Selkie was in indoor cold storage over the winter in northern Michigan and I had no access to her. The storage contract provided that the batteries would be disconnected and that trickle charges were not permitted and only staff could run chargers. We heard from the yard that the 2 year old AGM batteries are not accepting a charge.
We questioned the yard about its failure to monitor battery status or charge them and this was the reply, in part:
"We have found and backed by battery manufactures specs that if a AGM battery is good when all loads are unhooked they can sit dormant for six months without going bad or needing charged. "
I have owned cruising boats for 50 years and have never left a battery without attention over winter storage. And I know that Lifeline-the premium US AGM manufacturer calls for battery maintenance during winter storage.
I would welcome other’s thoughts on this topic.
Don Ringsmuth
Selkie 30U 425
Traverse City, MI