Crazy battery idea
 

I'm a plumber...got a metric ton of dewalt 12v batteries. Any reason why I can't use them for fishfinder?

I remember guys doing this 9-10 years ago. Not as easy to connect the accessories to the battery but no reason you cant use them.

thanks.

Actualy they would work very well for what you intend on using them. I know of some guys who would build motorcycle batteries like that as they would be small very light weight and you really needed to use them to start the bike for the race. The rest of the time they were mostly there for the ride lol. Test each cell before to make sure they are good . I don't remember exactly how they put them togher but it was soldering.
If you got that many and you live close to LA I would be more then happy to take half a metric ton off your hands lol.

Dewalt
 

The 18 volt are great for Hummingbird fish finders. They can operate betwee twenty and ten volts.

I will have to check and see if I still have my set up so I can post up the photo, but I have used them plenty of times. They also work great at night with squid lights or floating fishing lights. Main thing is being careful putting them together. The prongs on the batteries are very close together. Easy to zap yourself or smoke your battery

Are you planning on using the batteries as is, or are you going to take out the individual cells? Generally those batteries are only about 3ah as is, so you might need to change batteries after a few hours or so. If you take the batteries apart, you will find 10 1.2v cells which you can connect in series and parallel to make the voltage and amps you like.

I was planning on using the battery as is. Thinking of getting an old drill and cutting off the handle and attaching the handle for the fish finder and then just unplugging or plugging in the battery.

That would make it pretty nice for quick change. You just need to keep everything protected from the elements.

Just looked at the lowrance....am thinking of using dewalt 18 volt batteries....manual says it's good for 10-19 volts.