Simple Transom mount and Battery Basket

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So as of right now, you have a deep cycle battery but no motor. Is the battery you're using just for the sonar? If so, I'd rethink that and get a smaller 1280mah 12 v SLA battery until you get a motor. And getting an AC inverter to run anything else like charging a fish finder isn't going to happen.
An inverter runs off your 12v battery- so does your fish finder. So if the fish finder is running out of juice, so is your battery so an inverter is a moot point. Need light? 12v LED's fit the bill. Or if it's a light you drop in the water, I'm sure you can get on in 12v.
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