(Help) Raymarine Dragonfly -Hobie outback

[Apex]

Upgraded to this dragonfly, looks cool and all but can't get this thing to work for me. Went to basspro and exchanged for a new one thinking the original was faulty. Didn't solve the problem so here's the issue, for the last 2 days I've been testing the fishfinder out at my local lake to dial it in. But can't seem to figure out the problem. While on the water at a drift, depth will zero out. I know I'm in more than 3 ft of water and then out of no where it starts reading. Really annoying and inconsistent, even the bottom reads with lots of detail then on some passes really unclear. At times it loses the bottom completely and for a minute or so won't read at all. Speed and temp work fine and never glitche out, I'm using 12volt 12 amp lead acid battery rechargeable (new).. Tansducer is mounted in my lowrance ready slot in my hobie outback level and exposed enough for a good read all connections are solid . Used the same battery on my elite dsi no problems. I've come to the conclusion that the unit is not getting enough juice to power the unit to its full potential ? Any advise would be greatly apreciated thanks for reading