My B.S. detector is quivering...
Lifeline, made by Concorde is considered the gold standard in the industry. By experts. Sort of like Rolls & Surrette for flooded batteries. The Concorde battery cycle DOD chart does not come close to the "Northstar". Personally I have never heard of this brand and manufacturing an AGM battery is a big enterprise.
This battery would just about having to be manufactured overseas, with Germany being a top guess. Home of Sonnenschein and other top originators of accumulator quality. To put it bluntly the chances of me venturing forth and blindly putting my money on a mysterious brand battery making rather robust claims is well, near zero. Of course this is my opinion based on my own needs and wants.
I've seen a lot of battery braggadocio come and go in the last 50 years. You may consider me a skeptic about wild claims. There is only so much room in a group 31 jar. Fitting plates, envelope separator glass mats and cell connectors leaves only so much extra space. Concorde claims it has squeezed out the last mm of available space. After giving their technology the eleventh and twenty sixth over, I would have to agree. Where does this leave the North Star claims in my humble opinion?
Coming back down to reality I think your choice is a good one regarding battery type. I would myself, choose an accumulator that fit my budget, and seemingly has the best service and warranty procedures. If my goal was the longest lived battery I would take a hard look at Concorde's Lifeline. There is no thinner AGM positive plate that is going to outlive Concorde's .115" positive plate. That and they are the only OEM that uses AGM envelope separators which stop plate mossing shorts which is hyper critical when plates and mats are stuffed as tight as they are in the Lifeline.
But all of this is my opinion. Most importantly, the AGM is going to give you a solid uptick with electric motor operation. In fact I would have to say flooded batteries here would be inappropriate.
Hope this helps
