Good Day - I am a program manager supporting a team of CET's maintaining a number of small, but high density data centers for a large client. We have encountered an issue with two separate strings of batteries (140 ea.) at two different locations. The batteries are out of manufacturer warranty, but less than three years old (VRLA). The batteries are labeled from the UPS manufacturer, but our third party UPS support vendor has stated that these batteries are private labeled for the UPS manufacturer from an OEM in Asia and have exhibited an abnormally high rate of premature failure.

I've queried the third party vendor for "official" documentation on their assertion, checked the UPS manufacturer website and have done a number web searches (based on UPS manufacturer, Battery OEM name, etc.) and have found nothing indicating that this may be a known or widely known issue.

I am trying to gather information so that our client can go back to the UPS manufacturer with data/technical service bulletins, etc. and request replacement, if these are substandard batteries. So I am not necessarily looking for an answer as to why the batteries failed, but whether someone may have resources or specific sites they may be able to point me to, so I can do further research.

Apologies if this is the incorrect venue for my question, I realize my question may not be completely on topic for this forum. I've been intentionally vague about the parties involved, as I don't want to cast aspersions with nothing but "tribal knowledge". Your help would be greatly appreciated.

I don't think I can offer the level of expertise you need, and it's been quite a few years since I've had close contact with batteries, but in the absence of other responses, I offer the following.

You don't identify the cause of failure, or indeed if the failure mode was common. Batteries can be built to different standards, so a starting point could be to enquire of this from the vendor or from contract documentation. Does the design duty properly meet the duty demanded by your operations - eg are these batteries being float charged with occassional short periods of discharge, or are they being frequently discharged to a low state of charge - this latter duty being more onerous, particularly if being taken to states of charge <20%, where the life expectancy can fall like a stone.

Other factors reducing operational life are:
- batteries getting too hot, either because inadequate space for airflow between battery units, or high ambient temperatures in the battery room
- charge voltages too high. VRLA batteries are very sensitive to even small increases in float voltage from that specified (2.27 volts per cell comes to mind at ~ 20deg C, but check the manual)
- charge voltages too low (or insufficient time being allowed to recharge) resulting in the batteries never being fully recharged
- high levels of ac ripple on the dc charge voltage
- poor temperature compensation on float voltage levels
- excessive number of parallel battery strings (resulting in poor sharing between strings and/ or circulating currents)

The culpability of your vendor may be moderated by operational or environmental conditions that are outwith their control, or that weren't advised at the time of contract award, so some detective work may be necessary. It sound like there could be substantial costs in the battery replacements, so employing an appropriately experienced consultant may be a good way forward.

Good luck and keep us posted.

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Jonno