Maybe a few “ignorant” questions… (The only dumb question is… ) I know that our traditional lead-acid batteries require use/charging, and I have been delinquent… I have a 20-year old battery charger with a needle and a red/green scale. Half of the times when I have used it on assorted batteries the needle has moved, and the battery came back to life. And sometimes it just never moves… Semi-intelligent questions: Is that just a volt meter? Is there a direct relationship between a battery has X volts and its ability to start the car…??? (In other words, can a battery show 12v, but not have the amps to start a car…??? Being a “numbers guy,” not a “red-green” guy…) Maybe just wishful thinking on my part, but I imagined that in our “high tech” world there were “battery tester/charger/tenders.” With an LED display that would (politely) say “You’re screwed, buy a new battery,” or “Your battery will be charged in XXX hours.” I just hunted the Summit site, and found no such thing… (If you read this far, that is really what I’m asking…) Pending helpful responses, I promise to treat a new Group 24 battery (AC Delco or Interstate, to fit under my topper, LOL!), and the ’70 GS in which it sits, better…!!! (I can’t help adding, since my local racetrack closed, I have lost some enthusiasm for even just “keeping the car running…”) Nick A P.S. ,of possible humor… A couple of years ago I brought a 2-year old Duralast battery from my daily driver back to Auto Zone for pro-rated warranty replacement. (A brake light switch failure had drained the battery. Seriously, who does a “walk around” after parking their daily driver! Probably, some of you do!!! I bow in disgrace…LOL!) They put it on their “machine” and said it could be charged in four days. Replacement was not an option. Get my original “warrantied” battery back in four days, or buy new… Obviously I bought a new battery, and acknowledge that the brake light wasn’t their fault. But that planted the seed of my perhaps fantasy of a “smart battery tester/charger/tender…”
There is a chart or table somewhere showing "state of charge" in % and the open-circuit voltage that it refers to, for lead-acid batteries
I like to put my charger/maintainer on a timer so the battery only gets a charge for about a half an hour in a 24 hour period. This seems to maintain the 5 batteries i do this with very well. All are 12 volt, and inside a heated area. 2 are my lawn mowers.
There are intelligent battery tender/chargers that can maintain a charge over long period of inactivity, and also resurrect SOME dead batteries. I have one that looks like this. https://www.amazon.com/Battery-Save...0&psc=1&mcid=ef8984d7774a3bb6a8ac7a397e1de9c2
Couple of things (These are "estimates") - Battery needs to be about 13.5 volts to start a car. When they get to 12v it's iffy. see amperage below - plates can short out ruining the battery - low fluid (even on "maintenance free") ie water can ruin a battery, but adding fluid (distilled water) may fix it. - glass mat batteries may not charge when dead. A trick is to put a regular lead acid battery in parallel with it. The charge needs to see some voltage or it won't charge. Once it starts to charge you can remove the lead acid battery - load test checks the amperage capability of a battery. Voltage really doesn't count. - deep cycle (marine) batteries can be completely discharged with out damage. Mostly. - A Smart Charger or batter tender usually doesn't have enough amperage to charge a dead battery. You need at least 5 amps for hours to bring one back. - Car alternators aren't designed to charge a dead battery. It shortens their life done too often. Jump start a car only if you really need to. - And - you must drive a car hours to fully charge the dead battery. Put it on a charger when you get home if your trip was short. Now argue with me...or at least correct me! lol
Battery tender for the win. Keep them on 24-7. Batteries in my enclosed trailer are ten’ish years old and nothing wrong with them
