UPS battery replacement schedule

On 02/05/2009 05:39 PM, (PeteCresswell) sent:

Hello Pete:

We never had to try something like that. We only needed something to absorb sudden dips and spikes. Our UPS systems just needed to last long enough for our banks of big diesel driven generators to start, stabilize and switch in.

However, your question is excellent. The problem lies in the design differences of the batteries.

Typical thin plate automotive batteries will not withstand many deep discharge cycles.

I believe the old adage that an automotive battery looses one year's life for each deep discharge, is still mostly true. I believe that sulphate damage begins with the very first deep discharge and would accumulate with each additional deep discharge.

Industrial grade Sealed Lead Acid (SLA) batteries are constructed to withstand these cycles with extra thick plates. This is not to say that an automotive battery couldn't be used in a rare emergency, but to see continued use would call for the proper industrial deep cycle type battery.

Someone may post a follow-up in this thread regarding the unmodified UPS, sensing the automotive battery's soon dwindling voltage as an unanticipated/early battery discharge.

I suppose you could look into using true/real marine/RV batteries, and possibly modifying your UPS. However, UPS manufacturers are usually not very forthcoming with their product's maintenance manuals, schematics, piece parts, etc.

I encourage you to Google this for a deeper understanding.

My warm regards to you.

Pete

You would want a deep cycle battey... Which will not be cheap(er) but whatever floats your boat so to speak!

I'd use something like an Optima (there are many similar brands). A regular non-deep cycle battery *will* fail very quickly as they don't like being fully discharged.

Check WalMart (if you're in the US) for deep-cycle batteries. (Sometimes these are referred to marine batteries, but check carefully!)

Is this a sealed lead acid? I've never seen one of those swell.

Yes, it is. It is so swollen it was quite a challenge to remove it from the UPS.

I have had to completely dismantle a couple UPS that had the battery so swollen it couldn't be pried out of the battery compartment.

I wasn't aware those type of batteries swelled up under corect usage. Maybe the UPS is faulty and overcharging it?

the UPS is faulty and overcharging it?

The main cause of small (home and SOHO) UPS failure is barttery failure. The main cause of battery failure in small (home and SOHO) UPS is overcharge.

(They nearly all overcharge.)

the UPS is faulty and overcharging it?

The only failure I've seen in small and large UPSs is a drastically reduced battery capacity.

the UPS is faulty and overcharging it?

battery capacity.

I'd suspect that is due to electrolyte drying as a result of ... overcharging.

Normally a UPS sits there being with its battery being slowly baked while the AC supply is present. UPS failures become apparent to *most* home/SOHO users when the AC fails as they do not have a testing regime in place.

Depending what you mean by "drastically reduced battery capacity" you may have seen it a bit sooner than most. But drying electrolyte is the most common capacity reduction mechanism, accompanied at later stages by the characteristic case swelling and often splitting.