Battery drainage help

[foilled]

Not realizing what’s been killing my battery till now. But if I leave ignition in run I can watch battery voltage off battery drop continuously. It just continues to drop by the the second ticking down. I haven’t let it drain past 8.5 or so volts but as so as I turn ignition back off the battery voltage starts rising at almost same pace it dropped maybe slower. Why is this happening? I can still operate boat but it appears if I accidentally leave ignition in run for even a full minute I’m probably not gonna be able to start it. Battery is fully charged and tested at Napa, which they said it was a good battery.

 

[alldodge]

Why is this happening?

Need a new battery, that one is in bad shape.

Battery is fully charged and tested at Napa

Would sure like to know how there testing it and if its a NAPA bat

 

[foilled]

Need a new battery, that one is in bad shape.



Would sure like to know how there testing it and if its a NAPA bat

Figured but yea not a Napa battery. It’s a diehard 50723.

What size battery should i be looking into? This is my starter battery and also have a deep cycle already. This dead battery is currently a 500 CCA, group 24. Boat is 25ft 5.7 v8.

 

[alldodge]

Get the biggest one that will fit and you can afford, also the 500CCA is minimum (700 to 800 would be good). I would suggest go to Sam's and get their Duracell AGM, but they are pricey

 

[Fed]

I'd want to track down what is draining the battery just to satisfy my curiosity.

 

[89retta]

Don't leave it turned on.

 

[Silvertip]

If the battery is bad, it means it cannot support any significant load. If you have accessories wired so the ignition switch must be in the RUN position to operate those accessories, then that is big NO-NO. Wire them through a MASTER power switch. Inquiring minds wonder why you leave the ignition in the RUN position with the engine OFF.

 

[foilled]

If the battery is bad, it means it cannot support any significant load. If you have accessories wired so the ignition switch must be in the RUN position to operate those accessories, then that is big NO-NO. Wire them through a MASTER power switch. Inquiring minds wonder why you leave the ignition in the RUN position with the engine OFF.

Ignition was left it run just testing battery load not for to long. I have Left in run once on accident overnight. Do not plan on it again. No accessories only turn on when ignition is turned on that I no about so all should be good.

 

[foilled]

I'd want to track down what is draining the battery just to satisfy my curiosity.

Seems like battery just can’t hold load. Put in a second battery and volts don’t drop past 12.4 to 12.5 volts with ignition in run. While other bad battery continuously drops well below even being able to start with that battery within 1 full minute of ignition being on

 

[Silvertip]

What type of boat is this? I/O, inboard, or outboard? If it's an I/o or inboard, turning the key to ON (RUN) sends power to the ignition system. If it's a point style ignition and the points are closed, you can burn the points and drain the battery at the same time. All the more reason to NOT leave the key in RUN.

 

[Scott Danforth]

same issue the guy had here https://forums.iboats.com/forum/eng...0648960-voltage-drop-at-voltmeter-ignition-on

multiple threads on same topic

 

[foilled]

What type of boat is this? I/O, inboard, or outboard? If it's an I/o or inboard, turning the key to ON (RUN) sends power to the ignition system. If it's a point style ignition and the points are closed, you can burn the points and drain the battery at the same time. All the more reason to NOT leave the key in RUN.

Electronic ignition and it’s an I/O