06-18-2004, 08:52 PM
[cool][blue][size 1]There are conversion tables of watts to amps and all that stuff, but it gets confusing when you are talking sonar systems. They advertise "peak to peak" watts, as an indicator of how strong the signal is and how sensitive they are. The higher the rating the higher the sensitivity.[/size][/blue]
[#0000ff][size 1]The kicker is that you have to think "RMS" watts (root mean square) which is an averaging of power used to be able to convert to how many hours you can get out of a battery. That is usually a much lower number than peak to peak.[/size][/#0000ff]
[#0000ff][size 1]I gave up trying to make sense of it and I tend to subscribe to some advice I got from a guy that sells RV systems. He said that you need to just see how long you can run something off the battery without draining it totally to really know what the drain is. His advice was to never run a battery lower than about 50 percent of capacity. [/size][/#0000ff]
[#0000ff][size 1]Most gel cell batteries will put out just under 14 volts when fully charged. When they show 12 volts, they are getting down to the point they should be charged. You should never run them down below about 11 volts.[/size][/#0000ff]
[#0000ff][size 1]What I have found through experience with the lower wattage Eagle products is that the amp hour draw is about 1/100 of the peak to peak wattage. In other words, when I ran a 500 watt unit, I used about 1/2 amp per hour...5 amp hours in a long 10 hour day. My current 800 amp Cuda 168 sucks about half again as much, meaning I can get a good 7 or 8 hours out of my 6 amp/hour gel cell without fully draining it.[/size][/#0000ff]
[#0000ff][size 1]A 1200 watt unit would probably max out a 6 amp hour battery in 4 or 5 hours. A 4000 watt unit would need a big marine battery to give you a full day on the water. Of course, you could take a couple of 7.5 amp gel cells and switch over when the first one gave up. But, that would be rough on the battery life. That big system would show a lot of detail you would need for deep dropping to macks, but would be wasted on shallow water lakes for bass and trout.[/size][/#0000ff]
[#0000ff][size 1]My disclaimer is that these computations are based upon actual useage and not on any scientific formulas. The manufacturers are real good (bad) about not publishing specifics along those lines. [/size][/#0000ff]
[#0000ff][size 1]Hope that puts a little more structure to it. We have had some formulas posted in the past, but actual useage sometimes throws X factors into the equation. The only thing you can be certain of is what you experience for yourself, using your own gear.[/size][/#0000ff]
[signature]
[#0000ff][size 1]The kicker is that you have to think "RMS" watts (root mean square) which is an averaging of power used to be able to convert to how many hours you can get out of a battery. That is usually a much lower number than peak to peak.[/size][/#0000ff]
[#0000ff][size 1]I gave up trying to make sense of it and I tend to subscribe to some advice I got from a guy that sells RV systems. He said that you need to just see how long you can run something off the battery without draining it totally to really know what the drain is. His advice was to never run a battery lower than about 50 percent of capacity. [/size][/#0000ff]
[#0000ff][size 1]Most gel cell batteries will put out just under 14 volts when fully charged. When they show 12 volts, they are getting down to the point they should be charged. You should never run them down below about 11 volts.[/size][/#0000ff]
[#0000ff][size 1]What I have found through experience with the lower wattage Eagle products is that the amp hour draw is about 1/100 of the peak to peak wattage. In other words, when I ran a 500 watt unit, I used about 1/2 amp per hour...5 amp hours in a long 10 hour day. My current 800 amp Cuda 168 sucks about half again as much, meaning I can get a good 7 or 8 hours out of my 6 amp/hour gel cell without fully draining it.[/size][/#0000ff]
[#0000ff][size 1]A 1200 watt unit would probably max out a 6 amp hour battery in 4 or 5 hours. A 4000 watt unit would need a big marine battery to give you a full day on the water. Of course, you could take a couple of 7.5 amp gel cells and switch over when the first one gave up. But, that would be rough on the battery life. That big system would show a lot of detail you would need for deep dropping to macks, but would be wasted on shallow water lakes for bass and trout.[/size][/#0000ff]
[#0000ff][size 1]My disclaimer is that these computations are based upon actual useage and not on any scientific formulas. The manufacturers are real good (bad) about not publishing specifics along those lines. [/size][/#0000ff]
[#0000ff][size 1]Hope that puts a little more structure to it. We have had some formulas posted in the past, but actual useage sometimes throws X factors into the equation. The only thing you can be certain of is what you experience for yourself, using your own gear.[/size][/#0000ff]
[signature]