Battery question

Cranking battery is a 2014 Neverstart.

Fished Friday. Went out this AM, master switch off, nothing running, hooked up charger and sure enough...battery is at 70 % again. It charges back up quickly, but will drop back towards the 70 mark quicker than it should.

Humminbird gave low voltage alert twice on Friday.

I hate to replace right before winter...but I don't want to be dead on the water either.

Ideas...

For peace of mind, I'd go ahead and change it. No older than it is you might have some warranty on it or at least get a good pro-rate towards a new one. This one sounds like it definitely has a discharge issue. Just a thought but have you checked your charger on other batteries?

Could be the charger or the connections too. I just went through the same thing. The boat had matching deep cycle batteries, using one as a starting battery. So I bought another battery tray and paralleled the two deep cycles to run my 12v tm and bought a marine cranking battery for the motor and three humminbirds. No more voltage warnings.

The high charge rate when a battery is connected is called surface charge. It's normal.

I had 2 band new optima blue tops and this use to happen to me i just changed the votage settings on my unit and it took care of it i ran 2 for cranking and 2 for trolling the boat alway cranked hard that was the reason for the 2nd battery but i could just have my unit on one battery and cranking of the other and it still did it after about 30 mins of running my unit changing the low voltage settings on you unite lathe way down