Humminbird updates cable

[Bud-dy]

I have a 797 c2 side imaging sounder/GPS.
I bought the computer link cable the other day with the idea of upgrading to the latest update. When I got the cable home the end that goes onto a power supply has 2 by 9volt ends, when I hook up one little 9v battery there is nothing coming throught the sounder end then when i hook up 2 9v batteries the voltage output at sounder end is 18.93volts. there is NO fuse holder inline. I haven;t connected it up because was worried about the 18.93v going into sounder ?
I normally run a 12volt gel battery in the boat for the front sounder (a humminbird 777 ) so was going to cut the cable put a 2amp fuse inline then use it that way BUT why would it be supplied with the ends the way it was ? Haven't been back to shop were I bought it yeat to ask why ?
Has anyone bought there computer link cables this way and used it ? If so how did it go ? Any information would be great !
Thanks
Paul

[Toddy_again]

Gday Paul.
You dont need the cable for the 797.You can just download the updates to an sd card,restore to your factory defaults before hand ,put the card in and it will do it all for you.
Its really that easy to do.Let me know it you need any more info but there really isnt any more than that.


Toddy

[hodges4]

Paul
I bought the same cable a couple of years ago.
The info on the Humminbird site says if it has 2 x 9 volt battery connections then you need to connect 2 x 9 volt fresh batteries. The unit is safe to use at 18 volts. I rewired mine to work off a 12 volt battery so there is no chance of a flat battery while updating software which can cause a major problem.

John

[Izzey!]

9v batteries are not cheep so I rewired mine to run off a 12v transformer I had off an old kids toy, don't remember what amperage it was but worked fine.

[Bud-dy]

thanks for info guys. With the 12volt converstion did you put a fuse inline if so what size fuse ?

[hodges4]

You could place a fuse in the wiring if you desire but all your really protecting is the wiring. If anything goes faulty in the sounder which blows the fuse then it's probably a bin job anyway. Use the same fuse size that Humminbird use in the boat installation.

A fuse may blow if you connect the 12 volts around the wrong way. Damage would probably still be caused to the sounder but it may be an economical repair, but not always.

John