Drain on boat batteries

[yesmarwh]

I have three different lithium batteries. One for my hummingbirds, one for my garmins, and one for the trolling motor. Each has a cut off switch. They were fully charged on Saturday. Today two were down to 99 percent and one 98. Why are they draining?

 

[fairchaser]

I think they will drain over time alone. Try unhooking one completely and you'll have your answer.

 

[Jon]

Perfectly normal for lithium.

 

[WTM]

normal. lfp self discharge is 2-3%/month and sometimes up to 5% if there is bluetooth and battery monitor.

 

[mike243]

Easy way to ck, take a battery cable loose put volt meter between battery and the cable, if it shows voltage something is using it.

 

[7mm08]

normal. lfp self discharge is 2-3%/month and sometimes up to 5% if there is bluetooth and battery monitor.

Interesting. What about straight old lead core batteries? Thanks for the info

 

[WTM]

Interesting. What about straight old lead core batteries? Thanks for the info

up to 10% for flooded and up to 4% for AGM.

lfp and agm you usually dont have to worry as a fully charged batt could be ok for 6 months off charger but you need to keep an eye on charge.

if any of them sit for a bit fully discharged then youll be buying a new battery.