On Mon, June 26, 2023 1:03 pm, Dave via time-nuts wrote: > The other, an "APC SMART-UPS 600" seems to have space for two batteries. > > I have found a manual for the "600" unit but it mentions nothing about > the number of batteries or if they should be connected in series or > parallel :-( The APC and CyberPower consumer grade UPS units I have all connect the batteries in series. They are usually taped together in such a way that a short jumper can go between the terminals, and the pair will slide in and out together. -- Chris Caudle