korbe wrote:
Well, I have been using my volt meter and measuring the readings in volts for a lot of years. Doesn't the volt reading measure state of charge? I must be missing something.
You're not missing anything. Using a voltmeter is just fine for assessing the general SOC of your battery provided you measure with the battery's open circuit voltage and take care to avoid measuring surface charge. Those with a significant investment in multiple batteries and a costly solar system will of course want the means to more accurately track what their DC system is doing but for the vast majority of us who just want a general idea using a voltmeter is fine.
Case in point - some years ago we we dry camped in Yellowstone for 4 nts during July and our one G27 battery handled the task just fine. On the morning we were leaving I measured the battery's open circuit voltage with a DVM and saw ~ 11.9 volts ... we towed all that day and intentionally camped that night at a KOA because I knew we'd have 120 vac shore power available for fully recharging the battery. Upon our arrival around suppertime and before plugging in I bled off battery surface charge with a light bulb, then measured the battery's open circuit voltage at ~ 12.6 volts so obviously the charge line from our Explorer
did accomplish a decent battery recharge over the course of 8 hrs of driving that day. The next morning we left the KOA and headed to RMNP where we successfully dry camped for several more days with no issues at all.
