Adding dedicated battery for depth finder

[Mr. Mac]

I'm wanting to add a lithium ion battery in a storage area of my boat dedicated only to a depth finder. I have 2 questions. 1, Does the battery have to be grounded? If so, how? 2. Do lithium ion batteries need to be vented?

 

[JimS123]

I can't answer your question about the grounding.

Back in the day when we had CRTs and Flashers, they used a ton of juice. Modern day depth finders use hardly any.

Adding a dedicated battery is a wasted effort. Besides, now you're adding a battery that must be charged periodically. Having it in storage is a pita.

If you use the main engine's battery, the charging / recharging will be automatic. Easy, peasy.

 

[Scott Danforth]

Yes, all the grounds must be tied together. You know you need a different type of charger for the lithium battery than a standard lead acid battery

 

[dingbat]

I'm wanting to add a lithium ion battery in a storage area of my boat dedicated only to a depth finder. I have 2 questions. 1, Does the battery have to be grounded?

Not if dedicated for use with the depth finder. Wire DF direct to battery.

2. Do lithium ion batteries need to be vented?

Just so you know….Lithium ion batteries are known to catch fire via different causes.

A boat is the last place I want a run-away, self sustaining fire….

Why do Lithium-ion Batteries Catch Fire? How to Avoid the Mishap? - Saur Energy International

Lithium-ion batteries catch fire due constituent elements - electrolyte consisting organic solvents, oxygen-rich cathode, flammable gases.

www.saurenergy.com

 

[Horigan]

I suspect he means a LiFePO4 battery, which are safe for boats.
They don't need venting, but the above points are valid. A depth finder wouldn't be a big draw on the main battery.

 

[BWR1953]

I have this Nocqua battery and it works great for powering my Garmin Striker Plus 4. Lasts for hours and hours and hours.

I just hung it underneath the bow area and it stays safe and dry.

Nocqua battery & charger

 

[airshot]

On my Islander I ran a standard group 27 lead acid battery for everything on board except the engine itself. Sonar, ship to shore, gps, nav lights, stereo you name it! I could get three 8 hr days on the water before charging with ease. Your sonar only uses a tiney bit of power, no need for overkill!!

 

[briangcc]

I think this is a case of fixing something that isn't broken.

My boats have/had fishfinders/gps on them and have never had issues starting the boat after use. Bayliner had an Eagle (forget the model), Four Winns had an Eagle Fish Elite, and Chap has a Garmin Styker 4 Plus (desparately needs replacement as the screen is way, way too small and GPS is horrible). Typical day is go from dock 5-15 min to fishing spot, kill the engine, drift/anchor/troll, move as needed, go back to dock for meal then rinse & repeat.

If you're overly concerned about your battery surviving....replace it with one with more reserve capacity. I got 5 years out of mine before replacement was required.

 

[Silvertip]

Whether the dedicated battery is a LiFe or LiPo you will need a charger specific to that battery chemestry. Cell voltages and charge profiles are different for the two. And I agree that the last place I want a LiPo battery is on a boat. Being dropped, kicked, bounced around or heaven forbit punctured, you risk a fire that you cannot put out with water as the battery creates its own oxygen.