Batteries were shipped from lifeline to Marina. Date of manufacture last month. Put on multimeter ( didn't want to depend on phillipi) and seemed fully charged before install. Will leave on float for now from shore power. Get divergent info from Internet. Risk of hydration etc.
Do I lose anything by just avoiding going past 50% and using the things in the 65%-100% range I usually do? I have a big enough bank that I won't get to 50% unless I intentional set out to do so. Would need to cover panels and set wind on break or plug in an AC load to run off invertor.
You will get longer life out of the batteries if you shallow discharge. 65% SOC is far better than going to 50% SOC.
The information I put forth is straight from Lifeline's technical manual, years of experience with AGM's (as a marine electrician) or conversations and communications with their head engineer Dave V.... I have had numerous conversations with him over the years about how to get the best life out of Lifeline batteries, in the real world of marine specific installations.. I have also had many conversations with Justin G. too..
Some on the net have
challenged the fact that Lifelines do actually prefer to be be charged at .2C or better for the longest life. What most don't know, or have access to, is that Dave V. presented these findings back in the 90's to his peers (a study done while he was still with Enersys) so it is well known that Lifeline AGM's actually prefer higher current charging and it does lead to longer life. This is the same with the TPPL AGM technology only they want/need even higher current. Of course this is but one piece of a larger puzzle that all come together to = good or poor cycle life.
I am also directly & currently involved in marine specific testing (PSOC testing) with an AGM battery manufacturer. I have been testing them for almost 7 months. Nigel is the other tester. While these are new batteries the technology seems very promising and could be a real game changer for AGM's... As a result we get lots of direct access to some of the best battery engineers in the world to bounce these questions off and learn a lot in the process..
Many owners buy AGM's and destroy them quickly. They can be made to last but it needs to be done as a system based approach.
John Harries has written extensively on this and it is worth the read:
Morgan's Cloud AGM Batteries