With the possible exceptions of a few fans, a few monitors, and probably Air Conditioning units, all of the rack units are powered by self adjusting transformers/rectifiers. The 5 % low supply voltage probably meets their requirements/design. Large fans may be at or under their design. The AC unit(s) almost certainly are at the max of their design limits. If the only problem is burning up batteries, I think your cut-over switch sensors could be the only thing that needs bucking transformers. I'm sure that you have 3 leg sensors, and a several minute minimum cycle time to prevent chatter. Your split AC system compressors are probably on the roof. I'd also guess that you have a redundant AC system, since that is probably the most critical element of the works. System shutdown should only lose info being transfered in in the event of complete failure. Error-correction raid storage means that your data is at least secure. You probably have off-site continuous Ø storage, and additional daily, or weekly back-ups to protected storage.

The powersupply for the Dell laptop that I am using now is rated 100-240 VAC. Your 196 V should equate to 113 V/leg, which should fall into the self correcting range of all of your 3.5, 5, and 12 V DC power supplies. If the racks are ventilated, those vent fans are probably line voltage. The fan in the evaporator unit in your data center is certainly line voltage, maybe even 208 V, either 1 Ø or 3 Ø. This is probably less than a 1 hp fan, but even a 3 hp 3 Ø will be less than a 15 A draw and is a fine candidate for bucking if it needed it. I doubt it. The rack fans, if individual, are almost certainly 120 V, and 113 V should be satisfactory for their operation. If they use a system ventilation, that could potentially be a 3 Ø fan, and checking draw would tell you if you are within operating range. If not, most 3 Ø fans are belt driven, and if not equiped with adjustable sheaves, should be, and can be brought into range easily, unless your air flow is already minimum. Rarely, at full rated draw. A 3 Ø motor will not run underspeed if it runs at all. Overloading will occur at as little as 2% phase slippage, and vibration will make you aware of the difficulty pretty quick.

That mouthful said, I really doubt that anything other than your line voltage sensing circuits are suffering, and there is a strong possibility that you are crying wolf for a mouse. Try bucking your line voltage sensors only to 208 V, and that should solve the only problem you have described, which is frying your UPS batteries from over-sensitivity at too near their set point. That, of course would be based on non-adjustable set points, which is unlikely.

By the way, is your battery room exhausted to prevent Hydrogen accumulation?

RichH