every time i start my motor (200hp mercury efi) my hds 8 unit reboots. i have taken it back to the marina where i got it installed and he says he hooked it up right and suggested i get a new battery. i got a new one but this didn't fix the problem either and hen doesn't know what else to do. has anybody else had this problem, and if so, what can be done to fix it? thanks and Happy New Year!

It does sound like a voltage problem..

I have had the same issue and it may still be the battery. It definitely sounds like a voltage issue. Does it happen every time that you start the motor or just later in the day after you have fished for a while? If you are running other graphs or things off of your cranking battery you may need to move to a battery with a longer life ( I beleive it is measured in Amp hours, denoted AH on the battery). This may solve the issue that you are talking about. I run an HDS 10 at the console and a HDS 8 at the bow and when I run those units simultaneously for a day of fishing both graphs will shut off when I crank the motor. I solved this problem with a new optima blue top 31 series. It is an expensive battery but has enoough power in it to run all of my stuff for days at a time. (i.e. powerpole, structurescan,livewell pumps)

Hope this helps

What is the CCA rating on the battery? I believe they spec a minimum of 1000. If you have a voltmeter, how low does the voltage drop when you start it? If it's not the battery, your starter may be dragging and drawing excessive current causing a large voltage drop.

newer motors really pull the cold cranking amps down. if its a merc opti- you really need the CCA to be above 1000. when you crank these big powerful motors, it pulls the battery down and is making the available battery voltage go below the minimum voltage threshold for your graph. get a bigger battery(group 31 size) with the most cold cranking amps you can find.

+1 and also make sure your power wire is not spliced into another hot wire. It needs to have its own hot wire directly to the battery.

i run my graph power through my fuse panel. you shouldnt have any problems doing it through the fuse panel- as long as you have a good battery and clean terminals at the battery. I like using my fuse panel because it shuts off the graph when I turn the master power switch off, so I wont leave it one mistakenly and run down my battery.

i will look tonight on the specifics of my new battery but it is the biggest one the marina sells. it is wired through the main power switch because if the main boat power is off, the unit is also off. i guess i could get a battery just for the hds unit, but i really dont have room for it. well, thanks for the suggestions.

I wired mine to run off of my trolling motor battery and it solved the problem.

i thought running it through your trolling motor would cause lots of interference?

Wire it directly to the battery and you will probably solve your problem It is also very important to power your graph off with the switch on the graph itself I know that people have shut the graph off with the key switch for years but you run a huge risk of damaging your unit by doing it this way It's kind of like nuking your computer by unplugging it or hitting the power switch rather then going through the normal shut down process. Also note that most graphs don't pull alot of juice I can leave my graph on all night and the boat fires right up the next morning.

It needs to be a fused connection no matter how its wired. I like to go through a power switch as that will shut down everything. Depending on how your network is set up, your antenna can still be going with your graph turned off. Will fry the antenna over time and drain your battery.

I had the same problem. Get power from another source & you will be good.