BlueSea ML-ACR but dead chassis battery

[gksmith]

I was surprised the other morning to find my chassis battery dead and am now trying to figure out why. It was plugged into shore power for about two weeks. I have a BlueSea Magnetic Latch Automatic Charging Relay installed and it has previously worked fine. However, after charging the chassis battery with an external charger, I am now having doubts that the ACR is functioning properly. I cannot get it to latch or unlatch automatically. Plus the remote switch is non functional. My testing consisted of turning off the engine, but turning on my coach refrigerator, running on 12V. The ACR was in latch position, but never unlatched, even after 1/2 hour or so. This was the largest drain I could think of for the coach 12V system. Similarly, I manually unlatched the ACR and started the engine, thinking that it should latch after a period of time, but it never happened.

Another problem, which may be related, is that I have discovered that when on shore power, I am not getting any current delivered to the chassis battery even though the ACR is latched. Similarly, when running the engine and off shore power, I do not detect any voltage being sent to the coach batteries. Voltage does get sent to the coach batteries when using the genset. But I cannot start it unless the ACR is latched. And to further confuse me, the genset will shut down if the ACR is unlatched.

I am confused!! Are the symptoms related? Or do I have multiple problems? As far as I knew, everything was fine until now. Our last long trip was in August, but have used it a couple weekends since then. What is most baffling at the moment is that the engine is not charging the coach batteries. The trips since spring have involved using shore power, but our major trip last spring involved doing a lot of dry docking. However, upon returning home when the Covid scare began, I thought my coach batteries had gone bad, so I replaced them before returning home for the 1,500 mile trip. In retrospect, my charging problem may have started even before then. But I believe that my ACR was working properly before and after then. But. unfortunately not now!

This became an awfully long exposition, but I hope that it gives enough information that I might receive some guidance from some of you out there! I will appreciate any help you can give. Thanks in advance!

[markopolo]

Maybe work through the troubleshooting steps -> http://assets.bluesea.com/files/reso...FAQ_Matrix.pdf - could be open ground.

[gksmith]

Solved it! I was positive the ground was fine as it was firmly attached to the clamp on the negative battery post. However due to your comment and the troubleshooting guide, I decided to undo the negative battery post clamp and put a proper ring terminal on the ground wire instead of merely having the bare wire stuck between the clamp and the post. Success! The ACR now works as before. Thank you for your response and help. People like you are invaluable to this site!!