Dual Batteries, only one is charging

[c_harksen]

I have a 2016 234LR with a 250 Yamaha and dual batteries. I have the Blue Sea Systems 6011 battery switch and the BEP voltage sensing relay, both part of the boat when purchased. Power pulls from both batteries/circuits (starting and accessories), however only the starting battery gets charged when underway. The accessory battery drains down to nothing. My guess is the BEP unit is bad. Any other thoughts?
Thanks in advance!
Chris

 

[Scott Danforth]

welcome aboard

and based on your description, yes

 

[dingbat]

I have a 2016 234LR with a 250 Yamaha and dual batteries. I have the Blue Sea Systems 6011 battery switch and the BEP voltage sensing relay, both part of the boat when purchased. Power pulls from both batteries/circuits (starting and accessories), however only the starting battery gets charged when underway. The accessory battery drains down to nothing. My guess is the BEP unit is bad. Any other thoughts?
Thanks in advance!
Chris

They are rather simple units. Not much to go wrong with them.

The first thing to do is to check that it’s installed correctly, fuses are intact and the cable lugs are clean.

From there, I’d check to make sure the charging system is working properly. You need a sustained 13.2 vdc at the input to actuate the combine circuit.

From the brochure, what is different from my Blue Seas is it prioritizes the “starting battery” over house. It will not open to charge house until the start is fully charged.

Have you load tested your batteries lately?

https://www.bepmarine.com/-/media/inriver/710-140A_INSTR_BEP.pdf?modified=20191030114145