Originally Posted by mtntrek
Ever been in a POTS Plain old telephone system exchange? Large rooms of commercial heavy wet cell batteries wired in parallel doing little or nothing just in case they might be required to provide 48V for phone service in an outage. May only happen once or twice in their entire lifetime.
There was an interesting article discussing large 48-Volt battery banks assembled from 24 X 2-Volt cells which started out with an extra cell (25 total), making it literally a 50-Volt system. The idea is that if one cell fails, you remove it and keep going. Furthermore, if another cell fails, the system can still operate at 23 X 2-Volts, or 46 Volts. This was for solar homes and or buildings, but sounds similar to submarine procedure mentioned above.
The premise was that 48-Volt inverters can function adequately within the higher and lower ranges, so the only requirement from the owner/operator is to reset charging voltages to adjust for 50, 48, or 46 nominal Volts.
This idea wouldn't be practical for most RVs because that many 2-Volt flooded or AGM cells would be too large/heavy; but it does get around rare problem of individual cell failures.
The funny thing is that lithium batteries often connect tiny cells in series to make higher voltages, and then in parallel to increase capacity. It's the same principle but they can get away with it because lithium cells can be so small while remaining practical.