UPS / Battery Query
Chez Feline (aka The Cathouse) is undergoing a UPS review (there being six active UPS's in use on a clear day). This was initiated by one UPS only giving 46 seconds output after losing mains power (despite replacing the battery).
As a replacement, I pulled a duff UPS out of the must-get-around-and-look-at-it--someday (!) pile.
On opening its case, I discovered there were two CS3 12 volt 7.2AH lead acid sealed batteries - both completely dead. Replacing both batteries is somewhat cheaper than replacing the whole unit (though not by very much).
What rather worries me is that the batteries are hard-wired in parallel rather than in series which seems rather dumb to me. Surely it would be better to wire them in series and design the converter/charger circuitry to run at 24 volts? I would add that this is a Brand "X" unit and was acquired on the basis of price rather than anything else.
I would have thought that wiring them in parallel is not a good design philosophy since if the internal resistance of one battery increases relative to the other battery, there will be an imbalance in both the discharge and charge rates, which will lead to premature failure of both batteries.
Question: Is this a valid concern? And should I be worried or very worried?