They have upgraded the screens for the Lives. Team Colibri keeps a nice comparison going between generations that should give all the details. Perhaps something else is obvious in the new features.

One other thing to check: is the brightness level the same between the units?

Correct me if I am wrong but isn't supply voltage just the amount getting to the unit and have nothing to do with what the unit is drawing?

[Team Colibri]

Correct me if I am wrong but isn't supply voltage just the amount getting to the unit and have nothing to do with what the unit is drawing?

The first part is correct, the last part is wrong. Voltage supplied to the unit will vary with draw due to voltagedrop.

[Team Colibri]

HDS Live 9 has aprox 12% higher draw than HDS Gen 3 in the same size. I would expect the difference to be larger on Gen 3 12 versus Live 12.

[fisheye216]

HDS Live 9 has aprox 12% higher draw than HDS Gen 3 in the same size. I would expect the difference to be larger on Gen 3 12 versus Live 12.

If that's the case, why is the supply voltage on my 12" Live at the bow .2-.3 volts higher than my 12" Gen 3 at the console? Thanks.

[Team Colibri]

If that's the case, why is the supply voltage on my 12" Live at the bow .2-.3 volts higher than my 12" Gen 3 at the console? Thanks.

There are several potential reasons. :) The by far most usual reason is voltagedrop due to different length of wiring. I have seen one or two examples of Lowrance-units showing incorrect voltage over the years, but usually the voltage-meter in these units is well within a 0,1V margin of error. But it could be that your unit(s) are one of the rare exeptions.
Start by swapping them around, is the difference the same?