China's cheapest agms have their time and place.
You've found their limitations in actual use with tools knowledge and observational focus that few ever bother with.
Agms on automotive forums seem to be viewed as magical upgrades that are immune to anything a human can do to them. Marketer's sense more profit, More bonuses and more shiny objects obtainable for their significant others who are enraptured by such things and judge everything and everybody by them.
Cheap as possible agms made in usa now can compete with China's cheapestfree shipping online agms in autoparts stores nationwide, and will proudly state deep cycle on their stickers too.
The deka intimidator agm tested horribly in actual deep cycle use, although east penn can certainly make top quality if the profit motive is there. It is not.
Any battery can be marketed for deep cycle use. Whether it is built for actual deep cycle use is apparently now irrellevant, if it gets in the way of max profit.
Many batteries that are 'still going strong' according to their owners, would likely also jump off a cliff if subjected to your high occassional loads below 75%soc
But ignorance is indeed bliss,for a while anyway.
Then it's finger point city.
