Using your will be maintained vehicle/equipment batteries as a needs-must bank is correct as what i was trying to promote.
Not ideal. No. But very DOable. And at only an ~20% higher cost then it WILL cost you to keep all your electric starting equipment's, charged, maintained, hot and ready to go.
So . . . put in your home-house battery bank. Now get to weekly, monthly inspect and maintain THAT; in addition to all of your electric starting batteries too!!
I can count on one hand out all of the hundreds of fellows (and gals) who have set up big house banks who actually Do, Do their banks inspections and maintenance's.
"Form follows Function" An old truism that has to be re-proven over and over again. Wear sensible shoes and boots!
"Practical endures. Idealism's peter-away to crying" Another truism many still must learn.
J-I-C Steve Unruh