GraniteStaters Posted November 15, 2022 Share Posted November 15, 2022 This is an update containing some new information about the AGM battery issues that we experienced this fall. Most of the background is in a T105 post by another Oliver owner. It is my host that an admin may be able to advise on how I might migrate some of the info contained into this new entry, but until then, I will briefly summarize concentrating on the new information. This fall we were boondocking in Maine and were using the furnace overnight, we had a low battery alarm that surprised us, but we had notice the furnace was cycling a bit more than we had experienced on the previous nights. Overnight temps weren't approaching freezing and we only set the temp to 58 overnight so we really didn't understand why it was cycling so much. When we had the alarm, the batteries were below 12V. We did some testing in our driveway when we returned from camping on several cold nights after insuring the batteries were completely charged by the solar panels. After some alarming test voltages on both strings of batteries that showed the first 6V battery in each string had very low voltage while just running the furnace, cell booster, and Wi-Fi extender for several hours after the sun had set. It was suggested that we have the batteries tested and I took the two suspect batteries, one was 3 years old and the other 2 years old, to Batteries-Plus for a load test after both batteries had been charged and sat for a day and both passed. I reinstalled all the batteries again and monitored for a few weeks during the warm fall weather with the intent of testing under colder temperatures. I completed my first major overnight test attempt with temperatures in the 20's last night. I had disconnected the shore power yesterday morning before the solar kicked in and it was a very sunny day so I ran the furnace, cell booster and Wi-Fi extender for the duration. The solar stopped charging at about 2pm, but everything else continued to use about 11Ah during the latter part of the day into the early evening. I went to bed in the LEII at about 10pm EST. We were at 12.7V on both strings when I went to bed and at 12.4V when the furnace and blower were cycling. When I woke up at 12AM, I discovered the voltage at 11.4V when the furnace blower was on and decided to shut off the furnace and move back to the house. The voltage was 12.3V when the furnace was shutdown. When I got up this morning at 6AM well before the sun has risen and started charging the batteries the battery voltage was at 12.7V. I was flabbergasted. I suspected that it would be about the same voltage. My Victron SmartShunt confirmed that we were at 94 percent SOC and had a very modest .37 amp parasitic draw. I am completely baffled by all this and still suspect that we have a battery issue or a furnace issue due to excessive cycling. We had a 34Ah draw down at 6am this AM since the last complete charge. 2 David Caswell and Paula Saltmarsh Hull 509 "The Swallow" Link to comment Share on other sites More sharing options...
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