# How to run a FishinBuddy with an external 12v power source



## JMichael (Feb 16, 2013)

I've spent a good deal of time trying to find where some one had done this. Unfortunately, all I found were others posting the same questions asking what is the acceptable voltage range, can I use it with a 12v battery, etc etc. For those that are not aware, the FishinBuddy series of fish finders are designed to operate on 6 x AA batteries (9v). After all of this, I decided I would figure it out for myself. And this is what I came up with so I thought I would post it in hopes that it saves someone else some time and trouble figuring out what to do to make this work. 

First I removed the internal battery holder and packing foam. Then I drilled a small hole to run 2 wires through. I connected these into the back side of the plug that the internal battery pack connects to and covered them with heat shrink. There are 2 reasons I did it this way. 1. Power must enter the unit here because the power goes through some circuits that are internal to the transducer assembly. If you try to run power directly to the back of the display it will not power up. 2. I wanted to be able to keep the ability of running the unit with 6 AA batteries should the need arise in the future. 






Next I sealed the hole around the wires with some black 3M 5200 to keep water out and and installed a 2 pin connector on the wires. Then I replaced the foam and internal battery holder.









Initially, I purchased this variable DC to DC converter with a filtered output to cut down on interference in case I ended up using my trolling motor battery as my power source. 





It was working well in my testing but about that time Cabella's decided to have a sale on their 12v 8ah rechargeable batteries. After purchasing one of those, I started digging through some of my old electronics and found my Passport radar detector that had a very compact 12v to 9v dc converter. After wiring some spade connectors to the converter so I could connect it to the battery, I strapped it to the side of the battery with some zip ties and then ran some gorilla tape (bada$$ tape) around the battery to hold the wires in place. Although you can't see it in this pic there is a fuse installed in the + line on the back side of the battery. 





I leave the + lead disconnected from the battery when not in use because the converter will gradually drain off battery voltage if left connected. I've got about 6-7 feet of wire between the converter and fishfinder so I can put the batter well out of the way in the boat. Here's what the finished product looks like. 





The one question that still remains is "what is the acceptable voltage range of these FishinBuddy units". Since I already have the variable converter, I intend to find the answer to that question in the near future but for now I'm tired of messing with this thing and just want to fish with it. :mrgreen:


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## Jonboat Jerry (Feb 26, 2013)

Very Cool Upgrade JMike!
I have a Fisin Buddy 140c, and I have been trying to understand why 
Humminbird would develop a product for fishing that ran on 9 volts 
when virtualy everything else in the industry operates on 12 volts. :roll: 
You have come up with a very good solution and I will "upgrade" mine 
soon. Keep Hacking,
Jerry


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## JMichael (Feb 26, 2013)

Thanks Jerry, I found your build thread shortly after joining the site and have been admiring your work every since. 

You know it just boggles my mind why a manufacturer would go to the all the trouble of changing their existing circuitry up in order to run it on a non standard boat voltage when all of their other FF are designed to take advantage of and use that existing 12v. I understand the whole concept of it was to make it portable, but did they really think that adding 2 more AA batteries to bring it up to 12v would hurt that portability?


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